Clinical significance and pathological features of ectopic lymphoid-like structures in IgG4-related tubulointerstitial nephritis / 中华肾脏病杂志

ABSTRACT

Objective To investigate the clinical significance and pathological features of lymphocytes and plasma cells infiltration and related ectopic lymphoid-like structures in IgG4-related tubulointerstitial nephritis (IgG4-TIN). Methods Complete data was collected from 24 patients with IgG4-TIN confirmed by pathology in the Peking University First Hospital. The renal specimens were examined by routine light microscopy, immunofluorescence and electron microscopy examination. In addition, immunohistochemistry was used to detect the distribution of CD20+ B lymphocytes, CD3+ T lymphocytes and CD138+ plasma cells. Results A total of 24 patients were enrolled in the study, including 21 males (87.5％), 3 females (12.5％). The age was (58.0 ± 10.8) years (38-75 years). Pathology analysis showed ectopic lymphoid-like structures were located in 16 (66.7％) cases and Russell bodies were detected in infiltrative plasma cells of 19(79.2％) cases with IgG4-TIN. Compared with cases without Russell body formation, cases with Russell body formation in renal interstitial plasma cells were more prone to show ectopic germinal center-like structure formation (P=0.001), tubular basement membrane (TBM) electron dense deposits (P=0.040) and reduced blood C3 levels (P=0.028). Conclusions Abnormal tubulointerstitial infiltration of ectopic lymphoid-like structures and plasma cells with prominent Russell body exist in IgG4-TIN patients, which suggests the persistent activation of lymphocytes and plasma cells in renal interstitium may contribute to the pathogenesis of IgG4-TIN.