I've heard that several companies are looking into developing AIDS treatments based on immune reconstitution. I've heard that there are trials going on where a patient's own killer T cells are taken out and those specific for HIV are selected and grown up, then given back to the patient in large doses. It's supposed to reconstitute the patient's own immune response against HIV. Is there good information out there on whether this is likely to work? How can I find out more about this type of therapy and immune reconstitution in AIDS? It sounds more natural and less toxic than pills. Thank you.

The approach you describe has been tried using a variety of methods in small numbers of patients over the past few years. It's an interesting concept, but so far it has failed to demonstrate much benefit. One of the potential problems is that the virus is capable of mutating to escape the antiviral activity of the specific clone that is reinfused. The peptides that are used to stimulate and grow these clones are from laboratory strains of HIV, which may be quite different from the strains infecting the patient. Unless the approach can be "polyclonal" it may be doomed to failure.

Another potential problem is that cytotoxic T-lymphocytes (CTL) need T-helper cells to work and grow, so in people with low CD4 cell counts, reinfusing CTL may not be enough.

Finally, it is estimated that if such a technique did work, it would be about as expensive as a bone marrow transplant.

Despite these potential drawbacks, the concept of immune reconstitution is an interesting one and deserves further study. The NIH is funding research into novel immune and genetic therapies. You could contact the NIH or check their Web page for details.

(Thanks to my colleague Robert Bollinger, MD, MPH, for his input on this subject.)