Purpose: Elevated serum beta-2 microglobulin (beta 2M) levels are associated with poor prognosis in several lymphoproliferative disorders including multiple myeloma and lymphoma. Their prognostic relevance in acute lymphocytic leukemia (ALL) is unknown. We analyzed the associations of serum beta 2M levels at diagnosis with pretreatment characteristics and with prognosis in adult ALL.
Patients and methods: One hundred fifty-nine adults with newly diagnosed ALL were investigated. Serum beta 2M levels were determined at diagnosis, on fresh peripheral blood samples, using a radioimmunoassay, the Pharmacia beta 2 Micro RIA (Pharmacia Diagnostics, Uppsala, Sweden). Statistical correlations were assessed by standard methods, and further independent prognostic value of serum beta 2M was determined by multivariate analysis.
Results: Patients with beta 2M levels of 4.0 mg/L or above had a lower complete response rate (61% versus 80%; p = 0.02), a significantly worse survival (p < 0.01), and a significantly higher association with development of central nervous system (CNS) leukemia (p < 0.01). High beta 2M levels were more common among patients with older age, with elevated creatinine, bilirubin, and alkaline phosphatase levels, with low albumin levels, and with B-cell disease. Multivariate analysis for survival indicated the beta 2M level to be an independent prognostic variable (after adjusting for pretreatment creatinine level and age). The evaluation of beta 2M levels within low- and high-risk groups for CNS disease suggested an association of elevated beta 2M levels with a worse incidence of CNS disease in the high-risk patients.
Conclusion: Monitoring serum beta 2M levels may provide significant prognostic information in adults with ALL and should be included in their pretreatment evaluation. Its importance in childhood ALL requires investigation.