[Serum beta 2-microglobulin in multiple myeloma. II. Its significance in monitoring the disease].

: In a group of 71 patients with multiple myeloma the importance of beta 2-microglobulin (S-B2M) serum levels was evaluated with regard to their importance for monitoring of the disease. No significant relationship was found between B2M levels and monoclonal serum immunoglobulin, only in one third of the patients parallel changes of the two proteins were observed. One third of the patients had permanently normal S-B2M values and thus could not be evaluated with regard to the therapeutic results, 9% of the patients had very low S-B2M values throughout the disease regardless of the high activity of the latter and the marked increase of myeloma mass (stage III A). "Non-corrected" values of S-B2M proved useful in the evaluation of therapeutic results in patients with primarily elevated S-B2M values and satisfactory renal function but not in patients with elevated serum creatinine values. Normal or only slightly variable S-B2M values were part of the plateau phase of the disease, while during the relapse a rise of varying speed and extent occurred. S-B2M appears a suitable, though in some patients only supplementary, indicator for the long-term follow-up of the course of multiple myeloma.