12th International AIDS Conference Geneva, Switzerland - June 28-July 3, 1998

Int Conf AIDS 1998 Jun 28-Jul 3; 12:260 (abstract no. 11/21107)

Philpott S, Burger H, Charbonneau T, Grimson R, Nachman S, Kovacs A, Weiser B
Wadsworth Center, NYS Dept of Health, Albany 12208, USA.

BACKGROUND: Recent studies have identified a human gene which plays a role in susceptibility to HIV-1 infection. The gene codes for CCR-5, the co-receptor for macrophage tropic strains of HIV-1, and a homozygous deletion in this gene confers a high degree of natural resistance to sexual and parenteral transmission of HIV-1. The frequency of the mutant gene varies among different racial populations.

METHODS: To determine whether CCR-5 plays a role in mother-to-child transmission of HIV-1, we studied the CCR-5 genotype of 552 children born to HIV-1 infected mothers in the United States and determined the HIV-1 infection status of the children. Genotypes were determined by PCR and restriction analysis.

RESULTS: 13% of the children were Caucasian, 30% were Latino, and 56% were African American, and 1% were of mixed or other ethnic ancestry, a distribution which reflects the ethnic make-up of infected women in the US. Approximately 27% of the children in each ethnic group were HIV-1-infected. The frequency of the mutant allele in the three main racial groups was 0.08 in Caucasians and 0.02 in both Latinos and African Americans. Two uninfected Caucasians (3.77%) and 2 uninfected Latinos (1.68%), but no African Americans, were homozygous for the mutation. No HIV-1-infected children were homozygous for the mutation. In Latinos and Caucasians the number of uninfected children who were homozygous for the mutation was significantly greater than that predicted by the Hardy-Weinburg equilibrium (p = 0.001 for Latinos and p = 0.04 for Caucasians). This study suggests that the homozygous deleted CCR-5 genotype may confer a high degree of protection from mother-to-child transmission of HIV-1. These data also suggest that sexual, parenteral, and vertical transmission involve processes that utilize CCR-5 as a coreceptor for primary HIV-1 infection. Therefore, blocking the CCR-5 receptor may provide an additional strategy to prevent mother-to-child transmission of HIV-1.

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