β₂‐Microglobulin in Chronic Lymphocytic Leukaemia

The serum level of beta 2-microglobulin (S-beta 2 m), a cell membrane protein associated with HLA-antigens, was quantitated in a series of 23 consecutive patients with chronic lymphocytic leukaemia (CLL). Markedly elevated values of S-beta 2 m (greater than 4.5 mg/1) were found in 10 patients, while only 3 patients had normal values (less than 3.0 mg/1). High serum values correlated with a large tumour mass, as estimated by Rai's clinical staging and by the total peripheral lymphocyte count. Blood lymphocyte proliferative activity, which has been suggested as reflecting disease activity in CLL, was measured by 3H-thymidine uptake in cells in vitro. The 3H-thymidine uptake was high in 3 patients all of whom were among the 5 patients with the highest S-beta 2m-values. S-beta 2m-determinations seem to be of definite interest in the study of patients with CLL although long term studies will be necessary for evaluation of the practical clinical value.