EBV serum test could be diagnostic tool for AIDS lymphoma

Epstein-Barr virus (EBV) DNA load may be helpful in the diagnosis and management of patients with AIDS-related lymphoma, researchers report.

Dr. Margaret L. Gulley of the University of North Carolina at Chapel Hill and colleagues found that HIV-positive patients with lymphoma tended to have higher EBV levels than those without lymphoma, and that EBV loads dropped with successful treatment.To investigate the role of serum EBV testing, she and her colleagues tested plasma samples from 61 AIDS patients. Thirty-five had lymphoma, and a total of 232 plasma samples were tested. Twenty-six patients with opportunistic infections but no lymphoma acted as controls, and 128 samples were tested from this group. The researchers also used in situ hybridization to test lymphoma biopsy samples from some of the patients to look for EBV RNA.EBV was detectable by quantitative-polymerase chain reaction (Q-PCR) in the plasma of the 17 patients with EBV-positive lymphoma, in amounts ranging from 34 to 1,500,000 copies per milliliter of plasma, while EBV loads in patients with EBV-negative lymphomas and those without lymphoma were generally low or undetectable.The Q-PCR test takes about 5 hours to complete, the researchers note, making it useful in a clinical setting.Among the 13 patients for whom pre- and post-therapy plasma samples were available, EBV load dropped quickly after therapy began. In two of the patients, EBV remained detectable 3 and 6 months after starting treatment, and there was clinical evidence of persistent tumor.EBV levels were detectable in the plasma of only two of five patients with lymphoma in the brain, suggesting the test is not a sensitive way to screen for brain lymphomas, Dr. Gulley and her colleagues note.The researchers found a plasma EBV load above 2500 copies/mL “strongly correlates with the presence of lymphoma,” while levels approaching 2000 copies/mL may be seen in non-EBV-associated disease. However, they note, “overlap in viral loads made it impossible to set a cutoff that distinguished lymphoma from non-lymphoma patients.””A prospective study is warranted to optimize timing of sample collection, to evaluate the kinetics of EBV load over time, and to further evaluate the utility of EBV load as a harbinger of impending lymphoma, as a tool for evaluating the efficacy of lymphoma therapy, and as a predictor for relapse,” the researchers conclude.”We need to do more to enhance the availability of these tests and really study them to make sure that we’re optimizing their use,” Dr. Gulley added.(Source: Journal of Medical Virology, Reuters Health, January 2005)