Increased superoxide generation by normal granulocytes incubated in sera from patients with psoriasis

Sera from patients with untreated psoriasis were found to induce increased superoxide anion (O₂^-) generation when incubated with normal granulocytes (PMNs) and zymosan. Sera from patients receiving systemic chemotherapy induced O₂^- generation which was similar to that of normal sera and significantly lower than sera from the untreated patients. O₂^- production was measured by suproxide dismutase inhibitable ferricytochrome C reductiona and was dependent on the presence of both zymosan and a heat labile serum factor. Serum C3c and C5 levels were elevated in both treated and untreated groups of psoriasis patients while C4 was elevated only in untreated patients. Serum ceruloplasmin, a O₂^- scavenger, was not decreased in patients with psoriasis, and consequently does not account for the increased O₂^- generation. These data suggest that sera from patients with psoriasis have an increased capacity to activate PMNs. Activation of PMNs in cutaneous and joint lesions may play a pathogenic role in psoriasis.