The relationship between complement factors and function (C3, C4 e CH50) during juvenile systemic lupus erythematosus (JSLE) presentation and nephritis outcome

Abstract

Objective: The complement system is related to the lupus pathogenesis and genetics , because C1q and C2 deficiency associates with family incidence and low onset age . Active disease results in C3, C4 and CH50 low serum levels, in particular during glomerulonephritis or haematologic features. The objective of the study is establish the association of serum levels of C3, C4, CH50 at presentation in relation to disease activity measures , damage accrual and glomerulonephritis outcome. Methods: Secondary analysis of a multicentre cohort primarily describing rare lupus manifestations in 846 subjects from 10 paediatric rheumatology centres. Clinical and laboratory parameters of all organs and systems involved, activity index (SLEDAI 2K), damage index (SLICC-SDI), renal function, Complement factors C3, C4 and CH50 as well as renal biopsy classified according to WHO classification for lupus glomerulonephritis. Statistical analysis Descriptive statistics will be presented by mean-standard deviation for continuous variables and frequency for categorical variables comparing cases with and without glomerulonephritis on follow up. Association analysis of lupus glomerulonephritis and its outcome with all the explanatory variables independently or associated in relation to glomerulonephritis, estimating risk factors or protective factors. Expected results The relationship of serum C3, C4 and CH50 and activity during lupus presentation in association with glomerulonephritis in a representative paediatric cohort could better establish the role of Complement factors as paediatric lupus biomarkers.