The Prognostic Significance of Beta2 Microglobulin in Patients with Hemophagocytic Lymphohistiocytosis.

To determine the prognostic significance of beta2 microglobulin (β2-m) concentrations in patients with hemophagocytic lymphohistiocytosis (HLH), a rare disorder caused by pathologic activation of the immune system. The study population consisted of 74 patients diagnosed with HLH and 35 healthy controls. Serum β2-m levels were measured using a latex agglutination photometric immunoassay. Median serum β2-m levels were significantly higher in HLH patients than in healthy controls (4.05 versus 1.5 mg/L; P < 0.001) and were significantly higher in patients with lymphoma associated hemophagocytic syndrome (LAHS) than in patients with benign disease-associated HLH (4.2 versus 3.3 mg/L; P < 0.001). Higher serum β2-m levels were positively correlated with LAHS (P = 0.005), abnormal lactate dehydrogenase concentrations (P = 0.009), and hypoalbuminemia (P = 0.003). ROC analysis showed that overall survival (OS) was significantly shorter in LAHS patients with serum β2-m levels ≥4.03 mg/L compared to <4.03 mg/L (P < 0.001). Moreover, multivariate analysis showed that serum β2-m level was an independent prognostic of OS (P = 0.034) in patients with LAHS. High serum β2-m levels and LAHS were associated with markedly poorer OS in patients with HLH. Serum β2-m concentration was a powerful and independent prognostic factor for OS in patients with LAHS.