C. Goldsmith / CDCAids virus: more aggressive varieties reduce immunity at an earlier stageC. Goldsmith / CDC
The presence of more virulent varieties of HIV-1, which normally only appear in the most advanced stages of Aids, may now be more frequent among patients who have recently become infected with the virus in the city of São Paulo and might be why the disease progresses faster in these individuals. According to a study by researchers from the Federal University of São Paulo (Unifesp) and the University of São Paulo (USP), people who have recently been contaminated with strains of the virus that bind with the CXCR4 receptor of T lymphocytes of the CD4 type, one of the organism’s important defense cells, tend to suffer early on from a greater decline in the immune system than those who have been infected by other forms of the virus (Plos One, January 26). The study monitored 72 individuals in the São Paulo state capital for up to 78 weeks after they had been informed that they were HIV positive and observed that 12 patients had the most pathogenic form of HIV-1. Their defense cell count was lower than desirable more often, statistically, than among the other individuals, whose virus binds with CCR5, the other chemical receptor of T-lymphocytes of the CD4 types. The scientists cannot say for sure whether the precocious appearance of more pathogenic strains of the HIV-1 is the cause or the consequence of the drop in patients’ immune level, but there are significant indications that the former hypothesis makes more sense.
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