[Complement system in disseminated lupus erythematosus].

The levels of C3, C4 and CH50 in patients with lupus erythematosus disseminatus (LED) were lower than in the controls. However, although in many patients these levels were below the normal values, there was no statistically significant difference between the two group. The levels are reduced during the acute phases and in some patients they remain high. On the whole, C3 was lower in patients with nephropathy (p less than 0,025) than in patients presenting with clinical activity (p less than 0,02). The positive relationship existing between C3 and C4 (r = 0,641, p less than 0,01) suggests activation of the complement system in LED via the classic route. In cases with concurrent lupus nephropathy a relationship between C3 and C3PA was seen, suggesting that in this case the alternative route is involved.