Deficiency of lymphocyte lectin-dependent cytotoxicity in myelodysplastic syndromes.

We studied a group of patients with myelodysplastic syndromes (MDS) for surface markers and cytotoxic activities of peripheral blood mononuclear cells (PBMNC). The results indicate a significant increase in the total count of CD11b+, Leu7+ and CD16+ with a percent reduction in CD4+. A reduction in PHA-induced cellular cytotoxicity (PHA-ICC) and NK activity were found. A similar phenotype was found both in refractory anemia (RA) and (RA) with excess of blasts (RAEB/RAEB-t). However, the functional activities reached the normal level only in RA patients; while in RAEB/RAEB-t patients a significant reduction was detected in PHA-ICC and NK activity.