Association between the IL1B (-511), IL1B (+3954), IL1RN (VNTR) polymorphisms and Graves' disease risk: a meta-analysis of 11 case-control studies

Programmed Cell Death in the Small Intestine: Implications for the Pathogenesis of Celiac Disease

The small intestine has a high rate of cell turnover under homeostatic conditions, and this increases further in response to infection or damage. Epithelial cells mostly die by apoptosis, but recent studies indicate that this may also involve pro-inflammatory pathways of programmed cell death, such as pyroptosis and necroptosis. Celiac disease (CD), the most prevalent immune-based enteropathy, is caused by loss of oral tolerance to peptides derived from wheat, rye, and barley in genetically predisposed individuals. Although cytotoxic cells and gluten-specific CD4⁺ Th1 cells are the central players in the pathology, inflammatory pathways induced by cell death may participate in driving and sustaining the disease through the release of alarmins. In this review, we summarize the recent literature addressing the role of programmed cell death pathways in the small intestine, describing how these mechanisms may contribute to CD and discussing their potential implications.

Polymorphism in the IL-1β promoter is associated with IgG antibody response to circumsporozoite protein repeats of Plasmodium vivax

BACKGROUND

It is well established that infection by Plasmodium vivax is a result of host-parasite interactions. In the present study, association with the IL1/IL2 cytokine profiles, anticircumsporozoite protein antibody levels and parasitic loads was evaluated in individuals naturally infected with P. vivax in an endemic area of the Brazilian Amazon.

METHODS

Molecular diagnosis of P. vivax and variants was performed using the PCR-RFLP method and IL1B -511C>T, IL2 -330T>G and IL2+114T>G polymorphisms were identified using PCR-RFLP and allele-specific PCR. IL-1β and IL-2 cytokine levels were detected by flow cytometry and circumsporozoite protein (CSP) antibodies were measured by ELISA.

RESULTS

Three variants of P. vivax CSP were identified and VK247 was found to be the most frequent. However, the prevalence and magnitude of IgG antibodies were higher for the VK210 variant. Furthermore, the antibody response to the CSP variants was not associated with the presence of the variant in the infection. Significant differences were observed between the single nucleotide polymorphism (SNP) -511T>C in the IL1B gene and levels of antibodies to the VK247 and P. vivax-like variants, but there were no associations between SNPs in IL1 and IL2 genes and their plasma products.

CONCLUSIONS

Individuals with the rs16944 CC genotype in the IL1β gene have higher antibody levels to the CSP of P. vivax of VK247 and P. vivax-like variants.

Helicobacter pylori and cytokine gene variants as predictors of premalignant gastric lesions

Gastric cancer remains the third leading cause of mortality from cancer worldwide and carries a poor prognosis, due largely to late diagnosis. The importance of the interaction between Helicobacter pylori (H. pylori) infection, the main risk factor, and host-related genetic factors has been studied intensively in recent years. The genetic predisposition for non-hereditary gastric cancer is difficult to assess, as neither the real prevalence of premalignant gastric lesions in various populations nor the environmental risk factors for cancer progression are clearly defined. For non-cardiac intestinal-type cancer, identifying the factors that modulate the progression from inflammation toward cancer is crucial in order to develop preventive strategies. The role of cytokines and their gene variants has been questioned in regard to non-self-limiting H. pylori gastritis and its evolution to gastric atrophy and intestinal metaplasia; the literature now includes various and non-conclusive results on this topic. The influence of the majority of cytokine single nucleotide polymorphisms has been investigated for gastric cancer but not for preneoplastic gastric lesions. Among the investigated gene variants onlyIL10T-819C, IL-8-251, IL-18RAP917997, IL-22 rs1179251, IL1-B-511, IL1-B-3954, IL4R-398 and IL1RN were identified as predictors for premalignant gastric lesions risk. One of the most important limiting factors is the inhomogeneity of the studies (e.g., the lack of data on concomitant H. pylori infection, methods used to assess preneoplastic lesions, and source population). Testing the modifying effect of H. pylori infection upon the relationship between cytokine gene variants and premalignant gastric lesions, or even testing the interaction between H. pylori and cytokine gene variants in multivariable models adjusted for potential covariates, could increase generalizability of results.

Association of polymorphic variants of IL-1β and IL-1RN genes in the development of Graves' disease in Kashmiri population (North India)

PURPOSE

Graves' disease (GD) is a multigenic, organ specific autoimmune disorder with a strong genetic predisposition and IL-1β has been shown to be involved in its pathogenesis. The present study was aimed to determine the genetic associations between polymorphisms of IL-1β gene promoter region (-511 T>C) (rs16944), exon 5 (+3954 C>T) (rs1143634) and IL-1RN gene VNTR (rs2234663) polymorphism in patients with GD in ethnic Kashmiri population.

METHODS

A total of 135 Graves' disease patients and 150 healthy individuals were included in the study. PCR and PCR-based restriction analysis methods were done for IL-1RN^VNTR and IL-1β gene polymorphisms respectively.

RESULTS

We found statistically significant increased frequencies of the C/C + CT genotype (P = 0.001; odds ratio (OR) = 5.04, 95% confidence interval (CI) = 3.02-8.42) and the C allele (P = 0.001; OR = 3.10, 95% CI = 2.14-4.50) in IL-1β gene promoter polymorphism (rs16944) with GD patients compared to normal controls. Also in the exon 5 (rs1143634), a significant increase in frequency of the C/C homozygous genotype (P = 0.001; OR = 0.18, 95% CI = 0.11-0.30) and C allele (P = 0.001; OR = 0.31, 95% CI = 0.20-0.48) was observed in GD cases as against controls. For IL-1RN^VNTR (rs2234663), we didn't observe any significant difference in the allelic and genotypic frequencies between cases and controls.

CONCLUSION

Our findings suggest that both promoter and exon polymorphisms of IL-1β gene have a significant role in the risk of developing GD, whereas IL-1RN^VNTR has no association with GD.

Association of Interleukin-1B and Interleukin-4 Gene Variants with Autoimmune Thyroid Diseases in Tunisian Population

Autoimmune thyroid diseases (AITD) including Graves' disease (GD) and Hashimoto's thyroiditis (HT) are complex genetic diseases. Cytokines IL-1B and IL-4 play a role in the pathogenesis of AITD. This study was conducted on Tunisian patients with GD or HT to investigate the association of IL-1B and IL-4 gene polymorphisms with the risk and the prognosis of AITD. A total of 358 healthy controls and 341 patients with AITDs (249 HT and 92 GD) were genotyped for IL-1B+3953C/T and IL-4 intron 3 VNTR polymorphisms. A significant association was found between IL-1B+3953C/T polymorphism and GD or HT, both in the dominant and additive models. The IL-1B+3953T allele was associated with GD (p = 0.0003, OR = 1.93, CI = 1.34-2.78) and HT (p = 0.009, OR = 1.43, CI = 1.09-1.88). The IL-4 VNTR polymorphism was associated only with HT risk both in additive (p = 0.03, OR = 0.31, CI = 0.11-0.86) and recessive (p = 0.03, OR = 3.04, CI = 1.13-8.17) models. No significant association was found between IL-1B+3953C/T polymorphism and change in the serum concentrations of TSH and FT4 in GD and HT patients. In HT patients, the IL-1B+3953T allele (p = 0.009, OR = 0.42, CI = 0.22-0.83) and the IL-1B+3953T/T genotype (p = 0.03, OR = 0.21, CI = 0.04-1.07) were more frequent in the absence than in the presence of an anti-TPO antibody. The proportion of HT patients with the P1P2 genotype of the IL-4 gene was significantly higher in the absence than in the presence of the anti-TPO antibody (p = 0.04, OR = 0.39, CI = 0.17-0.89). These preliminary results suggest that IL-1B and IL-4 gene polymorphisms may be associated with GD and HT susceptibility and may represent prognostic factors for predicting the severity of HT.

Expression levels and genetic polymorphisms of interleukin-2 and interleukin-10 as biomarkers of Graves' disease

The aim of the present study was to determine whether the expression levels of interleukin (IL)-2 and IL-10 may be used as biological markers in Graves’ disease (GD) patients. A total of 256 individuals, including 118 GD patients and 138 healthy individuals, were enrolled into the study. Blood samples were collected from each patient and healthy individual, which were then subjected to enzyme-linked immunosorbent assay (ELISA). Total RNA and total proteins were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. In addition, restriction fragment length polymorphism (RFLP) analysis was performed to detect the presence of genetic polymorphisms. The ELISA results indicated that the IL-2 and IL-10 serum levels in the GD patients were increased by ~5.2 and ~7-fold when compared with the levels in the healthy controls. The results of RT-qPCR indicated that the mRNA expression levels of IL-2 and IL-10 were upregulated in the GD patients when compared with the healthy controls. Furthermore, the western blot analysis results revealed that the protein expression levels of IL-2 and IL-10 were significantly increased in the GD patients. RFLP analysis indicated that the increased number of GG single nucleotide polymorphisms (SNPs) in the GD group were detected in the −330 locus of the IL-2 promoter and the −1082 locus of the IL-10 promoter. In addition, the results indicated that the relatively high rates of homozygous GG SNPs (IL-2 −330T/G and IL-10 −1082A/G polymorphisms) on the alleles may be associated with the incidence of GD. The serum, mRNA and protein expression levels of IL-2 and IL-10 were significantly increased in GD patients when compared with the levels in the healthy controls. In conclusion, the expression levels and genetic polymorphisms of IL-2 and IL-10 may be potential biomarkers for the incidence of Graves’ disease in the population studied.

Allele-specific induction of IL-1β expression by C/EBPβ and PU.1 contributes to increased tuberculosis susceptibility

Mycobacterium tuberculosis infection is associated with a spectrum of clinical outcomes, from long-term latent infection to different manifestations of progressive disease. Pro-inflammatory pathways, such as those controlled by IL-1β, have the contrasting potential both to prevent disease by restricting bacterial replication, and to promote disease by inflicting tissue damage. Thus, the ultimate contribution of individual inflammatory pathways to the outcome of M. tuberculosis infection remains ambiguous. In this study, we identified a naturally-occurring polymorphism in the human IL1B promoter region, which alters the association of the C/EBPβ and PU.1 transcription factors and controls Mtb-induced IL-1β production. The high-IL-1β expressing genotype was associated with the development of active tuberculosis, the severity of pulmonary disease and poor treatment outcome in TB patients. Higher IL-1β expression did not suppress the activity of IFN-γ-producing T cells, but instead correlated with neutrophil accumulation in the lung. These observations support a specific role for IL-1β and granulocytic inflammation as a driver of TB disease progression in humans, and suggest novel strategies for the prevention and treatment of tuberculosis.

IL-1β is important for the initial establishment of antimicrobial adaptive immunity, but prolonged IL-1β expression can also cause progressive immunopathology during M. tuberculosis infection. The paradoxical activities of IL-1β in promoting both antimycobacterial immunity and chronic tissue damage have left the ultimate contribution of this cytokine to TB progression in human populations unclear. In this work, we address the role of IL-1β-mediated inflammation using a combination of human genetics and molecular biology, and suggest that exuberant IL-1β responses are causatively associated with TB progression and poor treatment outcome in humans. This work furthers our understanding of the immunological factors that underlie TB disease and provide a strong rationale for the development of specific anti-inflammatory adjunctive therapies that could improve the long-term outcome of TB treatment. In addition, these insights inform the design of future TB control efforts that include the rational design of disease-preventing vaccines and genotype-targeted delivery of TB chemotherapy.