TreatmentUpdate59; Vol 7, No. 5 - May 1995
Sean Hosein

Researchers in France used data collected on 499 subjects to try and find out which subjects would develop the life-threatening brain infection toxo. At the time these subjects entered the study none had toxo. The average CD4+ cell count was 70 cells. About 60% of subjects had less than 50 CD4+ cells. Technicians tested the blood samples from 410 subjects to find antibodies against toxo. A total of 298 had anti- toxo antibodies. When subjects entered the study 80 received Bactrim/Septra as preventative therapy against PCP/toxo; '34 received pyrimethamine'; 19 received dapsone; '11 received [Fansidar(R)]' and 1 received pyrimethamine- sulphadiazine.

* RESULT-SURVIVAL

Researchers monitored subjects for an average of 1 year during which 16% (83) subjects developed toxo; 75 had it as a brain infection, 7 had the infection in their eyes and 1 developed toxo in the lungs. Altogether, 67% of the 499 subjects died while in this study.

* CD4+ CELL COUNTS

In this study subjects with CD4+ cell counts of less than 100 cells were at high risk for developing toxo. This link between low CD4+ cell counts and toxo was statistically significant; that is, not likely due to chance alone. When subjects developed toxo they had an average CD4+ cell count of 31 cells. About 18% of subjects who had less than 100 CD4+ cells when they entered the study developed toxo. By contrast, only 9% of subjects who entered the study with CD4+ cell counts of at least 100 cells developed toxo.

* ANTIBODIES

Subjects who had anti-toxo antibodies in their blood were very likely to develop toxo while in the study. Over a period of 1 year 21% of these subjects developed toxo compared to none of the subjects without these antibodies. This difference was statistically significant.

* BACTRIM/SEPTRA REDUCES THE RISK

"Three of 80 [subjects] receiving Bactrim/Septra and 72 of 419 subjects not receiving Bactrim/Septra developed toxo in their brains". This was statistically significant. "One of 34 [subjects] receiving pyrimethamine and 74 of 465 subjects who [did not use] pyrimethamine when they entered the study developed toxo." This difference was also statistically significant.

* CHECKING THE RISKS

There were 149 subjects with less than 100 CD4+ cells who had anti-toxo antibodies but did not receive antibiotics. Forty-eight (32%) of these subjects developed toxo in their brains. Of the 74 subjects with less than 100 CD4+ cells who had antibodies against toxo but did receive antibiotics, 5 (7%) developed toxo in their brain. This difference was also statistically significant.

* SURVIVAL

All subjects who developed toxo died at some point during the study. Taking antibiotics did not seem to affect survival. When researchers adjusted their calculations to take into account different CD4+ cell counts, again there was no difference in survival.

REFERENCES:

1. Oksenhendler E, Charreau I, Tournerie C, et al. Toxoplasma gondii infection in advanced HIV infection. AIDS 1994;8:483-487.

950501
CATE5907

Copyright © 1995 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284  http://www.catie.ca