Clinical significance of serum membrane attack complex and complete factor H level in lupus nephritis

Abstract

Objective To discuss the clinical significance of serum membrane attack complex (MAC) and complete factor H (CFH) level in lupus nephritis (LN). Methods Indirect enzyme-linked immunosorbent assay was used to detect MAC and CFH respectively in 30 LN patients and 25 healthy controls. At the same time other laboratory indexes were detected and the relation between the change of serum MAC and CFH levels and other indexes were analyzed. The data were analyzed by t test, Chi-square test and Spearman correlation analysis. Results The level of serum MAC in LN group was significantly higher than that in healthy controls and non-active group [(74±100)] vs (18±8) μg/ml, Z=2.777, P<0.05; (92±53) μg/ml vs (32±23) μg/ml, t=3.661, P<0.05]. The level of serum CFH in the LN group was lower than that in healthy controls and non-active group [(311±146) ng/ml vs (412±76) ng/ml, Z=-3.139, P<0.05; (282±11) ng/ml vs (330±20) ng/ml, t=-8.333, P<0.05]. The serum levels of MAC in the LN group showed negative correlation with the 1evel of C3 (r=-0.603, P<0.05) , and showed positive correlation with dsDNA, 24 hours urine protein quantification, as well as the scores of SLEDAI and BILAG (rdsDNA=0.481, P<0.05; r24 hpro=0.694, P<0.05; rBILAG=0.709, P<0.05; rSLEDAI=0.613, P<0.05). The levels of serum CFH in LN group was positively correlated with the 1evel of C3 (r=0.568, P<0.05) , while negatively correlated with dsDNA, 24 hours urine protein quantification, as well as the scores of SLEDAI and BILAG (rdsDNA=-0.443, P<0.05; r24hpro=-0.485, P<0.05, rBILAG=-0.639, P<0.05, rSLEDAI=-0.597, P<0.05). The pathology of lupus nephritis in the active group of 18 patients showed proliferation of glomerular cells and degenerated tubular epithelial cells, and those in the non-active group was mainly the proliferation of mesangial cells. Conclusion In summary, the increase of MAC and decrease CFH level accelerates the development of lupus nephritis, while they are positively correlated with the change of pathology in active lupus nephritis, and it would be good indirect serological markers for lupus nephritis. Key words: Lupus nephritis; Complement system; Membrane attack complex; Factor H