C-C chemokine receptor type 5 (CCR5) is chemokine receptor encoded by CCR5 gene located on the short arm of chromosome 3. Asthma is a chronic bronchial inflammatory disease of either allergic or idiopathic etiology. CCR5 Δ32 mutation is a common deletion of 32 nucleotides resulting in a frameshift and non-functional receptor. Its prevalence in European population ranges between 4 and 16% (frequency of homozygotes is 1%). The current study was aimed to assess frequency of this mutation in asthmatics and its possible impact on asthma. The study was conducted on 254 subjects (125 diagnosed with asthma and 129 in control group). Isolated DNA was analysed by PCR. Primers were designed to flank the deletion region, thus PCR products could be genotyped by mere agarose gel electrophoresis. The variant alleles were represented as bands of 270 and 238 pb lengths. The shorter amplification product was diagnostic for the presence of CCR5-delta32 deletion. Visualisation of agarose gel revealed non-mutated, mutated homozygotes as well as heterozygotes. In the control group there were 37 women and 92 men, whereas the study group comprised 87 women and 38 men. In the control group genotypes distribution was: 105 non-mutated homozygotes, 21 hetezygotes and 3 mutated homozygotes, whereas in the study group 103, 21 and 1 respectively. No statistically significant differences between these groups were detected. Prevalence of homozygotes was 1,6%. Current study revealed no association between CCR5 Δ32 mutation and incidence of asthma. It may be assumed that CCR5 Δ32 deletion is neutral as a risk factor of asthma.
Keywords: CCR5-delta32; asthma; chemokines.