Distribution of Genetic Polymorphism in the CCR5 among Caucasians, Asians and Africans: A Systematic Review and Meta-Analysis

Abstract

Background: Cysteine-Cysteine Chemokine Receptor 5 (CCR5), also referred to as CD195, is a component of the mammalian cell membrane and is receptor for chemokines that are activated during cell damage and inflammations. This receptor is coded by a gene located in the human chromosome 3. A Mutation on this CCR5 through deletion of 32 base pairs results into a non-destructive gene CCR5Δ32. It enables protection against HIV infection to its homozygous carriers and slows progression of the disease to heterozygous carriers. Objective: To systematically review and establish global distribution of CCR5Δ32 allele in HIV-1 infected individuals over the history of the epidemic and compare regions inhabited by Caucasians, Asians and Africans. Methodology: This meta-analysis comprised of published papers with over 10,000 individuals from whom CCR5-Delta 32 allele was successfully genotyped and recorded. The study review period was from 1984 to 2017. The search targeted online sources such as Hinari specifically PubMed Central, Google scholar, Science Direct, Research4Life, National Center for Biotechnology Information (NCBI), OVID databases, AIDS Journal and Google. The searches were not limited to a particular publication language or study design but excluded letters of correspondence and conference presentations. Search strategy using key words from a combination of Medical Subject Heading (MeSH) and free text including terms related to CCR5, CCR5Δ32 and HIV were performed in Medical Literature Analysis and Retrieval System Online (MEDLINE) through Ovid Open Access. Additional studies were identified by perusing the reference list of relevant and included articles. The review considered studies conducted among general population, both HIV positive and HIV negative individuals, exposed seronegatives (ESN), exposed seropositives (ESP) and highly exposed seronegatives (HESN) and resultant data

Prevalence of CCR5delta32 in Northeastern Iran

“…Moreover, Iran has a key role in linking different populations in the Silk Road, between Asia and Europe [33]. Ongadi et al in a systematic review analysis revealed that the CCR5Δ32 allele frequency is at 93% in Caucasians and 7% is in the other populations [34]. The frequencies of this allele in some European countries were demonstrated that is moderate such as Italy (3%), Cyprus (2.8%) and Greece (2.4%), but a high frequency (9.21%) was reported in southwest Germany [35, 36].…”