Eosinophils, pruritus and psoriasis: Effects of treatment with etretinate or cyclosporin-A

Abstract

Background The antipsoriatic drugs cyclosporin A (CyA) and etretinate have been found to influence proinflammatory eosinophilic leukocytes and pruritus. Aim: We compared the number of blood eosinophils, concentration of serum eosinophil cationic protein (ECP), and pruritus in patients with psoriasis treated with either CyA or etretinate. Study design Patients with psoriasis vulgaris were randomly assigned to treatment for 10 weeks with either CyA (n = 21) or etretinate (n = 10). The psoriasis area-and-severity index (PASI-score) and pruritus (according to a 0-3 scale) served as clinical parameters, the blood esosinophil counts (Coulter Counter) and the serum ECP (RIA, Pharmacia) as laboratory parameters. Results: After CyA treatment the PASI-score amounted to 24 ± 4%, after etretinate to 56 ± 6% of the initial values (mean ± SEM). One week after CyA treatment, esosinophils dropped from 190 ± 21 to 137 ± 16/μl (P = 0.038, Wilcoxon test), after 10 weeks to 127 ± 18/μl (P = 0.006). By contrast, under etretinate blood eosinophil counts only changed marginally. Before treatment, ECP concentrations of 15.71 ± 1.30 (CyA) and 15.3 ± 5.53 μg/l (etretinate) were measured (normal range 3- 16 μg/l), ECP remained constant under both CyA and etretinate or tended to increase after 10 weeks; about 50% of the patients exhibited elevated ECP concentrations. Pruritus diminished more with CyA than etretinate therapy. PASI-scores and pruritus were directly proportional. Outcome We conclude that treatment of psoriasis with CyA leads to a rapid drop of blood eosinophils and that the activation state of eosinophils does not decrease after antipsoriatic treatment. Pruritus in psoriasis is coupled to disease severity. The underlying antipsoriatic mechanisms of CyA may be linked to lowering the number of blood eosinophils.