Value of cell-bound complement activation products in the diagnosis of systemic lupus erythematosus / 临床检验杂志

ABSTRACT

Objective@#To investigate the values of T lymphocyte-bound complement activation products such as T-C3d and T-C4d, B lymphocyte-bound complement activation products such as B-C3d and B-C4d and erythrocyte-bound complement activation products such as E-C3d and E-C4d in the diagnosis of systemic lupus erythematosus (SLE). @*Methods@#Peripheral blood samples from 68 SLE patients, 70 patients with non-SLE autoimmune diseases and 68 healthy controls were collected randomly, and the expression levels of T-C4d, B-C4d, E-C4d, T-C3d, B-C3d and E-C3d in these samples were detected by flow cytometry. Meanwhile, antinuclear antibodies (ANA), anti-double stranded DNA antibodies (anti-dsDNA), peripheral blood cell count and other markers were also detected. The differences of cell-bound complement activation products in three groups were analyzed with the area under the receiver operating characteristic curve (AUC), nonparametric test, sensitivity and specificity. @*Results@#The specific median fluorescence intensity (SMFI) of T-C4d, B-C4d, E-C4d, T-C3d, B-C3d and E-C3d in SLE patients were significantly higher than those in the patients with non-SLE autoimmune diseases and healthy controls (all P＜0.05). The SMFI (median \[P 25, P 75\]) of T-C4d, B-C4d and E-C4d in SLE patients were 3.8(1.2, 13.1), 22.1(6.2, 67.9) and 19.6(1.8, 52.4), respectively. The SMFI of T-C4d, B-C4d and E-C4d in SLE patients with reduced red blood cells and/or lymphocytes were significantly higher than that with normal red blood cell and lymphocyte count (all P＜0.05). The AUCs of T-C4d, B-C4d, E-C4d, T-C3d, B-C3d and E-C3d were 0.711, 0.763, 0.663, 0.631, 0.611 and 0.615, respectively (all P＜0.05). The sensitivity of the combination of T-C4d with B-C4d (73.5%) in the diagnosis of SLE was superior to that of anti-dsDNA (36.8%). @*Conclusion@#The cell-bound complement activation products (CB-CAPs) are specifically expressed in SLE patients, and their combination detection is helpful for the diagnosis of SLE.