Peripheral lymphocytes in paraproteinemia.

In 22 cases of myeloma and 12 cases of benign paraproteinemia, the function of circulating lymphocytes was studied. The technique used was the incorporation of 3H thymidine after PHA stimulation. E rosette formation and immunoglobulin bearing cells were evaluated. A reduction of 3H thymidine incorporation in the blastic cells was seen in the myeloma patients (2,942 ± 421 cpm/10 6 lymphocytes in respect to 13,182 ± 920 of the control group). The difference was statistically significant: p <0.001. In benign monclonal gammopathies the reduction was moderate and was at the limits of the significance: 9,482 ± 1,100. The percentage of E rosettes and of immunoglobulins bearing cells was normal. The different behavior of the blastic response in vitro in the 2 groups of patients tested confirms that the respective condition of the immunocompetent system is clearly different. A possible interpretation of this type of behavior is discussed.