Distribution of 32 alelle of the CCR5 gene in the population of Poland.

The chemokine receptor CCR5 constitutes a major co-receptor for the R5 strains of HIV-1, and a mutant allele of the CCR5 gene, especially in the homozygous form delta32/delta32, confers resistance against infection by the virus. The frequency of the delta32 allele was determined in blood donors from 16 provinces, covering the entire territory of Poland. Among 861 individuals 182 (21.1%) were carriers of the mutated allele: 7 of them (0.8 %) were homozygotes delta32/delta32, and 175 (20.3%) were heterozygotes +/delta32, resulting in a 10.9% frequency of the delta32 allele. The highest frequencies of the mutated allele were found in the eastern and western provinces, and the lowest frequencies of the delta32 allele were detected in the provinces in the center of the country. This pattern of distribution may reflect the migration of the population from the eastern territories of Poland to the western part of the country after World War II.