HLA class II genotypes in Mexican Mestizos with familial and nonfamilial multiple sclerosis.

Predisposition to MS is associated with the HLA-DR2 antigen in white patients. The authors investigated the genetic factors behind the increasing frequency of MS in the Mexican population. HLA-DR and DQ were analyzed in 17 patients with MS, 15 of their first-degree relatives, and 99 healthy ethnically matched controls. DR2 or DR3 was found in 15 of 17 patients. In controls, both alleles had frequencies less than 0.05. MS in Mexican patients was associated with HLA-DR2 and DR3.

Genetic features of Mexican women predisposing to cancer of the uterine cervix.

Cervical carcinoma is the most common neoplasia in Mexican women. Previous studies report association of this neoplasia with the major histocompatibility complex (MHC) antigens in Caucasians. In the present study, we compared antigen frequencies of class I and class II MHC phenotypes in patients and ethnically matched healthy controls. Patients had significantly increased frequencies of HLA-A2 (PC = .000003) and HLA-DR5 (PC = .01) as compared with healthy controls. Conversely, we found a significant decrease of HLA-DR6 (PC = .01), HLA-DR2 (PC = .0005) and HLA-DR1 (PC = .0009) as compared with healthy controls. These results confirm some previous studies on HLA-associations with cervical carcinoma and reinforce the theory of independent mechanisms of MHC class I and class II genes in the etiopathogenesis of this disease.

Intron 2 and exon 3 sequences may be involved in the susceptibility to develop Takayasu arteritis.

We studied Major Histocompatibility Complex (MHC) Class I and Class II genes in seven Mexican Mestizo patients with Takayasu arteritis. Takayasu arteritis is an uncommon condition in Mexican Mestizo, however, previous studies report association of the disease in this population with Human Leukocyte Antigen (HLA)-B39 and HLA-DRB1*1301. The results in the present study show that the haplotypes of the Mexican Mestizo patients with Takayasu arteritis are very heterogeneous, even when the disease is much more rare in Mexico than in Japan. The sequence analysis of HLA-B39 shows that Mexican patients exhibit the HLA-B*39061 and HLA-B*39062 subtypes. These subtypes are more common in Mexico than in Japan, where the predominant subtype is HLA-B*3901. Interestingly, HLA-B*39061 and B-39062 share the 3' end of intron 2 and the 5' end of exon 3 with HLA-B*5101 and B*52012, alleles associated to Takayasu arteritis in Japanese. This fact suggests that Takayasu arteritis patients may share a specific sequence rather than a specific allele, even when the gene involved in the susceptibility to develop Takayasu arteritis may be a neighboring gene located between the genes related at present time with the disease, i.e. a gene located between MHC Class I and Class II regions.