Serial beta-2 microglobulin measurement as an auxilliary method in the early diagnosis of cytomegalovirus infection in renal transplant patients

Infection by cytomegalovirus is one of the most important causes of morbidity and mortality after renal transplant. During episodes of acute rejection serum levels of beta-2 microglobulin (B2M) are elevated due to decreased excretion and/or increased production from T-cell proliferation. Sequential measurement of B2M in the first months after transplantation may detect patients at increased risk of rejection. This study assesses the usefulness of serum B2M for early detection of patients with increased risk of cytomegalovirus disease. Among 16 of 18 cases of CMV infection, there was an increase in serum B2M levels before CMV diagnosis. In all cases, B2M serum levels increased at an average of 10.8 days before the symptoms or the positive antigenemia. From a mean baseline B2M value of 5.0 mg/L, the mean value at the time of diagnosis was 7.7 mg/L before any clinical or laboratory evidence of CMV infection. These findings suggest that B2M serum levels can be used as a marker for early diagnosis of cytomegalovirus infection.