Aids or Chronic Fatigue?
Rosemary Stevens recalls vividly how her life changed 11 years ago. She was 37, recently separated, raising two kids, and working as a store clerk in Stevensville, Mich., when she came down with the most bone crushing flu she'd ever had. Her doctor called it acute mononucleosis, but it never went away. She kept working, but year after year, she suffered fevers and infections that sometimes lasted months despite treatment with antibiotics. She thought she'd figured out what was wrong in 1986, when a gynecological exam revealed extensive endometriosis. But a hysterectomy brought no relief. "I thought,' This is it, I'm finally going to be better'," she says. "I just got worse." Since then, doctors have given her everything from antidepressants to antihistamineseven performed two root canals on the theory that her ear and sinus infections might originate in her teeth. Yet her illness persists. At 48, she gets by on disability checks and wonders whether she'll ever work again.
Until a few weeks ago, chronic fatigue syndrome was the only name for Steven's strange illness. Thousands, perhaps millions, of people have come down with CFS over the past decade. The debilitating flu-like condition seems rooted in the immune system, but nearly everything about it is a mystery. Unlike most CFS patients, Stevens can also count herself among sufferers of the "AIDS-like illness" that public-health officials are now scrambling to investigate. She tests negative for HIV-1 and HIV-2, the known AIDS viruses. Yet, like an AIDS patient, she has virtually lost a vital class of immune cells known as CD4 lymphocytes. Officials at the National Institutes of Health and the Atlanta based Centers for Disease Control have dubbed the phenomenon ICL (for idiopathic CD4+T-lymphocytopenia) , and scientists are searching for common threads among sufferers. So far, the search has produced few answers. But as more cases come to light, it's far becoming clear that the newly defined syndrome has as much in common with CFS as it does with AIDS.
The specter of a new epidemic surfaced earlier this summer, when Newsweek reported that researchers had identified a dozen cases of AIDS-like illness in people not infected with HIV. At least one patient had died of AIDS-related infections. And because many of them had HIV risk factors, such as needle-sharing or unprotected sex, some scientists worried that the cases could mark the emergence of a new AIDS virusan agent transmitted like HIV but undetectable by any available blood tests. When doctors reported still more cases in late July, during an international AIDS conference, U.S. health officials decided to launch a formal surveillance program.
To get the broadest possible view of the syndrome, the officials defined ICL not as full-blown AIDS without HIV but as a severe and inexplicable loss of CD4 cells. A person needn't be outwardly sick to qualify for the diagnosis. The definition requires only that someone free of HIV and other known causes of immune deficiency score under 300 on two consecutive CD4 tests (the normal range is 800 to 1 ,200). Using that standard, epidemiologists at the CDC have identified 35 cases, dating back to 1985, and started investigating 30 of them. As Dr. Martha Rogers of the CDC's Division of HIV/AIDS reported at a recent meeting in Atlanta, the patients look quite different from people with AIDS, both individually and as a group.
Of the 30 patients under study, 29 are still alive. Twenty-five have suffered symptoms, but only 13 have developed "AIDS defining" illnesses such as pneumocystis carinii pneumonia. By the time someone with HIV develops an AIDS defining illness, death usually follows within two years, but ICL patients have turned up symptom-free seven years after crossing that threshold. Fewer than half of the government's ICL patients report HIV risk factors (the rate is 96 percent among AIDS patients), and their demographic profile differs markedly: 84 percent are white, 30 percent are female and 27 percent are at least 50 years old. By contrast, just 53 percent of U.S. AIDS patients are white, 11 percent female, and 10 percent over 50. Laboratory scientists have found hints that some ICL patients harbor HIV-like viruses. But those findings are far from conclusive, and there's no evidence that the syndrome is spreading like a viral illness. The CDC has yet to find clusters of ICL among patients' sexual or household contacts. And rather than mushrooming, as AIDS has since 1981, ICL has turned up at a fairly steady rate.
Such enigmas are nothing new to Dr. Paul Cheney of Charlotte, N.C. Cheney, the nation's best-known chronic fatigue syndrome specialist, has spent eight years examining people who develop mysterious immune problems in the absence of HIV. Like the ICL patients under investigation in Atlanta, Cheney's CFS patients suffer an array of illnesses-some mild, some devastatingthat come and go for years. Some have HIV risk factors. Most don't. And though some harbor what appear to be HIV-like viruses, no researcher has shown that the illness stems from such a virus, or even that it's transmissible. Cheney says 30 to 40 percent of his patients report having a close associate with a similar illness, but he has never managed to identify "a behavior pattern that places people at risk."
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 Cheneybut 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.