Polymorphisms in tumour necrosis factor alpha (TNFalpha) gene in patients with acute pancreatitis

Phospholipase D2: A biomarker for stratifying disease severity in acute pancreatitis?

In this editorial, we critically evaluate the recent article by Niu et al, which explores the potential of phospholipase D2 (PLD2) as a biomarker for stratifying disease severity in acute pancreatitis (AP). AP is a clinically heterogeneous inflammatory condition that requires reliable biomarkers for early and accurate classification of disease severity. PLD2, an essential regulator of neutrophil migration and inflammatory responses, has emerged as a promising candidate. Although current biomarkers such as C-reactive protein and procalcitonin provide general indications of inflammation, they lack specificity regarding the molecular mechanisms underlying AP progression. Recent studies, including the research conducted by Niu et al, suggest an inverse correlation between PLD2 expression and AP severity, offering both diagnostic insights and mechanistic understanding. This editorial critically evaluates the role of PLD2 as a biomarker in the broader context of AP research. Evidence indicates that decreased levels of PLD2 are associated with increased neutrophil chemotaxis and cytokine release, contributing to pancreatic and systemic inflammation. However, several challenges remain, including the need for large-scale validation and functional studies to establish causation, and standardization of measurement protocols. Additionally, further investigation into the temporal dynamics of PLD2 expression and its variability across diverse populations is warranted. Looking ahead, PLD2 holds the potential to revolutionize AP management by integrating molecular diagnostics with precision medicine. The utilization of large-scale multi-omics approaches and advancements in diagnostic platforms could position PLD2 as a fundamental biomarker for early diagnosis, prognosis, and potentially therapeutic targeting. While promising, it is crucial to conduct critical evaluations and rigorous validations of PLD2's role to ensure its efficacy in improving patient outcomes.

Role of Genetic Polymorphisms -238 G>A and -308 G>A, and Serum TNF-α Levels in a Cohort of Mexican Pediatric Neuroblastoma Patients: Preliminary Study

The results of in vitro and in vivo studies have shown the pro-tumor effects of TNF-α, and this cytokine's increased expression is associated with poor prognosis in patients with some types of cancer. Our study objective was to evaluate the possible association of TNF-α genetic polymorphisms and serum levels with susceptibility and prognosis in a cohort of Mexican patients with NB. We performed PCR-RFLP and ELISA methods to analyze the genetics of these SNPs and determine serum concentrations, respectively. The distribution of the -308 G>A and -238 G>A polymorphisms TNFα genotypes was considerably different between patients with NB and the control group. The SNP rs1800629 GG/GA genotypes were associated with a decreased risk of NB (OR = 0.1, 95% CI = 0.03-0.393, p = 0.001) compared with the AA genotype, which was associated with susceptibility to NB (OR = 2.89, 95% CI = 1.45-5.76, p = 0.003) and related to unfavorable histology and high-risk NB. The rs361525 polymorphism GG genotype was associated with a lower risk of developing NB compared with the GA and AA genotypes (OR = 0.2, 95% CI = 0.068-0.63, p = 0.006). Circulating TNF-α serum concentrations were significantly different (p < 0.001) between patients with NB and healthy controls; however, we found no relationship between the analyzed TNF-α serum levels and SNP genotypes. We found associations between the rs1800629AA genotype and lower event-free survival (p = 0.026); SNP rs361525 and TNF-α levels were not associated with survival in patients with NB. Our results suggest the TNF-α SNP rs1800629 as a probable factor of NB susceptibility. The -308 G/A polymorphism AA genotype has a probable role in promoting NB development and poor prognosis associated with unfavorable histology, high-risk tumors, and lower EFS in Mexican patients with NB. It should be noted that it is important to conduct research on a larger scale, through inter-institutional studies, to further evaluate the contribution of TNF-α genetic polymorphisms to the risk and prognosis of NB.

Tumor necrosis factor-α (TNF-α) -308G >a promoter polymorphism (rs1800629) promotes Asians in susceptibility to Plasmodium falciparum severe malaria: A meta-analysis

The multifactorial pathogenesis of severe malaria is partly attributed to host genes, such as those encoding cytokines involved in complex inflammatory reactions, namely tumor necrosis factor-alpha (TNF-α). However, the relationship between TNF-α -308G >A gene polymorphism (rs1800629) and the severity of Plasmodium falciparum (P. falciparum) malaria remains unclear, which prompts a meta-analysis to obtain more precise estimates. The present meta-analysis aimed to better understand this correlation and provide insight into its association in populations with different ethnicities. Literature search outcomes included eight eligible articles in which TNF-α -308G >A polymorphism was determined in uncomplicated malaria (UM) and severe malaria (SM) of P. falciparum as represented in the case and control groups. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated in standard homozygous, recessive, dominant, and codominant genetic models. Subgroup analysis was based on ethnicity, i.e., Africans and Asians. The analyses included overall and the modified outcomes; the latter was obtained without the studies that deviated from the Hardy-Weinberg Equilibrium. The significant data also underwent sensitivity treatment but not publication bias tests because the number of studies was less than ten. Interaction tests were applied to differential outcomes between the subgroups. Overall and HWE-compliant analyses showed no significant association between the TNF-α -308G >A polymorphism and susceptibility to P. falciparum SM (ORs = 1.10-1.52, 95%CIs = 0.68-2.79; Pa = 0.24-0.68). Stratification by ethnicity revealed that two significant associations were found only in the Asians favoring SM for dominant (OR = 1.95, 95% CI = 1.06-3.61, Pa = 0.03) and codominant (OR = 1.83, 95% CI = 1.15-2.92, Pa = 0.01) under the random-effects model, but not among the African populations. The two significant Asian associations were improved with a test of interaction with P-value of0.02-0.03. The significant core outcomes were robust. Results of the meta-analysis suggest that TNF-α -308G >A polymorphism might affect the risk of P. falciparum SM, particularly in individuals of Asian descent. This supports ethnicity as one of the dependent factors of the TNF-α -308G >A association with the clinical severity of malaria. Further large and well-designed genetic studies are needed to confirm this conclusion.

Role of tumor necrosis factor-alpha -238 G>A promoter region polymorphism on recurrent miscarriage: An association study and meta-analysis

BACKGROUND

Recurrent miscarriage (RM) is defined as the loss of two or more consecutive pregnancies. A functional SNP, -238G>A in the promoter region of TNF-α, affects the gene transcription activity with implications on human pregnancy. Previous limited studies, linking the TNF-α -238 G>A to the risk of recurrent miscarriage have been inconclusive.

MATERIAL AND METHOD

The PCR-RLFP technique was used to evaluate this polymorphism in 199 RM cases and 215 control women from Amritsar, Punjab. For a meta-analysis, a total of 13 eligible studies (including the present study) comprising 2947 cases and 2933 controls were included. To evaluate the association among different genetic models, odds ratio with a 95% confidence interval (CI) and chi-square were used.

RESULTS

Genotype and allelic frequency did not differ significantly between both groups (p = .07 and p = .24, respectively). In the present meta-analysis, a significant association was found with the recessive model (OR-1.78 CI:1.24-2.55, p = .002).

CONCLUSION

Although, TNF-α -238 G>A polymorphism did not provide any risk in the case-control study but provided risk towards the development of RM with the recessive genetic model in the pooled analysis.

Fire in the belly: A scoping review of the immunopathological mechanisms of acute pancreatitis

Introduction

Acute pancreatitis (AP) is characterised by an inflammatory response that in its most severe form can cause a systemic dysregulated immune response and progression to acute multi-organ dysfunction. The pathobiology of the disease is unclear and as a result no targeted, disease-modifying therapies exist. We performed a scoping review of data pertaining to the human immunology of AP to summarise the current field and to identify future research opportunities.

Methods

A scoping review of all clinical studies of AP immunology was performed across multiple databases. Studies were included if they were human studies of AP with an immunological outcome or intervention.

Results

205 studies met the inclusion criteria for the review. Severe AP is characterised by significant immune dysregulation compared to the milder form of the disease. Broadly, this immune dysfunction was categorised into: innate immune responses (including profound release of damage-associated molecular patterns and heightened activity of pattern recognition receptors), cytokine profile dysregulation (particularly IL-1, 6, 10 and TNF-α), lymphocyte abnormalities, paradoxical immunosuppression (including HLA-DR suppression and increased co-inhibitory molecule expression), and failure of the intestinal barrier function. Studies including interventions were also included. Several limitations in the existing literature have been identified; consolidation and consistency across studies is required if progress is to be made in our understanding of this disease.

Conclusions

AP, particularly the more severe spectrum of the disease, is characterised by a multifaceted immune response that drives tissue injury and contributes to the associated morbidity and mortality. Significant work is required to develop our understanding of the immunopathology of this disease if disease-modifying therapies are to be established.

Multifactorial Scores and Biomarkers of Prognosis of Acute Pancreatitis: Applications to Research and Practice

Acute pancreatitis (AP) is a severe inflammation of the pancreas presented with sudden onset and severe abdominal pain with a high morbidity and mortality rate, if accompanied by severe local and systemic complications. Numerous studies have been published about the pathogenesis of AP; however, the precise mechanism behind this pathology remains unclear. Extensive research conducted over the last decades has demonstrated that the first 24 h after symptom onset are critical for the identification of patients who are at risk of developing complications or death. The identification of these subgroups of patients is crucial in order to start an aggressive approach to prevent mortality. In this sense and to avoid unnecessary overtreatment, thereby reducing the financial implications, the proper identification of mild disease is also important and necessary. A large number of multifactorial scoring systems and biochemical markers are described to predict the severity. Despite recent progress in understanding the pathophysiology of AP, more research is needed to enable a faster and more accurate prediction of severe AP. This review provides an overview of the available multifactorial scoring systems and biochemical markers for predicting severe AP with a special focus on their advantages and limitations.

Association between tumor necrosis factor-alpha gene rs1800629 (-308G/A) and rs361525 (-238G > A) polymorphisms and prostate cancer risk in an Iranian cohort

BACKGROUND

Prostate cancer (PCa) as the first men's common cancer in the world and the third cancer in Iranian men is a heterogeneous disorder which sometimes several biopsies are needed for its diagnosis.

OBJECTIVES

The aim of current study is finding new biomarkers in order to diagnose of PCa at the earliest possible stage. Hence, the relationship between rs1800629 and rs361525 polymorphisms of TNF-α gene with PCa was investigated.

MATERIALS AND METHODS

Blood DNA samples were collected from 100 patients with PCa, 110 with BPH, and 110 controls. Collected samples were examined using PCR-RFLP and Tetra-ARMS-PCR techniques to detect the desired polymorphisms.

RESULTS

The frequency of rs1800629 genotypes in smokers was significantly different from non-smokers with PCa (p= 0.001). Logistic regression analysis results showed that GA heterozygotes in comparison to GG homozygotes had higher risk of developing Benign Prostatic Hyperplasia (BPH) or prostate cancer. However, no significant correlation was considered between the risk of PCa and the TNF-α gene polymorphisms (rs1800629 and rs361525).

CONCLUSIONS

Although, the achieved results of this investigation demonstrated that the two examined genetic variants do not seem to be suitable markers for early diagnosis of prostate cancer in this pilot study; however increased risk for the disease is shown in GA heterozygotes and smokers which is indicative of some epigenetic factors influence on prostate cancer etiology.

The association between chronic pancreatitis and the iNOS-2087A>G polymorphism

INTRODUCTION

Chronic pancreatitis is morphologically characterized by ductal dysplasia, breeding grounds for the proliferation of the ductal cells, the degenerative changes in pancreatic acinar cells and fibrosis, and it is defined on the basis of the clinical, morphological and functional criteria.

AIM

The aim of our study is to examine the existence of a possible correlation between the iNOS-2087A>G polymorphism and chronic pancreatitis by means of the genetic analysis.

MATERIAL AND METHOD

We have conducted the study at the Gastroenterology Clinic and the Research Center of Gastroenterology and Hepatology of the University of Medicine and Pharmacy, Craiova, between March 2015 - September 2016. The study had a prospective character. Both for the 58 patients diagnosed with chronic pancreatitis and for the 132 patients in the witness group, the biological material was represented by blood, (around 2.5 - 5 milliliters of venous blood) let on EDTA and kept at 4°C up to the separation of the DNA molecule. All the patients were genotyped for the iNOS - 2087A>G polymorphism, by means of the Real Time PCR technique with TaqMan probes.

RESULTS

Analysing the prevalence of the iNOS genotypes within the study group and witness group, we have noticed that, statistically speaking, there are no significant differences between the two groups.

CONCLUSION

As a conclusion, in the study lot we can sustain that the risk of developing chronic pancreatitis is not increased by the presence of the iNOS-2087A>G polymorphism.

Determination of VEGFR-2 (KDR) 604A>G Polymorphism in Pancreatic Disorders

Pancreatic disorders have a high prevalence worldwide. Despite the fact that screening methods became more effective and the knowledge we have nowadays about pancreatic diseases has enhanced, their incidence remains high. Our purpose was to determine whether single nucleotide polymorphism (SNP) of VEGFR-2/KDR (vascular endothelial growth factor receptor 2/kinase insert domain receptor) influences susceptibility to develop pancreatic pathology. Genomic DNA was extracted from blood samples collected from patients diagnosed with acute pancreatitis (n = 110), chronic pancreatitis (n = 25), pancreatic cancer (n = 82) and healthy controls (n = 232). VEGFR-2 (KDR) 604A>G (rs2071559) polymorphism frequency was determined with TaqMan allelic discrimination assays. Statistical assessment was performed by associating genetic polymorphism with clinical and pathological data. In both pancreatic disorders and healthy control groups the polymorphism we studied was in Hardy-Weinberg equilibrium. Association between increased risk for pancreatic disorders and studied polymorphism was statistically significant. KDR 604AG and AG + GG genotypes were more prevalent in acute pancreatitis and pancreatic cancer patients than in controls. These genotypes influence disease development in a low rate. No association was found between chronic pancreatitis and KDR 604AG and AG + GG genotypes. In Romanian cohort, we found an association between the KDR 604A→G polymorphism and acute pancreatitis and pancreatic cancer. Carriers of the -604G variant allele were more frequent among acute pancreatitis and pancreatic cancer than among controls, suggesting that KDR 604G allele may confer an increased risk for these diseases. In the future, more extensive studies on larger groups are necessary, in order to clarify the role of VEGFR2 polymorphisms in pancreatic pathology.

Tumour necrosis factor alpha promoter polymorphism, TNF-238 is associated with severe clinical outcome of falciparum malaria in Ibadan southwest Nigeria

Tumour necrosis factor (TNF) - α has been shown to play an important role in the pathogenesis of falciparum malaria. Two TNF promoter polymorphisms, TNF-308 and TNF-238 have been associated with differential activity and production of TNF. In order to investigate the association between TNF-308 and TNF-238 and the clinical outcome of malaria in a Nigerian population, the two TNF polymorphisms were analysed using Sequenom iPLEX Platform. A total of 782 children; 283 children with uncomplicated malaria, 255 children with severe malaria and 244 children with asymptomatic infection (controls) were studied. The distribution of TNF-308 and TNF-238 genotypes were consistent with the Hardy-Weinberg equilibrium. Distribution of both TNF polymorphisms differed significantly across all clinical groups (TNF-308: p=0.007; TNF-238: p=0.001). Further tests for association with severe malaria using genotype models controlling for age, parasitaemia and HbAS showed a significant association of the TNF-238 polymorphism with susceptibility to severe malaria (95% CI=1.43-6.02, OR=2.94, p=0.003237) The GG genotype of TNF-238 significantly increased the risk of developing cerebral malaria from asymptomatic malaria and uncomplicated malaria (95% CI=1.99-18.17, OR=6.02, p<0.001 and 95% CI=1.78-8.23, OR=3.84, p<0.001 respectively). No significant association was found between TNF-308 and malaria outcome. These results show thegenetic association of TNF-238 in the clinical outcome of malaria in Ibadan, southwest Nigeria. These findings add support to the role of TNF in the outcome of malaria infection. Further large scale studies across multiple malaria endemic populations will be required to determine the specific roles of TNF-308 and TNF-238 in the outcome of falciparum malaria infection.

A Meta-analysis on the Effect of Ulinastatin on Serum Levels of C-Reactive Protein, Interleukin 6, and Tumor Necrosis Factor Alpha in Asian Patients with Acute Pancreatitis

OBJECTIVES

We aimed to investigate the influence of ulinastatin (UTI) on the serum levels of C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) in Asian patients with acute pancreatitis (AP) by performance of a meta-analysis.

METHODS

Two investigators independently searched 11 databases, including PUBMED, EBSCO, Ovid, SpringerLink, Wiley, Web of Science, Cochrane Library, Wanfang database, China National Knowledge Infrastructure (CNKI), Chinese Journal Full-text Database, and China Biomedicine Database. The full-text articles were screened and the data were extracted using a standardized data extraction form. All statistical analyses were conducted with Stata software, version 12.0 (Stata Corporation, College Station, TX).

RESULTS

A total of 94 studies were initially retrieved, and 10 studies containing 424 Asian patients with AP were ultimately enrolled in this meta-analysis. The results revealed that the serum levels of CRP, IL-6, and TNF-α in Asian AP patients significantly decreased after UTI therapy (CRP: standardized mean difference [SMD] = 3.26, 95% confidence interval [CI] = 1.69-4.83, p < 0.001; IL-6: SMD = 5.92, 95% CI = 2.09-9.75, p = 0.002; TNF-α: SMD = 4.07, 95% CI = 0.79-7.35, p = 0.015).

CONCLUSION

The results of this meta-analysis suggest that UTI can effectively depress the serum levels of CRP, IL-6, and TNF-α in Asian patients with AP, and thereby inhibit inflammation.

Epidemiologic and Mechanistic Associations Between Smoking and Pancreatitis

OPINION STATEMENT

Alcohol has long been associated with pancreatitis. Although first described more than three decades ago, smoking has been widely accepted as an important risk factor for all forms of pancreatitis only in the past few years. Empiric data has confirmed smoking as an independent and dose-dependent risk for both acute and chronic pancreatitis. Smoking also increases the risk of recurrences and progression of established chronic pancreatitis. The effects of smoking are enhanced in the presence of alcohol consumption. Indirect evidence suggests that smoking cessation may be beneficial in preventing disease progression. Smoking cessation can therefore be an important strategy for primary as well as secondary prevention of pancreatitis. Therefore, in addition to alcohol, physicians should routinely counsel patients for the benefits of smoking cessation. The mechanisms through which cigarette smoke triggers pathological cellular events, resulting in pancreatitis, are unresolved. Although cigarette smoke contains greater than 4000 compounds, principally nicotine and the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) have been broadly studied with regard to pancreatic diseases. Both nicotine and NNK have been shown to induce morphological changes in the pancreas consistent with those seen in pancreatitis. Furthermore, nicotine affects pancreatic secretion and NNK induces premature zymogen activation, two well-known features of pancreatitis. These cigarette toxins may mediate both pro- and anti-inflammatory pathways and can induce changes in pancreatic acinar cell function at the level of transcription, leading to conditions such as thiamin deficiency and mitochondrial dysfunction. Such circumstances could leave the pancreas prone to the development of pancreatitis. This review summarizes relevant research findings and focuses on the epidemiologic links between smoking and pancreatitis, and the cellular pathways that may be significant in induction and evolution of smoking-related pancreatitis.

Meta-analysis: Tobacco smoking may enhance the risk of acute pancreatitis

BACKGROUND AND AIM

Questions remain unclear about the association of smoking status and the development of acute pancreatitis (AP). We performed a meta-analysis of observational studies explore this association.

METHODS

A computerized literature search was performed in MEDLINE and EMBASE through November 30, 2014. We also searched the reference lists of pertinent articles. We used a random-effects model to calculate the summary relative risks (SRRs) and their corresponding 95% confidence intervals (CIs).

RESULTS

A total of 3690 incident cases of AP included 12 observational studies (6 case-control and 6 prospective cohort/nested case-control studies) were identified. Compared with never smokers, the summary RR estimates were 1.54 (95% CI, 1.31-1.80) for ever smokers, 1.71 (95% CI, 1.37-2.14) for current smokers, and 1.21 (95% CI, 1.02-1.43) for former smokers. Smoking is found to be a potential risk factor for alcohol use, idiopathic factors and drugs related AP, but not for gallstone related AP, in the ever and current smokers. A dose-response effect of tobacco use on the risk was ascertained: current smokers had a 40% (95% CI, 30%-51%) increased risk of AP for every additional 10 cigarettes per day.

CONCLUSION

The present analysis suggests that smokers have an elevated risk of AP development. Further studies, however, are warranted before definitive conclusions can be drawn.

A single-nucleotide polymorphism in tumor necrosis factor-α (-308 G/A) as a biomarker in chronic pancreatitis

OBJECTIVE

Chronic pancreatitis is a gradual, long-term inflammation of the pancreas that results in alteration of its normal structure and function. The study aims to investigate the role of -308 (G/A) polymorphism of TNF-α gene in chronic pancreatitis.

MATERIAL AND METHODS

A total of 200 subjects were included in this case-control study. A total of 100 in patients admitted in the Gastroenterology Unit of Gandhi Hospital and Osmania General Hospital, Hyderabad were included in the present study. An equal number of healthy control subjects were randomly selected for the study. The genotyping of TNF-α gene was carried out by tetra-primer ARMS PCR followed by gel electrophoresis. The TNF-α levels were assayed by enzyme-linked immunosorbent assay.

RESULTS

A significant variation with respect to the genotypic and allelic distribution in the disease group when compared to control subjects [OR=2.001 (1.33-3.005), p<0.0001**] was observed. Subjects homozygous for the A allele had higher TNF-α levels compared to G allele.

CONCLUSION

The present study revealed a significant association of the TNF-α gene promoter polymorphism with chronic pancreatitis. Thus, TNF-α genotype can be considered as one of the biological markers in the etiology of chronic pancreatitis.

Genetics of acute and chronic pancreatitis

PURPOSE OF REVIEW

Acute pancreatitis, recurrent acute pancreatitis (RAP) and chronic pancreatitis are interrelated and progressive inflammatory disorders of the pancreas with highly variable and complex susceptibility, severity and outcomes. The role of genetics in acute pancreatitis, RAP and progression to chronic pancreatitis within a new framework is needed.

RECENT FINDINGS

The first genome-wide association study in the pancreas has been published with genome-wide significance linked with noncoding variants at the PRSS1-PRSS2 locus on chromosome seven and the CLDN2 locus on the X chromosome. A new personalized medicine paradigm is being considered to facilitate organization of genetic and other susceptibility risk compared with the risk of disease progression or resolution and risk of complications.

SUMMARY

A new framework for organizing multiple, complex data sets is emerging. The role of genetics in the context of other variables is important in understanding susceptibility to RAP and in the modification of disease severity and progression to chronic pancreatitis. Questions of when to order testing, what to order and how to use the data in real time remains an area for future research and development.

Lack of association between TNF-α gene promoter polymorphisms and pancreatitis: a meta-analysis

BACKGROUND/AIMS

Tumor necrosis factor alpha (TNF-α) is a major proinflammatory cytokine involved in the etiology of pancreatitis. The association between pancreatitis and the -308G>A and -238G>A polymorphisms in TNF-α gene has been analyzed in several studies, but results have been inconsistent. The purpose of this study was to integrate previous findings and explore whether these polymorphisms are associated with susceptibility and severity to pancreatitis.

METHODS

A meta-analysis was performed by searching PubMed, Cochrane Library, and ScienceDirect databases. Data were extracted using predefined form and odds ratios (OR) with 95% confidence intervals (CI) were calculated.

RESULTS

Our meta-analysis of a total of 1569 pancreatitis cases and 1330 control subjects from twelve published case-control studies for the -308G>A polymorphism (OR 0.98; 95% CI 0.83-1.17), and of 480 cases and 302 controls from four studies for the -238G>A polymorphism (OR 0.92; 95% CI 0.58-1.47) did not show any significant associations of susceptibility to pancreatitis with the variant GA+AA genotypes compared with the GG genotype. An association between severity of acute pancreatitis and -308G>A polymorphism was not found either (OR 0.93; 95% CI 0.69-1.24).

CONCLUSION

Polymorphisms in two sites of TNF-α gene promoter do not alter the risk of pancreatitis.

Association between tumor necrosis factor-alpha gene -308A/G polymorphism and the risk of acute pancreatitis: a meta-analysis

BACKGROUND

Epidemiologic studies have evaluated the association between tumor necrosis factor-alpha (TNF-α) gene -308A/G polymorphism and the risk of acute pancreatitis (AP), but the results are inconsistent. In order to derive a more precise estimation of the associations, a meta-analysis was performed.

MATERIALS AND METHODS

Systematic searches of electronic databases PubMed, Embase, and Web of Science, as well as hand searching of the references of identified articles, were performed. All case-control studies investigating the association between TNF-α gene -308A/G polymorphism and AP risk were included. The association was assessed by odds ratio (OR) with 95% confidence intervals (CIs). Publication bias was analyzed by Begg's funnel plot and Egger's regression test.

RESULTS

The initial search revealed 818 potentially eligible studies. Having read the title, abstract, or full text, we included six relevant studies in the final meta-analysis, which contained 1,006 AP cases and 782 controls. Overall, no significant association was found between TNF-α gene -308A/G polymorphism and AP risk when all studies were pooled into the meta-analysis (for A/A+A/G versus G/G: OR = 1.03, 95% CI = 0.83-1.28, P = 0.79; for A/A versus A/G+G/G: OR = 0.97, 95% CI = 0.65-1.45, P = 0.87; for A/A versus G/G: OR = 1.23, 95% CI = 0.79-1.91, P = 0.37; for A allele versus G allele: OR = 0.99, 95% CI = 0.83-1.18, P = 0.90). In addition, the similar results were obtained in the subgroup analysis based on the ethnicity and subtype of AP.

CONCLUSIONS

The present meta-analysis reveals that the TNF-α gene -308A/G polymorphism is not associated with AP risk. However, due to the small number of subjects included in analysis and the selection bias in some studies, the results should be interpreted with caution.

Tumour necrosis factor gene polymorphism and disease prevalence

Tumour necrosis factor (TNF), an important proinflammatory cytokine, plays a role in the regulation of cell differentiation, proliferation and death, as well as in inflammation, innate and adaptive immune responses, and also implicated in a wide variety of human diseases. The presence of DNA sequence variations in regulatory region might interfere with transcription of TNF gene, influencing the circulating level of TNF and thus increases the susceptibility to human diseases (infectious, cancer, autoimmune, neurodegenerative and other diseases). In this review, we have comprehensively analysed various published case-control studies of different types of human diseases, in which TNF gene polymorphism played a role, and computationally predicted several single nucleotide polymorphisms (SNPs) lie in transcription factor-binding sites (TFBS) of transcription factors (TFs). It has been observed that TNF enhancer polymorphism is implicated in several diseases, and TNF rs1800629 and rs361525 SNPs are the most important in human disease susceptibility as these might influence the transcription of TNF gene. Thirty-two SNPs lies in TFBS of 20 TFs have been detected in the TNF upstream region. It has been found that TNF enhancer polymorphism influences the serum level of TNF in different human diseases and thus affects the susceptibility to diseases. The presence of DNA sequence variation in TNF gene causes the modification of transcriptional regulation and thus responsible for association of susceptibility/resistance with human diseases.