Clinico-histomorphologic Characteristics of Lupus Nephritis, Experience at a Center at Dhaka.

Abstract

Lupus nephritis (LN) is one of the most serious systemic lupus erythematosus complications since it is the major predictor of poor prognosis. We present the clinico-histomorphologic characteristics of LN at a center in Dhaka. The study group comprised diagnosed cases of LN on core-needle renal biopsy specimens received in the Department of Histopathology, Armed Forces Institute of Pathology, Dhaka, from January 2018 to June 2019. Histological evaluation and direct immunofluorescence (DIF) study was carried out on each specimen. Each case was classified according to the International Society for Nephrology/Renal Pathology Society (ISN/RPS) Classification 2003 of LN. A total of 104 (9.20%) LN cases were included of total 1130 nonneoplastic renal biopsy specimens. The mean age was 28.29 ± 12.24 years, with a male:female ratio of 1:4.47. According to the ISN/RPS 2003 classification, most of the LN belong to class IV (42, 40.38%), followed by class III (27, 25.96%), class II (22, 21.15%), and so on. The mean age of class IV LN was 25.95 ± 10.15 years, with M:F = 1:4.25. The mean urinary total protein (UTP) was 4.62 ± 4.47 g/24 h and the mean serum creatinine was 1.87 ± 1.12 mg/dL. On histopathology, 22 (52.38%) had crescent formation, 27 (64.28%) had wire loop formation with subendothelial thrombi, and 30 (71.42%) had necrotizing lesion. Interstitial fibrosis and tubular atrophy (IFTA) was ≥25% in eight (19.04%) class IV LN. Among the subclasses, most common was IV-G (A/C) - 16 (38.09%), followed by IV-S (A/C) - nine (21.42%) and IV-S (A) and IV-G (A) each eight (19.04%). In four (9.52%) cases, class IV + V lesion was found. The mean age of class III LN was 26 ± 11.02 years, with a male:female of 1:26. The mean UTP was 3.45 ± 2.4 and serum creatinine was 1.71 ± 1.51. Among these, crescent was found in eight (29.63%) cases, wire loop and subendothelial thrombi in 11 (37.04%) cases, and necrotizing lesions in eight (29.63%) cases. IFTA was >25% in 14.81% of cases of class III LN. Among 27 class III LN, 17 (62.96%) were classified as III (A) and 10 (37.04%) as III (A/C). Two class III LN had an association with class V and two have presented with TMA. The mean age of class II LN was 29.95+ 12.26 years, with M:F = 1:2.66. UTP was 3.53 ± 2.43 g/24 h and serum creatinine was 1.52 ± 1.5 mg/dL for class II LN. Histologically, these cases had focal/diffuse mesangial proliferation with 25% IFTA in 9.09% of cases. One of the class II LN had associated amyloidosis. Among class V LN, the mean age was 45.12 + 13.64 years, with M:F = 1:3. The mean UTP was 4.06 ± 1.71 g/24 h and serum creatinine was 1.64 ± 0.94 mg/dL. Histologically, 37.5% had >25% IFTA. The mean age of class I lesion was 27.25 ± 17.42 years with equal number of males and females. The mean serum creatinine level was 0.65 ± 0.18 mg/dL and UTP was 2.71 ± 2.3 g/24 h for class I lesion. Only one class VI LN case was found which had IFTA 40% and presented with generalized edema. On DIF, among 100 cases, 86 were found with full-house immune deposits of different intensity; IgM was lacking in 10 cases and IgA was lacking in seven cases, while three cases lacked C3 deposits. The mean activity index was 7.10 and the mean chronicity index was 3.23 among 69 cases of proliferative LN. Among different histological classes of LN, the prevalence of class IV was more in this study which had the most severe form of clinical presentation, biochemical parameters (raised serum creatinine level), and histological findings (crescent formation and IFTA).