Relationship of complement activation pathway to clinical and pathological characteristics and renal outcome in patients with lupus nephritis; [Zusammenhang zwischen dem Komplementaktivierungssignalweg und klinischen bzw. pathologischen Merkmalen sowie renalen Auswirkungen bei Patienten mit Lupusnephritis]

Background: Involvement of the complement system in the pathogenesis of lupus nephritis (LN) is well accepted, but its exact role remains unclear. The aim of this study was to investigate the relationship of complement activation pathway to clinical and pathological characteristics and renal outcome in patients with LN. Material and methods: Patients with LN were divided into two groups: those in whom the complement system was mainly activated through the classical pathway (low serum C3 and C4 levels; CP group); and those in whom the complement system was solely activated through the alternative pathway (low serum C3 with normal C4 levels; AP group). Clinical and pathological data and renal outcomes were compared between the two groups. Results: A total of 102 LN patients were enrolled in this study, 63 patients (61.8%) in the CP group and 39 patients (38.2%) in the AP group. LN patients in the CP group had significantly higher SLEDAI (p < 0.001), more anti-dsDNA (p = 0.001), higher renal activity index (p < 0.001), and more class IV LN (p = 0.008) than LN patients in the AP group. Mean length of follow-up was 50.6 ± 26.4 months. Renal outcome in the form of progression of kidney disease was significantly poorer in the CP group in the AP group (p = 0.037). Conclusion: Our findings suggest that evaluation of the complement activation pattern may be useful for evaluating disease activity and predicting the prognosis of LN. © 2021, Springer Medizin Verlag GmbH, ein Teil von Springer Nature.