Persistent oligoclonal CD4dimCD8+T cells in peripheral blood

Background: Routine CD4/CD8 T-cell phenotyping may shows a small fraction of CD4 (dim)CD8(+) T cells with a homogeneous appearance as described for lymphoproliferative syndromes or chronic infections. The aim of this study was to elucidate the significance of CD4(dim)CD8(+) T cells and their degree of diversity. Methods: Phenotyping was performed in 272 samples from healthy donors, elderly patients, and immunocompromised (human immunodeficiency virus or renal transplantation) patients. Results: The CD4(dim)CD8(+) T cells had decreased fluorescence intensity for CD4 but not for CD8. The frequency of patients with CD4(dim)CD8(+) T cells (> 20 cells/mu l; 10.3% of patients with human immunodeficiency virus and 7.7% with renal transplantation) was not significantly different when compared with healthy donors (9.7%). The CD4(dim)CD8(+) T cells did not express the activation marker CD69. The CD8 of CD4(dim)CD8(+) T cells expressed the heterodimeric (alpha beta) isoform. In 13 of 26 samples, the apparently highly homogeneous CD4(dim)CD8(+) T cells expressed one predominant T-cell receptor V beta clonotype. These predominant clonotypes were widely distributed among patients: V beta 5.2, 17, 2, 3, 5.1, 13.1, 14, and 20. Conclusions: Whether these findings demonstrate an oligoclonal reaction to chronic inflammation or an emerging lymphoproliferative disorder must be elucidated in a long-term longitudinal study. By analogy to monoclonal gammopathy, we propose to name this phenomenon "oligoclonal clonopathy of undetermined significance." (c) 2005 Wiley-Liss, Inc.