Clinicopathological study of mixed cryoglobulinemic glomerulonephritis secondary to Hepatitis B virus infection

Abstract

Background Cryoglobulinemic glomerulonephritis (CryoGn) caused by hepatitis B virus (HBV) infection was rarely reported. Our study aimed to investigate the clinical features, renal pathology findings, and prognosis in patients with HBV related CryoGn.

Methods This was a retrospective study including seven Chinese patients with HBV related CryoGn in a tertiary referral hospital from April 2016 to March 2019. The clinical and pathological data were collected and analyzed.

Results Age at renal biopsy was 47±12 years, with female/male ration 3/4. Urine protein was 5.6(3.0, 6.6) g/d and five cases presented with nephrotic syndrome. The baseline eGFR was 23.5 (20.2, 46.3) ml/min per 1.73m2. The extrarenal manifestations included purpura (n=6), arthralgia (n=1), peripheral neuropathy (n=1), and cardiomyopathy (n=1). Six cases had type II cryoglobulinemia with IgMκ, the other one had type III. The median cryocrit was 4.0 (1.0, 15.0) %. Renal pathologic findings on light microscopy: endocapillary proliferative glomerulonephritis (Gn) (n=3), membranoproliferative Gn (n=3), and mesangial proliferative Gn (n=1). On immunofluorescence microscopy, the predominant type of immunoglobulin deposits was IgM(n=5). HBsAg and HBcAg deposits were found in one case. Ultrastructural studies showed granular subendothelial and mesangial electron-dense deposits in all patients and microtubules in one case. All patients received antiviral medications. They were given corticosteroid alone (n=2) or combined with cyclophosphamide (n=4) or mycophenolate mofetil (n=1). Two patients received plasmapheresis. The median follow-up time was 18 (6, 37) months. Four patients got remission, two patients died of pneumonia, and one progressed to end-stage renal disease (ESRD). At endpoint of follow-up, 24hUP was 2.1 (0.8-5.2) g/d, and eGFR was 55.3 (20.7, 111.8) ml/min per 1.73m2. The median cryocrit decreased to 1.0 (0, 5.75) %.

Conclusions The etiology of mixed CryoGn should be screened for HBV infection. Endocapillary proliferative Gn and membranoproliferative Gn were the common pathologic patterns. Diagnosis and treatment in early-stage benefit patients’ renal outcomes. Immunosuppressive therapy should be considered for severe renal disease, based on efficient antiviral therapy.