Figure 4.

Immunohistochemistry for complement factors in glomeruli of patients infected with STEC. In the glomeruli of patients with STEC-elicited TMA, the presence of complement factors C1q, C3, C4 and C5b-9 (membrane attack complex) was investigated by immunohistochemistry (alkaline phosphatase/anti-alkaline phosphatase; APAAP method). For C1q, C3 and C5b-9, membranous glomerulopathy served as a positive control. For C4d, an AB0-incompatible kidney transplant showing staining in the peritubular capillaries was used as a positive control. In contrast to the strong staining in the positive control, only faint focal segmental staining for C1q and C3 was detected in STEC-associated TMA. For C4d and C5b-9, virtually no staining was observed in STEC-infected patients; magnification = ×400