Decreased T helper cells in the myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are disorders in which the abnormalities are thought to be confined to cells of the myeloid series. However, examination of peripheral blood from 56 patients with MDS showed that the majority had low lymphocyte counts. In a detailed study of 25 patients, using OKT3, OKT4 and OKT8 monoclonal antisera together with SRBC rosettes, it was shown that there is a consistent and significant reduction in peripheral blood T lymphocytes. This decrease was primarily confined to the OKT4-defined helper subpopulation. There is a consequent relative increase in the OKT8-defined subset but in absolute numbers however, suppressor cells are reduced compared to normal particularly in those patients with lymphopenia. No correlations between T cell abnormalities and the different morphological groups of MDS were found. The possible implications of the reversed helper/suppressor ratio in the pathogenesis of MDS are discussed.