Settin et al. (2007) studied 50 children with chronic RHD (29 males and 21 females) from the Nile Delta region with rheumatic heart disease (RHD); in addition to 98 healthy unrelated controls. Cases were further classified on the basis of echocardiographic findings into those with only mitral valve disease (MVD) or multivalvular lesions (MVLs) and also as mild, moderate, or severe valve lesions. For all cases and controls, single nucleotide polymorphisms (SNPs) in the promoter regions of cytokine genes tumor necrosis factor (TNF)-alpha(-308 )G/A, interleukin (IL)-10(-1082 )G/A, and IL-6(-174 )G/C as well as a variable number of tandem repeats (VNTRs) in intron 2 of the IL-1Ra gene were analyzed. All cases showed a significantly higher frequency of homozygous genotypes of TNF-alpha(-308 )A/A [odds ratio (OR) = 5.7, p < 0.001], IL-10(-1082) A/A (OR = 3.1, p < 0.05), IL-10(-1082) G/G (OR = 5.2, p < 0.05), and IL-1Ra A1/A1 (OR = 2.2, p < 0.05). Cases with MVD showed higher frequencies of genotypes TNF-alpha(-308 )A/A, G/G; IL-10(-1082) G/G; and IL-1Ra(VNTR) A1/A1 (p < 0.05). Cases with MVL showed a significantly higher frequency of homozygous A/A genotype of both TNF-alpha(-308 )(OR = 10.6, p < 0.05) and IL-10(-1082) (OR = 5.2, p < 0.05). The same was observed for cases with severe valve lesions. On the other hand, all studied groups showed significantly lower frequency of heterozygous genotypes of TNF-alpha(-308 )G/A, IL-10(-1082) G/A, and IL-1Ra(VNTR) A1/A2.

Masri et al. 2003 studied the impact of cytokine gene polymorphisms on graft acceptance in a cohort of 163 transplant patients and their donors. Expression rates of gene polymorphisms in graft recipients-donors cohort were determined using sequence-specific polymerase (SSP) PCR primers corresponding to high, intermediate, or low producers of TNF-α, TGF-β, IL-10, IL-6, and interferon. The results were compared with a control group consisting of normal healthy Lebanese individuals. TGF-β production was observed to be high (81.6%) in patients with biopsy-proven graph rejection compared to patients with normal graph function. Patients with high TGF-β, low IL-10, and low interferon were found to have the highest CMV infection rates. Similar patterns were observed in patients with cyclosporine toxicity. Masri et al. concluded that their study indicated association of TGF-β with cyclosporine toxicity, chronic rejection, and immunosuppression.

Meenagh et al. (2002) used PCR-SSOP method to detect the frequencies of IL10 polymorphisms in different populations, in order to identify global allelic variation and to establish a databank for future studies. Along with the other populations, 80 healthy Omani blood and bone marrow donors were also used in the study. Genomic DNA from these subjects was PCR amplified and resolved. Oligonucleotide probes were used to identify the regions of SNPs by subjecting the PCR products to hybridization with digoxigenin-labeled probes and chemiluminescent detection procedures. Chi-squared test was used to compare allele and genotype frequencies between the populations studied. The IL10 gene was found to have three SNPs (G1082A, C819T, and C592A) within its promoter region. Among the Omani population, in the G1082A polymorphism, the A allele predominated (as in the Zulu, Singapore Chinese and Mexican populations) with a frequency of 65.2%, and this was reflected on the genotype with predominance of AA genotype (44.3%), followed by GA (41.8%) and GG (13.9%). On the other hand, the IL10 -819 and IL10 -592 allele and genotype frequencies were identical among the Omani population (as well as among each studied population). The C and T alleles of IL10-819 SNP had identical frequencies to those of the C and A alleles of IL10-592 polymorphism, respectively (75.3% and 24.7%, respectively), and this yielded similar genotypes of CC, CT, and TT of IL10-819 SNP to CC, CA, and AA genotypes of IL10-592 polymorphism (57%, 36.7% and 6.3%, respectively). Three IL10 haplotypes were identified (GCC, ACC, and ATA), and their which frequencies were found to differ significantly between the populations studied. In the Omani population, IL10 low producer haplotype (ACC) predominated with a frequency of 40.5%, while the haplotype associated with higher production of IL10 (GCC) had a frequency of 34.8%.

Abanmi et al. (2008) investigated the association between IL-10 polymorphisms and vitiligo in Saudi patients. The study included 83 Saudi vitiligo patients (40 males, 43 females) and 101 healthy controls. PCR was used to detect the presence of three SNPs in the IL-10 gene in this population; G(-1082)A, C(-592)A, and C(-819)T. The results showed that the -1802GG, -819 CC, and -592CC genotypes were susceptible to vitiligo, while -1082GA, -819CT, and -592CA offered protection against the condition. Abanmi et al. (2008) surmised that these findings did not support the inflammatory theory of vitiligo.