Some people remain uninfected by HIV despite frequent exposure. In 1996 a mutation (delta 32) in the CCR5 co-receptor for HIV was found to protect from the infection in homozygotes, i.e. people in whom the CCR5 gene copies on both chromosomes bear the mutation. About 1% of Caucasians are homozygous for the mutation, while about 10% of Europeans are heterozygous (only one gene copy bears the mutation). Heterozygotes can be infected by HIV, but contradictory results had been reported on the possible influence of the mutation on disease progression in adult cohorts. Up to now no study had been perfomed in children.
INSERM (The French National Institute of Health and Medical Research) and hospital research teams led by Marie-Jeanne Mayaux (INSERM Unit 292, Paris), Stéphane Blanche (INSERM Unit 429, Necker Hospital, Paris), Micheline Misrahi, Molecular Biology Laboratory, and Jean-François Delfraissy at Bicetre Hospital, have now reported in the January 28 issue of the Journal of the American Medical Association that heterozygosity for the delta 32 mutation significantly slows HIV disease progression in children born to seropositive mothers. Their work was supported by the French AIDS research organization ANRS.
The main problems encountered when investigating the influence of delta 32 heterozygosity on HIV disease progression in adults are that it is usually difficult to determine the precise date of infection and to rule out multiple infections. The French researchers examined maternofetal HIV-1 transmission in children enrolled in the French Pediatric Cohort. The timing of the infection is known in children and other modes of infection can be ruled out.
512 children born to HIV-1-seropositive mothers of European origin1 were
studied 2. The delta 32 mutation was screened in both infected (n=276) and
uninfected children (n=236). The proportion of heterozygotes was found to be
similar in the two groups. This showed that, like
Contact: Marie-Jeanne Mayaux
French National Institute for Health and Medical Research (INSERM)