TreatmentUpdate 76. 9(2): 3; March, 1997
Sean Hosein

Although HIV infects CD4+ cells in the blood, most of the virus and 98% of CD4+ cells are in the lymph nodes/tissues. For a therapy to be effective, it must deal with HIV hiding in those sites. The tonsils are part of the network of lymph tissues, therefore several teams have been studying tonsils to uncover the effects of anti-HIV therapy.

Ritonavir plus

Doctors recruited 10 HIV-infected adults who had never used anti-HIV drugs before this study. They received a combination of ritonavir, AZT and 3TC at standard doses for at least 6 months. At different points in the study researchers removed small pieces of the tonsils for study.

Results

By the 6th month of the study, technicians could not detect HIV in one subject, though pieces of the virus could be found in the tonsils of all subjects. Readers should keep in mind that the technology used to detect HIV in these experiments had its limits and it could easily have missed the virus.

Indinavir plus

One American team studied the effect of various combinations of indinavir, AZT and 3TC on 9 subjects who received therapy for between 8 to 12 months. According to the researchers, ?of 5 subjects on indinavir/AZT/3TC,? only 2 had their viral load in their blood fall to undetectable levels. Readers should note that the lower limit of detection for the viral load test used was 20 copies. If the viral load was 15 copies, it would be considered ?undetectable?. Technicians still detected HIV in the lymph nodes of the 2 subjects. The viral load there ranged between 50-100 copies/mg of lymph node tissue. Despite taking triple therapy, two other subjects still had low viral load in the blood ? between 2,000 to 8,000 copies. By contrast, the viral load in their lymph nodes was 20-30 times greater.

In New York

Doctors at the Aaron Diamond AIDS Research Centre in New York have been treating and monitoring at least 18 subjects recently infected (?within 90 days?) with HIV. Combinations used included AZT/3TC with either indinavir, ritonavir or ritonavir-saquinavir, all at standard doses.

Results

Technicians could not detect HIV in subjects? blood samples. Yet samples of lymph nodes taken from the intestine contained traces of HIV. The CD4+ cell counts of the subjects increased while production of antibodies against HIV continued to fall. This research team suggests that these subjects may be recovering from HIV infection, perhaps because they received early and powerful anti-HIV treatment. Readers should note, however, that these subjects are not yet ?cured? of HIV infection.

REFERENCES:

1. Markowitz M. Recent HIV infection treated with AZT, 3TC and a potent protease inhibitor. Oral presentation LB8.

2. Cavert W, Staskus K, Zupancic M, et al. Quantitative in situ hybridization measurement of HIV-1 RNA clearance kinetics from lymphoid tissue cellular compartments during triple-drug therapy. Oral presentation LB9.

3. Wong JK, Gunthard HF, Havlir DV, et al. Reduction of HIV in blood and lymph nodes after potent antiretroviral therapy. Oral presentation LB10.

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