Abstract. The CCR5 chemokine receptor has been implicated in the pathogenesis of multiple sclerosis (MS). This research was carried out to investigate the association between the CCR5-Δ32 deletion in 124 patients with MS from Southern Brazil. Ninety-eight (79.0%) patients presented with relapsingremitting MS (RR-MS), 17 (13.7%) secondary progressive MS (SP-MS), 8 (6.5%) primary progressive MS (PP-MS) and one (0.8%) clinically isolated syndrome (CIS). The control group consisted of 127 healthy blood donors from the same geographic region. The disease severity was assessed clinically using the Expanded Disability Status Scale (EDSS). Genomic DNA was extracted from peripheral blood cells and the genetic polymorphism was evaluated by polymerase chain reaction. Of the MS patients, 85 (68.5%) were females (p=0.0093). The CCR5-Δ32 frequency among the controls was 5.5%, and did not differ from that observed among the MS patients (4.8%) (p=0.7337). The mean (±SD) age at disease onset among the carriers and non-carriers of the CCR5-Δ32 allele was 31.7 (±11.1) and 36.6 (±12.0) years, respectively (p=0.1312). The duration (±SD) of the disease was 11.2 (±12.9) and 7.7 (± 5.6) years among the CCR5-Δ32 heterozygous, and CCR5 wild type, respectively (p=0.396). The mean (±SD) EDSS among the MS patients carriers and non-carriers of the CCR5-Δ32 allele was 2.4±1.2 and 2.67±2.2, respectively (p=0.9796). The MRI findings in MS patients with the CCR5-Δ32 genotype exhibited lower positive gadolinium enhancing-imaging (p=0.0013) and lower brain atrophy (p=0.1333) than MS patients with the CCR5 wild-type genotype. Despite that the differences were not significant, the results suggested that the disease onset and progression to disability may be prolonged in MS carriers of CCR5-Δ32, and CCR5-Δ32 could be considered a favorable prognostic biomarker of MS. Further studies comprising larger numbers of individuals carrying non-wild-type haplotypes are needed to determine CCR5-Δ32 involvement in the specific process of MS pathology and pathogenesis.

Abstract. Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system that causes neurological disorders in young adults. Previous studies in various populations highlighted an association between the Hla-drB1 * 15 allele and MS. This study investigated the association between Hla-drB1 * 15 and other Hla-drB1 alleles and MS in a Brazilian caucasian population sample from londrina, Southern Brazil. Hla-drB1 alleles were analyzed by polymerase chain reaction with specific sequence oligonucleotide primers in 119 MS patients and in 305 healthy blood donors as a control. among the MS patients, 89 (75.0%) presented with relapsing remitting MS, 24 (20.0%) with secondary progressive MS and 6 (5.0%) with primary progressive MS. The frequency of the Hla-drB1 * 15 allele observed in the MS Brazilian patients was similar to findings reported in previous studies carried out in populations worldwide. However, the results showed a higher frequency of the Hla-drB1 * 15 allele in the MS patients compared to the controls, with a relative frequency of 0.1050 (10.50%) and 0.0443 (4.4%), respectively (or=2.53; 95% ci 1.43-4.46; p=0.0009). a protector allele was also detected. The frequency of the Hla-drB1 * 11 allele was reduced in the MS patients compared to the controls, with a relative frequency of 0.1345 (13.4%) and 0.1869 (18.7%), respectively (or=0.67; 95% ci 0.44-1.03; p=0.0692). The results demonstrated that the Hla-drB1 * 15 allele in heterozygosity is positively associated with MS (p=0.0079), and may be considered a genetic marker of susceptibility to the disease. a negative association between the Hla-drB1 * 11 allele in homozygosity and MS was also verified (p=0.0418); this allele may be considered a genetic marker of resistance to MS in the Brazilian population.

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