Most people won't get rid of their pets. Would you?

Always treatable, not curable If you know what triggers allergic asthma, the obvious strategy is to reduce exposure to those allergens. To pinpoint what causes hyper-reactivity in the lung in allergic asthma, allergists use skin tests, then suggest that the patient reduce or eliminate contact with the allergens. Vacuum the floor. Rip up the carpet. Jettison dusty crud. Nuke the roaches. This is almost starting to sound like fun, until you remember that pet cats are a potent cause of allergies. Bummer. Ciao, Gato. Double bummer: The sad part is that these measures doesn't always control allergic asthma. Some dust mites will plague the cleanest houses, and roach control can be problematic -- to say the least -- in poor neighborhoods. And even good allergen control still leaves patients with symptoms. That disturbing news came from a recent test of immune therapy for allergic asthmatics (see "A Controlled Trial of Immunotherapy..." in the bibliography). In fact, the study contained a double whammy. The goal was to to control allergic asthma with the same kind of allergy shots that relieve sneezing and itching allergies. (Allergies are essentially an overreaction of the immune system to foreign proteins, and these tiny doses of allergens were supposed to "teach" the immune system to tolerate the allergen.) Although such "immunotherapy" has been used for years in asthmatics, the recent study of 121 children with severe asthma found that it just did not work: Allergy shots reduced neither the number of emergency-room visits nor the need for medication. Unexpected The results were a bit of a shock, says lead researcher N. Franklin Adkinson, professor of medicine at the Johns Hopkins Medical Institutions.

"We were surprised at the unequivocal, across-the-board finding, that we could not find any aspect of asthma care that was influenced." Adkinson's allergist colleagues quickly responded that the study did not reflect the real world. For one thing, patients actually evicted their pets, which many patients refuse to do. For another, the patients saw their doctors every two or three weeks, while most patients are lucky to see their asthma doctors twice a year. Finally, the "astounding 90 percent compliance rate" among patients did not reflect clinical reality. That's according to Michael Kaliner, who spoke to The Lancet (2/8/97) on behalf of the American Academy of Allergy, Asthma and Immunology.

Adkinson admits that the subject population was inevitably tilted toward patients who would obey the rules for the required two to three years. And he adds that while immunotherapy did not help the severe cases who he'd hoped would benefit, there were indications that it might help milder cases, and/or patients with more recent diagnoses.

Norman Edelman, a consultant to the American Lung Association, says the study should be seen in context. "If allergy shots were dramatically successful, we'd know it by now. And if they didn't work at all, we'd know that by now too. So it may work in some selected cases." As we mentioned previously, there's another lesson in the results: a missing piece of the asthma picture. These patients cleaned out their environments, they saw their doctors, they took their meds, and they still had symptoms. Why? Probably, Adkinson says, "due to an unknown or complicating factor." There are any number of candidates for unknown asthma factors, but the one that intrigued The Why Files is the personal history of infection. In a recent Japanese study of 867 children, asthma symptoms correlated with reactions to tuberculosis skin tests (see "The Inverse Association..." in the bibliography). A positive skin test signals "exposure" to TB, meaning the person has either had the disease or been vaccinated against it. The study found that asthma symptoms were one-half to one-third as common among those who were exposed to TB as those who had not been exposed. That indicates, but does not prove, that having TB, or getting the vaccination, somehow protects against allergic asthma. Enough speculation. What's new on the asthma drug front?

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