[Functions of neutrophils in vivo on the human skin. Applications to the study of psoriasis and anti-inflammatory agents].

A reproducible method for sequential study of migration out of human skin, phagocytosis and bactericidal activity of neutrophils is described. Untreated psoriatics exhibit an early increase of chemotactic activity (0-8 h, p less than 0.02) and subsequently a strong inhibition of chemotaxis (8-24 h, p less than 0.01), a slight decrease of phagocytosis and a decrease in bactericidal activity (20 mn, p less than 0.02; 30 mn, p less than 0.003); 60 mn, p less than 0.001; 120 mn, p less than 0.001) as compared with controls. After clearing of skin lesions, the early increased chemotactic activity returned to normal values but the subsequent chemotactic inhibition remains as strong as before treatment. Phagocytosis increased to normal values (p less than 0.02) and bactericidal activity also increased but remained significantly low. The abnormalities were more evident in migrating than in circulating neutrophils, underlining the sensitivity of the described method. Using the same method we have shown that the aromatic retinoid etretinate (Ro 10-9359) and its main metabolite (Ro 10-1670) significantly inhibit the migration of neutrophils from the blood to tissues when applied into skin chambers (0.1 mg/ml) or when given orally (1 mg/kg/day) for 8 days to normal volunteers. This pharmacological property could be closely linked to the antipsoriatic properties of these drugs.