Abstract
<title>Abstract</title> <p>Introduction Emerging evidence suggests a pathogenic role for B cells in idiopathic nephrotic syndrome (INS). Podocyte injury may be mediated by a circulating factor or antibody derived from EBV (Epstein Barr Visus)-infected B cells. This makes EBV an attractive target for further research in the pathogenesis of INS. Methods A subgroup of participants with INS, and controls, from the South African NephroS cohort were included in a substudy evaluating the possible role of EBV in INS. Children under 4 years were excluded due to a higher likelihood of congenital disease. EBV prevalence was assessed using ELISA (enzyme linked immunosorbent assay) serology and PCR (polymerase chain reaction) for viral replication. The entire NephroS cohort was screened for the NPHS2 (podocin gene) V260E mutation, previously reported in over 30% of Black African paediatric patients. Results Almost no participants showed evidence of acute EBV infection. Over 90% had serology consistent with past infection. Anti-EBNA1 (Epstein Barr nuclear antigen 1) levels were higher in the controls than in the patient group, with the lowest prevalence in the relapsing group who had received immunosuppression. The prevalence of the NPHS2 mutations in the entire NephroS cohort was 1.7% homozygous in adults with 0% heterozygous, and 11.4% homozygous and 2.4% heterozygous in the paediatric cohort. Conclusion Our cohort of INS patients demonstrated a high prevalence of past EBV infection, and virtually no acute EBV infection. The EBNA 1 levels suggest a potential link between EBV and podocyte dysfunction. Importantly a genetic cause for INS was not prevalent in the substudy participants.</p>