NEW YORK (Reuters Health) - Starting combination drug therapy as soon as possible after a person becomes infected with HIV may be the best way to help the immune system to recover, new study findings suggest.

Combination therapy, which usually includes a powerful drug called a protease inhibitor, can suppress HIV to undetectable levels, but the benefits often come with a cost. Some studies have suggested that the drugs, besides causing short-term side effects, may increase the risk of cardiovascular disease and diabetes in the long run.

According to a team of researchers led by Dr. Gilbert R. Kaufmann, of the National Centre in HIV Epidemiology and Clinical Research in Sydney, Australia, there is some evidence that early combination therapy may prevent some of the irreversible damage to the immune system caused by HIV. But because of the drawbacks of combination therapy, more convincing proof of the benefits of early treatment are needed, the authors note in the journal AIDS (news - web sites).

Kaufmann's team compared the immune system benefits of combination therapy in 28 men with acute HIV infection (that is, infected within the previous 6 months) and 30 men with chronic HIV infection. None of the participants had taken any HIV medications before enrolling in the study. For a minimum of one year, the investigators monitored the patients' T-cells--the disease-fighting white blood cells that are killed off in HIV infection.

In both groups of patients, treatment suppressed HIV to undetectable levels, Kaufmann and his colleagues report.

But T-cell levels rebounded significantly more in patients who had been recently infected, particularly during the first 3 months of therapy. Participants with a recent infection tended to have fewer T-cells than the chronically infected patients at the beginning of the study, but after treatment, 93% had a normal T-cell count, compared with just 37% of chronically infected individuals.

And in contrast to patients with a new infection, patients with a chronic HIV infection had extremely low levels of so-called na Jive T-cells, a sign that the immune system is not fully recovered, the report indicates.

``Early therapy therefore may allow for a much better reconstitution of the immune system,'' Kaufmann told Reuters Health. ``However, it is unknown whether therapy has to be initiated in the first weeks of the infection or how long treatment can be delayed,'' he added.

``This crucial issue needs to be addressed in a future study,'' Kaufmann said.

The study received funding from several drug companies, including Merck, Agouron, Glaxo-Wellcome and Bristol-Meyers-Squibb.

Source: Aids 2000;14:2643-2651.