T‐cell subpopulations in patients with monoclonal gammopathies: Essential monoclonal gammopathy, multiple myeloma, and Waldenstrom macroglobulinemia

Abstract

T‐cell subsets defined by monoclonal antibodies (OKT3, OKT4, and OKT8) were analyzed in 117 patients with monoclonal gammopathies—69 multiple myeloma (MM) (30 untreated and 39 treated), 14 Waldenström's macroglobulinaemia (WM), and 34 essential monoclonal gammopathy (EMG) patients. The percentage and absolute numbers of total T‐lymphocytes (E⁺, OKT3⁺ cells) were within the normal range in all groups except for the treated MM patients, in which a decrease in the absolute number could be observed. The percentages of OKT4⁺ cells were significantly lower in MM (35 ± 1.7) than in EMG patients (43 ± 2) and controls (50 ± 2). In contrast, OKT8 cells correspondingly increased in MM (38 ± 1.6) compared with EMG patients (29 ± 1) and controls (27 ± 1). The OKT4/0KT8 ratio was lower in MM than that in EMG patients and controls (p < 0.01) and was shown to be one of the four most significant variables in a linear discriminant analysis used to distinguish between MM and EMG groups. The MM patients in clinical stage III as well as Bence‐Jones myeloma patients showed a more pronounced OKT4/0KT8 imbalance. The treatment did not influence the percent distribution of T‐cell Subpopulations. The patients with WM exhibit an alteration in the distribution of the T‐cell subsets similar to the MM patients with a T4/T8 ratio of 1.1±0.1. This imbalance was more pronounced in WM patients with monoclonal B‐lymphocytes in peripheral blood (leukaemic phase of WM). The functional significance of the altered T‐cell subsets in MM and WM patients remains to be established, though it is probable that such an imbalance plays an important role in regulating these B‐cell proliferations.