CD4 depletion is not a hallmark of CFS but it's one of many possible manifestations. In the wake of the recent furor over ICL, Cheney amassed CD4 counts for 873 patients he's seen since 1989.
Twenty of them had dropped below the crucial 300 mark, and nearly four times that numbered had dipped below 500 (anything below 800 is abnormal).
Dr. Anthony Komaroff, a CFS specialist at Boston's Bringham and Women's Hospital, says similar percentages of his patients with the lowest counts are not necessarily the sickest–" some of my sickest patients have elevated CD4 counts," says Cheney–but both specialist plan to report their cases to the CDC. Between them, they could substantially boost the tally.
The challenge, of course, is to start making sense of the muddle. How many different illnesses does the newly defined syndrome include? Are they new, or just newly recognized? Do any of them have viral causes? If so, what's the threat to public health! The evidence is still too sketchy to provide good answers. Dr. Anthony Fauci of the National Institutes of Health predicts that researchers will succeed at isolating unusual viruses in the patients. But he also predicts that most of those viruses will turn out, on close inspection, to be innocent bystanders.
Dr. Jeffrey Laurence, the New York City AIDS expert whose arresting case descriptions helped spur the ICL investigation, still worries about the prospect of a new viral illness. He argues that by zeroing in on the ICL cases that most resemble AIDS, researchers may yet uncover a phenomenon far more menacing than chronic fatigue syndrome.
Other experts favor widening the net rather than tightening it. By looking beyond CD4 depletion to other mystery immune problems, they say, scientists might finally begin to fathom why so many are forced to live the way Rosemary Stevens does. Happily, neither of those quests excludes the other.