CD123 immunoexpression in cutaneous lupus erythematosus, polymorphous light eruption, pityriasis rosea, and mycosis fungoides

INTRODUCTION: CD123-positive plasmacytoid dendrocytes are prominent in the infiltrate of cutaneous lupus erythematous. AIM: To determine the significance of the CD123 immunostain, which labels plasmacytoid dendritic cells (PDC), in cutaneous lupus erythematous (CLE), polymorphous light eruption (PLE), pityriasis rosea (PR) and mycosis fungoides (MF). MATERIAL AND METHODS: A total of 76 cases, including MF (n = 27), CLE (n = 19), PR (n = 19), and PLE (n = 11), were included in the study after reviewing their diagnostic clinical features and pathologic findings. The primary antibody against CD123 was performed in all cases. RESULTS: CD123+ immunostaining in PDCs was positive in all cases. The highest mean percentage was noted in CLE (15.2%), followed by PLE (15%), PR (8.8%), and MF (2%). Besides, the clustering of CD123-positive cells was significant in CLE and PLE compared to MF and PR. CONCLUSIONS: PDC may have an important role in the aetiology of PLE and CLE cases. CD123 is a useful marker for differentiating CLE and PLE from MF and PR.