CLq precipitin in the sera of patients with allergic vasculitis (Gougerot-Ruiter Syndrome).

The sera from two well-documented cases of allergic vasculitis were examined for the presence of C1q precipitins. Both sera contained material capable of precipitating C1q in agarose gel. The material from one of the sera was partially purified using ammonium sulfate precipitation. Sephadex G-200 filtration, and DEAE-cellulose chromatography. Attempts to identify the nature of C1q precipitin were unsuccessful, but it resembled the high-molecular-weight precipitins of sera from patients with systemic lupus erythematosus. In a lesion, deposition of fibrinogen, immunoglobulins, and complement were noted mainly in the vessel walls. No correlation between immunoglobulin and complement deposition in the skin and the presence of C1q precipitins in the blood could be established.