Adenovirus Infections, Human ; pathology ; virology ; Glomerulonephritis, Membranous ; pathology ; virology ; HIV Infections ; pathology ; virology ; Hepatitis B ; pathology ; virology ; Hepatitis C ; pathology ; virology ; Herpes Zoster ; pathology ; virology ; Herpesvirus 3, Human ; isolation & purification ; Humans ; Kidney ; pathology ; virology ; Kidney Diseases ; pathology ; virology ; Nephritis, Interstitial ; pathology ; virology ; Parvoviridae Infections ; pathology ; virology ; Parvovirus B19, Human ; isolation & purification

OBJECTIVEHepatitis B virus-associated membranous nephropathy (HBV-MN) is a disease characterized by podocytopathy. Podocyte is a terminally differentiated cell with limited capability of proliferation. Thus, damage of podocyte might result in decreased cell number, and then lead to the development of marked proteinuria and glomerulosclerosis. The present study aimed to investigate the changes of glomerular podocyte number in the children with hepatitis B virus-associated membranous nephropathy (HBV-MN), and their significance in the pathogenesis of HBV-MN.

METHODSPodocytes were identified through specific immunohistological staining of Wilms tumor gene protein 1 (WT1), a characteristic marker for podocyte nuclei, and podocyte numerical density (Nv), mean glomerular tuft volume (V) and the podocyte number per glomerulus (Npodo) were estimated through Weibel-Gomez method in 19 children with biopsy-proven HBV-MN and 8 children with thin basement membrane disease (control group), and analyses were made for possible correlation with clinical, serological and pathological data.

RESULTSAmong the 19 cases with HBV-MN, 3 showed microvillus-like foot process of podocytes, granular degeneration of podocyte were found in 4 cases, vacuolization in 1 case and podocyte detachment in 2 cases. Nv and Npodo were significantly decreased in children with HBV-MN compared with control group (t = 12.851, P = 0.0002 and t = 6.433, P = 0.0002, respectively). Moreover, the number of podocytes decreased more significantly in patients with stronger HBsAg deposition (> ++) than those with weak HBsAg deposition (< or = ++), P = 0.004, but no significant difference was found between patients with phase III or IV of HBV-MN and those with phase Ior II in podocyte number per glomerulus (P = 0.5262) and podocyte numerical density (P = 0.3564). Podocyte numerical density decreased more significantly in patients with massive proteinuria (> or = 2 g/24 h) than those with moderate proteinuria (< 2 g/24 h), P = 0.0488. The numbers of podocyte correlated significantly with serum levels of C(3) (r = 0.548, P = 0.028), but did not correlate with serum levels of albumin (r = -0.037, P = 0.891).

CONCLUSIONAll patients with HBV-MN showed podocyte damage and decreased number per glomerulus, which may play an important role in the pathogenesis of HBV-MN in children.

Cell Count ; Child ; Glomerulonephritis ; pathology ; Glomerulonephritis, Membranous ; complications ; virology ; Hepatitis B ; complications ; pathology ; Hepatitis B virus ; Humans ; Kidney Diseases ; pathology ; Kidney Glomerulus ; pathology ; Podocytes ; pathology ; Proteinuria ; pathology

BK virus-associated nephropathy (BKVAN) is one of the major causes of allograft dysfunction in kidney transplant (KT) patients. We compared BKVAN combined with acute rejection (BKVAN/AR) with BKVAN alone in KT patients. We retrospectively analyzed biopsy-proven BKVAN in KT patients from 2000 to 2011 at Seoul National University Hospital. Among 414 biopsies from 951 patients, biopsy-proven BKVAN was found in 14 patients. Nine patients had BKVAN alone, while 5 patients had both BKVAN and acute cellular rejection. BKVAN in the BKVAN alone group was detected later than in BKVAN/AR group (21.77 vs 6.39 months after transplantation, P=0.03). Serum creatinine at diagnosis was similar (2.09 vs 2.00 mg/dL). Histological grade was more advanced in the BKVAN/AR group (P=0.034). Serum load of BKV, dose of immunosuppressants, and tacrolimus level showed a higher tendency in the BKVAN alone group; however it was not statistically significant. After anti-rejection therapy, immunosuppression was reduced in the BKVAN/AR group. Renal functional deterioration over 1 yr after BKVAN diagnosis was similar between the two groups (P=0.665). These findings suggest that the prognosis of BKVAN/AR after anti-rejection therapy followed by anti-BKV therapy might be similar to that of BKVAN alone after anti-BKV therapy.
Acute Disease ; Adult ; Antiviral Agents/therapeutic use ; BK Virus/*physiology ; Creatinine/blood ; Female ; *Graft Rejection/diagnosis/virology ; Humans ; Immunosuppressive Agents/administration & dosage ; Kidney/*virology ; Kidney Diseases/pathology/surgery/*virology ; *Kidney Transplantation ; Male ; Middle Aged ; Polyomavirus Infections/drug therapy/*etiology/pathology ; Retrospective Studies ; Tacrolimus/administration & dosage ; Time Factors ; Transplantation, Homologous/adverse effects ; Tumor Virus Infections/drug therapy/*etiology/pathology

Cytosolic retinoic acid-inducible gene I (RIG-I) is an important innate immune RNA sensor and can induce antiviral cytokines, e.g., interferon-β (IFN-β). Innate immune response to hepatitis B virus (HBV) plays a pivotal role in viral clearance and persistence. However, knowledge of the role that RIG-I plays in HBV infection is limited. The woodchuck is a valuable model for studying HBV infection. To characterize the molecular basis of woodchuck RIG-I (wRIG-I), we analyzed the complete coding sequences (CDSs) of wRIG-I, containing 2778 base pairs that encode 925 amino acids. The deduced wRIG-I protein was 106.847 kD with a theoretical isoelectric point (pI) of 6.07, and contained three important functional structures [caspase activation and recruitment domains (CARDs), DExD/H-box helicases, and a repressor domain (RD)]. In woodchuck fibroblastoma cell line (WH12/6), wRIG-I-targeted small interfering RNA (siRNA) down-regulated RIG-I and its downstrean effector-IFN-β transcripts under RIG-I' ligand, 5'-ppp double stranded RNA (dsRNA) stimulation. We also measured mRNA levels of wRIG-I in different tissues from healthy woodchucks and in the livers from woodchuck hepatitis virus (WHV)-infected woodchucks. The basal expression levels of wRIG-I were abundant in the kidney and liver. Importantly, wRIG-I was significantly up-regulated in acutely infected woodchuck livers, suggesting that RIG-I might be involved in WHV infection. These results may characterize RIG-I in the woodchuck model, providing a strong basis for further study on RIG-I-mediated innate immunity in HBV infection.
Animals ; Cell Line, Tumor ; Cloning, Molecular ; DEAD Box Protein 58 ; antagonists & inhibitors ; genetics ; immunology ; Fibroblasts ; immunology ; pathology ; Gene Expression ; Hepatitis B ; genetics ; immunology ; pathology ; veterinary ; Hepatitis B Virus, Woodchuck ; Immunity, Innate ; Interferon-beta ; genetics ; immunology ; Isoelectric Point ; Kidney ; immunology ; pathology ; virology ; Liver ; immunology ; pathology ; virology ; Marmota ; genetics ; immunology ; virology ; Open Reading Frames ; Protein Domains ; RNA, Double-Stranded ; RNA, Small Interfering ; genetics ; metabolism ; Rodent Diseases ; genetics ; immunology ; pathology ; virology

Reactivation of polyoma virus (BK virus) is a significant cause of morbidity in kidney transplant patients. This seemingly insignificant viral infection that affects the majority of population at a young age, once reactivated by immunosuppression, is a major factor contributing to graft loss. Screening techniques have been developed for early prediction of BK virus reactivation. These include plasma and urine assays for detection of BK virus DNA by PCR, urine cytology for detection of "decoy cells" and electron microscopy. Combining urine cytology and serology screening can be more effective for early detection of BK virus reactivation. Immunohistochemistry can be utilized as an additional tool to support the diagnosis. Once screening tests reveal a suspicious BK virus reactivation, tissue biopsy should be performed to confirm the diagnosis, rule out acute cellular rejection and plan treatment approaches. Treatment normally includes decreasing immunosuppression and the use of antiviral drug therapy. Unfortunately, disease outcome is often unfavorable and can culminate with eventual graft loss. Renal retransplantation has been performed with mixed results. As new data emerges, we will gain a better understanding of the disease caused by BK virus and respond with improved early diagnosis and treatment to preserve graft function.
Antiviral Agents/therapeutic use ; *BK Virus ; Humans ; Immunosuppression/*adverse effects ; Kidney Diseases/pathology/*virology ; *Kidney Transplantation ; Polyomavirus Infections/*complications/drug therapy/etiology ; Tumor Virus Infections/*complications/drug therapy/etiology