NEW YORK (Reuters Health) - Treatment with a combination of anti-HIV drugs, known as highly active antiretroviral therapy (HAART), can improve the immune systems of infected patients, but new research indicates that in young children this effect may increase the risk of asthma.

In asthma, an excess amount of inflammatory and immune cells are produced in the lungs. Thus, any condition that directly or indirectly increases these cells might have an unwanted effect.

"Investigators have assumed that asthma is not a complication of pediatric HIV infection, because studies (conducted before HAART was introduced in the mid-1990s) did not detect the problem," senior author Dr. William T. Shearer, at Texas Children's Hospital in Houston, told Reuters Health.

The reason was that without HAART, immune system T cells would drop, preventing an asthmatic reaction, he explained. "It was not until the era of HAART, which restored the (T cell) levels, that an increased incidence of asthma was noted."