Tumor necrosis factor and interleukin-10 gene promoter polymorphisms in Brazilian population and in Terena Indians

Frequency of TNFA, INFG, and IL10 Gene Polymorphisms and Their Association with Malaria Vivax and Genomic Ancestry

Polymorphisms in cytokine genes can alter the production of these proteins and consequently affect the immune response. The trihybrid heterogeneity of the Brazilian population is characterized as a condition for the use of ancestry informative markers. The objective of this study was to evaluate the frequency of -1031T>C, -308G>A and -238G>A TNFA, +874 A>T IFNG and -819C>T, and -592C>A IL10 gene polymorphisms and their association with malaria vivax and genomic ancestry. Samples from 90 vivax malaria-infected individuals and 51 noninfected individuals from northern Brazil were evaluated. Genotyping was carried out by using ASO-PCR or PCR/RFLP. The genomic ancestry of the individuals was classified using 48 insertion/deletion polymorphism biallelic markers. There were no differences in the proportions of African, European, and Native American ancestry between men and women. No significant association was observed for the allele and genotype frequencies of the 6 SNPs between malaria-infected and noninfected individuals. However, there was a trend toward decreasing the frequency of individuals carrying the TNF-308A allele with the increasing proportion of European ancestry. No ethnic-specific SNPs were identified, and there was no allelic or genotype association with susceptibility or resistance to vivax malaria. Understanding the genomic mechanisms by which ancestry influences this association is critical and requires further study.

Tumor necrosis factor haplotype diversity in Mestizo and native populations of Mexico

The so-called tumor necrosis factor (TNF) block includes the TNFA, lymphotoxin alpha and beta (LTA and LTB) genes with single-nucleotide polymorphisms (SNP) and microsatellites with an allele frequency that exhibits interpopulation variability. To date, no reports have included both SNPs and microsatellites at the TNF block to study Mestizo or Amerindian populations from Mexico. In this study, samples of five Mexican Mestizo populations (Durango, Guadalajara, Monterrey, Puebla, and Tierra Blanca) and four native-Mexican populations (North Lacandonians, South Lacandonians, Tepehuanos, and Yaquis) were genotyped for two SNPs (LTA+252A>G and TNFA-308G>A) and four microsatellites (TNFa, d, e, and f), to analyze the genetic substructure of the Mexican population. Allele and haplotype frequencies, linkage disequilibrium (LD), and interpopulation genetic relationships were calculated. There was significant LD along almost all of the TNF block but the lowest D' values were observed for the TNFf-TNFd pair. Mestizos showed higher allele and haplotype diversity than did natives. The genetic differentiation level was reduced among Mestizos; however, a slightly, but significant genetic substructure was observed between northern and southern Mexican Mestizos. Among the Amerindian populations, the genetic differentiation level was significantly elevated, particularly in both North and South Lacandonians. Furthermore, among Southern Lacandonians, inhabitants of Lacanja town were the most differentiated from all the Mexicans analyzed. The data presented here will serve as a reference for further population and epidemiological studies including these TNF polymorphisms in the Mexican population.

Association of estrogen receptor alpha and interleukin-10 gene polymorphisms with endometriosis in a Chinese population

OBJECTIVE

To determine whether polymorphisms of the estrogen receptor alpha (ERalpha) and interleukin-10 (IL-10) genes are associated with endometriosis in a Chinese population.

DESIGN

Association study.

SETTING

University hospital.

PATIENT(S)

Chinese women diagnosed with endometriosis by laparotomy or laparoscopy.

INTERVENTION(S)

Determination of polymorphisms of the ERalpha and IL-10 genes was performed by polymerase chain reaction and restriction fragment length polymorphism analysis in 214 affected women and 160 controls.

MAIN OUTCOME MEASURE(S)

Frequency and distribution of PvuII and XbaI polymorphisms of ERalpha and of BslI, SspI, and RsaI polymorphisms of IL-10.

RESULT(S)

There was no significant difference between the endometriosis patients and the control groups in the genotype frequency of ERalpha-PvuII and promoter of IL-10 gene polymorphisms in the position of -1082. However, the frequency of ERalpha-XbaI and -592 or -819C alleles of IL-10 in the endometriosis group was significantly higher than that of controls, and further analysis showed that the X allele of ERalpha-XbaI was associated with endometriosis.

CONCLUSION(S)

The X allele of ERalpha-XbaI and the -592 or -819 C allele of IL-10 are associated with endometriosis.

Epstein-Barr virus infection and single nucleotide polymorphisms in the promoter region of interleukin 10 gene in patients with Hodgkin lymphoma

CONTEXT

Hodgkin lymphoma is a neoplastic disease in which the immune system plays a major role in its pathogenesis. Interleukin 10 (IL-10), an immunosuppressive cytokine actively produced in patients with Hodgkin lymphomas, favors the survival of the Hodgkin/Reed-Sternberg cells. Individual variations in IL-10 levels may be due, in part, to the presence of single nucleotide polymorphisms in the IL10 gene promoter.

OBJECTIVE

To evaluate whether particular single nucleotide polymorphisms in the IL10 gene are found more frequently in Hodgkin lymphoma cases associated with Epstein-Barr virus infection.

DESIGN

The identification of single nucleotide polymorphisms at positions -1082 and -819/-592 in the IL10 gene was performed by polymerase chain reaction and restriction length fragment polymorphisms analysis in 65 cases of Hodgkin lymphoma and 50 cases of reactive benign follicular lymphoid hyperplasia (non-Hodgkin lymphoma control group).

RESULTS

The frequency of the genotype GG at position -1082 was found to be significantly higher in patients with Epstein-Barr virus-positive Hodgkin lymphoma compared with Epstein-Barr virus-negative cases.

CONCLUSIONS

The results suggest that the presence of specific single nucleotide polymorphisms in the IL10 gene, notably those associated with high IL-10 production, may play a role in the susceptibility to Epstein-Barr virus-positive Hodgkin lymphoma development.

Association of CD14, IL1B, IL6, IL10 and TNFA functional gene polymorphisms with symptomatic dental abscesses

AIM

To investigate in individuals with symptomatic dental abscesses the occurrence of functional polymorphisms within five genes involved with the immune response. The functional gene polymorphisms analysed were CD14 (-260 C/T), IL1B (+3954 C/T), IL6 (-174 G/C,), IL10 (-1082 G/A) and TNFA (-308 G/A).

METHODOLOGY

Genomic DNA obtained from oral swabs from individuals with symptomatic dental abscesses and asymptomatic inflammatory periapical lesions, without previous exacerbation, was submitted to restriction fragment length polymorphism (RFLP) analyses to determine each individual genotype. The chi-square and principal components analysis tests were used for statistical analysis.

RESULTS

A significant association was observed between the occurrence of the GG genotype or the G allele expression of the polymorphic locus-174 (G/C) of the IL6 gene, and the presence of the symptomatic dental abscesses in women and in individuals < or =35 years old. The principal components analysis suggested predominance of the symptomatic dental abscesses in individuals displaying: high-producer IL6 genotype; intermediate and high-producer IL1B genotypes and low-producer TNFA genotype.

CONCLUSIONS

The present study suggests that genetic factors are associated with susceptibility to develop symptomatic dental abscesses.

Impact of aboriginal ethnicity on HCV core-induced IL-10 synthesis: interaction with IL-10 gene polymorphisms

The host immune response is a critical determinant in viral infection outcome. Epidemiological studies indicate that North American indigenous peoples are more resistant to chronic HCV infection than other populations. Due to the prominence of IL-10 in chronic HCV infection, we investigated the genetic tendency to produce IL-10 in Caucasian (CA) and First Nation (FN) populations. Peripheral blood mononuclear cells (PBMCs) from CA subjects had a greater tendency to produce IL-10 defined by allelic polymorphisms, as well as genotypes and haplotypes, at the -1082, -819, and -592 positions of the IL-10 promoter. More importantly, we directly evaluated the influence of ethnicity on the ability of HCV core protein to induce IL-10 synthesis and found significantly higher IL-10 production by PBMCs isolated from healthy CA subjects compared with FN subjects. Further examination of the underlying relationship between core-induced IL-10 with the high, intermediate, and low phenotypes at the -1082, -819, and -592 position revealed that spontaneous and core-induced IL-10 synthesis tended to interact negatively with defined polymorphisms. This was particularly evident for the FN cohort, in which the relationship was strengthened by a stronger interaction of core with the low-IL-10-producing phenotypes. As with previous studies, concanavalin A induced IL-10 synthesis from the CA cohort positively associated with defined genetic phenotypes.

CONCLUSION

Cells from FN subjects had a reduced capacity to produce IL-10 in response to HCV core protein, suggesting that reduced susceptibility of FN immunity to virally induced IL-10 synthesis might contribute to epidemiological observations of enhanced HCV clearance.

Interleukin-10 gene promoter polymorphisms and their protein production in peritoneal fluid in patients with endometriosis

Although associations of interleukin-10 (IL-10) gene promoter polymorphisms and their protein production with endometriosis risk have been reported, the correlations remain controversial. The objective of this study was to determine IL-10 gene promoter polymorphisms at -1082, -819 and -592 sites and their protein production in peritoneal fluid (PF) in patients with and without endometriosis. IL-10 gene promoter polymorphisms at -1082 site were detected by amplification refractory mutation system (ARMS)-PCR and that at -819 and -592 sites was genotyped by restriction fragment length polymorphism (RFLP)-PCR. Protein levels of IL-10 in PF were measured by enzyme-linked immunosorbent assay (ELISA). There were no significant differences in the genotype and allele frequencies of IL-10 gene promoter polymorphisms at position -1082 between the endometriosis and the control groups. However, the frequency of -819 or -592 C alleles was significantly increased in patients with endometriosis compared with controls. The protein levels of IL-10 in PF were statistically higher in the endometriosis group than in the control group. Moreover, the polymorphisms at -1082, -819 and -592 sites were associated with protein levels of IL-10 in PF in the endometriosis group while in the control group only the polymorphisms at position -1082 correlated with protein levels. Increased frequency of -819 or -592 C allele and increased protein production of IL-10 in PF in patients with endometriosis compared with controls and correlations of polymorphisms at -819 and -592 sites with protein levels of IL-10 in PF in patients with endometriosis may suggest that polymorphisms at -819 and -592 sites and their protein production are associated with endometriosis risk.