Inflammatory cell subpopulations in keloid scars

The aim of this study was to investigate the contribution of lymphocytes and macrophages to keloid scarringby morphologically characterising inflammatory cell subpopulations in keloid scars in comparison with normal skin. We took 3 mm punch biopsies from the anterior forearms of eight normal healthy volunteers. Eight keloid scars were excised using an intralesional technique. All tissue was snap frozen in liquid nitrogen and serial sections were stained with a panel of anti-inflammatory cell monoclonal antibodies. The numbers of macrophages and lymphocytes and the proportions of the subpopulations were compared. Higher numbers of both macrophages and lymphocytes were found in keloid dermis (P=0.01 and P=0.02, respectively (Mann-Whitney U-test). There was no significant increase in the expression of the lymphocyte activation markers, CD25 and CD27. However, there was a significantly higher CD4+:CD8+ (Th:Ts) ratio (P=0.046) in keloid tissue. This suggests that an imbalance in these inflammatory cell subpopulations may contribute to keloid scarring in man.