TNF-alpha Polymorphisms Research Articles

Genetic variation in the stress protein hsp70-2 gene is highly associated with obesity.

Tumor necrosis factor-alpha (TNF-alpha) expression is increased in adipose tissue of both rodent models of obesity and obese humans. It has therefore been considered as a candidate gene for obesity. Several studies have indeed shown statistical evidence of linkage between obesity and the chromosomal region encompassing the TNF-alpha gene, suggesting that TNF-alpha and/or a nearby gene (eg hsp70 gene) is involved in the onset and progression of weight gain. We designed a case-controlled study to investigate the potential association of polymorphism of the TNF-alpha and that of a stress protein (hsp70-2) with obesity. We used the polymerase chain reaction and restriction enzyme digestion to characterize the variation of the TNF-alpha promoter region and that of the hsp70-2 gene in 343 unrelated Tunisian patients with obesity and 174 healthy control subjects. Analysis of the -308 TNF-alpha polymorphism in patients with obesity and in control subjects did not reveal an association between TNF-alpha alleles and obesity. In contrast, polymorphism analysis of the hsp70-2 gene in patients with obesity demonstrated highly significant differences in genotypic distribution of this bi-allelic locus compared to the control subject group. Homozygosity for one hsp70-2 allele was highly associated with obesity (r2=7.12; P<10(-6)). Tunisian persons carrying the P2/P2 genotype of the hsp70-2 gene may have an increased risk of obesity.

Role of cytokine gene polymorphisms in acute rejection and renal impairment after liver transplantation.

Although immunosuppressive regimens are effective, rejection occurs in up to 50% of patients after orthotopic liver transplantation (OLT), and there is concern about side effects from long-term therapy. Knowledge of clinical and immunogenetic variables may allow tailoring of immunosuppressive therapy to patients according to their potential risks. We studied the association between transforming growth factor-beta, interleukin-10, and tumor necrosis factor alpha (TNF-alpha) gene polymorphisms and graft rejection and renal impairment in 121 white liver transplant recipients. Clinical variables were collected retrospectively, and creatinine clearance was estimated using the formula of Cockcroft and Gault. Biallelic polymorphisms were detected using polymerase chain reaction-based methods. Thirty-seven of 121 patients (30.6%) developed at least 1 episode of rejection. Multivariate analysis showed that Child-Pugh score (P =.001), immune-mediated liver disease (P =.018), normal pre-OLT creatinine clearance (P =.037), and fewer HLA class 1 mismatches (P =.038) were independently associated with rejection. Renal impairment occurred in 80% of patients and was moderate or severe in 39%. Clinical variables independently associated with renal impairment were female sex (P =.001), pre-OLT renal dysfunction (P =.0001), and a diagnosis of viral hepatitis (P =.0008). There was a significant difference in the frequency of TNF-alpha-308 alleles among the primary liver diseases. After adjustment for potential confounders and a Bonferroni correction, the association between the TNF-alpha-308 polymorphism and graft rejection approached significance (P =.06). Recipient cytokine genotypes do not have a major independent role in graft rejection or renal impairment after OLT. Additional studies of immunogenetic factors require analysis of large numbers of patients with appropriate phenotypic information to avoid population stratification, which may lead to inappropriate conclusions.

Is tumor necrosis factor genotype (TNFA2/TNFA2)a genetic prognostic factor of an unfavorable outcome in IgA nephropathy?

The purpose of this study was to examine whether there are the associations between TNF alpha and TNF beta gene polymorphisms and the development and progression of Ig A nephropathy (IgAN). A cross-sectional study on TNF alpha and TNF betagene polymorphisms by polymerase chain reaction with restriction fragment length poly-morphisms was performed on 76 patients with primary IgAN confirmed by renal biopsy and 100 healthy controls. The allele with G-->A substitution was designated as TNFA2 for the TNF alpha gene and TNFB2 for the TNF betagene. A patient in whom dialysis treatment was started or whose serum creatinine became double or over during the follow-up duration was designated as a "progressor". The TNFA2/ TNFA2 genotype was more prevalent in the progressor than in the non-pregressor group (20.0 vs 3.3%, p<0.05). Clinical factors such as serum creatinine, systolic and diastolic blood pressure (p<0.001, respectively) were higher and pathologic factor such as Grade IV or V renal lesions was more prevalent (p<0.01) in the progressor than in the non-progressor group. Therefore, TNFA2/TNFA2 genotype may be a risk factor for the progression of IgAN.

Association between -G308A tumor necrosis factor alpha gene polymorphism and schizophrenia.

Dysregulation of the inflammatory response system has been linked to pathophysiology of schizophrenia. Evidence of immune activation has derived from the detection of abnormal levels of proinflammatory cytokines and their receptors in peripheral blood and cerebrospinal fluid from schizophrenic patients. Cytokines are involved in normal CNS development as well as in the pathogenesis of many neuro-psychiatric disorders, acting directly on neural cells or modulating neurotransmitter and neuropeptide systems. In particular tumor necrosis factor alpha (TNFalpha), depending on its concentration, can exert both neurotrophic and neurotoxic effects and influence neural cell growth and proliferation. Moreover, TNFalpha gene is located on the small arm of chromosome 6 (6p21.1-21.3), a locus associated with genetic susceptibility to schizophrenia. We studied the distribution of -G308A TNFalpha gene polymorphism in 84 schizophrenic patients and in 138 healthy volunteers. This biallelic base exchange polymorphism directly affects TNFalpha plasma levels. Frequency of the TNF2(A) allele is significantly increased in schizophrenic patients as compared to controls (P = 0.0042). Genotype distribution is also significantly different (P = 0.0024). TNF2 homozygotes are represented only in the patient group (P = 0.002). These data suggest a potential role of TNFalpha as a candidate gene for susceptibility to schizophrenia and suggest that immune dysregulation in schizophrenic patients could also have a genetic component.

Contribution of TNF-alpha and IL-10 gene polymorphisms to graft-versus-host disease following allo-hematopoietic stem cell transplantation.

Some cytokines are believed to play a role in the development of acute and chronic GVHD after allo-hematopoietic stem cell transplantation. It has been reported that TNF-alpha and IL-10 gene polymorphisms are associated with the production of those cytokines and the development of graft failure after organ transplantation and systemic lupus erythematosus. We examined whether TNF-alpha and IL-10 gene polymorphisms affect the severity of acute GVHD (aGVHD) and chronic GVHD (cGVHD). Sixty-two and 54 patients were available for the analysis of aGVHD and cGVHD, respectively. We analyzed the gene polymorphisms derived from pre- and post-transplant blood cells. Donor-derived TNF2 allele (A) was more frequently detected in patients with aGVHD III/IV than those aGVHD 0-II (2/6 vs 2/56) (P = 0.04). The donors of the patients with cGVHD more frequently possessed a greater number of alleles (allele 13 or more which contain 26 or more CA repeats) in IL-10.G than those without (13/26 vs 5/28) (P = 0.02), and the patients with cGVHD had more CA repeats in donor-derived IL-10.G than those without (mean = 25.2 vs 23.4) (P = 0.01). Donor-derived TNF-308 and IL-10.G alleles may contribute to severe aGVHD and cGVHD, respectively, and will help us distinguish those patients at high risk for GVHD.

Lack of association between adult asthma and the tumour necrosis factor alpha-308 polymorphism gene.

Tumour necrosis factor (TNF)alpha is a cytokine endowed with potent inflammatory properties that may contribute to airway inflammation in asthma. It has previously been shown that the single base pair polymorphism-308 (G to A substitution) in the promoter of TNFalpha gene results in enhanced cytokine secretion. Whether this polymorphism is associated with the presence of phenotypic expression of asthma is questioned. In this study the relative frequency of TNF1 and TNF2 alleles in a population of adult healthy subjects (n=98) and adult Caucasian asthmatics (n=95) was compared taking into account their disease severity, atopic status and their smoking habit. For the whole group of asthma the genotype frequency for 1/1, 1/2, 2/2 were 67%, 33% and 0%, respectively, and not significantly different from those found in the control group that reached 70%, 28% and 2% respectively (p>0.05). The allele frequencies in asthma were 86% and 14% for TNF1 and TNF2 respectively while the corresponding figures were 85% and 15% in the control group (p>0.05). Furthermore, subdividing asthmatics into severe forced expiratory volume in one second <60% pred), atopic or smoking patients did not show any significant association with this TNFalpha polymorphism. To conclude the polymorphism -308 in the promoter of the TNFalpha gene does not confer a susceptibility to develop asthma nor to grade its severity.

Impact of interleukin-1 receptor antagonist and tumor necrosis factor-α gene polymorphism on IgA nephropathy

It is evident that cytokines play an important role in the pathogenesis as well as disease progression in IgA nephropathy (IgAN). The level of cytokine production is influenced by different genotypes that reflect gene polymorphism of the pertinent cytokine. Interleukin-1 receptor antagonist (IL-1ra) and tumor necrosis factor-alpha (TNF-alpha) gene polymorphism have been found to affect disease susceptibility and activity in several inflammatory diseases. However, the impact of these polymorphisms in IgAN patients has not previously been thoroughly studied. We investigated 111 cases of biopsy-proven IgAN and 100 healthy, normal controls for their IL-1ra and TNF-alpha gene polymorphism. IL-1ra gene polymorphism was characterized as a variable number of tandem repeats of a 86 bp sequence within intron 2. Five alleles were identified and were designated as IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5, corresponding to 4, 2, 5, 3, 6 repeats, respectively. A polymorphism in the promoter region of the TNF-alpha gene was also studied. This polymorphism involved a guanidine to adenosine transition at position -308 and was designated as TNF1 (-308G) and TNF2 (-308A). There were 54 male and 57 female patients with a mean age of 30.3 +/- 12.5 years and a disease duration of 66. 8 +/- 47.2 months. The mean duration of the follow-up period was 47. 3 +/- 32.6 months. In the patient group, the allele frequencies of IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5 were 89.6%, 9.9%, 0%, 0.5%, and 0%, respectively, whereas the corresponding carriage rates were 100%, 19.8%, 0%, 0.9%, and 0%, respectively. An excessive carriage of IL2RN*2 was found in the patients when compared with normal controls (allele frequency, 9.9 vs. 2.5%, P < 0.0001). The allele frequencies of TNF1 and TNF2 were 94.1 and 5.9%, respectively, and the carriage rates were 99.1 and 10.8%, respectively, in the patients, which was not significantly different from those of normal controls. When the patients were stratified into mild and severe groups according to their initial presentation, none of the studied alleles correlated with the severity. However, patients with gross hematuria were associated with a higher carriage rate of TNF2 when compared with patients without gross hematuria (allele frequency, 15. 4 vs. 4.6%, P = 0.0552; carriage rate, 30.8% vs. 8.2%, P = 0.0272). Renal survival analysis revealed that the TNF2 carrier had a renal survival comparable with TNF2 (-) patients. However, the carriage of the IL1RN*2 allele was associated with a significantly poorer long-term outcome with a median survival time of 72 months, as compared with those without IL1RN*2 (134 months, P < 0.01). IL-1ra and TNF-alpha gene polymorphism may affect disease susceptibility as well as disease activity and long-term outcome in human IgAN. Treatment with an IL-1ra or IL-1 blocking agent may be relevant in those carrying the IL1RN*2 allele.

TNF-alpha gene polymorphism does not affect the clinical and radiological outcome of rheumatoid arthritis.

The present study was undertaken in order to investigate the relationship between tumor necrosis factor-alpha (TNF-alpha) gene polymorphism and the radiological progression of rheumatoid arthritis (RA) within the first 3-years of the disease. Sixty-eight RA patients (59 women and nine men) were observed for 3-years. TNF-alpha polymorphism analysis was performed in all patients. Radiographs of the hands were taken at the onset of study and after 3-years of follow-up. Radiographs were assessed according to the Larsen index (damage score and progression of damage score). We did not observe any correlation between TNF gene polymorphism and damage score or progression of damage score. The obtained data suggests that TNF-308 polymorphism cannot serve as an indicator of the disease course in RA patients.

Interleukin 6, tumour necrosis factor alpha, interleukin 1beta and interleukin 1 receptor antagonist promoter or coding gene polymorphisms in multiple myeloma.

Proinflammatory cytokines such as interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-alpha) and IL-1beta are considered to be involved in the pathogenesis of multiple myeloma (MM). In the present study, we examined a G/C polymorphism at position -174 in the promoter region of IL-6, a biallelic polymorphism at position -308 in the promoter region of TNF-alpha, the TaqI restriction fragment length polymorphism in exon 5 of IL-1beta and a variable number of identical tandem repeat polymorphisms in intron 2 of IL-1 receptor antagonist (IL-1Ra) genes. The alleles of these loci are known to influence the level of production of the cytokines and the IL-1Ra. Seventy-three patients with MM, 27 with monoclonal gammopathy of undetermined significance (MGUS) and 129 healthy individuals were included. No difference was found between patients and healthy controls or between MM and MGUS patients in the distributions of genotypes and frequencies of alleles of the IL-6 (-174), TNF-alpha (-308), IL-1beta TaqI and IL-1Ra gene polymorphisms. No associations between the polymorphisms at the loci under study and clinical factors such as age, sex, clinical stage at onset and M-protein type were observed. Our results indicate that the cytokine (IL-6, TNF-alpha and IL-1beta) and IL-Ra gene polymorphisms do not confer susceptibility to the development of MM.

Cytokine (TNF alpha, LT alpha and IL-10) polymorphisms in inflammatory bowel diseases and normal controls: differential effects on production and allele frequencies.

The influence of biallelic polymorphisms in the tumour necrosis factor-alpha (TNF alpha), lymphotoxin-alpha (LT alpha) and interleukin-10 (IL-10) genes on stimulated TNF alpha and IL-10 production was studied in ulcerative colitis (UC) patients, Crohn's disease (CD) patients and in healthy controls. A polymerase chain reaction sequence-specific primer (PCR-SSP) system was developed to type nine biallelic polymorphisms, three in each of the TNF alpha, LT alpha and IL-10 genes. Production of the TNF alpha and IL-10 was measured by ELISA in lipopolysaccharide (LPS) stimulated whole blood. Four haplotypes of the TNF alpha gene, three haplotypes of LT alpha and three haplotypes of IL-10 were identified. No significant differences in haplotype frequencies were found between patients and controls overall. On subgroup analysis however, haplotype TNF-2 was more frequent in women with extensive colitis compared to distal colitis (31% vs 12%; P = 0.028). This difference was even greater for the combined TNF-2-LT alpha-2 haplotype (56% vs 21%; P = 0.0007). The TNF-2 and LT alpha-2 haplotypes were associated with higher TNF alpha production in CD patients, and the TNF-4 haplotype was associated with lower TNF alpha production in UC patients. The A allele in the IL-10 promoter region at position -1082 was associated with decreased IL-10 production in CD patients and controls (P = 0.005, P = 0.015 respectively). These data provide evidence that the effect of TNF alpha, LT alpha and IL-10 gene polymorphisms on cytokine production differ in CD, UC patients and controls.

Insulin resistance and inflammation in an evolutionary perspective: the contribution of cytokine genotype/phenotype to thriftiness.

To describe a unifying hypothesis of the relation between insulin resistance and inflammatory response in the development of diabetes. Review of the literature and authors' research. Infection and injury activate the immune system and bring about widespread metabolic changes which disadvantage and destroy the invading organism and facilitate repair of damaged tissue. Tumour necrosis factor-alpha is involved in inflammatory events and fight against infection. No study has extensively investigated its numerous metabolic effects. From induction of hyperlipidaemia to regulation of intracellular insulin signalling, TNF-alpha has been even associated with nutrient-sensing pathways. Certain TNF-alpha gene polymorphisms (linked to a high transcription rate of TNF-alpha), and the plasma concentrations of the TNF-alpha soluble receptor are simultaneously associated with insulin resistance, body fat, and with mortality after chronic infections. Thus, the TNF system seems to be designed for an effective fight against infection and for providing survival advantages during periods of food shortage. By inducing muscle insulin resistance, the energetic substrates are safeguarded for brain metabolism. In the presence of an insulin resistance genotype and westernization (high carbohydrate diet, increased saturated fat, low fibre and sedentary habit), a high cytokine responder genotype would be prone to deterioration of insulin resistance and, finally, to Type II (non-insulin-dependent) diabetes mellitus and atherosclerosis. For our ancestors, the advantages of a high cytokine responder (eradication of injury) or moderate insulin resistance (protection against starvation) overcame the possible inconveniences of atherosclerosis. We propose that the latter are good adaptations to the environment or "maladaptations" of actual lifestyle to our genome. [Diabetologia (1999) 42: 1367-1374]

Cytokine gene polymorphisms predict acute graft rejection following renal transplantation

The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) has been implicated in the pathogenesis of acute rejection, while animal models suggest a role for interleukin-10 (IL-10) in promoting graft survival. It has also been shown that polymorphisms in the TNFA gene promoter (position -308) and in the IL-10 gene promoter (position -1082) correlate with differential production of these cytokines in vitro. The aim of this study was to determine whether TNF-alpha and IL-10 gene polymorphisms influence the incidence and severity of acute rejection in the first six months following renal transplantation. The cytokine genotypes of 115 consecutive first cadaveric kidney allograft recipients and their donors were screened. The rejection episodes (REs) were defined clinically and confirmed histologically where possible and further classified according to severity (RS), namely steroid-resistant or responsive REs. The genotypes were then correlated with the REs and RS. The recipient TNF-alpha high producer genotype and IL-10 high producer genotype were significantly associated with multiple REs (>/=2) in human leukocyte antigen (HLA)-DR mismatched transplants (P = 0.0047 and P = 0.045, respectively), whereas only the TNF-alpha high producer genotype was associated with steroid-resistant REs (P = 0.025). When recipient cytokines were analyzed together, the TNF-alpha high/IL-10 high producer genotype had the worst prognosis, whereas TNF-alpha low/IL-10 low producer genotype was protective. We conclude that recipient TNF-alpha and IL-10 gene polymorphisms are determinants of REs and RS following kidney transplantation. Routine screening of these gene polymorphisms may have a clinical role in identifying patients at risk of multiple REs and severe rejections.

Genetic heterogeneity within ulcerative colitis determined by an interleukin-1 receptor antagonist gene polymorphism and antineutrophil cytoplasmic antibodies.

Although there is strong evidence implicating genetic predisposition in the pathogenesis of the chronic inflammatory bowel diseases, the number and identity of susceptibility genes remain uncertain. Cytokine genes are tentative candidate loci, but data regarding association studies in different populations are conflicting. To determine potential associations of interleukin-1 receptor antagonist (IL-1ra), tumour necrosis factor alpha (TNF alpha), and tumour necrosis factor beta (TNF beta) gene polymorphisms with ulcerative colitis or subsets of ulcerative colitis in a Spanish population. Genotyping for IL-1ra, TNF alpha and TNF beta gene polymorphisms was performed by the polymerase chain reaction in 95 patients with ulcerative colitis and 74 healthy controls. A variable number of tandem repeats (VNTR) in the IL-1ra gene, and a single base pair polymorphism in the TNF alpha gene promoter region (-308) and in the first intron of the TNF beta gene were analysed. Anti-neutrophil cytoplasmic antibodies (ANCA) were detected using an indirect immunofluorescence assay. There were no significant differences between ulcerative colitis patients and controls in either polymorphism analysed, nor between ulcerative colitis subgroups as a function of the clinical disease pattern. However, when stratified by their ANCA status, perinuclear ANCA (p-ANCA) ulcerative colitis showed an increased frequency of the genotype 1,2 of the IL-1ra gene compared with ANCA-negative ulcerative colitis (52% versus 28%; P = 0.02, Pcorr = 0.1). Furthermore, p-ANCA ulcerative colitis had a statistically significant increase of this genotype compared with cytoplasmic ANCA (c-ANCA)/ANCA-negative ulcerative colitis (52% versus 26.5%; P = 0.01, Pcorr = 0.05). In the Spanish population studied, the polymorphisms analysed in the IL-1ra, TNF alpha and TNF beta genes are unlikely to be important in the overall susceptibility to ulcerative colitis. However, the combination of a subclinical (p-ANCA) and a genetic (IL-1ra gene) marker identified a distinct ulcerative colitis subgroup (p-ANCA; IL-1ra genotype 1,2). These findings provide further evidence of genetic heterogeneity within ulcerative colitis, and support the concept that ANCA may represent a subclinical marker of genetic heterogeneity.

Functional Analysis of a Human Tumor Necrosis Factor α (TNF-α) Promoter Polymorphism Related to Joint Damage in Rheumatoid Arthritis

Functional heterogeneity in the tumor necrosis factor alpha (TNF-alpha) gene may be responsible for the TNF-alpha response in infectious and autoimmune diseases. Recently, the TNF-238 promoter polymorphism was observed as being associated with a more destructive disease in rheumatoid arthritis (RA). To determine the relation between TNF-238 and disease progression, the extent of joint destruction in a cohort of 101 RA patients followed for 12 years was analyzed. Furthermore, we have attempted to link this polymorphism to TNF-alpha gene transcription in monocytes and lymphocytes in vitro. The extent of joint destruction determined on X-rays of hands and feet assessed after 0, 3, 6, and 12 years was compared with TNF-238 genotypes. Functional consequences of TNF-alpha gene polymorphisms using reporter gene constructs were analyzed in cells of the monocyte and lymphocyte lineage by means of transient transfection systems. The rate of joint damage in -238GA patients was lower than that in the -238GG patients, independent of HLA-DR4. Damage after 12 years was 76 +/- 30 for the -238GA versus 126 +/- 13 for the -238GG patients as determined by the van der Heijde's modification of Sharp's method. Furthermore, TNF-238A was found to be in linkage disequilibrium with an additional polymorphism at position -376. Functional assays revealed no significant differences in the level of inducible reporter gene expression between the TNF-238/-376 promoter constructs in the cell types tested. In a prospective study, we show that the TNF-238GG genotype contributes to progression of joint destruction in RA, independent of the presence of HLA-DR4. However, in vitro transfection assays indicate that TNF-238A by itself or in combination with TNF-376A is not likely to be of direct functional relevance for transcriptional activation. Therefore, these polymorphisms may serve as markers for additional polymorphisms in the TNF/LT locus or neighboring genes that may influence disease severity.

Dissection of the effects of tumor necrosis factor-alpha and class II gene polymorphisms within the MHC on murine systemic lupus erythematosus (SLE).

Gene(s) in the MHC of the NZW strain (H-2z) up-regulate(s) systemic lupus erythematosus (SLE) in (NZB x NZW) F1 mice. So far, two plausible mechanisms have been implicated: (i) unique mixed haplotype class II molecules formed in the F1 mice act as a restriction element for self-reactive T cells and (ii) a unique polymorphism in the H-2-linked NZW tumor necrosis factor (TNF)-alpha allele which down-regulates TNF-alpha is contributory. Because of the difficulty in dissecting these alleles within the H-2 complex, it has not been determined which is indeed the case. We addressed this issue by establishing three different H-2-congenic (NZB x NZW) F1 mice bearing distinct haplotypes at class II and TNF-alpha regions, i.e. (NZB x NZW) F1 (H-2d/z:A(d/u)E(d/u)TNF(d/z)), (NZB x NZW.PL) F1 (H-2(d/u):A(d/u)E(d/u)TNF(d/d)) and (NZB x NZW.H-2d) F1 (H-2(d/d):A(d/d)E(d/d)TNF(d/d)). Among these, only (NZB x NZW) F1 produced a markedly lower level of TNF-alpha, due to the unique NZW TNF-alpha allele (TNF(z)). Studies of anti-DNA antibodies and lupus nephritis revealed that, compared to (NZB x NZW) F1, the disease of (NZB x NZW.H-2d) F1 was markedly reduced. In (NZB x NZW.PL) F1, the onset of renal disease was significantly delayed, while the extent of proteinuria and renal histopathology in individuals that had developed the disease was comparable to that seen in (NZB x NZW) F1. It seems likely that both class II and TNF-alpha gene polymorphisms are functioning as H-2-linked predisposing genetic elements, and that the TNF-alpha polymorphism acts to modulate an initial process of the renal disease.

Tumor necrosis factor gene polymorphisms in ankylosing spondylitis.

Despite the strength of the association of ankylosing spondylitis (AS) with HLA-B27, other genetic elements could play a possible role in the pathophysiology of AS. In view of its gene location, in the proximity of the HLA-B locus, and biological effects, tumor necrosis factor (TNF) genes are potential candidates for additive susceptibility factors to AS. TNFalpha and TNFbeta genotypes were analyzed by PCR-RFLP in 57 patients with AS, 102 random controls and 30 HLA-B*27-positive controls. No significant differences of TNFalpha promoter variations at position -308 and -238 were found in AS patients in comparison with controls. The -244 polymorphism was not detected in our population. The TNFbeta genotype frequency was significantly different between AS patients and random controls. However, when the distribution of the TNFbeta genotype was compared in B*27-positive AS patients and controls, these differences disappeared. In addition, we demonstrated that the TNFbeta*1 was in strong linkage disequilibrium with the B*27 allele, which may explain the differences observed for the TNFbeta genotype among AS patients and random controls. Our data suggest that the polymorphisms of TNFalpha and TNFbeta genes do not have an independent effect on AS susceptibility.

Study on the relationship between tumour necrosis factor gene polymorphism and prognosis in the patients with renal cell carcinoma

Clinical significance of polymorphism of tumour necrosis factor (TNF) genes encoded on the short arm of the 6th chromosome in the patients with renal cell carcinoma (RCC) has not been evaluated well so far. We studied on the TNF genes polymorphism of RCC focusing on the relationship between the genetic polymorphism and the prognosis. The subjects were seventy-three patients with RCC treated at our hospitals during the past 20 years. The genomic DNA was examined by the methods of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) from frozen peripheral blood of these patients. The items examined were the genetic polymorphisms of TNF-alpha (alpha 1, alpha 2) and TNF-beta (beta 1, beta 2), and we tried to study on the prognostic outcome of RCC based upon each zygote of TNF. 1) The proportion of TNF-alpha and TNF-beta polymorphisms: We observed TNF-alpha 1/1 homozygote in 71 patients (97.3%). As to TNF-beta polymorphism, we observed TNF-beta 2/2 homozygote in 33 patients (45.2%), TNF-beta 1/2 heterozygote in 31 (42.5%) and TNF-beta 1/1 homozygote in 9 (12.3%). The proportion of TNF-beta polymorphism was almost the same as that of healthy Japanese. 2) PROGNOSIS: Regarding the 17-year survival, all patients with TNF-beta 1/1 homozygote were alive, and we observed a significantly favourable prognosis in the patients with TNF-beta 1/1 homozygote compared with other zygotes of TNF-beta polymorphism. The reasons for these favourable prognosis were thought that the patients with TNF-beta 1/1 homozygote showed much lower stage and/or grade than those of other zygotes. We conclude that the TNF-beta gene polymorphism is a useful marker for understanding the prognosis of RCC and a part of cellular immunity related to the tumour and its host.

Polymorphism in the tumor necrosis factor-alpha promotor region and in the heat shock protein 70 genes associated with malignant tumors.

Tumor necrosis factors (TNFs) and heat shock protein 70 (hsp70) are determining factors in immunologic mechanisms to tumor cells. The authors designed a case-controlled study to investigate the potential association of the polymorphisms of TNF-alpha and of hsp70-2 and hsp70-hom genes with malignant tumors. The authors used an allele specific polymerase chain reaction to characterize the variation of the TNF-alpha promotor region in 124 unrelated Tunisian patients with malignant tumors (non-Hodgkin's lymphoma, breast carcinoma, and other tumors) and 106 healthy control subjects. Using polymerase chain reaction and restriction enzyme digestion, polymorphic analysis of hsp70-2 and hsp70-hom genes was performed in patients with non-Hodgkin's lymphoma, in those with breast carcinoma, and in control subjects. Analysis of TNF-alpha polymorphism in patients with malignant tumors and in control subjects demonstrated a high relative frequency of the TNF2 allele in the cancer patients. The relative risk (RR) of lymphoma was especially high in association with TNF1/TNF2 heterozygotes (RR = 6.7; P < or = 0.0001). Polymorphism analysis of the hsp70-2 and hsp70-hom genes in patients with lymphoma and in those with breast carcinoma revealed that these patients had highly significant differences in the genotypic distribution of these biallelic loci compared with the control subjects. Homozygosity for one hsp70-2 allele was significantly associated with lymphoma (RR = 18.2; P < or = 0.0001) and with breast carcinoma (RR = 16.3; P < or = 0.001). Tunisian persons carrying the TNF2 allele may have an increased risk of cancer. In this study, non-Hodgkin's lymphoma and breast carcinoma were significantly associated with polymorphism in hsp70 genes.

Polymorphism in tumor necrosis factor genes associated with mucocutaneous leishmaniasis.

Recent studies have shown that mucocutaneous leishmaniasis (MCL), a severe and debilitating form of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis infection, is accompanied by high circulating levels of tumor necrosis factor (TNF)-alpha. Analysis of TNF polymorphisms in Venezuelan ACL patients and endemic unaffected controls demonstrates a high relative risk (RR) of 7.5 (P < 0.001) of MCL disease in homozygotes for allele 2 of a polymorphism in intron 2 of the TNF-beta gene, especially in females (RR = 9.5; P < 0.001) compared with males (RR = 4; P < 0.05). A significantly higher frequency (P < 0.05) of allele 2 at the -308-basepair TNF-alpha gene polymorphism was also observed in MCL patients (0.18) compared with endemic control subjects (0.069), again associated with a high relative risk of disease (RR = 3.5; P < 0.05) even in the heterozygous condition. Because both the TNF-alpha and TNF-beta polymorphisms have previously been linked with functional differences in TNF-alpha levels, these data suggest that susceptibility to the mucocutaneous form of disease may be directly associated with regulatory polymorphisms affecting TNF-alpha production.

A tumour necrosis factor alpha polymorphism is not associated with rheumatoid arthritis.

To determine whether a polymorphism within the tumour necrosis factor alpha (TNF alpha) gene is associated with susceptibility to, or severity of, rheumatoid arthritis (RA). Consecutive patients with recent onset RA were enrolled in a prospective trial. DNA was collected, disease activity was measured at presentation, and radiographic progression at three years was assessed. Typing of TNF alpha was by polymerase chain reaction and single stranded conformation polymorphism analysis. No association of TNF alpha alleles and susceptibility to, or severity of, RA was demonstrated. These results indicate that this TNF alpha polymorphism does not play a part in the genetic background of RA.