T-cell subpopulations in patients with monoclonal gammopathies: essential monoclonal gammopathy, multiple myeloma, and Waldenstrom macroglobulinemia.

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/OKT8 ratio was lower in MM than that in EMG patients and controls (p less than 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/OKT8 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.