Complement Diagnostics: Concepts, Indications, and Practical Guidelines

Figure 4

Complement activation and hemolytic function during an SLE exacerbation. C3, C4, factor B, and other components are consumed, leading to a depression in hemolytic function (red line). The resulting activation products, C3d,g, C3a, and sC5b-9 (green line), peak concomitantly with the SLE disease index (SLEDAI).