Monoclonal antibody-defined T-cell phenotypes and phytohemagglutinin reactivity of E-rosette-forming circulating lymphocytes from untreated chronic myelocytic leukemia patients.

T-cell phenotypes, as defined by murine monoclonal antibodies, (OKT3, OKT4, OKT8, OKIa1), and phytohemagglutinin (PHA) reactivity, were evaluated in E-rosette forming cells (T-cells) from 10 untreated chronic myelocytic leukemia patients. The proportion of T4+ cells was lower in patients than in controls (41.6 versus 61.7%, P less than 0.02); whereas the proportion of T8+ cells was similar in patients and controls. The decrease in T4+ cells in CML resulted in a decrease in circulating T4+/T8+ ratio (P less than 0.02). The Ia1+ T-cells were increased in most CML (8 of 9) patients, while control subjects never displayed Ia1+ T-lymphocytes (P less than 0.01). The PHA reactivity of E-rosette forming lymphocytes was significantly impaired in CML patients with respect to controls (P less than 0.02). The presence of Ia antigen on T-cells was positively correlated with the T8+ cell phenotype (P less than 0.001) and inversely correlated with the T4+ (helper) cell phenotype (P less than 0.05). Furthermore, there was a trend towards an inverse correlation between the PHA response and the level of Ia1+ or T8+ cells, there is no correlation between PHA reactivity and T4+ phenotype. The results suggest that the T-lymphocyte population from untreated CML patients is intrinsically abnormal.