Cross-sectional study on cytokine polymorphisms, cytokine production after T-cell stimulation and clinical parameters in a random sample of a German population

Cytokine storm-based mechanisms for extrapulmonary manifestations of SARS-CoV-2 infection

Viral illnesses like SARS-CoV-2 have pathologic effects on nonrespiratory organs in the absence of direct viral infection. We injected mice with cocktails of rodent equivalents of human cytokine storms resulting from SARS-CoV-2/COVID-19 or rhinovirus common cold infection. At low doses, COVID-19 cocktails induced glomerular injury and albuminuria in zinc fingers and homeoboxes 2 (Zhx2) hypomorph and Zhx2+/+ mice to mimic COVID-19-related proteinuria. Common Cold cocktail induced albuminuria selectively in Zhx2 hypomorph mice to model relapse of minimal change disease, which improved after depletion of TNF-α, soluble IL-4Rα, or IL-6. The Zhx2 hypomorph state increased cell membrane to nuclear migration of podocyte ZHX proteins in vivo (both cocktails) and lowered phosphorylated STAT6 activation (COVID-19 cocktail) in vitro. At higher doses, COVID-19 cocktails induced acute heart injury, myocarditis, pericarditis, acute liver injury, acute kidney injury, and high mortality in Zhx2+/+ mice, whereas Zhx2 hypomorph mice were relatively protected, due in part to early, asynchronous activation of STAT5 and STAT6 pathways in these organs. Dual depletion of cytokine combinations of TNF-α with IL-2, IL-13, or IL-4 in Zhx2+/+ mice reduced multiorgan injury and eliminated mortality. Using genome sequencing and CRISPR/Cas9, an insertion upstream of ZHX2 was identified as a cause of the human ZHX2 hypomorph state.

Association of the Interleukin-6 rs1800795 Polymorphism with Type 2 Diabetes Mellitus in the Population of the Island of Crete, Greece

BACKGROUND

Interleukin 6 (IL-6), a proinflammatory cytokine, is elevated in patients with type 2 diabetes (T2D), and is considered an independent predictor of T2D. IL-6 single-nucleotide polymorphisms (SNPs) have been associated with higher levels of IL-6. This study investigated the role of an IL-6 gene polymorphism and its possible association to T2D in the genetically homogeneous Greek population of the island of Crete.

MATERIALS AND METHODS

A total of 144 patients with T2D and 180 controls, all Cretans, selected from the Diabetes Clinic and the Department of Internal Medicine at the University Hospital of Heraklion, Crete, Greece, were genotyped for the IL-6 -174G>C (rs1800795) SNP by the restriction fragment length polymorphism method.

RESULTS

The G/C genotype and the minor allele C of the IL-6 rs1800795 SNP were more common in individuals with T2D than controls (p = 0.004, odds ratio [OR] = 1.98, 95% confidence interval [CI]: 1.24-3.18 and p = 0.011, OR = 1.59, 95% CI: 1.11-2.26, respectively).

CONCLUSION

An association of the rs1800795 SNP of the IL-6 gene with T2D has been detected for the first time in Cretans. The present results, in combination with those presented previously from different ethnic/racial populations, highlight the necessity of comparative studies among different ethnic/racial populations to detect genetic characteristics and associations with T2D.

In vitro Production of IL-6 and IFN-γ is Influenced by Dietary Variables and Predicts Upper Respiratory Tract Infection Incidence and Severity Respectively in Young Adults

Assessment of immune responses in healthy adults following dietary or lifestyle interventions is challenging due to significant inter-individual variability. Thus, gaining a better understanding of host factors that contribute to the heterogeneity in immunity is necessary. To address this question, healthy adults [n = 36, 18-40 years old, body mass index (BMI) 20-35 kg/m(2)] were recruited. Dietary intake was obtained via 3-day dietary recall records, physical activity level was evaluated using the International Physical Activity Questionnaire, and peripheral blood mononuclear cells were isolated from peripheral blood. Expression of activation markers on unstimulated immune subsets was assessed by flow cytometry. T-cell proliferation and cytokine secretion was assessed following in vitro stimulation with anti-CD3 or lipopolysaccharide. Furthermore, the incidence and severity of cold or flu symptoms were obtained from self-reported upper respiratory tract infection (URTI) questionnaires. The relationship between activation marker expression on T cells and T-cell effector functions; and in vitro cytokine secretion and URTI was determined by linear or logistic regression. CD69 and CD25 expression on unstimulated T cells was significantly associated with T-cell proliferation and interleukin-2 secretion. Incidence and severity of cold or flu symptoms was significantly associated with in vitro interleukin-6 and interferon-gamma secretion, respectively. Furthermore, host factors (e.g., age, BMI, physical activity, and diet) contributed significantly to the relationship between activation marker expression and T-cell effector function, and cytokine secretion and cold and flu status. In conclusion, these results suggest that lifestyle and dietary factors are important variables that contribute to immune responses and should be included in human clinical trials that assess immune endpoints.

Polymorphisms of immunity genes and susceptibility to otitis media in children

BACKGROUND

Acute otitis media (OM) is a common disease which often develops through complex interactions between the host, the pathogen and environmental factors. We studied single nucleotide polymorphisms (SNPs) of genes involved in innate and adaptive immunity, and other host and environmental factors for their role in OM.

METHODS

Using Sequenom Massarray platform, 21 SNPs were studied in 653 children from prospective (n = 202) and retrospective (n = 451) cohorts. Data were analyzed for the relationship between SNPs and upper respiratory infection (URI) frequency, risk of acute OM during URI episodes, and proneness to recurrent OM.

RESULTS

Increased risk for OM proneness was associated with CX3CR1 (Thr280Met) SNP and with a jointly interactive group of IL-10 (-1082) SNP, IL-1β (-511) wild type genotype and white race. Family history of OM proneness independently increased the risk for frequent URIs, OM occurrence during URI, and OM proneness. Additionally, IL-1β (-31) SNP was associated with increased risk for frequent URIs, but IL-10 (-592), IL-1β (-511), IL-5 (-746) and IL-8 (-251) SNPs were associated with decreased risk of URI.

CONCLUSION

IL-1β (-31), CX3CR1 (Thr280Met), IL-10 (-1082) and IL-1β (-511) SNPs were associated with increased risk for frequent URIs or OM proneness.

Maternal interleukin-6 (-174) C/C polymorphism is associated with chorioamnionitis and cystic periventricular leucomalacia of the preterm infant

OBJECTIVE

To evaluate the association between maternal interleukin (IL)-6 G(-174)C polymorphism and cystic periventricular leukomalacia (cPVL) of the preterm newborn.

STUDY DESIGN

After searching a local database, we recruited 132 preterm infants with diagnosis of cPVL, 44 Caucasian mothers were also recruited to participate in this candidate gene-association study at a single teritary care center. Data related to maternal IL-6 G(-174)C polymorphisms were compared with 41 controls, and furthermore compared with data from umbilical cord blood samples from a consecutive birth cohort of 395 healthy newborns, and published data from Caucasian populations including 1104 adults, respectively. In addition, subgroup analysis was performed in cases with either history of preterm premature rupture of the membranes (PPROM) or clinical chorioamnionitis (CCA). IL-6 genotyping was performed using an allele-specific polymerase chain reaction technique.

RESULT

Frequencies of the IL-6 G(-174)C polymorphisms did not differ between cases (GG, 29.5%; GC, 54.5% and CC, 15.9%) and controls (GG, 34.2; GC, 51.2 and CC, 14.6%). Subgroup analysis of 31 cases with history of PPROM (GG, 25.8; GC, 54.8 and CC 19.4%) and controls did not reveal significant differences, but a significantly higher frequency of the CC genotype was found in 23 cases with a history of CCA (34.8%) compared with controls by either univariate (P=0.032; odds ratio 3.11, 95% confidence interval (CI) 1.11 to 8.68) or multivariate analysis (P=0.049, odds ratio 2.54, 95% CI 1.01 to 6.45). These data were confirmed by a comparing the CC genotype frequency to 395 term controls (CC 14.7%, P=0.005) and to the mean CC genotype frequency of 1104 Caucasian adults (CC 15.6%, P<0.0001).

CONCLUSION

Frequencies of the IL-6 G(-174)C polymorphisms did not differ between groups. Subgroup analysis revealed an association of the CC genotype with CCA and cPVL in the preterm newborn.

IL-2 and IL-10 gene polymorphisms are associated with respiratory tract infection and may modulate the effect of vitamin E on lower respiratory tract infections in elderly nursing home residents

BACKGROUND

Vitamin E supplementation may be a potential strategy to prevent respiratory tract infections (RIs) in the elderly. The efficacy of vitamin E supplementation may depend on individual factors including specific single nucleotide polymorphisms (SNPs) at immunoregulatory genes.

OBJECTIVE

We examined whether the effect of vitamin E on RIs in the elderly was dependent on genetic backgrounds as indicated by SNPs at cytokine genes.

DESIGN

We used data and DNA from a previous vitamin E intervention study (200 IU vitamin E or a placebo daily for 1 y) in elderly nursing home residents to examine vitamin E-gene interactions for incidence of RI. We determined the genotypes of common SNPs at IL-1beta, IL-2, IL-6, IL-10, TNF-alpha, and IFN-gamma in 500 participants. We used negative binomial regression to analyze the association between genotype and incidence of infection.

RESULTS

The effect of vitamin E on lower RI depended on sex and the SNP at IL-10 -819G-->A (P = 0.03 for interaction for lower RI). Furthermore, we observed that subjects with the least prevalent genotypes at IL-2 -330A-->C (P = 0.02 for upper RI), IL-10 -819G-->A (P = 0.08 for upper RI), and IL-10 -1082C-->T (P < 0.001 for lower RI in men) had a lower incidence of RI independent of vitamin E supplementation.

CONCLUSIONS

Studies that evaluate the effect of vitamin E on RIs should consider both genetic factors and sex because our results suggest that both may have a significant bearing on the efficacy of vitamin E. Furthermore, common SNPs at cytokine genes may contribute to the individual risk of RIs in the elderly. This trial was registered at clinicaltrials.gov as NCT00758914.

The interleukin 6 -174 C/C genotype predicts greater rhinovirus illness

Background. In adults and children with respiratory syncytial virus (RSV) infection, a polymorphism in the interleukin 6 (IL-6) promoter at position −174 predicts illness magnitude. In addition, polymorphisms in the interleukin 10 (IL-10), tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) genes are associated with immune responsiveness and the frequency of complications. Here, the effect of these polymorphisms on illness and seroconversion during infection with rhinovirus type 39 (RV39) was evaluated.

Methods. Seventy-two adults were genotyped for the selected polymorphisms, experimentally exposed to RV39, and followed to track infection, seroconversion, and symptoms and signs of illness. Regression analysis was used to determine whether these polymorphisms predicted seroconversion and illness magnitude in 57 infected subjects.

Results. The low-production IL-6 −174 phenotype (C/C genotype) was associated with greater symptom magnitudes, and the IFN-γ phenotype +874 predicted the frequency of seroconversion. No relationship between the IL-10 or TNF-α polymorphisms and any measured outcome was documented. The concentration of IL-6 protein, as measured in nasal wash fluids from subjects, was positively correlated with symptom magnitude, but it was independent of the IL-6 −174 genotypes representing the high- and low-production phenotypes.

Conclusions. These results document statistically significant associations between the IL-6 −174 and IFN-gγpolymorphisms and specific responses to experimental RV39 infection. For the IL-6 −174 polymorphism, the results replicate those for experimental RSV infection.

Genetic variants in immunoregulatory genes and risk for childhood lymphomas

To investigate whether single nucleotide polymorphisms (SNPs) in key cytokine and innate immunity genes influence risk for childhood lymphomas, we genotyped 37 children with Hodgkin's (HL) and 48 with non-Hodgkin's lymphoma (NHL), aged (1 month-14 yr), along with their 85 age- and gender-matched controls suffering from mild medical conditions. Genotypic analysis was performed for 10 SNPs from nine genes with important role in immunoregulatory pathways (IL4, IL4R, IL6, IL10, IL12, IL18, TNFalpha, IFNgamma, CD14). Analysis of SNPs genotypes revealed that the CD14 -159 C>T polymorphism was associated with significantly increased risk for HL regarding both the CC and CT genotypes (OR(CC): 5.36; 95% CI, 1.30-22.14; P = 0.02, OR(CT): 3.76; 95% CI, 1.00-14.16; P = 0.05). An indicative association between IL18-137 G>C polymorphism with the CC genotype and NHL did not reach, however, statistical significance (OR(CC), 3.78; 95% CI, 0.87-16.38; P = 0.08). In conclusion, our findings suggest that genetic variation in the CD14-159 loci may be associated with childhood HL risk; these preliminary findings need to be further confirmed in sizeable multi-centre studies along with determination of cytokines, which could provide an insight on the biologic basis underlying these findings.

DNA polymorphisms and response to treatment in patients with chronic hepatitis C: results from the HALT-C trial

BACKGROUND/AIMS

Certain host genetic polymorphisms reportedly affect the likelihood of a sustained virological response (SVR) to interferon treatment in subjects infected with hepatitis C virus (HCV). As part of the HALT-C trial we evaluated genetic associations among patients infected with HCV genotype 1 who had failed previous interferon treatment.

METHODS

SVR was determined 24 weeks after completing treatment with pegylated interferon alfa-2a and ribavirin. Eight single nucleotide polymorphisms (SNPs) were selected on the basis of previously reported associations with treatment response. Genotypes were assessed by polymerase chain reaction-based assays. The percentage of patients who achieved SVR was determined for each genotype and for an IL10 promoter diplotype.

RESULTS

Among 637 non-Hispanic Caucasian patients there were no significant associations between genotype for any individual SNP (IL10-1082, IL10-592, TNF-308, TNF-238, TGFB1 codon 25, CCL2-2518, EPHX1 codon 113 and AGT-6) and SVR, but SVR was more common among the patients who were homozygous for the ACC IL10 promoter diplotype (adjusted odds ratio, 3.24; 95% confidence interval, 1.33-7.78; p=0.001).

CONCLUSIONS

Among non-Hispanic Caucasian patients treated with peginterferon and ribavirin after failing previous treatment with interferon, homozygosity for the ACC IL10 promoter diplotype was associated with SVR.

Genetic polymorphisms in immunoresponse genes TNFA, IL6, IL10, and TLR4 are associated with recurrent acute otitis media

OBJECTIVE

Cytokines and other inflammatory mediators are involved in the pathogenesis of otitis media. We hypothesized that polymorphisms in inflammatory response genes contribute to the increased susceptibility to acute otitis media in otitis-prone children.

PATIENTS AND METHODS

DNA samples from 348 children with > or = 2 acute otitis media episodes, who were participating in a randomized, controlled vaccination trial, and 463 healthy adult controls were included. Polymorphisms in TNFA, IL1B, IL4, IL6, IL10, IL8, NOS2A, C1INH, PARP, TLR2, and TLR4 were genotyped. Genotype distributions in children with recurrent acute otitis media were compared with those in controls. Within the patient group, the number of acute otitis media episodes before vaccination and the clinical and immunologic response to pneumococcal conjugate vaccinations were analyzed.

RESULTS

The IL6-174 G/G genotype was overrepresented in children with acute otitis media when compared with controls. In the patient group, TNFA promoter genotypes -238 G/G and -376 G/G and the TLR4 299 A/A genotype were associated with an otitis-prone condition. Furthermore, lower specific anticapsular antibody production after complete vaccination was observed in patients with the TNFA-238 G/G genotype or TNFA-863 A allele carriage. Finally, the IL10-1082 A/A genotype contributed to protection from the recurrence of acute otitis media after pneumococcal vaccination.

CONCLUSIONS

Variation in innate immunoresponse genes such as TNFA-863A, TNFA-376G, TNFA-238G, IL10-1082 A, and IL6-174G alleles in the promoter sequences may result in altered cytokine production that leads to altered inflammatory responses and, hence, contributes to an otitis-prone condition.

Optimization of candidate-gene SNP-genotyping by flexible oligonucleotide microarrays; analyzing variations in immune regulator genes of hay-fever samples

Background

Genetic variants in immune regulator genes have been associated with numerous diseases, including allergies and cancer. Increasing evidence suggests a substantially elevated disease risk in individuals who carry a combination of disease-relevant single nucleotide polymorphisms (SNPs). For the genotyping of immune regulator genes, such as cytokines, chemokines and transcription factors, an oligonucleotide microarray for the analysis of 99 relevant SNPs was established. Since the microarray design was based on a platform that permits flexible in situ oligonucleotide synthesis, a set of optimally performing probes could be defined by a selection approach that combined computational and experimental aspects.

Results

While the in silico process eliminated 9% of the initial probe set, which had been picked purely on the basis of potential association with disease, the subsequent experimental validation excluded more than twice as many. The performance of the optimized microarray was demonstrated in a pilot study. The genotypes of 19 hay-fever patients (aged 40–44) with high IgE levels against inhalant antigens were compared to the results obtained with 19 age- and sex-matched controls. For several variants, allele-frequency differences of more than 10% were identified.

Conclusion

Based on the ability to improve empirically a chip design, the application of candidate-SNP typing represents a viable approach in the context of molecular epidemiological studies.

Myxovirus-1 and protein kinase haplotypes and fibrosis in chronic hepatitis C virus

Candidate genes, including myxovirus resistance-1 (Mx1), protein kinase (PKR), transforming growth factor-beta1 (TGF-beta), interleukin-10 (IL-10), and interferon-gamma (IFN-gamma), were evaluated for associations with liver fibrosis in 374 treatment-naive patients with genotype-1 chronic HCV infection [194 Caucasian Americans (CAs) and 180 African Americans (AAs)], using a genetic haplotype approach. Among the 18 haplotypes that occurred with a frequency >or=5% in the cohort overall, the Mx1-(-123C)-(+6886A)-(+19820G(379V))-(+38645T) (abbreviated Mx1-CAGT), and PKR-(+110T)-(+7949G)-(+13846A)-(+22937T)-(+40342T) (abbreviated PKR-TGATT) haplotypes were independently associated with less severe hepatic fibrosis (Ishak >or= 3 versus <3). These associations persisted after adjustment for potential confounders such as alcohol use, sex, age (which is strongly correlated with the estimated duration of HCV infection [Spearman's correlation coefficient (r(s)) = 0.6)], and race (for Mx1-CAGT: OR = 0.33; 95% CI: 0.16-0.68; P = 0.0027; and for PKR-TGATT: OR = 0.56; 95% CI: 0.32-0.98; P = 0.0405). Population structure was evaluated using the structured association method using data from 161 ancestry-informative markers and did not affect our findings. We used an independent cohort of 34 AA and 160 CA in an attempt to validate our findings, although notable differences were found in the characteristics of the two patient groups. Although we observed a similar protective trend for the Mx1-CAGT haplotype in the validation set, the association was not statistically significant.

CONCLUSION

In addition to other factors, polymorphisms in cytokine genes may play a role in the progression of HCV-related fibrosis; however, further studies are needed.

Effects of chronic stress and interleukin-10 gene polymorphisms on antibody response to tetanus vaccine in family caregivers of patients with Alzheimer's disease

OBJECTIVE

To assess the effects of psychological stress on the antibody response to tetanus vaccine adjusting for cytokine gene polymorphisms and other nongenetic factors in caregivers of patients with Alzheimer's disease (AD).

METHODS

A family-based follow-up study was conducted in 119 spouses and offspring of community-dwelling patients with AD. Psychological stress was measured by the Perceived Stress Scale (PSS) and the Center for Epidemiologic Studies Depression (CES-D) scale at baseline and 1 month after the vaccination. Nutritional status, health behaviors, comorbidity, and stress-buffering factors were assessed by self-administered questionnaires, 10 single nucleotide polymorphisms (SNP) from six selected cytokines genotyped, and anti-tetanus toxoid immunoglobulin G (IgG) concentrations tested using enzyme-linked immunosorbent assays. The effects of stress and other potential confounders were assessed by mixed models that account for familial correlations.

RESULTS

The baseline PSS score, the baseline CES-D score, the interleukin-10-1082 A>G SNP GG genotype, and the baseline anti-tetanus IgG were inversely associated with antibody fold increase.

CONCLUSION

Both psychological stress and cytokine gene polymorphisms affected antibody fold increase. The study provided additional support for the detrimental effects of psychological stress on the antibody response to tetanus vaccine.

Dexamethasone in adults with community-acquired bacterial meningitis

Bacterial meningitis in adults is a severe disease with high fatality and morbidity rates. Experimental studies have shown that the inflammatory response in the subarachnoid space is associated with an unfavourable outcome. In these experiments, corticosteroids, and in particular dexamethasone, were able to reduce the inflammatory cascades in the subarachnoid space. The use of corticosteroids as adjunctive therapy in adults with bacterial meningitis has been evaluated in six studies, performed over a time period of 40 years. Most studies on adjunctive dexamethasone therapy in adults with bacterial meningitis were limited by methodological flaws. In 2002, a study with sufficient statistical power to show significant differences was published. This European Dexamethasone Study showed that adjunctive dexamethasone therapy reduced the rate of unfavourable outcomes in adults with bacterial meningitis from 25% to 15%. In this study, adjunctive treatment with dexamethasone was given before or with the first dose of antibacterials, without serious adverse effects. A quantitative review showed a consistent beneficial effect of dexamethasone on mortality and a borderline statistical beneficial effect on neurological sequelae. On the basis of the available evidence, adjunctive dexamethasone therapy should be initiated before or with the first dose of antibacterials and continued for 4 days in all adults with suspected or proven bacterial meningitis, regardless of bacterial aetiology. In patients with both meningitis and septic shock, dexamethasone therapy cannot be unequivocally recommended, but the use of lower doses seems reasonable at present. Since prompt use of dexamethasone and appropriate antibacterials improves the prognosis of adults with bacterial meningitis, hospitals will require protocols to include dexamethasone with the initial antibacterial therapy.

Cytokine typing: SNP allele frequencies in the Iranian population

Single nucleotide polymorphisms within the promoter or other regulatory sequences of cytokine genes were evaluated and compared between an Iranian population and populations of different ethnic/geographical background. In 40 healthy Iranian subjects, cytokine typing was performed by polymerase chain reaction-sequence-specific primers assay. Allele frequencies were calculated and compared with those of other populations.

Case-control study in basal cell carcinoma of the skin: single nucleotide polymorphisms in three interleukin promoters pre-analysed in pooled DNA

BACKGROUND

Basal cell carcinoma (BCC) is one of the most common neoplasms in the world. Development of BCC is associated with environmental factors (especially sun exposure) as well as heritable factors.

OBJECTIVES

To analyse three single nucleotide polymorphisms (SNPs) in the promoter regions of interleukin (IL) genes in genomic DNA from 527 cases of BCC and 530 matched controls and to examine if DNA pooling is a useful method on which to base decisions regarding further SNP analysis.

METHODS

The SNPs analysed were IL6-597, IL10-1082 and IL1B-511. The SNPs were first analysed from pooled DNA and afterwards from individual samples. The DNA pools resulted from a division of the samples into cases and controls, female and male, and three age groups. In these pools the allele frequencies were estimated by two methods, real-time polymerase chain reaction with allele-specific primers, and quantitative sequencing.

RESULTS

No significant association was found when the allele frequencies in cases and controls were compared. However, by analysis of the individual genotypes we found SNP IL6-597 G/A to be significantly associated with BCC risk (P =0.007). Hereby the heterozygous genotype 'GA' had a protective effect (odds ratio 0.64, 95% confidence interval 0.49-0.84). No significant association was found for IL10-1082 and IL1B-511.

CONCLUSIONS

The association of SNP IL6-597 with BCC could be found only by individual genotyping, but would have been missed if only data from the pooling analysis had been known.

Cytokine Single Nucleotide Polymorphisms in Iran

Overall expression and secretion of cytokines are dependent on genetic nucleotide variations within or adjacent to regulatory regions of cytokine genes. This study allows the comparison of the prevalence of particular genetic markers. In 40 Iranian healthy subjects, cytokine single nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies for the following cytokine genes: interleukin-1alpha (IL-1alpha) (T/C -889), IL-1beta (C/T -511, T/C +3962), IL-12 ( C/A-1188), interferon-gamma (IFN-gamma) (A/T UTR 5644), transforming growth factor-beta (TGF-beta) (C/T codon 10, G/C codon 25), tumor necrosis factor alpha (TNF-alpha) (G/A -308, G/A -238), IL-2 (T/G -330, G/T +166), IL-4 (T/G -1089, T/C -590, T/C -33), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-1R (C/T pst11970), IL-1RA (T/C mspa 111100), IL-4RA (G/A +1902). All typing was performed using the PCR-SSP assay. Iranian and Italian, English, German, and Greek populations had similar cytokine profiles, but in some cases, the Iranian allele and genotype frequencies were significantly different from those of other Asian and African American populations for the majority of polymorphisms.

Combined polymorphisms of tumour necrosis factor alpha and interleukin-10 genes in patients with alcoholic hepatitis

OBJECTIVES

The development and progression of alcoholic hepatitis are controlled by an extensive cytokine network which involves pro-inflammatory and anti-inflammatory cytokines. Genetic variations determining production of these cytokines have been described and the susceptibility to the disease may be determined by an imbalance in the expression of several candidate genes.

METHODS

We have studied biallelic single nucleotide polymorphisms at positions (-308) and (-238) in the promoter region of the pro-inflammatory tumour necrosis factor alpha (TNF-alpha) and at positions (-1,082) and (-592) in the promoter of anti-inflammatory interleukin-10 (IL-10) in 134 patients with severe biopsy-proven alcoholic hepatitis and 145 healthy subjects.

RESULTS

The frequency distribution of isolated cytokine genotypes did not differ between the two groups. The combination of at least one A or A allele for TNF-alpha, associated with a TNF-alpha high-producer phenotype, and one A or A allele for IL-10, associated with an IL-10 low-producer phenotype, was less frequent in patients (20.9 vs 33.8%, P=0.016, OR (95% CI)=0.52 (0.30-0.89)). The same combination in patients was associated with a higher risk of septic complications (32.5 vs 16.0%, P=0.031, OR (95% CI)=1.79 (1.07-6.00)) but not with in-hospital mortality.

CONCLUSIONS

We have not found any relationship between the isolated polymorphisms and the risk of alcoholic hepatitis. Moreover, the imbalance between the pro-inflammatory and anti-inflammatory responses leading to high TNF-alpha production and low IL-10 was uncommon in alcoholic hepatitis. However, patients with this particular genotype appeared more susceptible to severe septic complications.

No Association Between Selected Candidate Gene Polymorphisms and Severe Chronic Periodontitis

BACKGROUND

Chronic periodontitis (CP) risk is influenced by environmental and genetic factors. Using a case-control design, we tested for associations between CP and selected DNA sequence variations (single nucleotide polymorphisms [SNPs]) in or near genes coding for proteins that play a role in the pathogenesis of this disease.

METHODS

DNA was analyzed from 219 whites who were examined clinically. Cases (N=137) were >or=35 years of age with eight or more teeth having >or=5 mm of proximal clinical attachment loss. Controls (N=82) were >or=45 years of age with minimal or no proximal attachment loss or pocketing. Nine diallelic polymorphisms (gene and SNP descriptor) were studied in subjects: cytotoxic T-lymphocyte antigen-4 (CTLA-4, 49 A>G), human beta-defensin-1 (DEFB1, 692 G>A), intercellular adhesion molecule-1 (ICAM-1, 1548 A>G), Fas ligand (fasL, -844 C>T), inducible costimulator (ICOS, 3990 G>T), interleukin-6 (IL-6, -174 G>C), cysteine-cysteine chemokine receptor-5 (CCR5, 59653 C>T), osteoprotegerin (OPG, 245 T>G), and osteopontin (OPN, 707 C>T). Genotypes were determined using an automated fluorogenic 5'-nuclease, polymerase chain reaction-based assay. Gender and smoking history (pack-years) were included as covariates in logistic regression analyses.

RESULTS

Heavy smoking (>10 pack-years) and male gender were significantly associated with disease (P<0.001). For all SNPs tested, the allele frequencies and distributions of genotypes did not differ between cases and controls (P>0.05). No unadjusted or adjusted odds ratios (comparing genotypes in cases versus controls) were significantly different than 1.0 (P>0.05) under any additive, dominant, or recessive inheritance model.

CONCLUSIONS

None of the SNPs tested were strongly associated with generalized severe chronic periodontitis in North American whites. A potentially more fruitful approach in future studies will be to test for associations between periodontitis and haplotype blocks constructed from either multiple SNPs in candidate gene regions or from panels of markers that span the entire genome.

Frequencies of the common promoter polymorphisms in cytokine genes in a Polish population

Common polymorphisms in cytokine genes, widely distributed in many populations, may affect gene transcription, leading to individual variations in cytokine levels. Some of those polymorphisms were associated with the risk of graft rejection or autoimmune and parasitic diseases development as well as treatment outcome. In the current study the frequencies of promoter polymorphisms in genes encoding interleukin-2 (-330 G/C), interleukin-4 (-590 C/T), interleukin-6 (-174 G/C), interleukin-10 (-1082 G/A, -592 C/A) and TNFalpha (-307 G/A) have been studied in a sample of 205 unrelated healthy Polish subjects of Caucasian origin. The frequencies of the determined cytokine alleles were as follows: interleukin-2 (-330 G/C): T -64.9%, G -35.1%; interleukin-4 (-590 C/T): C -79.8%, T -20.2%; interleukin-6 (-174 G/C): G -53.4%, C -46.6%; interleukin-10 (-1082 G/A, -819 G/T, -592 C/A): GCC -44.1%, ACC -32.0, ATA -23.9%; TNFalpha (-307 G/A): G -85.1%, A -14.9%. We also compared our results with other populations studied to date, describing some significant differences.

Polymorphism in the genes of alpha and beta tumor necrosis factors (TNF-alpha and TNF-beta) and gamma interferon (IFN-gamma) among Iranian women with breast cancer

The association of the polymorphism in the genes of TNF-alpha, TNF-beta and IFN-gamma with breast cancer was investigated in the present study. There were no differences in the TNF-alpha and TNF-beta alleles and genotypes frequencies between breast cancer patients (n=223) and control subjects (n=267). The correlations between TNFA or TNFB alleles or genotypes and clinicopathological indices were also insignificant. However, the frequency of IFN-gamma+874 T/T genotype was significantly higher in breast cancer patients compared to those of controls (P<0.002; OR=2.03, 95% CI=1.28-3.2) which indicates that Iranian women carrying the IFN-gamma+874 T/T genotype may be exposed to an increased risk of breast cancer development.

The intercellular adhesion molecule-1 (ICAM-1) gene K469E polymorphism is not associated with ischaemic heart disease: an investigation using family-based tests of association

The possible role of the K469E polymorphism in the intercellular adhesion molecule-1 (ICAM-1) gene in the susceptibility to ischaemic heart disease (IHD) was investigated in a well-defined Irish population using two recently described family-based tests of association. One thousand and twelve individuals from 386 families with at least one member prematurely affected with IHD were genotyped for the ICAM-1 K469E polymorphism. Using the combined transmission disequilibrium test (TDT)/sib-TDT and the pedigree disequilibrium test (PDT), no association between the ICAM-1 K469E polymorphism and IHD was found. Our data demonstrate that, in an Irish population, the ICAM-1 K469E polymorphism is not associated with IHD.

Immunosurveillance of childhood ALL: polymorphic interferon-γ alleles are associated with age at diagnosis and clinical risk groups

Interferon-gamma (IFN-gamma) has been implicated as an important mediator of antitumor immunity in murine model systems. To determine whether a CA-repeat associated with differential NFkappaB-binding and IFN-gamma-expression levels may influence the incidence, manifestation and early clinical treatment response of childhood acute lymphoblastic leukemia, we performed PCR-based genotyping of 393 patients with ALL and 207 healthy controls. We could not find any differences in the allele distribution comparing patients and controls. However, when we further analyzed the allele frequencies with respect to age of clinical manifestation, we found that patients with B-lineage ALL showing the IFN-gamma high-expressing genotype presented at a more advanced age compared to those patients with intermediate and low-expressing genotypes (median 6 vs 4.4 years, P=0.01). Furthermore, we found a significantly higher number of low expressors in the group of high-risk patients (HR n=32 and MR/SR n=266, P=0.025, defined by prednisone response, cytological remission and minimal residual disease (MRD)) with B-lineage ALL. Thus, we provide evidence that polymorphic IFN-gamma alleles are associated with age at clinical presentation and risk groups such as prednisone response in B-lineage ALL, suggesting distinct effects of IFN-gamma in immunosurveillance and early response to steroid therapy.

Comprehensive Analysis of Genetic Polymorphisms in the Interleukin-10 Promoter: Implications for Immune Regulation in Specific Ethnic Populations

The association of interleukin-10 (IL-10) promoter single-nucleotide polymorphisms (SNPs) as risk factors for certain inflammatory diseases, viral infections, cancers, and transplant rejection have been the subject of recent studies. The SNPs -1082 G --> A, -819 C --> T, and -592 C --> A, which have been associated with differential IL-10 production, are strongly linked with ethnicity. In this study, we determined the ethnic distribution of IL-10 promoter SNPs and their haplotype rates among Hispanics, African Americans, and Caucasians from Texas and Ashkenazi Jews from New York. Significant differences in prevalence rates of IL-10 SNPs (and their haplotype distribution) were found. African Americans and Hispanics have a lower rate of putative high-producer SNPs and a higher rate of low IL-10 producers when compared to Caucasians or Ashkenazi Jews. No statistically significant differences in allelic frequencies and haplotype rates were observed between Caucasians and Ashkenazi Jews. This study provides critical new information on the ethnic distribution of IL-10 promoter SNPs in a regional U. S. population and is the first to analyze the rate of SNPs in an unstudied ethnic population, Ashkenazi Jews. Knowledge of IL-10 promoter polymorphisms may prove useful in prediction of immunization responses, disease severity, and in the intelligent design of customized immunotherapy.

Single nucleotide polymorphisms in the interferon-gamma and interleukin-10 genes do not influence chronic hepatitis C severity or T-cell reactivity to hepatitis C virus

BACKGROUND

The mechanisms by which interferon-gamma (IFN-gamma) contributes to inter-individual heterogeneity in the severity of chronic hepatitis C (CH-C) are unknown. In 116 consecutive patients with CH-C, we tested the hypothesis that host genetic factors regulating IFN-gamma production and activity influence the severity of liver damage and hepatitis C virus (HCV)-specific T-cell reactivity.

METHODS

We determined the genotypes of functionally significant polymorphisms in the IFN-gamma gene and in the promoter of interleukin-10 (IL-10), a cytokine that counteracts IFN-gamma. We also measured concanavalin A (Con A)-stimulated IL-10 and IFN-gamma production, and the frequency of virus-specific T-cells, producing IFN-gamma or IL-10.

RESULTS

The grade of inflammation and the stage of fibrosis of CH-C showed no associations with either the IFN-gamma or IL-10 promoter polymorphisms or with Con A-stimulated IL-10 or IFN-gamma production. Similarly, there were no associations between HCV-specific T-cell frequencies and these host genetic factors. On multivariate analysis, the grade of inflammation and the duration of HCV infection accounted for only 37% of the variance in the stage of CH-C (P<0.0001). This percentage did not increase by including any genetic variables in the analyses.

CONCLUSION

Future studies investigating the entire cytokine gene sequences will provide better information regarding genetic variations responsible for inter-individual differences in the severity of CH-C.

Association of polymorphisms in Th1, Th2 cytokine genes with hayfever and atopy in a subsample of EPIC-Heidelberg

BACKGROUND

Hayfever is determined by an interaction of environmental and genetic factors and biologically characterized by an imbalanced T helper cell 1 (Th1) and Th2 immune response and elevated IgE levels against inhalant allergens. Indications exist that polymorphisms in cytokine genes involved in the regulation of the Th1/Th2 balance may contribute to the allergic phenotype.

OBJECTIVE

We investigate whether polymorphisms in genes directly or indirectly involved in Th1, Th2 immune response are associated with hayfever and elevated IgE levels against inhalant allergens.

METHODS

From a subsample of the European Prospective Investigation into Cancer and Nutrition-Heidelberg, 322 subjects with hayfever and 322 age- and sex-matched non-allergic controls were selected and genotypes determined for 15 polymorphisms in 13 genes. Plasma IgE against inhalant allergens was measured via CAPSX1 (Phadiatop) test. We computed odds ratios (ORs) by logistic regression, tests on group differences of IgE-levels in dependence upon genotype and tests for trend by means of non-parametric methods.

RESULTS

We found decreased OR for hayfever (OR=0.60, 95%CI=0.4-0.9) and sensitization to inhalant antigens (OR=0.5, 95%CI=0.4-0.8) in heterozygotes of the IL-6 -174 G/C polymorphism. Homozygotes of the G-allele in IL-2 -330 T/G were at increased risk of hayfever (OR=2.6, 95%CI=1.3-5.2). Moreover, we found indications for differences in IgE levels against inhalant allergens in dependence upon genotypes of polymorphisms in IL-4R, IL-6, IL-13, and IL-18.

CONCLUSION

Our data suggest an association of genetic variants in IL-6 and IL-2 with hayfever, confirm a role of polymorphisms in IL-4R, IL-13, and IL-18 for the elevated IgE phenotype, and add IL-6 to the list of candidate genes.

Cytokine gene polymorphisms in multifactorial diseases: gateways to novel targets for immunotherapy?

Recent advances in cytokine biology have led to novel approaches to the treatment of inflammatory diseases. In this article, we review recent data regarding the role of functional polymorphisms in the genes encoding the prototypic Th1 cytokine interferon gamma and Th2 cytokine interleukin 4 in multifactorial disorders. We have compared genetic data across a heterogeneous assortment of such conditions using a 'haplotype tagging' approach, and demonstrate that cytokine gene association studies are instrumental in the identification of specific disease states or clinical manifestations that are probably caused by genetically determined aberrant cytokine expression. Some of these new findings suggest cytokine effects that go beyond a classical Th1-Th2 dichotomy. Thus, we propose that this information could provide novel targets for immunotherapy and, in particular, might facilitate the identification of clinical subgroups of patients who, by virtue of their genetic constitution at these cytokine gene loci, are more likely to benefit from cytokine agonist or antagonist therapy.

Genetic and environmental influences on IL-6 and TNF-alpha plasma levels in apparently healthy general population

Dysregulation of cytokines synthesis is thought to play a role in the development of a number of age-related conditions, such as rheumatoid arthritis, osteoporosis, atherosclerosis, and others, but observational studies have led to contradictory results. We investigated potential familial influences on the plasma levels of IL-6 and TNF-alpha in 91 nuclear and more complex pedigrees of Caucasian ethnic origin (N=401 individuals). The maximum likelihood based variance decomposition analysis showed significant positive correlation between circulating IL-6 and age in both genders. The magnitude of these correlations in our sample ranged from 0.22 in females to 0.28 in males (P<0.001). Significant association between TNF-alpha and IL-6 (r=0.28, r=0.43; P<0.001; respectively for men and women) was also observed. Likelihood ratio test clearly revealed that additive genetic effect for TNF-alpha was highly significant (P<0.001), and accounted over 80% of its variation, adjusted for IL-6 levels and age. In contrast, heritability estimate for IL-6 adjusted for age and TNF-alpha, revealed small contribution of genetic factors (24.1 +/- 10.2%). The bivariate variance component analysis demonstrated that significant relationship between IL-6 and TNF-alpha was due to shared environment only (r(E)=0.760 +/- 0.140). As evinced from our complex segregation analysis the nature of the genetic determinant of each of these two cytokines is quite complex and it is probably oligogenic.

Genotyping for cytokine polymorphisms: allele frequencies in the Italian population

It has been demonstrated that many cytokine genes [e.g. tumour necrosis factor alpha (TNF-alpha) and interleukin 10 (IL-10)] show polymorphisms which may affect gene transcription, causing individual variations in cytokine production. The majority of polymorphisms described are single nucleotide polymorphisms (SNPs). In 140 healthy Italian subjects, the allelic and genotype frequencies were determined for the cytokine genes IL-1 alpha (T/C -889), IL-1 alpha (C/T -511, T/C +3962), IL-12 (C/A -1188), interferon (IFN)-gamma (A/T UTR 5644), transforming growth factor (TGF)-alpha (C/T codon 10, G/C codon 25), TNF-alpha (G/A -308, G/A -238), IL-2 (T/G -330, G/T +166), IL-4 (T/G -1098, T/C -590, T/C -33), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-1R (C/T pst11970), IL-1RA (T/C mspa111100) and IL-4RA (G/A +1902). All typings were performed with PCR-SSP assays. Allele and genotype frequencies and linkage disequilibria were calculated and compared with those of other populations.

Are cytokine gene polymorphisms related to in vitro cytokine production profiles?

Currently, there is much interest in the genetic basis for diseases or disease manifestations and, in particular, in whether they are related to cytokine gene polymorphisms. It has become accepted to denote such single-nucleotide polymorphisms of cytokine genes by their presumed association with high or low in vitro cytokine production. In this article, we analyze the relationship between cytokine gene polymorphisms and in vitro tumor necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma), and interleukin (IL)-10 and IL-13 production, both in liver transplant recipients and in healthy volunteers. The evaluated cytokine gene polymorphisms involved TNF-A-308; TNF-d3; IFN-G+874; IL-10-1082, -819, and -592; and IL-13+2043, and -1055. For healthy volunteers, we observed a relationship between polymorphisms of TNF-d3 and IL-10-1082 with in vitro production of TNFalpha and IL-10, respectively, whereas no significant associations were found for the other tested cytokine gene polymorphisms. For liver transplant recipients, no significant relationship could be established between any of the cytokine gene polymorphisms and in vitro production of corresponding cytokines. Also, we reviewed the literature for the association between cytokine gene polymorphisms and in vitro cytokine production in various patient groups and healthy volunteers. We found that the cellular sources, from which the cytokines were released into the culture supernatant, were different between studies. They were either whole blood, isolated monocytes, or peripheral blood mononuclear cells (PBMC). Also, the in vitro incubation protocol varied to a great extent between studies. This applied for the used in vitro stimulant, the concentration of a particular stimulant, and the length of the incubation period. Moreover, the study populations were either healthy individuals or very diverse patient groups. Therefore, it was impossible to evaluate whether in vitro cytokine production profiles really can be deduced from a particular cytokine gene polymorphism. Given the inconclusive findings, we propose to set up a multicenter workshop in which the relationship between certain cytokine gene polymorphisms and in vitro cytokine production is analyzed, using an identical in vitro cell culture system and study population. Furthermore, we suggest that cytokine gene polymorphisms be described by their localization within the gene or gene-promoter, rather than by their presumed in vitro cytokine production profile, to properly evaluate the relationship between cytokine gene polymorphisms and disease manifestations.

Frequency of cytokine polymorphisms in populations from western Europe, Africa, Asia, the Middle East and South America

PCR-SSOP identification procedures for IL-2, IL-6, IL-10, TNF-alpha and TNF-beta cytokine polymorphisms have been developed. Application of the procedures to a range of diverse geographically distributed populations has identified ethnic differences within the groups studied. Five populations were investigated, Northern Ireland, South African Zulu, Omani, Singapore Chinese and Mexican Mestizos.

Differential regulation of interleukin-10 production by genetic and environmental factors--a twin study

Interleukin-10 (IL-10) has a critical role in the regulation of immune responses. The relative contribution of genetic and environmental factors to IL-10 production is under debate. We performed a twin study in 246 monozygotic and dizygotic twins to assess the heritability of IL-10 production after LPS stimulation in whole blood. In addition, the influence of promoter single nucleotide polymorphisms (-1082, -819 and -592) on transcriptional activity and their binding to nuclear factors was studied in luciferase reporter gene and electrophoretic mobility shift assays. IL-10 production showed a genetic determination with a heritability of 0.5. Decreasing body mass index (BMI), smoking and female gender lead to decreased IL-10 production. In monocytes, the -1082A allele showed higher binding affinity to the transcription factor PU.1 resulting in decreased transcriptional activity of -1082A promoter haplotypes. Genetic determination of IL-10 secretion is probably lower than that previously reported. Fifty percent of the observed variability explained by genetic factors. Female individuals produce less IL-10 than male subjects. Environmental factors like smoking and decreasing BMI exert suppressing effects on IL-10 production. Although the -1082A allele shows higher binding affinity to the PU.1 transcription factor and lower transcriptional activity, this polymorphism probably explains only a small fraction of the observed heritability.

Interferon-gamma gene polymorphisms and the development of sepsis in patients with trauma

BACKGROUND

The outcome of patients with trauma does not always correlate with injury severity or premorbid health status. This study evaluates the relationship between polymorphisms in the first intron of the interferon-gamma gene and the development of sepsis after trauma.

METHODS

DNA was extracted from peripheral leukocytes of patients with trauma and an injury severity score of 16 or greater. Data collected included demographics, injury mechanism, injuries sustained, development of sepsis, and outcome. A previously identified cytosine/adenine repeated polymorphism was amplified, alleles/genotypes identified, and the results correlated with patient outcome.

RESULTS

Sixty-one patients were evaluated. Thirty patients (49%) became septic. The injury severity score, race, age, and gender distribution was similar for both the septic and nonseptic groups. Six alleles and 10 genotypes were identified. Alleles C (34%) and D (52%) were the most common. Patients who were septic had a 62% chance of having a D allele (P =.06), whereas they had only a 29% chance of having a C allele. Homozygotes for allele D (DD) were the most likely to become septic (65%).

CONCLUSIONS

Homozygotes for the D allele (DD) of the interferon-gamma gene have an increased chance of developing sepsis after traumatic injury compared with other allelic combinations. This supports the hypothesis that genetic composition plays a role in patient outcome.

Is there a common cold constitution?

OBJECTIVE

Constitutional factors might play a role in the susceptibility to clinical illness during the common cold. This study seeks to determine if the likelihood of developing frequent common colds persists during childhood.

DESIGN

The Tucson Children's Respiratory Study involves 1246 children enrolled at birth and followed prospectively since 1980 and 1984. Parents reported the occurrence of frequent (> or =4) colds during the past year by questionnaire at 2, 3, 6, 8, 11, and 13 years of age. Blood for ex vivo interferon-gamma responses was obtained at 9 months and 11 years of age.

RESULTS

After adjustment for potential confounding variables, children with frequent colds at year 2 or 3 were twice as likely to experience frequent colds at year 6 (relative risk [RR], 2.8; 95% confidence interval [CI], 2.1-3.9), year 8 (RR, 2.6; 95% CI, 2.1-3.3), year 11 (RR, 2.4; 95% CI, 1.8-3.1), and year 13 (RR, 2.1; 95% CI, 1.4-3.3) compared with children who had infrequent colds at years 2 and 3. At 9 months of age, children who ultimately experienced persistent frequent colds had lower interferon-gamma titers than children without persistent frequent colds (3.05 +/- 1.61 vs 3.74 +/- 1.39, P =.016); this finding persisted at 11 years of age.

CONCLUSION

These data suggest the existence of a common cold constitution, whereby some children are more susceptible to infection and/or the expression of clinical symptoms when infected than are other children.

Allele frequencies of polymorphisms of TNFA, IL-6, IL-10 and IFNG in an Italian Caucasian population

Polymorphisms in the regulatory and intronic regions of several cytokines have been associated with differential cytokine production. In this paper we genotyped, using the polymerase chain reaction-sequence-specific primers (PCR-SSP) method, a series of 363 healthy Italian Caucasians with the aim of obtaining a reference population for further studies on the role of cytokines in the inflammatory and immune responses. We also compared the results to those for other populations. The polymorphisms analysed were those of tumour necrosis factor alpha (TNFA), interleukin 6 (IL-6), interleukin 10 (IL-10) and interferon gamma (IFNG). We found that the frequency of allele TNFA*1 at position -380 was 87.7% and that of TNFA*2 was 12.4%, significantly different from those of the UK and Japanese populations but not different from that of a population in Gambia. For IL-10 the frequencies of alleles -1082A and -1082G were 63.0% and 37.0% and those of alleles -819C, - 819T, -592C and -592A were 70.8, 29.2, 70.8 and 29.2%, respectively, significantly different from those observed in south-east England, in Manchester and in an Oriental population from southern China. The frequencies of IL-6 alleles - 174C and -174G were 29.0 and 71.0%, respectively; for IFNG polymorphisms at position -874, in the population under evaluation, the alleles -874T and -874A were present in 44.7 and 55.3% of the subjects, respectively. Genotype frequencies of IL-6 were significantly different from those observed in populations from Germany and from the UK. The analysis carried out by our group indicates that there is heterogeneity in the frequencies of the cytokine polymorphisms among the different Caucasian populations, and this underlines the importance of a 'local' reference population when evaluating the clinical relevance of cytokine gene polymorphisms.

Effect of HLA-DR matching on acute rejection after clinical heart transplantation might be influenced by an IL-2 gene polymorphism

BACKGROUND

To examine whether genetic factors are involved in the development of acute rejection (AR), we investigated a (CA)m(CT)n repeat in the 3'-flanking region of the interleukin (IL)-2 gene.

METHOD

We genotyped 290 heart transplant recipients with and without AR (International Society for Heart and Lung Transplantation criteria > or =3A) and 101 controls.

RESULTS

The frequency of allele 135 of the repeat and its genotype distribution (carriers/noncarriers) were significantly associated with freedom from AR (P=0.03 and P=0.02, respectively). We also found interaction between allele 135 and HLA-DR matching. More carriers of allele 135 with no or one mismatch remained free from AR compared to patients without the allele (P=0.01). This was not found in the HLA-DR group with two mismatches.

CONCLUSION

HLA-DR matching might only be effective in reducing AR after heart transplantation in recipients who carry allele 135 of the (CA)m(CT)n repeat in the 3'-flanking region of the IL-2 gene.