Serum beta-2 microglobulin in chronic lymphocytic leukaemia

How I Manage Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL), is a hematologic malignancy characterized by the uncontrolled proliferation of mature B lymphocytes. CLL is the most prevalent leukemia in Western countries. Its presentation can range from asymptomatic with the incidental finding of absolute lymphocytosis on a routine blood test, to symptomatic disease requiring immediate intervention. Prognosis of the disease is defined by the presence or absence of specific mutations such as TP53, chromosomal abnormalities such as del(17p), a type of IGHV mutational status, and elevation of B2M and LDH. Treatment of CLL in the United States and Europe has evolved over the recent years thanks to the development of targeted therapies. The standard of care has shifted from traditional chemoimmunotherapy approaches to targeted therapies including Bruton tyrosine kinase inhibitors (BTKis) and BCL2 inhibitors, administered either as monotherapy or in combination with CD20 monoclonal antibodies. Several clinical trials have also recently evaluated combinations of BTKi and venetoclax and showed the combination to be well tolerated and able to induce deep remissions. Targeted therapies have a good safety profile overall; however, they also have unique toxicities that are important to recognize. Diarrhea, fatigue, arthralgia, infections, cytopenias, bleeding, and cardiovascular toxicities (including atrial fibrillation, ventricular arrhythmias, and hypertension) are the adverse events (AEs) commonly associated with BTKis. Initiation of therapy with venetoclax requires close monitoring because of the risk for tumor lysis syndrome associated with this agent, particularly in patients with a high disease burden. Development of newer target therapies is ongoing and the therapeutic landscape in CLL is expanding rapidly.

Production of beta 2-microglobulin by chronic lymphocytic leukaemia cells in vitro

The in vitro production of beta 2-microglobulin (beta 2m) by leukaemic cells was studied in 22 patients with chronic B-lymphocytic leukaemia (CLL). In addition, the concentration of beta 2m in serum (S-beta 2m) was determined and expressed as percent of the upper normal limit, after a correction for elevated S-Creatinine values. Patients with progressive disease usually had CLL cells with a high rate of in vitro synthesis and an increased S-beta 2m. This was not found in patients with non-progressive disease. The in vitro synthesis of beta 2m X the lymphocyte count correlated with S-beta 2m in the total material (r = 0.65). The increased S-beta 2m frequently observed in CLL may therefore originate from the tumour cells. Hence, S-beta 2m is promising as a clinically useful tumour cell-associated marker in CLL.