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Subacute sclerosing panencephalitis (SSPE) is a progressive inflammatory and degenerative disorder of the central nervous system. The measles virus (MV) and host and environmental factors are involved in the development of SSPE , but the precise mechanism by which the MV causes SSPE is still unknown. Studies have indicated that in SSPE patients, specific polymorphisms of certain genes are most likely involved in impairing the host's ability to eradicate the MV. The purpose of our study was to elucidate the role of polymorphisms in the genes encoding interleukin (IL)-2, IL-18, and tumor necrosis factor alpha (TNF-α) in the development of SSPE. Using the polymerase chain reaction with sequence-specific primers, the single-nucleotide polymorphisms (SNPs) of the promoter regions of IL-2 (−330), TNF-α (−308), and IL-18 (−137 and −607) were studied in 54 patients with SSPE and 72 healthy controls. The frequency of SSPE patients with the AA genotype of IL-18 at position −607 was significantly higher than the frequency of those with the CC genotype ( p<0.001, odds ratio [OR]: 5.76), and a significantly higher proportion of patients had the C allele at −137 compared with the controls ( p=0.002, OR: 2.72). In a haplotype analysis of two SNPs in the IL-18 gene, the frequency of the CA haplotype was significantly higher in SSPE patients ( p<0.001, OR: 3.99) than in the controls. The IL-2 (−330) and TNF-α (−308) polymorphisms revealed no significant differences. In conclusion, these data suggest that the IL-18 gene polymorphisms at position −607 and −137 might be genetic risk factors for the SSPE disease. Two SNPs of the IL-18 gene were higher in SSPE patients than in controls. There was no difference between patients and controls in IL-2 or TNF-α polymorphisms in SSPE frequency. [ABSTRACT FROM AUTHOR]

Nasopharyngeal carcinoma (NPC) is one of the most common cancers in southern China. In addition to environmental factors such as Epstein-Barr virus infection and chemical carcinogen exposure, genetic susceptibility has been reported to play a key role in the development of this disease. Interleukin-2 (IL-2) is an immunoregulatory cytokine produced by T cells and plays an important role in antitumor immunity. Variations in the DNA sequence of the IL-2 gene may lead to altered cytokine production and/or activity, and thus modulate an individual's susceptibility to NPC. To test this hypothesis, we investigated whether IL-2 gene polymorphisms and its serum levels are associated with NPC in a Chinese population. We analyzed single-nucleotide polymorphisms of IL-2 gene −330 T/G and +114 T/G in 180 patients with NPC and 200 age- and sex-matched controls, using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing methods, and serum IL-2 levels were measured by enzyme-linked immunosorbent assay. Serum IL-2 levels were decreased in patients with NPC compared with controls ( p < 0.01). There were significant differences in the genotype and allele frequencies of IL-2 gene −330 T/G polymorphism between the group of patients with NPC and the control group ( p < 0.05). Moreover, genotypes carrying the IL-2 −330 G variant allele were associated with decreased serum IL-2 levels compared with the homozygous wild-type genotype in patients with NPC. Carrying the IL-2 −330 G variant allele was associated with a decreased ability to produce IL-2, which may contribute to NPC susceptibility. [ABSTRACT FROM AUTHOR]