Enhanced monocyte and neutrophil cytotoxicity and normal cyclic nucleotide levels in severe psoriasis

Eighteen patients with active psoriasis were investigated for antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by monocytes and neutrophil leukocytes. Patients with extensive psoriatic lesions showed increased ADCC whereas patients with minimal psoriasis had normal monocyte and neutrophil function. After clinical remission the ADCC became normal. No stimulatory factors in psoriatic serum could be demonstrated. The increased monocyte and neutrophil cytotoxicity in severe psoriasis is not explained by altered cyclic nucleotide levels as cAMP and cGMP levels were normal in psoriatic monocytes and neutrophils showing both increased and normal ADCC. Our results indicate that increased ADCC is secondary to the psoriatic activity.