Clinical and Morphologic Differences between Class IV-S and Class IV-G Lupus Nephritis

. The new ISN/RPS classification of lupus nephritis (LN) divides diffuse proliferative LN into two subcategories with predominantly segmental proliferative lesions (class IV-S) and with predominantly global proliferative lesions (class IV-G). This paper explores the validity of this distinction and possible differences between the two types of lesions. Patients and Methods. A retrospective analysis of biopsy-proven cohort of 231 patients with LN was performed. Clinical and laboratory data were available on all patients selected. Results. The prevalence of Class IV was 27,27% (41 patients had class IV-S, 22-class IV-G). The serum creatinine levels, proteinuria, and diastolic blood pressure were significantly greater in the IV-G class, but haemoglobin was significantly lower. Histologically combined lesions with segmental endocapillary proliferation and fibrinoid necrosis were more frequent in the class IV-S. No significant difference was detected in outcomes in the two groups after followups of 145,2 ± 76,87 months. Conclusions. There are definite clinical and morphologic differences between class IV-S and IV-G lesions. Data suggest that class IV-G lesions behave as an immune complex disease; however, in class IV-S lesions, the presence of proportionally greater glomerular fibrinoid necroses suggests that these lesions may have a different pathogenesis.