SC5B-9 IS THE MOST SENSITIVE MARKER IN ASSESSING DISEASE-ACTIVITY IN BRAZILIAN SLE PATIENTS

This study investigated whether increased plasma levels of terminal co mplement complex (SC5b-9) or split products correlate with disease act ivity and clinical manifestations in Brazilian systemic lupus erythema tosus (SLE) patients. Comparisons with conventional measurements of co mplement and other inflammatory markers were also performed. Plasma le vels of SC5b-9, C3a desArg, C1rs-C1Inhibitor, C3b(Bb)P, C3, C4, erythr ocyte sedimentation rate (ESR) and mucoproteins (MP) were measured in 41 patients with SLE of different disease activity: 10 patients with n one, 15 patients with mild, and 16 patients with moderate or severe ac tivity. An parameters, with the exception of C3 and C3b(Bb)P, showed a statistically significant correlation with disease activity. Plasma l evels of SC5b-9, C3a desArg, C4, CH50, ESR and MP revealed significant differences between the groups of patients without activity and those with moderate or severe disease. Although none of the variables were able to discriminate between patients without and those with mild acti vity, SC5b-9, C3a desArg, C4, ESR and mucoproteins showed significant differences between the patients with mild and those with moderate or severe disease. Among all the variables, SC5b-9 levels showed the most significant results and correlated well with the severity of the dise ase (p <0.0005). Our data suggest that elevated levels of complement a ctivation products, particularly of SC5b-9 are more sensitive markers in assessing disease activity than conventional laboratory diagnosis. Modern complement diagnosis is therefore recommended for monitoring di sease progress in SLE patients.