Background
Pityriasis rosea (PR) is an acute, self-limiting papulosquamous skin disease. T-helper lymphocytes play an important role in the pathogenesis of PR. However, the role of cytotoxic T-lymphocytes is poorly understood.
Objective
To investigate the immune profile of mixed inflammatory cell infiltrate in skin lesions with PR.
Methods
The study included 10 biopsy specimens from lesional skin with clinical diagnosis of PR. Ten biopsy specimens from normal skin served as a control. Monoclonal antibodies were used for targeting antigenic epitopes on several cell types including: CD3 (for T-cells), CD20 (for B-cells), CD68 (for macrophage/dendritic cells), and Granzyme B (Gr B) (for active cytotoxic T-cells).
Results
Levels of CD3 +ve, CD68 and Gr B were significantly higher in lesional skin as compared to normal skin (p<0.05). CD3 +ve cells was the predominant cell population in lesional skin.
Conclusion
The finding of significantly increased numbers of CD3 +ve cells in skin lesions with PR indicates an important role of cell mediated immunity in the pathogenesis of the disease. A significantly increased number of Gr B +ve cells in all lesions suggested that a fraction of CD3+ve cells have an active cytotoxic potential.