HLA-DR antigen expression on peripheral T cell subsets in pityriasis rosea and herpes zoster.

Using 2-color fluorescein-activated cytometric analysis, HLA-DR antigen expression on peripheral blood T cell subsets was studied in patients with herpes zoster (HZ), pityriasis rosea (PR) and psoriasis. In HZ and PR, HLA-DR was found to be significantly expressed on T cell surfaces (CD3+ cells), when compared to that of the normal control (HZ: p less than 0.001, PR: p less than 0.05). Among T cell subsets, such HLA-DR antigen was predominantly expressed on suppressor/cytotoxic cells (CD8+) in HZ (vs. normal control, p less than 0.01). However, in the case of PR, it was predominantly expressed on helper cells (CD4+; vs. control, p less than 0.05). On the other hand, activated T cell antigen (CD25+) was not significantly expressed on T cells (CD3+) in either HZ or PR. In the T cell subsets, HLA-DR antigen expression returned to normal levels during the recovery phases of HZ and PR.