del Rincón I, Escalante A
The University of Texas Health Science Center at San Antonio, 78284, USA.
Arthritis Rheum. 1999 Jul;42(7):1329-38. doi: 10.1002/1529-0131(199907)42:7<1329::AID-ANR5>3.0.CO;2-1.
To study the genetics (HLA-DRB1 allele associations) of rheumatoid arthritis (RA) susceptibility and severity among Mexican Americans, an important, but understudied, US population.
HLA-DRB1 alleles were compared between 141 Mexican American patients with RA and 54 unrelated Mexican Americans without RA, and the association of these alleles with articular deformities and disability was examined. HLA-DRB1 alleles were typed using polymerase chain reaction-sequence-specific primer amplification and were classified according to the 1996 World Health Organization nomenclature.
Of the 141 patients, 105 (74%) had at least 1 copy of the shared epitope (SE) sequence, compared with 29 (54%) of the 54 controls (P = 0.007). A significant gene-dose effect was observed, with 31 patients (22%) being homozygous for the SE compared with 1 (2%) of the controls (P = 0.004). In terms of disease severity, only 3% of RA patients who were "null" for the SE were outliers in the rate of development of articular deformities, compared with 10% of heterozygotes and 27% of homozygotes (P = 0.002). Patients who were DRB1*08 positive had significantly fewer deformities per year of disease and a slower rate of development of disability than did patients with other DRB1 alleles.
HLA-DRB1 alleles containing the SE are associated with susceptibility to RA in Mexican Americans, and may also be associated with a more rapid development of articular deformities and disability. HLA-DRB1*08 appears to have a protective influence on RA susceptibility and disease severity in Mexican Americans.
研究墨西哥裔美国人（美国一个重要但研究不足的人群）类风湿关节炎（RA）易感性和严重程度的遗传学（HLA - DRB1等位基因关联）。
比较141例患有RA的墨西哥裔美国患者和54例无RA的无关墨西哥裔美国人的HLA - DRB1等位基因，并检查这些等位基因与关节畸形和残疾的关联。使用聚合酶链反应 - 序列特异性引物扩增对HLA - DRB1等位基因进行分型，并根据1996年世界卫生组织命名法进行分类。
141例患者中，105例（74%）至少有1份共享表位（SE）序列拷贝，而54例对照中有29例（54%）有该序列（P = 0.007）。观察到显著的基因剂量效应，31例患者（22%）为SE纯合子，而对照中只有1例（2%）为SE纯合子（P = 0.004）。就疾病严重程度而言，SE为“无”的RA患者中只有3%在关节畸形发展速率方面属于异常值，相比之下，杂合子为10%，纯合子为27%（P = 0.002）。与其他DRB1等位基因的患者相比，DRB1*08阳性的患者每年的畸形明显更少，残疾发展速率也更慢。
含有SE的HLA - DRB1等位基因与墨西哥裔美国人对RA的易感性相关，也可能与关节畸形和残疾的更快发展相关。HLA - DRB1*08似乎对墨西哥裔美国人的RA易感性和疾病严重程度有保护作用。
