The Activity of Polymorphonuclear Leukocyte Neutral Proteinases and Their Inhibitors in Patients with Psoriasis Treated with a Continuous Peritoneal Dialysis

3 of 16 patients with extensive psoriasis have been completely cleared of skin lesions within 2–3weeks of continuous peritoneal dialysis, and 2 of them up to 2 mo after termination of therapy. In 5 cases there was a great improvement of psoriatic lesions and in 6 remaining cases only a slight improvement was found. The remission of psoriasis was correlated with extremely high polymorphonuclear leukocyte depletion through the peritoneal cavity in a short time. Neutral serine proteinases were extracted from polymorphonuclear leukocytes and quantitated. The quantity of enzymes in the cells recovered form peritoneal dialysates was found to decrease with duration of treatment, and it was 2–5 times lower than amounts of neutral proteinases extracted from peripheral blood polymorphonuclear leukocytes of psoriaties and normals. The enzyme content per polymorphonuclear leukocyte of patients with active psoriasis was significantly higher (2-fold) than that in inactive psoriasis and in normal controls. Proteinase activity was also found in the sera of psoriaties and normals, as well as in the peritoneal dialysates. However, this activity appeared to be about 30–50 times lower than serum inhibitory activity against neutral proteinases. The concentration of neutral proteinase inhibitors in 5 of 17 sera of patients with psoriasis was significantly lower than that in normal sera. These data indicate that the depletion of activated PMNL with increased amounts of neutral proteinases may account for the beneficial effect of peritoneal dialysis in the clearing of psoriatic lesions.