Influence of graft-versus-host disease prophylaxis on early T-lymphocyte regeneration following allogeneic bone marrow transplantation.

An early decrease in the ratio between T4+ and T8+ T lymphocytes has been shown to correlate with the development of grade II-IV GVHD in allogeneic bone marrow transplant (BMT) recipients receiving methotrexate (MTX) as prophylaxis for acute graft-versus-host disease (GVHD). This study compares the onset of T-cell regeneration in patients receiving cyclosporin A (CyA) with those receiving MTX. Firstly, lymphoid recovery occurred at a significantly faster rate in the patients on CyA. Secondly, in those patients, the repopulation of T4+ and T8+ T cells started simultaneously, whereas in patients on MTX the repopulation of the T8+ subset lagged about a week behind that of the T4+ subset. Thirdly, the decrease in the T4/T8 ratios as a function of the lymphocyte counts occurred at a significantly slower rate in the patients on CyA than in those on MTX. Thus, the differences in the onset of T-cell regeneration in BMT recipients on CyA as compared with those on MTX abolished the correlation of the T4/T8 ratio changes with grades II-IV GVHD as described in patients receiving MTX.