Drug-induced hypersensitivity syndrome associated with cytomegalovirus reactivation: immunological characterization of pathogenic T cells.

We report a case of tribenoside-induced hypersensitivity syndrome associated with cytomegalovirus reactivation and investigation of the immunological characteristics of the circulating and skin-infiltrating lymphocytes. Activated CD8+ T cells outnumbered CD4+ cells in both the circulation and the skin lesions. Upon in vitro stimulation with the drug, CD4+ cells proliferated and produced interferon-gamma. The circulating CD8+ cells used limited T-cell receptor Vbetas, some of which are restricted to cytomegalovirus-derived peptide in the context of the HLA-A2 haplotype. CD8+ cells and cytomegalovirus-containing cells closely co-localized in the skin lesions. These results suggested that CD4+ cells were drug-reactive, whereas cytomegalovirus activated CD8+ cells in the present case. These two cell types seemed to play a distinct role in drug-induced hypersensitivity syndrome.