Universidade Federal do Triângulo Mineiro, Uberaba, MG, Brasil.
Rev Soc Bras Med Trop. 2012 Jul-Aug;45(4):496-9. doi: 10.1590/s0037-86822012005000001. Epub 2012 Jul 5.
The cytolysis mediated by granules is one of the most important effector functions of cytotoxic T lymphocytes and natural killer cells. Recently, three single nucleotide polymorphisms (SNPs) were identified at exons 2, 3, and 5 of the granzyme B gene, resulting in a haplotype in which three amino acids of mature protein Q48P88Y245 are changed to R48A88H245, which leads to loss of cytotoxic activity of the protein. In this study, we evaluated the frequency of these polymorphisms in Brazilian populations.
We evaluated the frequency of these polymorphisms in Brazilian ethnic groups (white, Afro-Brazilian, and Asian) by sequencing these regions.
The allelic and genotypic frequencies of SNP 2364A/G at exon 2 in Afro-Brazilian individuals (42.3% and 17.3%) were significantly higher when compared with those in whites and Asians (p < 0.0001 and p = 0.0007, respectively). The polymorphisms 2933C/G and 4243C/T also were more frequent in Afro-Brazilians but without any significant difference regarding the other groups. The Afro-Brazilian group presented greater diversity of haplotypes, and the RAH haplotype seemed to be more frequent in this group (25%), followed by the whites (20.7%) and by the Asians (11.9%), similar to the frequency presented in the literature.
There is a higher frequency of polymorphisms in Afro-Brazilians, and the RAH haplotype was more frequent in these individuals. We believe that further studies should aim to investigate the correlation of this haplotype with diseases related to immunity mediated by cytotoxic lymphocytes, and if this correlation is confirmed, novel treatment strategies might be elaborated.
颗粒介导的细胞溶解是细胞毒性 T 淋巴细胞和自然杀伤细胞的最重要效应功能之一。最近，在颗粒酶 B 基因的exon 2、3 和 5 中发现了三个单核苷酸多态性（SNP），导致成熟蛋白 Q48P88Y245 的三个氨基酸发生改变，即 R48A88H245，导致蛋白质的细胞毒性活性丧失。在这项研究中，我们评估了这些多态性在巴西人群中的频率。
我们通过测序这些区域来评估巴西种族（白种人、非裔巴西人和亚洲人）中这些多态性的频率。
在非裔巴西人个体中，exon 2 上 SNP 2364A/G 的等位基因和基因型频率（42.3%和 17.3%）明显高于白人和亚洲人（p < 0.0001 和 p = 0.0007）。2933C/G 和 4243C/T 多态性在非裔巴西人中也更为常见，但与其他组相比没有任何显著差异。非裔巴西人群的单倍型多样性更大，RAH 单倍型在该人群中似乎更为常见（25%），其次是白人（20.7%）和亚洲人（11.9%），与文献中报道的频率相似。
非裔巴西人中存在更高频率的多态性，并且在这些个体中 RAH 单倍型更为常见。我们认为，进一步的研究应该旨在调查这种单倍型与细胞毒性淋巴细胞介导的免疫相关疾病的相关性，如果这种相关性得到证实，可能会制定新的治疗策略。
