eGFR: estimated glomerular filtration rate. 2 Laboratory features of seven patients with mixed cryoglobulinemic glomerulonephritis associated with HBV infection Hemoglobulin, Serum creatinine, Estimated glomerular filtration rate, Serum albumin, 24-h urine protein, Rheumatoid factor, Serum immunofixation electrophoresis, Urine immunofixation electrophoresis Anemia occurred in all patients. The median baseline eGFR (CKD-EPI) was 23.5(20.2, 46.3) ml/min per 1.73m2. 24hUP was 5.6(3.0, 6.6) g/d. Six cases (86%) had type II MC (IgM) and the other one (14%) had type III MC. Serum complement C4 levels were extremely low (median level 0.013?g/L) in all cases. Rheumatoid factors were PF-4618433 present with high levels (median 368?IU/ml) in all patients. Serum IgM elevated in four patients. Renal histopathological features The renal pathological features of seven patients were summarized in Table?3. Pathological patterns on light microscopy included Membranoproliferative glomerulonephritis (Membranoproliferative glomerulonephritis, Endocapillary proliferative glomerulonephritis, Mesangial proliferative glomerulonephritis, Dense deposit Immunofluorescence demonstrated subendothelial and intracapillary glomerular deposits of IgG, IgA, PF-4618433 IgM, C3 or C4. However, we only observed glomerular HBsAg and HBcAg deposition in one patient. Electron microscopy showed granular electron-dense deposits in glomeruli in all patients. We also found the subendothelial microtubule structure in one patient. Treatment and clinical outcomes Treatment and PF-4618433 follow-up data of seven patients were summarized in Table?4. All patients received antiviral medication (entecavir, Serum creatinine, Estimated glomerular filtration rate, 24-h urine protein, Entecavir, Lamivudine, Corticosteroid, Mycophenolate, Cyclophosphamide, Double-filtration plasmapheresis, Complete remission, Partial remission, Not available Open in a separate window Fig. 1 The change of eGFR (a) and proteinuria (b) in seven mixed cryoglobulinemic glomerulonephritis secondary to HBV infection at baseline and endpoint of follow-up. eGFR: estimated glomerular filtration rate. 24hUP: 24-h urine protein Discussion In 1977, Y. Levo and his PF-4618433 coworkers firstly described the association between HBV infection and MC [1]. It has been established that HBV is a rare infectious etiology of MC, compared with HCV infection. It was unknown what percentage of patients with chronic HBV infection may develop CV. A search of the literature revealed few studies Sox2 focusing on CryoGn associated with HBV infection. Our retrospective study described the spectrum of clinical presentations and pathological features of seven Chinese patients with HBV related CryoGn, as well as their response to therapy and renal outcome. We found that CryoGn associated with HBV were commonly associated with type II cryoglobulins. This finding was consistent with that of Italian study which reported type II cryoglobulins accounted for 88% in HBV related cryoglobulinemic vasculitis [5]. However, result in another previous Chines study suggested that type III cryoglobulinemia was more frequently seen in HBV related CryoGn [6]. This discrepancy may reflect differences in the laboratory methods in detection of cryoglobulin as well as patient selection bias considering a limited sample size. The most common extrarenal manifestation was cutaneous lesions (6/7) in our study, while other organs were seldom involved. Considering that only one case with Type III MC was included in our study, we were not able to conclude that clinical manifestation of the vasculitis is more frequently in Type II MC than in Type III MC reported in the literature [7]. Nephrotic syndrome was the most common syndrome with microscopic hematuria in our included patients. Acute renal injury or chronic renal insufficiency also occurred in most patients and some of them presented as RPGN and needed renal replacement therapy. We found HBsAg in the cryoprecipitate in two of our patients, confirming the pathogenic role of HBV in cryoglobulinemia. CryoGn with a membranoproliferative pattern of injury was mostly reported in the literature, no matter what etiology it is [8, 9]. Our data demonstrated that endocapillary proliferative Gn was also the common morphologic type on light microscopy, as well as membranoproliferative Gn. The PF-4618433 morphologic pattern of HBV related CryoGn varied in the limited number of previous studies. Membranous nephropathy was the predominant pattern.