amfAR, The Foundation for AIDS Research

Learning From AIDS: HIV Knowledge Helps Solve a Medical Mystery


May 29, 2009—When Dr. Zachary Bregman began practicing medicine in the early 1980s, he joined the ranks of young physicians in New York City who were battling the devastating effects of HIV/AIDS. As an internist and pulmonologist, he developed a deep knowledge of the virus and its insidious complications. But Dr. Bregman’s patient and friend Vincent Cavallo wasn’t thinking of his physician’s HIV/AIDS experience when he called his office late one evening in 2004. Mr. Cavallo’s wife Ellen had been living with bone marrow disease for a number of years, but now she was in New York Hospital with severe neurological symptoms for which her doctors could find no explanation. Her husband was desperately searching for answers.

“I was able as an HIV clinician to diagnose and recognize the problem, and then David was able to apply his experience in HIV research in a non-HIV setting.”

Dr. Bregman’s two decades of treating HIV, however, proved to be crucial in diagnosing Ms. Cavallo’s condition. To him, her symptoms suggested a condition he had often seen in his HIV/AIDS patients: progressive multifocal leukoencephalopathy (PML), which can cause a wide range of debilitating and even fatal neurological problems—including progressive weakness, visual and speech changes, fatigue, and cognitive impairment.

In the early years of the epidemic, Dr. Bregman explained, he and his fellow HIV specialists “would see PML once or twice a week, and it was very scary because there was no treatment for it. Especially before there was effective antiretroviral therapy, there was nothing you could do for it.”

Although she did not have HIV, Ms. Cavallo’s immune system had been compromised by the treatment she’d been undergoing for her bone marrow disease, thus rendering her more vulnerable to PML, which is rarely seen in non-HIV patients. Since the advent of highly active antiretroviral therapy (HAART), the survival rate for HIV-positive patients with PML has improved dramatically because recovery of the immune system often causes PML to go into remission. However, for patients without HIV, for whom HAART is not an option, the prognosis is still grim. Indeed, after Ms. Cavallo’s doctors tested her for PML as Dr. Bregman suggested, her husband learned that she did have the condition—but that nothing could be done to treat her.

In a final effort to help the Cavallos, Dr. Bregman enlisted the assistance of Dr. David Simpson, an early amfAR grantee who is now a neurologist and researcher at Mt. Sinai Hospital renowned for his work on HIV-related neurological conditions. 

When Ms. Cavallo arrived at Mt. Sinai, “she was a very traumatic case,” said Dr. Simpson. “She was in fairly serious neurological condition, with paralysis on one side of the body, severe visual impairments, and so forth. It wasn’t clear exactly which treatment we could use, because she wasn’t a candidate for HAART.” However, Dr. Simpson had recently read some experimental data suggesting that an antidepressant called Remeron could be effective in blocking the spread of the virus that causes PML, and decided to try the drug on Ms. Cavallo.

The results were better than anyone could have expected, according to Dr. Simpson. “She not only stabilized in her condition, but over the years the lesions in her brain dramatically regressed.” He and his colleagues eventually published a report of her case in the Journal of Infectious Diseases.

“I don’t think you come across stories like this that often,” said Dr. Bregman. “We had no idea what was going to happen; it was very suspenseful.” Ms. Cavallo’s case, he noted, revealed the ways that experience in treating and studying HIV can benefit many patients, not just those with the virus. “I was able as an HIV clinician to diagnose and recognize the problem, and then David was able to apply his experience in HIV research in a non-HIV setting.”

For Dr. Simpson, more than two decades of HIV research—including an amfAR-funded study of HIV-related neuromuscular disorders—have shown him how his work can be applied to conditions other than HIV. One of his main areas of research involves treatment of painful peripheral neuropathy, which has applications for HIV as well as to other diseases such as diabetes. “We learn from one disease and apply it to another,” he explained. As Dr. Simpson and his fellow researchers carry on their search for answers to the puzzles posed by this elusive virus, their vital work continues to improve and extend the lives of many outside the realm of HIV. 

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