Cryoglobulins in vasculitis.

Serum cryoglobulin levels were estimated in thirty-one patients with cutaneous vasculitis, twenty-nine patients with other skin disorders and forty-seven normal subjects. Eighteen of the normal sera contained mixed cryoglobulins—the upper limit of the normal range being 80 μg/ml. Twelve of the vasculitis patients had serum cryoglobulin levels above the normal range. All but one of these cryoglobulins were mixed cryoglobulins. A low serum C3 level was found in only one patient. The possible role of mixed cryoglobulins in the pathogenesis of vasculitis is discussed.