BAFFLING RESISTANCE TO SARS



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Last Updated

01 May 2003

Source: Newsday, April 30, 2003

Baffling Resistance to SARS

Seeking clues in AIDS patients

By Laurie Garrett, Staff Correspondent

Beijing - A small but potentially intriguing clue has emerged in the SARS fight, even as China's epidemic continues to spiral.

From the Beijing perspective, the epidemic couldn't look worse. The city added 152 cases yesterday. More residential complexes were placed under quarantine, bringing the total sequestered residents to more than 8,000. Throughout the rest of the nation, frightened citizens erected barricades and screening centers to bar travel by people from Beijing.

Amid the mounting toll, Newsday learned that a select population in Guangzhou, the southern Chinese city where the epidemic apparently began in November, appears to have resisted infection. At the peak of the outbreak there, in January and February, patients with the then-mystery illness were kept on the second floor of one hospital. The floor was already in use as an AIDS ward.

Guangzhou authorities divided the floor of People's Hospital No. 8 in half, putting SARS patients on one side of the elevator bank and AIDS patients on the other. Health care workers walked back and forth between the two sides, and some of those doctors and nurses contracted SARS.

Yet not one of the several dozen AIDS patients or their visitors, some of whom were also HIV positive, developed the disease. "I am wondering why there was no SARS virus co-infection in the AIDS cases," Dr. Zhang Fujie, director of AIDS treatment and care for China, said yesterday in an interview. "We are exchanging information with Hong Kong on this. We will continue to try to understand that."

Dr. Cheng Feng of the China/UK HIV/AIDS Project said he, too, was aware of the phenomenon. He wondered whether the drugs the AIDS patients were receiving for HIV control might be blocking a SARS infection. A similar notion was mentioned by Dr. Yuen Kowk-yung of the University of Hong Kong. With New York's Dr. David Ho, of the Aaron Diamond AIDS Research Laboratory, Yuen is exploring the AIDS apothecary for an effective SARS treatment.

But the puzzle may be deeper. That's because the most effective anti-HIV drugs - a class called protease inhibitors - are not available to Guangzhou patients, according to an HIV outpatient and activist who asked to be identified only as Thomas. Few Chinese patients have access to any but the cheapest, least effective of the anti-HIV drugs, Thomas said, which target a chemical not even present on the coronavirus that's been identified as causing SARS.

"I went in there to visit HIV patients, my friends," Thomas said. "We were all asked to wear masks, special clothes and latex gloves. But the HIV patients on the ward said they didn't like to wear masks, and they refused. But they all looked healthy."

SARS so far has presented scientists with a number of perplexing aspects. Some scientists speculate the virus doesn't actually kill human cells - that the immune system's overreaction actually precipitates destruction of cells of the lung and other parts of the body, precipitating the acute pneumonia that is the disease's hallmark. In theory, they say, death may be the result of an aberrant or overly sensitive immune response. If that is proved correct, it's possible HIV patients may actually be at lower risk for SARS precisely because they lack strong immune responses.

This is only speculation, of course, but the notion is garnering interest among physicians here. An added bit of evidence supports the theory: The most effective SARS treatment so far is steroids - agents that stifle the immune response.

Otherwise, there was little cause for optimism in China yesterday. Beijing's toll is swiftly approaching, in just three weeks, the cumulative total seen in Guangdong, the province that includes Guangzhou, over a six-month period: Beijing now has 1,347 reported cases; Guangdong has seen 1,399. Nationwide, the total reached 3,303.

The atmosphere here yesterday was eerie, as streets in many districts were nearly empty, most small businesses and restaurants were closed and apartment complexes throughout the city were under quarantine. In the Cao Jun Miao neighborhood, a squadron of police cordoned off entry to a residential complex, declining to confirm whether SARS cases were inside. Quarantine notices were posted, and people decked out in masks, gowns and gloves stacked boxes of food just outside the building entry, expecting residents to claim the goods.