FOXP3/Scurfin, a member of forkhead/winged-helix proteins, is involved in the regulation of T-cell activation, and essential for normal immune homeostasis. The FOXP3/Scurfin gene is located on chromosome Xp11.23, which includes one of the type 1 diabetes susceptible loci. Therefore, we investigated whether the human FOXP3/Scurfin gene might be a new candidate gene for type 1 diabetes. We first screened the human FOXP3/Scurfin gene for microsatellite and single nucleotide polymorphisms. Next, we performed an association study between the FOXP3/Scurfin gene and type 1 diabetes. Then, the evaluation of promoter/enhancer activity of the intron with (GT)(n) polymorphism was performed by dual luciferase reporter assay. We demonstrated two regions contained microsatellite polymorphisms; one was (GT)(n), located on intron zero and the other (TC)(n) on intron 5, which were under linkage-disequilibrium. The (GT)(15) allele showed a significantly higher frequency in patients with type 1 diabetes than in controls (43.1% vs 32.6%, P=0.0027). The genotype frequencies of (GT)(15)/(GT)(15) in female patients and of (GT)(15) in male patients tended to be higher than those in female ( P=0.064) and male ( P=0.061) controls, respectively. A significant difference in the enhancer activity between (GT)(15) and (GT)(16) dinucleotide repeats was detected. In conclusion, the FOXP3/Scurfin gene appears to confer a significant susceptibility to type 1 diabetes in the Japanese population.

MxA promoter -88 G/T SNP may confer host genetic susceptibility to SSPE in Japanese individuals. The finding that homozygotes of the MxA -88T allele with a high MxA-producing capability were more frequently seen in SSPE patients suggests that the MxA protein promotes the establishment of persistent MV infection of neural cells.

To our knowledge, this study is the first to demonstrate the possibility that the IL-4 promoter gene -589 T gene polymorphism with increased IL-4 synthesis in combination with IRF-1 allele 1 confers host genetic susceptibility to SSPE in Japanese subjects.

Natural resistance-associated macrophage protein 1 (NRAMP1) has an important role in regulating macrophage functions that affect innate resistance as well as immune responses. We analyzed the microsatellite polymorphism in the promoter region of the human NRAMP1 gene in 206 type 1 diabetes patients and 200 normal children to determine whether this polymorphism might be associated with type 1 diabetes in the Japanese population. The frequency of allele 2 (180 bp) of the promoter microsatellite polymorphism of the NRAMP1gene was slightly lower in the early-onset population (2-10 years of age) of type 1 diabetes patients than in controls, although the difference did not reach statistical significance. The association study of the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene, located near the NRAMP1 gene, and type 1 diabetes showed that the CTLA-4 gene significantly contributed to the development of type 1 diabetes, whereas NRAMP1 had an additional effect on the onset of type 1 diabetes in the young population.

Interleukin-12 (IL-12) secreted from macrophages or dendritic cells plays an important role in the protection against intracellular pathogens as well as the developmental commitment of T helper 1 cells. IL-12 exerts its biological effects through binding to specific IL-12 receptors (IL-12Rs) termed IL-12Rbeta1 and IL 12Rbeta2. In this paper, we performed association studies between the three reported polymorphisms (Q214R, M365T and G378R) of the IL-12Rbeta1 gene or the newly identified polymorphisms (P238L, IVS9 -7G>A, IVS13 -121G>A, A643T, P779P and c.3283T>G) of the IL-12Rbeta2 gene, and the development of type 1 diabetes or atopic asthma as representative Th1- and Th2- dominant diseases, respectively. The association study of each polymorphism of the IL-12Rbeta1 or IL-12Rbeta2 gene and type 1 diabetes or asthma showed that these IL-12R genes did not contribute to the development of type 1 diabetes or asthma in the Japanese population. Further analysis in individuals with susceptibility to intracellular pathogens may elucidate the importance of the IL-12R genes.