Evaluation of alternative pathway and factor B haemolytic activities in patients with systemic lupus erythematosus: correlations with the alternative pathway regulatory proteins
Aguado, M.T.; Perrin, L.H.; Ramirez, R.; Miescher, P.A.; Lambert, P.H.
Clinical and Experimental Immunology 42(3): 495-505
1980
ISSN/ISBN: 0009-9104 PMID: 6163579 Document Number: 165260
The hemolytic activities of the complement alternative pathway and factor B were studied using a 51Cr-release assay in 77 sera from patients with systemic lupus erythematosus (SLE). These values were compared to those of several complement components and of the regulatory proteins .beta.1H [macroglobulin .beta.1H] and C3b INA [complement component 3b inactivator]. There was a significant decrease in the alternative pathway activity, which correlated with a decrease in the hemolytic activity of factor B and with classical pathway activity. There was a significant decrease in the level of 1 regulatory protein, .beta.1H, while the level of the other regulatory protein, C3b INA, was increased; however, there was a positive correlation between these 2 parameters. Apparently the decreased activity of the alternative pathway observed in SLE reflects a consumption due to a triggering of the C3b amplification loop through the classical pathway activation. In 1 patient, an acquired deficiency of the capacity to activate the alternative pathway in the presence of inulin was observed.