EPIDERMAL DIFFERENTIATION CHARACTERISTICS OF THE PSORIATIC PLAQUE DURING TREATMENT WITH CALCIPOTRIOL

Treatment of psoriasis with vitamin D-3 analogues is well established in present dermatological practice, One of the clinical signs of the p soriatic plaque that reduces early and markedly during treatment with the vitamin D-3 analogue calcipotriol is scaling, Since scaling is the clinical manifestation of disordered epidermal differentiation, early changes in immunohistochemical markers for differentiation (transglut aminase, involucrin and filaggrin) were studied in patients who had be en treated with calcipotriol for 4 weeks, Markers for proliferation (K i-67 antigen) and inflammation (polymorphonuclear leucocytes and T lym phocytes) were also studied and correlated with the differentiation ch aracteristics. Clinically, a major improvement was seen in all patient s, A significant decrease in the percentage of transglutaminase-positi ve cell layers was observed during the first week of treatment, In con trast, an increase in transglutaminase activity in epidermal cell cult ures following incubation with calcipotriol has been reported, Involuc rin expression was only slightly modulated in vivo. However, a major r estoration of the filaggrin-positive cell layer and significant reduct ion in the recruitment of cycling epidermal cells characterized the ep idermal response to calcipotriol treatment, Markers for inflammation ( T11-positive cells and elastase-positive cells) were also reduced subs tantially during the first week of treatment with calcipotriol, From t his study it may be concluded that inhibition of epidermal growth and recovery of the filaggrin-positive cell layer are among the in vivo ef fects of calcipotriol.