[Significance of serum beta 2-microglobulin in the differential diagnosis of benign and malignant M-globulinemia].

Serum beta 2-microglobulin (S beta 2-M) and marrow plasma cell count were surveyed in 30 cases of M-globulinemia. The average value of S beta 2-M and number of patients with increased value were much higher in 20 malignant than 10 benign patients including cases of undetermined causes of M-globulinemia (P less than 0.005) with the same results as traditional examination of plasma cell. This method is useful in the differential diagnosis of benign and malignant cases. However, for those patients with undetermined causes of M-globulinemia and different lengths of disease course, the values may vary to a greater extent. In 11 cases multiple myeloma the value of S beta 2-M was high before treatment and decreased after chemotherapy. When the disease was exacerbated (as in 2 cases before dying), the value remained high persistently. Therefore, serum beta 2-M level can be used to predict the therapeutic effect as well as the prognosis.