PCR could help screen patients for CMV treatment

Researchers evaluating the use of polymerase chain reaction (PCR) testing conclude in a recent study in the journal AIDS that it is an effective and economical means of screening patients at high risk of cytomegalovirus (CMV) retinitis.1

Current federal guidelines recommend all patients with serological evidence of previous CMV infection and CD4 counts below 100 should have ophthalmological reviews every three or four months. This costly approach could be circumvented or modified with PCR screening, which the study found to be highly predictive of which patients would progress to CMV disease.

The National Eye Institute in Bethesda, MD, will also be studying PCR to further evaluate its predictive value in the clinical setting, and its usefulness as a way of determining treatment guidelines in the age of protease inhibitors, says Scott Whitcup, MD, the institute’s clinical director.

"In patients whose counts are up and who are PCR-negative, it may be okay to say, ‘Your immune system has eliminated it [CMV disease], so you can stop treatment.’"

Whatever the outcome, Whitcup says the findings are a reminder of how resilient and important the immune system is. "Immune restoration has done far better than any drug [for CMV]. You can’t compare taking intravenous medication every day or every two weeks to having your immune system doing it on your own."


1. Brown E, Sabin C, Wilson P, et al. Cytomegalovirus viraemia detected by polymerase chain reaction identifies a group of HIV-positive patients at high risk of CMV disease. AIDS 1997; 11:889-893.