Is cytomegalovirus infection a major cause of T cell alterations after (autologous) bone-marrow transplantation?

Peripheral-blood T cell subsets and functions were studied in 14 patients with malignancies treated with high-dose chemotherapy and radiotherapy followed by autologous bone-marrow transplantation (BMT). 8 CMV-positive patients (6 with latent infections and 2 with a primary infection) showed an inversion of the OKT4/OKT8 ratio caused by an increase in OKT8+ T cells and a decrease in OKT4+ T cells. This was accompanied by a pronounced increase in the percentage of HLA-DR + T cells, and functionally by increased suppressor T cell activity and decreased helper T cell activity and T cell proliferation. These alterations in T cell subsets and functions were not observed in 6 patients who were kept CMV-negative by a deliberate transfusion policy. In the 6 patients helper T cell activity and T cell proliferation capacity recovered well after day 30. Differences between the two groups were most striking 60 days after BMT. This study suggests that CMV infection, whether primary or secondary, is a major cause of T cell alterations after (autologous) BMT.