IMMUNOHISTOCHEMICAL CHARACTERIZATION OF THE CUTANEOUS CELLULAR INFILTRATE IN DIFFERENT AREAS OF CHRONIC LEG ULCERS

Current understanding of the immunological mechanisms involved in the pathogenesis of venous leg ulcers is insufficient. In this study the c ellular composition of skin biopsies taken from the center, the edge, and 2 cm distant from the edge of venous leg ulcers was characterized quantitatively by immunohistochemical staining. In the epidermis the m ean numbers of Langerhans cells (CD1a(+)) were four times lower at the edge of the ulcer compared to clinically intact epidermis 2 cm distan t from the edge. In the dermis a statistically significant increase in the mean numbers of macrophages (CD68(+)) and neutrophils (NP57(+)) f rom the distant area towards the center of the ulcer was observed. No significant differences were observed in the distribution of T cells n or in the ratio of CD4(+)/CD8(+) T-cell subsets between the different regions of the ulcer. About 30% of T lymphocytes were CD8(+) in all mi croenvironments. The center and the edge of the ulcer were dominated b y macrophages comprising 63% and 53% of the cells respectively, while T lymphocytes dominated the distant area. The area 2 cm distant from t he edge was also heavily infiltrated by macrophages and neutrophils. B cells (CD22(+)) and NK cells (CD56(+)) were relatively rare in all ar eas, comprising less than 3% of the dermal infiltrate. In conclusion, local microenvironments each with a different cellular composition can be defined within venous leg ulcers.