Lymphocyte subpopulations in benign monoclonal gammopathy

Peripheral blood samples from normal individuals and from patients with benign monoclonal gammopathy or multiple myeloma were separated and assayed by immunofluorescence and rosette formation for T, B, TG and TM subpopulations. When compared with normal individuals and multiple myeloma patients, the benign monoclonal gammopathy patients could be divided into 2 groups. The 1st group demonstrated a T/B ratio similar to normal individuals, whereas in the 2nd group the ratio resembled that of the myeloma patients, with a decrease in the fraction of T lymphocytes, accompanied by an increased number of B lymphocytes. An analysis of the monoclonal Ig fraction levels indicated that the 2 groups differ in this respect as well. In the 1st group, the level of the monoclonal immunoglobulin was stable, with small fluctuations. The 2nd group demonstrated a general increasing M-component, especially in the 4-6 months preceding the study. The 2 benign monoclonal gammopathy groups exhibited a trend to a lower TM/TG ratio compared to normals; this change is more prominent in the 2nd group. Analysis of the T lymphocyte subpopulations indicated an overall decrease in the fraction of TM multiple myeloma. The above-mentioned parameters might thus aid in discriminating among BMG patients with regard to their tendency towards a malignant transformation.