Cryoglobulinaemia & Renal Disease

📋 Key Information Summary

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Cryoglobulinaemia is defined by the presence of immunoglobulins that reversibly precipitate at temperatures below 37°C and redissolve on rewarming.
Three types: Type I (monoclonal, associated with haematological malignancy), Type II (mixed, monoclonal + polyclonal, strongly HCV-associated), Type III (mixed, polyclonal, often HCV or autoimmune).
Type II and III (mixed) cryoglobulins account for >80% of cases in Australia and cause immune complex-mediated membranoproliferative glomerulonephritis (MPGN).
Hepatitis C virus (HCV) is the driving aetiology in 80–90% of mixed cryoglobulinaemia cases; HCV serology and RNA testing is mandatory in all patients.
Renal involvement presents as proteinuria, haematuria, and declining eGFR; renal biopsy shows MPGN pattern with subendothelial deposits and double contours on silver stain.
Meltzer triad (palpable purpura, arthralgia, weakness) is the classic clinical presentation of mixed cryoglobulinaemic vasculitis.
First-line renal disease management: treat underlying HCV with direct-acting antivirals (DAAs) — PBS-subsidised glecaprevir/pibrentasvir (Maviret®) or sofosbuvir/velpatasvir (Epclusa®).
Rituximab (Mabthera®) is second-line immunosuppressive therapy for severe or refractory cryoglobulinaemic vasculitis with renal involvement; PBS Authority Required for vasculitis indications.
Plasmapheresis is reserved for life-threatening presentations (rapidly progressive GN, severe skin necrosis, hyperviscosity in Type I).
Avoid combination interferon + ribavirin regimens; use pangenotypic DAAs which achieve SVR rates >95% and significantly improve renal outcomes.
Type I cryoglobulinaemia (monoclonal) requires haematology-directed therapy targeting the underlying B-cell or plasma-cell malignancy; management differs substantially from mixed types.
Monitor cryocrit, complement levels (C4 classically low), HCV RNA, and renal function longitudinally to assess treatment response.
Aboriginal and Torres Strait Islander peoples have higher HCV prevalence; screen proactively and ensure DAA access in remote communities through telehealth-supported hepatology.

Introduction & Australian Epidemiology

Cryoglobulinaemia is a systemic immune-complex–mediated vasculitis caused by the presence of immunoglobulins (cryoglobulins) that precipitate at temperatures below 37°C and dissolve upon rewarming. When deposited in the renal glomeruli, cryoglobulins cause a characteristic membranoproliferative glomerulonephritis (MPGN) pattern, often leading to progressive chronic kidney disease if the underlying aetiology is not addressed.

In Australia, mixed cryoglobulinaemia (Types II and III) constitutes the vast majority of clinically significant cases, with hepatitis C virus (HCV) identified as the principal driver in 80–90%. Despite the success of Australia's national HCV elimination strategy and widespread access to PBS-subsidised direct-acting antivirals (DAAs) since 2016, cryoglobulinaemic renal disease persists — particularly among individuals with undiagnosed or inadequately treated HCV, and in those with underlying lymphoproliferative or autoimmune disorders.

An estimated 30–50% of patients with chronic HCV infection develop detectable cryoglobulins, though clinically significant cryoglobulinaemic vasculitis occurs in approximately 5–10%. Renal involvement is seen in 20–35% of those with symptomatic mixed cryoglobulinaemia. The introduction of pangenotypic DAAs has markedly improved outcomes, but a subset of patients continue to have active vasculitis and nephritis despite achieving sustained virological response (SVR), necessitating adjunctive immunosuppressive therapy.

Type I cryoglobulinaemia, while less common, is associated with haematological malignancies (multiple myeloma, Waldenström macroglobulinaemia) and carries distinct management priorities, including hyperviscosity syndrome risk and haematology-directed treatment. This guideline addresses the classification, pathophysiology, clinical features, investigation, and management of all cryoglobulinaemia types with emphasis on renal disease, framed within the Australian healthcare context including PBS availability, MBS-funded investigations, and special population considerations.

Classification: Type I, II & III Cryoglobulins

Cryoglobulins are classified by the Brouet system based on the clonality of the immunoglobulin component. Accurate classification is essential as it determines underlying aetiology, clinical features, and therapeutic approach.

Feature	Type I	Type II (Mixed)	Type III (Mixed)
Immunoglobulin composition	Single monoclonal Ig (IgM, IgG, or IgA)	Monoclonal IgM (rheumatoid factor) + polyclonal IgG	Polyclonal IgM (rheumatoid factor) + polyclonal IgG
Proportion of cases	~10–15%	~50–60%	~25–30%
Associated conditions	Multiple myeloma, Waldenström macroglobulinaemia, MGUS, CLL	HCV (~80–90%), HBV, HIV, Sjögren syndrome, lymphoma	HCV (~30–50%), autoimmune diseases (SLE, RA), chronic infections
Rheumatoid factor	Negative	Strongly positive	Positive (lower titres)
Primary mechanism	Hyperviscosity, vascular occlusion	Immune complex deposition, vasculitis	Immune complex deposition, vasculitis
Renal disease pattern	Thrombotic microangiopathy, intraglomerular thrombi	MPGN (most common renal pattern)	MPGN, mesangial proliferative GN
C4 complement	Normal or mildly low	Markedly low	Low to mildly low

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Clinical pearl: A markedly low C4 with positive rheumatoid factor in the setting of renal impairment should prompt cryoglobulin testing. C4 is typically more suppressed than C3 in mixed cryoglobulinaemia due to consumption by immune complexes.

Subclassification into Type II and III can be difficult as the monoclonal component in Type II may be at low concentration; immunofixation electrophoresis of the dissolved cryoprecipitate is required for accurate typing. In Australia, cryoglobulin testing is performed at major tertiary hospital laboratories and some private reference labs (e.g., Douglass Hanly Moir Pathology, Laverty Pathology). Samples must be collected and transported at 37°C to prevent in-vitro precipitation — coordinate with the laboratory before collection.

Pathophysiology & HCV Association

Mechanisms of Cryoglobulin-Mediated Renal Injury

Cryoglobulins cause renal disease through several interconnected mechanisms:

Immune complex deposition: Circulating cryoglobulin immune complexes deposit in the subendothelial and mesangial regions of glomerular capillaries, activating the classical complement pathway. This results in C4 consumption and triggers an inflammatory response with infiltration of monocytes and macrophages.
Membranoproliferative pattern: The histopathological hallmark is MPGN (now classified under the C3GN/immune complex MPGN spectrum in the 2016 ISN/RPS update) with double contours of the glomerular basement membrane on silver stain, subendothelial electron-dense deposits, and occasional intraluminal "thrombi" composed of cryoglobulin deposits with a characteristic amorphous or "fingerprint" ultrastructural appearance on electron microscopy.
Vasa vasorum vasculitis: Small-vessel vasculitis of the vasa vasorum contributes to ischaemic injury and can cause tubulointerstitial damage in addition to glomerular pathology.
Type I mechanism: In Type I cryoglobulinaemia, the high concentration of monoclonal protein causes direct vascular occlusion and hyperviscosity rather than classical immune complex-mediated inflammation; the renal lesion is typically thrombotic microangiopathy rather than MPGN.

HCV and Cryoglobulinaemia — The Australian Context

HCV drives mixed cryoglobulinaemia through chronic antigenic stimulation of B lymphocytes. The HCV envelope protein binds CD81 on B cells, promoting clonal expansion — particularly of B cells producing IgM with rheumatoid factor activity. This results in formation of immune complexes (HCV–anti-HCV–IgM-RF) that deposit in vessels and glomeruli.

Australia has an estimated 170,000–200,000 people living with chronic HCV. Since March 2016, unrestricted PBS access to DAAs has transformed outcomes, with over 100,000 Australians treated by 2023. However, cryoglobulinaemic vasculitis can persist or even emerge paradoxically after SVR in a small proportion of patients — likely reflecting ongoing autoreactive B-cell clones no longer suppressed by viral antigen. This phenomenon underscores the importance of continued renal monitoring post-SVR and the role of rituximab in selected patients.

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Key point: All patients with cryoglobulinaemia must be tested for HCV antibody and HCV RNA, regardless of risk factor history. In patients with known HCV, cryoglobulins should be tested when there is unexplained proteinuria, haematuria, purpura, arthralgia, or low C4.

Non-HCV Aetiologies

While HCV dominates, other causes of mixed cryoglobulinaemia encountered in Australian practice include:

Autoimmune diseases — Sjögren syndrome, systemic lupus erythematosus (SLE), rheumatoid arthritis
Hepatitis B virus (HBV) — less common than HCV in Australia
HIV co-infection
Lymphoproliferative disorders — B-cell non-Hodgkin lymphoma
Idiopathic — in approximately 5–10% of cases (Type III more often)

Clinical Features (Purpura, Arthralgia, GN)

The clinical spectrum of cryoglobulinaemia ranges from asymptomatic cryoglobulin detection to fulminant systemic vasculitis with multi-organ failure. The classic Meltzer triad — palpable purpura, arthralgia, and weakness — is present in approximately 70–80% of patients with symptomatic mixed cryoglobulinaemia.

Cutaneous Manifestations

Palpable purpura: The most common presenting feature (seen in ~80%). Typically affects the lower limbs and is exacerbated by cold exposure or prolonged standing. Histology shows leucocytoclastic vasculitis with perivascular IgM and C3 deposition.
Livedo reticularis: Mottled, net-like violaceous pattern, particularly on the legs.
Skin ulceration: Chronic, non-healing ulcers particularly over the malleoli; may be severe and refractory.
Digital ischaemia and gangrene: More common in Type I due to vascular occlusion by high cryoglobulin concentrations.
Raynaud phenomenon: Present in 30–40% of patients with mixed cryoglobulinaemia.

Musculoskeletal

Arthralgia: Symmetric, non-erosive polyarthralgia affecting the hands, knees, and ankles. Frank arthritis is uncommon but reported.
Myalgia: Diffuse muscle pain, often associated with fatigue.

Renal Manifestations

Renal involvement occurs in 20–35% of patients with symptomatic mixed cryoglobulinaemia and is a major determinant of morbidity and mortality. The presentation typically evolves over weeks to months:

Mild

Subnephrotic Proteinuria

Subnephrotic proteinuria (<3.5 g/day) with or without microscopic haematuria. eGFR often preserved. May be asymptomatic and detected on routine urinalysis in HCV patients.

Setting: Outpatient nephrology follow-up

Moderate

Nephritic–Nephrotic Syndrome

Nephrotic-range proteinuria (>3.5 g/day), haematuria with red cell casts, hypertension, oedema, and declining eGFR. Hypocomplementaemia (low C4) is characteristic.

Setting: Nephrology admission, renal biopsy indicated

Severe

Rapidly Progressive GN

Rapid decline in renal function (eGFR falling >25% over days–weeks), heavy proteinuria, active urine sediment, and crescents on biopsy. May accompany severe systemic vasculitis (skin necrosis, neuropathy, GI ischaemia).

Setting: Hospital admission, consider plasmapheresis + immunosuppression

Other Organ Involvement

Peripheral neuropathy: Present in 60–70%. Sensorimotor polyneuropathy or mononeuritis multiplex (e.g., foot drop from peroneal nerve involvement).
Hepatic: Hepatitis, cirrhosis (directly from HCV rather than cryoglobulinaemia per se).
Pulmonary: Interstitial lung disease, diffuse alveolar haemorrhage (rare but life-threatening).
Gastrointestinal: Abdominal pain from mesenteric vasculitis; rarely bowel ischaemia or perforation.
CNS: Rare; cerebral vasculitis, stroke.

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Emergency presentations: Rapidly progressive GN, severe skin necrosis/gangrene, diffuse alveolar haemorrhage, hyperviscosity syndrome (Type I), and bowel ischaemia require urgent hospital admission and may necessitate plasmapheresis, high-dose corticosteroids, and/or rituximab. Coordinate with nephrology and haematology early.

Investigations

Laboratory Investigations

Essential

Cryoglobulin testing

Blood collected and transported at 37°C (warm transport). Serum allowed to clot at 37°C, then refrigerated at 4°C for 7 days. Positive if visible precipitate or gel formation; quantified as cryocrit (%). Immunofixation of dissolved cryoprecipitate determines type. Available at tertiary hospital labs and select reference labs (e.g., DHM, Laverty). MBS item applies.

Essential

HCV serology & HCV RNA (viral load)

HCV antibody (ELISA) followed by HCV RNA PCR if positive or if high clinical suspicion despite negative serology (e.g., immunosuppressed). Quantitative HCV RNA guides treatment. MBS item 69491 (HCV RNA), widely available. Bulk-billed.

Essential

Complement levels — C3, C4, CH50

C4 is typically markedly reduced in mixed cryoglobulinaemia (more than C3) due to classical pathway activation. Serial C4 measurement monitors treatment response. MBS item 71138.

Essential

Rheumatoid factor (RF)

Typically strongly positive in Types II and III; negative in Type I. High titres correlate with disease activity. MBS item 66511, bulk-billed.

Available

Serum protein electrophoresis (SPEP) & immunofixation (IFE)

Essential to detect monoclonal protein (Type I and II). Free light chain assay (kappa/lambda ratio) adds sensitivity. MBS item 69200 (SPEP), 69205 (IFE).

Available

ANA, anti-dsDNA, anti-SSA/SSB, anti-CCP

To evaluate for underlying autoimmune disease (SLE, Sjögren, RA) in HCV-negative or serologically equivocal cases. MBS items bulk-billed.

Available

HBV serology, HIV serology

Hepatitis B surface antigen, core antibody, surface antibody; HIV 1/2 Ag/Ab combo. Exclude co-infection. MBS items bulk-billed.

Available

FBC, EUC, LFTs, LDH, ESR, CRP

Baseline organ function and inflammatory markers. ESR is often markedly elevated due to cryoglobulin interference (false elevation). CRP is more reliable. Bulk-billed.

Renal Biopsy

Percutaneous renal biopsy is indicated in patients with suspected cryoglobulinaemic glomerulonephritis (proteinuria, haematuria, declining eGFR) and is the gold standard for diagnosis and prognostication. Key histopathological findings:

Light microscopy: MPGN pattern with mesangial expansion, endocapillary proliferation, and double contours of GBMs on silver/PAS stain. Intracapillary "thrombi" — large, eosinophilic, amorphous or structured deposits — are characteristic and highly suggestive of cryoglobulinaemic GN when present.
Immunofluorescence: Granular staining for IgM, IgG, and C3 along capillary walls and in mesangium. IgM often predominates and may show kappa or lambda light chain restriction (Type II).
Electron microscopy: Subendothelial electron-dense deposits with a distinctive "fingerprint" or annular-tubular substructure representing organised cryoglobulin deposits. This finding is virtually pathognomonic.

Renal biopsy is performed by nephrology at all major Australian tertiary centres. Ultrasound-guided percutaneous biopsy is standard; MBS item 36500 applies.

Additional Investigations

Renal ultrasound: Assess kidney size, cortical thickness, exclude obstruction. MBS item 55034.
Nerve conduction studies/EMG: If peripheral neuropathy suspected. MBS item 11000.
Cryocrit serial monitoring: Quantify cryocrit percentage to track treatment response; correlate with complement and clinical parameters.
Serum viscosity: If Type I suspected or hyperviscosity symptoms present (visual disturbance, headache, confusion). Not routinely available; tertiary referral.
Bone marrow biopsy: If haematological malignancy suspected (Type I or refractory Type II); coordinate with haematology.

Management

Management of cryoglobulinaemic renal disease requires a dual approach: (1) treating the underlying cause (most commonly HCV) and (2) controlling the immune-mediated vasculitis when organ-threatening or refractory to antiviral therapy alone. Management should be guided by disease severity, cryoglobulin type, and the presence of life-threatening organ involvement.

Antiviral Therapy — HCV-Associated Cryoglobulinaemia

Direct-acting antivirals (DAAs) are the cornerstone of treatment for HCV-associated mixed cryoglobulinaemia. Eradication of HCV eliminates the chronic antigenic stimulus driving cryoglobulin production and immune complex formation. All patients with HCV-associated cryoglobulinaemia should receive DAA therapy regardless of renal disease severity.

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Glecaprevir / Pibrentasvir

Maviret® · NS3/4A protease + NS5A inhibitor · Pangenotypic

Adult dose 3 tablets (glecaprevir 100 mg / pibrentasvir 40 mg each) PO once daily with food

Duration 8 weeks (treatment-naïve, no cirrhosis) or 12 weeks (compensated cirrhosis or prior treatment)

Renal adjustment None required — safe in all stages of CKD and dialysis

Hepatic adjustment Contraindicated in decompensated cirrhosis (Child-Pugh B/C)

PBS status ✔ PBS General Benefit — Authority Required

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Sofosbuvir / Velpatasvir

Epclusa® · NS5B polymerase + NS5A inhibitor · Pangenotypic

Adult dose 1 tablet (sofosbuvir 400 mg / velpatasvir 100 mg) PO once daily

Duration 12 weeks (all genotypes, with or without cirrhosis)

Renal adjustment None required (sofosbuvir metabolite renally cleared but no dose adjustment needed in CKD)

Hepatic adjustment Contraindicated in decompensated cirrhosis (Child-Pugh B/C)

PBS status ✔ PBS General Benefit — Authority Required

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Sofosbuvir / Velpatasvir / Voxilaprevir

Vosevi® · NS5B + NS5A + NS3/4A inhibitor · Pangenotypic

Adult dose 1 tablet PO once daily with food

Indication DAA-experienced patients who have failed prior NS5A inhibitor-containing regimen

Renal adjustment None required

PBS status ✔ PBS General Benefit — Authority Required

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SVR and renal outcomes: Achieving sustained virological response (SVR at 12 weeks post-treatment) is associated with significant improvement in proteinuria, stabilisation or improvement in eGFR, reduction in cryocrit, and normalisation of C4 in the majority of patients. However, ~20–30% of patients have persistent cryoglobulinaemic vasculitis and/or nephritis despite SVR — these patients require immunosuppressive therapy.

Immunosuppressive Therapy

Immunosuppression is indicated for severe organ-threatening disease, and for patients with persistent vasculitis/nephritis despite SVR. It should be combined with antiviral therapy in HCV-positive patients to prevent viral flare.

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Rituximab

Mabthera® · Anti-CD20 monoclonal antibody

Adult dose 375 mg/m² IV weekly × 4 doses (induction); or 1000 mg IV × 2 doses (day 1 and 15)

Maintenance 1000 mg IV every 6 months if relapse occurs (case-by-case basis)

Paediatric dose 375 mg/m² IV weekly × 4 (paediatric dosing; specialist supervision required)

Renal adjustment None required

Key monitoring Screen for HBV (HBsAg, HBcAb) before first dose — risk of HBV reactivation. Check immunoglobulin levels pre-treatment (hypogammaglobulinaemia risk with repeated cycles).

PBS status ⚠ PBS Authority Required — vasculitis / refractory autoimmune disease

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Prednisolone

Solone® / Generic · Corticosteroid

Adult dose (severe vasculitis) 0.5–1 mg/kg/day PO (max 60 mg), tapered over 3–6 months to lowest effective dose or cessation

Pulse (life-threatening) Methylprednisolone 500–1000 mg IV daily × 3 days, then oral prednisolone

Paediatric dose 1–2 mg/kg/day PO (max 60 mg), taper as per specialist

PBS status ✔ PBS General Benefit

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Cyclophosphamide

Endoxan® · Alkylating agent

Adult dose IV pulse: 500–750 mg/m² every 2–4 weeks (Euro-Lupus or modified regimen). Oral: 1–2 mg/kg/day (rarely used now).

Indication Refractory or severe life-threatening cryoglobulinaemic vasculitis/GN not responding to rituximab. Use with caution; generally reserved for rescue therapy.

Renal adjustment Reduce dose by 25–50% if eGFR <30 mL/min/1.73 m²

PBS status ✔ PBS General Benefit

Plasmapheresis (Therapeutic Plasma Exchange)

Plasmapheresis physically removes circulating cryoglobulins and is reserved for life-threatening presentations where rapid clearance is required:

Rapidly progressive glomerulonephritis (RPGN) with deteriorating renal function
Severe skin necrosis / digital gangrene
Hyperviscosity syndrome (Type I — this is the primary indication for apheresis in Type I)
Diffuse alveolar haemorrhage
Severe neuropathy with motor deficit

Typical regimen: 3–6 exchanges (60 mL/kg per session with 5% albumin replacement) over 1–2 weeks, combined with immunosuppression to suppress new cryoglobulin production. Available at all Australian tertiary centres with apheresis services. MBS item 13700 applies.

Type I Cryoglobulinaemia — Specific Management

Type I cryoglobulinaemia is fundamentally different in pathophysiology and treatment. Management is directed at the underlying haematological malignancy:

Bortezomib-based regimens for myeloma-associated Type I
Rituximab ± chemotherapy for Waldenström macroglobulinaemia / B-cell lymphoma
Plasmapheresis as first-line emergency therapy for hyperviscosity
Avoid corticosteroids as monotherapy — they do not address the clonal B-cell population
Haematology co-management is essential

Treatment Algorithm Summary

1

Confirm diagnosis & classify type

Cryoglobulin testing (37°C collection), immunofixation, HCV RNA, complement, RF, SPEP/IFE, renal biopsy if renal involvement.

2

Treat underlying cause

HCV-positive → DAA therapy (Maviret® or Epclusa®). Type I → haematology-directed therapy. Autoimmune → treat primary disease.

3

Assess severity

Mild (subnephrotic, stable eGFR) → DAA alone + monitoring. Moderate–Severe (nephrotic, declining eGFR, organ-threatening vasculitis) → DAA + rituximab ± corticosteroids.

4

Life-threatening? Add plasmapheresis

RPGN, skin necrosis, hyperviscosity, alveolar haemorrhage → plasmapheresis + high-dose steroids + rituximab ± cyclophosphamide.

5

Monitor response

Cryocrit, C4, proteinuria, eGFR, HCV RNA at 12 weeks and 6-monthly. Repeat rituximab if relapse.

Monitoring

Longitudinal monitoring is essential to assess treatment response, detect relapse, and manage complications of therapy.

Baseline (Pre-treatment)

Cryocrit, C3/C4, RF titre, HCV RNA quantitative, serum creatinine/eGFR, urine ACR/protein:creatinine ratio, FBC, LFTs, serum immunoglobulins, HBV screen (if rituximab planned). Renal biopsy if indicated.

Week 4–6 (on DAA)

HCV RNA to confirm viral decline (expected undetectable by week 4 on DAA). Symptom review. Renal function — expect early improvement in proteinuria in responders.

Week 12 post-DAA (SVR12)

HCV RNA — confirm SVR (undetectable). Repeat cryocrit, C4, RF, urine ACR, eGFR. Clinical assessment of vasculitis (purpura, neuropathy, arthralgia).

6-monthly (Years 1–3)

eGFR, urine ACR, cryocrit, C4, FBC (if on rituximab — monitor for hypogammaglobulinaemia and neutropenia). HCV RNA to confirm persistent SVR (relapse after SVR is rare).

Annually (Long-term)

eGFR, urine ACR. Reassess for late relapse of cryoglobulinaemia despite SVR (occurs in 20–30%). Rituximab re-treatment if clinical and serological relapse. Monitor for HCC in patients with established cirrhosis (6-monthly AFP + ultrasound per national guidelines).

⚠️

Rituximab monitoring: Check serum immunoglobulins (IgG, IgA, IgM) before each rituximab cycle. Persistent hypogammaglobulinaemia (IgG <4 g/L) may require IVIG supplementation and deferral of further rituximab. Monitor FBC for delayed neutropenia (typically 1–5 months post-infusion).

Special Populations

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Pregnancy

DAAs (Maviret®, Epclusa®)

Not recommended in pregnancy — limited safety data. Defer HCV treatment to post-partum unless life-threatening vasculitis. Ribavirin-containing regimens are teratogenic and absolutely contraindicated.

Rituximab

Category D — avoid in pregnancy. Deplete foetal B cells. Washout period ≥12 months before conception. If inadvertently exposed, monitor neonatal B-cell counts and immunoglobulins.

Prednisolone

Category A — can be used at lowest effective dose if required. Monitor for gestational diabetes.

Cyclophosphamide

Category D — teratogenic. Avoid in pregnancy.

Plasmapheresis

Safe in pregnancy — can be used for life-threatening presentations.

General considerations

Coordinate management with obstetrics, nephrology, and hepatology. Pre-eclampsia can mimic renal flare. Monitor urine ACR and eGFR closely throughout pregnancy.

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Paediatrics

Incidence

Cryoglobulinaemia is rare in children. When seen, it is more often associated with autoimmune disease (SLE) or post-infectious rather than HCV.

DAAs

Maviret® is PBS-listed for children ≥12 years or ≥45 kg. Below this threshold, refer to paediatric hepatology for access through special access schemes.

Rituximab

375 mg/m² IV weekly × 4 doses. Specialist paediatric rheumatology or nephrology supervision required. Monitor for infections and hypogammaglobulinaemia.

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Elderly

DAAs

Well tolerated in elderly; no dose adjustment by age. Maviret® preferred over interferon-based regimens. Watch for drug interactions with multiple medications (particularly proton pump inhibitors — take Maviret® without PPI).

Immunosuppression

Higher infection risk with rituximab and cyclophosphamide. Ensure pneumococcal and influenza vaccination prior to rituximab initiation. Consider IVIG if recurrent infections with hypogammaglobulinaemia.

Steroid complications

Increased risk of osteoporosis, diabetes, falls. Use bone-protective agents (alendronate, denosumab) if prolonged prednisolone. Aim for early steroid taper.

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Renal Impairment

DAAs

Maviret® and Epclusa® are safe across all CKD stages including dialysis. No dose adjustment required.

Rituximab

No dose adjustment. Monitor for tumour lysis in high-burden lymphoproliferative disease.

Cyclophosphamide

Reduce dose by 25–50% if eGFR <30 mL/min/1.73 m². Monitor FBC closely.

Dialysis

DAA therapy can be administered on dialysis days. Plasmapheresis is technically feasible on dialysis but requires coordination. RRT patients should be managed jointly by nephrology and hepatology.

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Hepatic Impairment

DAA selection

Maviret® and Epclusa® contraindicated in decompensated cirrhosis (Child-Pugh B/C). For decompensated patients: sofosbuvir/velpatasvir + ribavirin or sofosbuvir/daclatasvir — refer to hepatology. Ribavirin requires dose adjustment for renal impairment.

Rituximab

No hepatic dose adjustment, but monitor LFTs. Hepatitis B reactivation risk — mandatory HBV screening.

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Immunocompromised

HIV co-infection

DAAs are effective in HIV/HCV co-infection. Check drug interactions with ART — Maviret® interacts with efavirenz (avoid); Epclusa® is generally safe with most ART regimens. SVR rates are comparable to HIV-negative patients.

Post-transplant

Cryoglobulinaemic GN can recur post-renal transplant. DAA treatment pre-transplant to achieve SVR reduces recurrence risk. Post-transplant, rituximab and plasmapheresis can be used for recurrent disease.

Vaccination

Complete all vaccinations ≥4 weeks before rituximab. Live vaccines contraindicated during and for 6–12 months after rituximab. Annual influenza and 5-yearly pneumococcal vaccination recommended.

Aboriginal and Torres Strait Islander Health Considerations

Aboriginal and Torres Strait Islander Health

Aboriginal and Torres Strait Islander peoples experience a disproportionate burden of hepatitis C infection and its complications, including cryoglobulinaemic renal disease. The AIHW reports that notification rates of HCV in Indigenous Australians are approximately 2–3 times higher than in non-Indigenous Australians, with particularly elevated prevalence in remote and very remote communities. Barriers to care intersect across multiple domains, compounding the risk of late presentation with established cryoglobulinaemic vasculitis and renal impairment.

HCV prevalence

HCV notification rates in Aboriginal and Torres Strait Islander peoples are 2–3 times the national average, particularly in remote NT, QLD, and WA communities. This drives a higher population-attributable burden of cryoglobulinaemic renal disease.

Remote access to nephrology

Nephrology services are concentrated in major cities. Aboriginal and Torres Strait Islander patients in remote areas rely on visiting specialist outreach or telehealth (MBS item 91822 for telehealth nephrology). Timely renal biopsy may require medical retrieval to a tertiary centre.

DAA access & PBS

DAAs (Maviret®, Epclusa®) are PBS-listed and available through any prescribing GP — no specialist restriction. However, DAA uptake remains lower in remote communities. Community-controlled health services (ACCHOs) play a vital role in HCV screening and treatment. Remote-area pharmacists can supply DAAs via Section 100 (S100) Remote Area Aboriginal Health Services.

Cryoglobulin testing limitations

Cryoglobulin testing requires 37°C specimen transport — logistically challenging in remote areas. Where testing is unavailable, clinical diagnosis (purpura + low C4 + positive RF + HCV positive + renal impairment) can support empiric treatment with DAAs and referral for biopsy when feasible.

Cultural safety

Engage Aboriginal Health Workers and Aboriginal Liaison Officers in care planning. Respect family and community decision-making structures. Stigma around HCV diagnosis and injecting drug use can be a significant barrier — offer confidential testing and treatment in culturally safe settings.

Comorbidities

Aboriginal and Torres Strait Islander peoples have higher rates of CKD, diabetes, and cardiovascular disease — comorbidities that compound cryoglobulinaemic renal damage. Integrate cryoglobulinaemia management with existing chronic disease programmes (e.g., MBS 715 health assessments, PBS Section 100 co-payment exemption).

RHDAustralia resources

RHDAustralia (www.rhdaustralia.org.au) provides clinical guidelines for rheumatic heart disease and related immune-complex diseases relevant to the ATSI context. While focused on ARF/RHD, their frameworks for remote-area management of immune-mediated conditions are applicable.

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Actionable recommendations: (1) Incorporate HCV screening into routine 715 health assessments in high-prevalence communities. (2) Ensure all ATSI patients with HCV are offered DAA treatment through ACCHOs or primary care. (3) Establish nephrology telehealth pathways for remote patients with proteinuria/haematuria. (4) Provide renal biopsy access through funded retrieval pathways. (5) Use PBS Section 100 supply for DAA access in remote communities.

📚 References

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