Polymorphisms within the CTLA4 gene are associated with infant atopic dermatitis

Evidence of Association between CTLA-4 Gene Polymorphisms and Colorectal Cancers in Saudi Patients

Cytotoxic T lymphocyte antigen-4 (CTLA-4) has been identified as an immunosuppressive molecule involved in the negative regulation of T cells. It is highly expressed in several types of autoimmune diseases and cancers including colorectal cancer (CRC). (1) Objective: To explore the association between CTLA-4 single nucleotide polymorphisms (SNP) and risk to (CRC) in the Saudi population. (2) Methods: In this case-control study, 100 patients with CRC and 100 matched healthy controls were genotyped for three CTLA-4 SNPs: rs11571317 (-658C > T), rs231775 (+49A > G) and rs3087243 (CT60 G > A), using TaqMan assay method. Associations were evaluated using odds ratios (ORs) and 95% confidence intervals (95% CIs) for five inheritance models (co-dominant, dominant, recessive, over-dominant and log-additive). Furthermore, CTLA-4 expression levels were evaluated using quantitative real-time PCR (Q-RT-PCR) in colon cancer and adjacent colon tissues. (3) Results: Our result showed a significant association of the G allele (OR = 2.337, p < 0.0001) and GG genotype of the missense SNP +49A > G with increased risk of developing CRC in codominant (OR = 8.93, p < 0.0001) and recessive (OR = 16.32, p < 0.0001) models. Inversely, the AG genotype was significantly associated with decreased risk to CRC in the codominant model (OR = 0.23, p < 0.0001). In addition, the CT60 G > A polymorphism exhibited a strong association with a high risk of developing CRC for the AA genotype in codominant (OR = 3.323, p = 0.0053) and in allele models (OR = 1.816, p = 0.005). No significant association was found between -658C > T and CRC. The haplotype analysis showed that the G-A-G haplotype of the rs11571317, rs231775 and rs3087243 was associated with high risk for CRC (OR = 57.66; p < 0.001). The CTLA-4 mRNA gene expression was found significantly higher in tumors compared to normal adjacent colon samples (p < 0.001). (4) Conclusions: Our findings support an association between the CTLA-4 rs231775 (+49A > G) and rs3087243 (CT60 G > A) polymorphisms and CRC risk in the Saudi population. Further validation in a larger cohort size is needed prior to utilizing these SNPs as a potential screening marker in the Saudi population.

T cell co-stimulatory and co-inhibitory pathways in atopic dermatitis

The use of immune checkpoint inhibitors (ICIs) targeting the T cell inhibitory pathways has revolutionized cancer treatment. However, ICIs might induce progressive atopic dermatitis (AD) by affecting T cell reactivation. The critical role of T cells in AD pathogenesis is widely known. T cell co-signaling pathways regulate T cell activation, where co-signaling molecules are essential for determining the magnitude of the T cell response to antigens. Given the increasing use of ICIs in cancer treatment, a timely overview of the role of T cell co-signaling molecules in AD is required. In this review, we emphasize the importance of these molecules involved in AD pathogenesis. We also discuss the potential of targeting T cell co-signaling pathways to treat AD and present the unresolved issues and existing limitations. A better understanding of the T cell co-signaling pathways would aid investigation of the mechanism, prognosis evaluation, and treatment of AD.

Association of cytotoxic T lymphocyte-associated protein 4 gene -1772T/C polymorphism with gastric cancer risk: A prisma-compliant meta-analysis

BACKGROUND

We performed a meta-analysis to more precisely evaluate the association between the cytotoxic T lymphocyte-associated protein 4 (CTLA-4) -1772T/C polymorphism and overall gastric cancer (GC) risk and the influence of ethnicity and the source of controls on that association.

METHODS

A systematic literature search was performed in PubMed, EMBASE, the Cochrane Library, Web of Science (WOS) Database, Chinese National Knowledge Infrastructure (CNKI), China biomedical literature database (CBM), Wanfang database, and VIP. Two investigators independently reviewed the articles, and disagreements were resolved by discussion and consensus. The odds ratio (OR) with 95% confidence intervals (CIs) was used to assess the strength of the association between the CTLA-4 -1722T/C polymorphism and GC risk, based on the genotype frequencies in cases and controls. The meta-analyses were performed with Stata 12.0, using two-sided P values. Trial sequential analysis (TSA) was calculated by TSA Software.

RESULTS

Overall, we identified 5 studies including 1039 GC cases and 2136 controls that evaluated the association of the CTLA-4 -1722T/C polymorphism and GC risk. Overall, there was no significant association between the CTLA-4-1722T/C polymorphism and the risk of GC. In the subgroup analysis based on ethnicity, the results showed that the relationship between the CTLA-4 -1722T/C polymorphism and GC susceptibility was strongest in the Chinese population rather than in the Iranian population (TC vs CC: OR = 1.405, 95% CI: 1.100-1.796, P = .007; TC+TT vs CC: OR = 1.329, 95% CI: 1.052-1.680, P = .017). Then, there was a significant association between the CTLA-4 -1722T/C polymorphism and the risk of GC in studies with HB controls. However, the above correlation can only be reflected in specific populations and gene models. Therefore, we believe that the evidence of this correlation is insufficient.

CONCLUSION

Our meta-analysis showed that the CTLA-4 -1722T/C polymorphism may be associated with the susceptibility to GC. However, the slight correlation can only be reflected in specific populations and gene models. Therefore, we believe that this association is negligible. The large and well-designed case-control studies are needed to validate our findings.

Atopic Dermatitis and Celiac Disease: A Cross-Sectional Study of 116,816 Patients

BACKGROUND

Both atopic dermatitis and celiac disease are often accompanied by other immune-mediated disorders.

OBJECTIVE

The objective of this study was to evaluate the potential association between atopic dermatitis and celiac disease in a broad community-based population.

METHODS

A cross-sectional observational design was used. Demographic and clinical data were collected for patients enrolled in a large health management organization who were diagnosed with atopic dermatitis by a dermatologist in 2002-17. The presence of celiac disease/celiac disease-related morbidities was recorded for the whole group, for adults (age > 18 years), and for adults with moderate-to-severe atopic dermatitis. Findings were compared with a matched control group without atopic dermatitis.

RESULTS

The study group included 116,816 patients of whom 45,157 were adults; 1909 adult patients had moderate-to-severe atopic dermatitis. Compared to the respective control subjects, the prevalence rate of celiac disease in the whole group was 0.6% vs. 0.4%; in the adults, 0.6% vs. 0.3%; and in the adults with moderate-to-severe atopic dermatitis, 0.8% vs. 0.3% (p < 0.001 for all). On multivariate analysis, atopic dermatitis was associated with a significantly higher prevalence of celiac disease (odds ratio = 1.609, 95% confidence interval 1.42-1.82, p < 0.001) in the entire study population and each subgroup.

CONCLUSIONS

We observed a significant association between atopic dermatitis and celiac disease. This association emphasizes the need for timely screening of gastrointestinal morbidities in individuals with atopic dermatitis to prevent long-term complications.

The role of regulatory T cells and genes involved in their differentiation in pathogenesis of selected inflammatory and neoplastic skin diseases. Part III: Polymorphisms of genes involved in Tregs' activation and function

Regulatory T cells (Tregs) represent a cell type that promotes immune tolerance to autologous components and maintains immune system homeostasis. The abnormal function of Tregs is relevant to the pathogenesis of several skin diseases like psoriasis, atopic dermatitis, systemic lupus erythematosus, cutaneous T-cell lymphomas, and skin cancer and is also important in rheumatoid arthritis, diabetes and other autoimmune diseases. In this review, we will summarize the role of mutations and/or polymorphisms of genes involved in Tregs development, and functions in the pathogenesis of selected skin diseases.

Impact of genetic polymorphisms on paediatric atopic dermatitis

In order to investigate whether polymorphisms of genes encoding some factors of innate and adaptive immunity play a role in the development of, or protection against atopic dermatitis (AD) and condition its severity, we genotyped 33 candidate genes and 47 single nucleotide polymorphisms (SNPs) using Custom TaqMan Array Microfluidic Cards and an ABI 7900HT analyser (Applied Biosystems, Foster City, CA, USA). The study involved 104 children with AD (29 with mild-to-moderate and 75 with severe disease; 42 girls; mean age ± SD, 5.8 ± 3.3 years) and 119 healthy controls (49 girls; mean age, 4.8 ± 3.0 years). IL10-rs1800872T, TG and MBL2-rs500737AG were all significantly more frequent among the children with AD ( P = 0.015, P = 0.004 and P = 0.030), whereas IL10-rs1800896C and TC were more frequent in those without AD ( P = 0.028 and P = 0.032). The VEGFA-rs2146326A and CTLA4-rs3087243AG SNPs were significantly more frequent in the children with mild/moderate AD than in those with severe AD ( P = 0.048 and P = 0.036). IL10-rs1800872T and TG were significantly more frequent in the children with AD and other allergic diseases than in the controls ( P = 0.014 and P = 0.007), whereas IL10-rs1800896TC and C were more frequent in the controls than in the children with AD and other allergic diseases ( P = 0.0055 and P = 0.0034). These findings show that some of the polymorphisms involved in the immune response are also involved in some aspects of the development and course of AD and, although not conclusive, support the immunological hypothesis of the origin of the inflammatory lesions.

Physiological roles of miR-155

miR-155 is involved in non-coding microRNAs found in humans, mice and chickens of which the sequence is conserved. Historically, miR-155 was identified as a B-cell integration cluster (bic), which induces B-cell leucosis in chickens, by its activation through viral promoter insertion. Subsequent studies have shown that transgenic mice expressing miR-155 in B cells generated lymphoma, showing that miR-155 is oncogenic. Biochemical investigation identifies many substrates of miR-155, and one of them in B cells and macrophages is the SH2-domain containing inositol-5'-phosphatase 1. A deficiency of miR-155 in the immune system causes attenuated immune functions. Clinically, several types of malignancy including diffuse large B-cell lymphoma have high miR-155 expression levels.

Celiac disease in children with atopic dermatitis

Celiac disease (CD) is an autoimmune disorder of the small intestine with highly variable clinical presentation and frequently associated with various immune-mediated diseases. Among these immune-mediated diseases, atopy has been found frequently in individuals with CD. We aimed to study the prevalence of CD in Estonian children with atopic dermatitis (AD), a common multifactorial chronic inflammatory skin disease. We recruited 351 consecutive children with active AD (mean age 5.8 yrs, 57.6% boys) at Tallinn Children's Hospital, Estonia. Sera of all patients were tested for total serum immunoglobulin (Ig) A, for IgA- and IgG-type autoantibodies to tissue transglutaminase (IgA-anti-TG2, IgG-anti-TG2) and to deamidated gliadin peptides (IgA-anti-DGP, IgG-anti-DGP). The diagnosis of CD was confirmed histologically by small intestine biopsy according to the European Society of Paediatric Gastroenterology, Hepatology and Nutrition diagnostic criteria. IgA deficiency was detected in nine patients with AD (2.6%), none of whom had IgG-anti-TG2 or IgG-anti-DGP seropositivity. IgA-anti-TG2 positivity was found in 4 (1.1%), IgG-anti-TG2 positivity in 2 (0.6%), IgA-anti-DGP positivity in 11 (3.1%), and IgG-anti-DGP in 10 (2.8%) patients. Celiac disease was confirmed in five (1.4%) patients with AD (95% confidence interval 0.46, 3.32) and all were histologically characterized as Marsh IIIa-IIIc stages and two presented with silent CD. In AD patients, CD prevalence was more than four times as high as in previously studied randomly selected schoolchildren in Estonia. Two patients with AD diagnosed with CD had no symptoms indicative of CD, in spite of extensive histologic changes in the small intestine mucosa. Therefore our study emphasizes the need for evaluating the cost-effectiveness of screening individuals with AD for CD in time to prevent long-term complications.

Increased risk of atopic dermatitis in preschool children with kawasaki disease: a population-based study in taiwan

Kawasaki disease (KD) is an acute febrile systemic vasculitis and has been reported to be associated with allergic disease. The risk of atopic dermatitis (AD) in preschool children with KD has not been investigated. The study was to determine the longitudinal risk of the development of AD in preschool children with KD. A nationwide 5-year population-based study was performed using data from the National Health Insurance Database in Taiwan between 1999 and 2003. The risk factors for AD were compared between the 2 study groups during the follow-up period using the Cox proportional hazards model. In addition, plasma interleukin (IL)-5 levels were analyzed in normal subjects and KD patients. Among the 1440 subjects included, 21.6% developed AD during the 5-year follow-up period, of which 30.3% and 18.7% belonged to the study cohort and the comparison group, respectively. Children with KD were 1.25 times more likely to have AD than those in controls (P = 0.04). Levels of IL-5 and IgE were significantly higher in KD patients. Children with KD had a higher risk of developing AD during the 5-year follow-up period than the control group. Increased IL-5 and IgE levels may be key factors contributing to the risk of AD.

Cytotoxic T-lymphocyte associated antigen 4 polymorphisms and asthma risk: a meta-analysis

Background

A number of studies assessed the association of cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) gene polymorphisms with asthma in different populations. However, the results were contradictory. We performed a meta-analysis to examine the association between CTLA-4 polymorphisms and asthma susceptibility.

Methods

Pubmed, EMBASE, HuGE Navigator, and Wanfang Database were searched. Data were extracted independently by two reviewers. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Seventeen studies involving 6378 cases and 8674 controls were included. Significant association between +49 A/G polymorphism and asthma was observed for AA vs. AG+GG (OR = 1.18, 95% CI 1.01–1.37, P = 0.04). There were no significant associations between −318 C/T, −1147 C/T, CT60 A/G, −1722 C/T, or rs926169 polymorphisms and asthma risk.

Conclusions

This meta-analysis suggested that the +49 A/G polymorphism in CTLA-4 was a risk factor for asthma.

An inverse association between history of childhood eczema and subsequent risk of type 1 diabetes that is not likely to be explained by HLA-DQ, PTPN22, or CTLA4 polymorphisms

BACKGROUND

Established genetic susceptibility loci for type 1 diabetes are important in immune regulation and may play a role also in atopic disorders, potentially explaining the inverse association between childhood eczema and subsequent risk for type 1 diabetes previously reported.

OBJECTIVE

We aimed to directly assess whether HLA-DQ, CTLA4, and PTPN22 genes could explain the putative association between childhood eczema and lower subsequent risk of type 1 diabetes observed in several case-control studies.

METHODS

We designed a case-control study with 339 incident cases of type 1 diabetes identified in the Norwegian childhood diabetes registry, and 985 population-based control children. DNA was collected, and physician-diagnosed childhood eczema was ascertained by a questionnaire administered to the parents of children with and without type 1 diabetes.

RESULTS

The previously reported association between childhood eczema and lower risk of type 1 diabetes was confirmed (odds ratio,OR, 0.61, 95% confidence interval, CI, 0.40-0.95] and this was consistent in subgroups defined by HLA-DQ, CTLA4, and PTPN22 genotypes. The OR was essentially not influenced by adjustment for genetic variation at these loci (OR simultaneously adjusted for the three genetic loci: 0.55, 95% CI: 0.32-0.92). The ratio of the unadjusted to adjusted OR was 1.12, with a corresponding 95% CI from 0.84 to 1.50.

CONCLUSION

In this first study of its kind, we demonstrated directly that the observed inverse association between childhood eczema and type 1 diabetes is not likely to be explained by the established diabetes susceptibility genes HLA-DQ, CTLA4, or PTPN22.

A role for the atopy-associated gene PHF11 in T-cell activation and viability

Polymorphisms within plant homeodomain finger protein 11 (PHF11) are associated with total IgE, allergic asthma and eczema. PHF11 is a transcriptional co-activator of the Th1 effector cytokine genes, interleukin-2 (IL2) and interferon-γ (IFNG), co-operating with nuclear factor kappa B (NF-κB). The involvement with NF-κB led us to test whether PHF11 might have a broader function in T-cell activation and viability. We show that PHF11 is abundant in the cytoplasm of T-cells and imported into the nucleus of activated T-cells. Consistent with its presence in the nucleus, PHF11 was recruited to the IFNG promoter and over-expression of PHF11 increased the binding of NF-κB to the IFNG promoter and IFNG gene transcription. Over-expression of PHF11 did not increase IL2 gene transcription, suggesting some specificity in promoter recognition. In contrast, small-interfering RNA knock-down of PHF11 decreased transcription of both IFNG and IL2 and led to decreased CD28 cell-surface expression and reduced NF-κB nuclear import and DNA binding. Knock-down of PHF11 also decreased cell viability and was accompanied by reduced expression of GIMAP4 and 5 genes required for T-cell differentiation, viability and homeostasis. Therefore, in addition to its earlier identified function in regulating Th1 cytokine gene expression, we now show that PHF11 has a broader function in contributing to T-cell activation and viability.

An update on the genetics of atopic dermatitis: scratching the surface in 2009

A genetic basis for atopic dermatitis (AD) has long been recognized. Historic documents allude to family history of disease as a risk factor. Before characterization of the human genome, heritability studies combined with family-based linkage studies supported the definition of AD as a complex trait in that interactions between genes and environmental factors and the interplay between multiple genes contribute to disease manifestation. A summary of more than 100 published reports on genetic association studies through mid-2009 implicates 81 genes, in 46 of which at least 1 positive association with AD has been demonstrated. Of these, the gene encoding filaggrin (FLG) has been most consistently replicated. Most candidate gene studies to date have focused on adaptive and innate immune response genes, but there is increasing interest in skin barrier dysfunction genes. This review examines the methods that have been used to identify susceptibility genes for AD and how the underlying pathology of this disease has been used to select candidate genes. Current challenges and the potential effect of new technologies are discussed.

Genetics of food allergy

PURPOSE OF REVIEW

Food allergy, a growing clinical and public health problem in the United States and worldwide, is likely determined by multiple environmental and genetic factors. The purpose of this review is to summarize recent advances in food allergy genetic research.

RECENT FINDINGS

There is compelling evidence that genetic factors may play a role in food allergy. However, the specific genetic loci that may modulate individual risk of food allergy remain to be identified. To date, only a limited number of candidate gene association studies of food allergy have been reported. Polymorphism(s) in nine genes have been associated with the incidence of food allergy or food allergy severity in at least one study. But most of these findings remain to be replicated in independent populations. In contrast, there are considerable advances in genetics of other allergic diseases such as asthma and atopic dermatitis. Although asthma and atopic dermatitis often coexist with food allergy, the relevance of their candidate genes to food allergy remains to be evaluated.

SUMMARY

Genetics in food allergy is a promising research area but is still in its infancy. More studies are needed to dissect susceptible genes of food allergy. A genome-wide association approach may serve as a powerful tool to identify novel genes related to food allergy. Furthermore, the role of gene-environment interaction, gene-gene interaction, and epigenetics in food allergy remains largely unexplored. Given the complex nature of food allergy, future studies need to integrate environment, genomics, and epigenomics in order to better understand the multifaceted etiology and biological mechanisms of food allergy.

Functional characterization of the atopy-associated gene PHF11

BACKGROUND

Polymorphisms in the plant homeodomain finger protein 11 gene (PHF11) are associated with increased total serum IgE levels, asthma, and severe atopic dermatitis (AD) in children. Although PHF11 includes a plant homeodomain, a motif often found in transcriptional regulators, the function of PHF11 has not been investigated.

OBJECTIVE

We sought to test (1) whether PHF11 regulates the transcription of genes involved in allergic disorders and (2) whether polymorphisms in PHF11 predict changes in the expression or function of this gene.

METHODS

Microarray analysis was used to examine the expression of PHF11 in different immune cell subsets, and the function of PHF11 was tested by using small interfering RNA-induced knockdown or overexpression of PHF11 in primary CD4+ T cells or Jurkat T cells. Genotype-dependent effects on PHF11 expression were tested by using an allele-specific gene expression, and the transcriptional activity of PHF11 was determined by using luciferase hybrid gene reporter assays and in vitro DNA-binding electromobility shift assays.

RESULTS

PHF11 expression was higher in T(H)1 cells relative to that in T(H)2 cells, and knockdown of PHF11 expression reduced expression of the T(H)1-type cytokines IFN-gamma and IL-2. The G-allele of a 3' untranslated region polymorphism associated with AD was correlated with reduced abundance of PHF11 RNA in T(H)1 cells, as well as an increase in a PHF11 isoform lacking exon II. Evidence was also found for a physical and functional interaction between PHF11 and the p65 subunit of nuclear factor kappaB.

CONCLUSION

PHF11 is a regulator of T(H)1-type cytokine gene expression. The reduction in PHF11 expression seen with an AD-associated genotype could contribute to the strong T(H)2 responses that characterize many allergic individuals.

High incidence of CTLA-4 AA (CT60) polymorphism in renal cell cancer

Polymorphism in genes encoding T-cell regulatory proteins and cytokines may influence inflammation and cancer development via regulation of antitumor immune response. In the current study we analyzed genotypic frequencies of cytotoxic T-lymphocyte antigen-4 (CTLA-4)/CT60, CTLA-4/A49G, interleukin (IL)-4, and IL-10 polymorphisms in 117 renal cell carcinoma patients, 96 patients with colorectal cancer, and 196 healthy controls to test for an association between polymorphism in these genes and the risk of renal and colon cancer in a Spanish group of patients. In the case-control study, DNA samples from cancer patients and controls were analyzed using a TaqMan single nucleotide polymorphism genotyping assay. The distribution of IL-4 and IL-10 polymorphisms was similar between renal cancer patients and controls. However, a higher incidence of CTLA-4/CT60-AA genotype (p = 0.005; odds ratio (OR)= 2.12 with 95% confidence interval (CI): 1.28-3.50) and CTLA-4/A49G-AA (p = 0.022; OR = 1.76 with 95% CI: 1.11-2.80) genotype was observed in renal cancer patients than in controls. In addition, we observed a positive correlation between the AA genotype in both CTLA-4 polymorphisms and RCC grade, suggesting a role for the CTLA4 gene in tumor development. Therefore, our data suggest the CTLA-4 gene may be a candidate as a renal adenocarcinoma susceptibility gene, but does not play an important role in colon cancer.

Siglecs and their roles in the immune system

Cell surfaces in the immune system are richly equipped with a complex mixture of glycans, which can be recognized by diverse glycan-binding proteins. The Siglecs are a family of sialic-acid-binding immunoglobulin-like lectins that are thought to promote cell-cell interactions and regulate the functions of cells in the innate and adaptive immune systems through glycan recognition. In this Review, we describe recent studies on signalling mechanisms and discuss the potential role of Siglecs in triggering endocytosis and in pathogen recognition. Finally, we discuss the postulated functions of the recently discovered CD33-related Siglecs and consider the factors that seem to be driving their rapid evolution.

Primary administration of Lactobacillus johnsonii NCC533 in weaning period suppresses the elevation of proinflammatory cytokines and CD86 gene expressions in skin lesions in NC/Nga mice

The administration of probiotic lactic acid bacteria (LAB) has been studied for its potential to prevent atopic dermatitis (AD). The objective of this study was to assess the inhibitory mechanism of a skin lesion by LAB using an experimental model that we previously demonstrated in NC/Nga mice. Lactobacillus johnsonii NCC533 (La1) was administered orally to the La1 group from 20 to 22 days after birth, while phosphate-buffered saline was given to the control group. After the induction of skin lesions in 6-week-old mice, the expression of genes supposedly involved in AD was evaluated. Gene expression of the proinflammatory cytokines [interleukin-8 (IL-8), IL-12 and IL-23] was significantly enhanced in the lesional skin of the control group by the induction of the lesion, whereas gene expression of those in the La1 group was not elevated. Interestingly, expression of the costimulatory molecule CD86 showed a pattern similar to the expression of the cytokines in the lesional skin. Moreover, the La1 group showed a significantly lower gene expression of CD86 in Peyer's patches and mesenteric lymph nodes than the control group. The suppression of proinflammatory cytokines and CD86 by primary administration of La1 may significantly contribute to the inhibitory effect on the skin lesion.

CTLA-4 polymorphisms and clinical outcome after allogeneic stem cell transplantation from HLA-identical sibling donors

CTLA-4 is an inhibitory molecule that down-regulates T-cell activation. Although polymorphisms at CTLA-4 have been correlated with autoimmune diseases their association with clinical outcome after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has yet to be explored. A total of 5 CTLA-4 single-nucleotide polymorphisms were genotyped on 536 HLA-identical sibling donors of allo-HSC transplants. Genotypes were tested for an association with patients' posttransplantation outcomes. The effect of the polymorphisms on cytotoxic T-lymphocyte antigen 4 (CTLA-4) mRNA and protein production were determined in 60 healthy control participants. We observed a reduction in the mRNA expression of the soluble CTLA-4 isoform in the presence of a G allele at CT60 and +49. Patients receiving stem cells from a donor with at least 1 G allele in position CT60 had worse overall survival (56.2% vs 69.8% at 5 years; P = .001; hazard ratio [HR], 3.80; 95% confidence interval [CI], 1.75-8.22), due to a higher risk of relapse (P = .049; HR, 1.71; 95% CI, 1.00-2.93). Acute graft-versus-host disease (aGVHD) was more frequent in patients receiving CT60 AA stem cells (P = .033; HR, 1.54; 95% CI, 1.03-2.29). This is the first study to report an association between polymorphisms at CTLA-4 and clinical outcome after allo-HSCT. The CT60 genotype influences relapse and aGVHD, probably due to its action on CTLA-4 alternative splicing.

Autoantibodies against CD28 are associated with atopic diseases

The B7-1/B7-2-CD28/CTLA-4 pathway is crucial in regulating T cell activation and tolerance. Autoantibodies to surface molecules on lymphocytes have already been described in various immune conditions, such as autoimmune diseases, infections and blood transfusions. The objective of this study was to test sera from healthy individuals and from patients for association of CD28 autoantibodies with inflammatory and non-inflammatory diseases. First, CD28 was obtained by digestion of CD28-Ig fusion protein with trypsin. The cleavage products were separated by sodium dodecyl sulphate-page gel electrophoresis. Additionally, a CD28/GST fusion protein was expressed in Escherichia coli and was used to establish an enzyme-linked immunosorbent assay for detection of autoantibodies against CD28. Sera from healthy individuals (n = 72) and patients with different inflammatory and non-inflammatory skin diseases (n = 196) were tested for the presence of autoantibodies against CD28. Using mixed lymphocyte reaction (MLR), purified autoantibodies against CD28 were tested for their effects on CTLA-4-Ig-induced T cell anergy. In this study, for the first time, we describe the existence of autoantibodies against CD28 in humans which are associated with atopic diseases, e.g. allergic rhinitis and asthma. These antibodies stimulate T cells and overcome the CTLA-4-Ig-induced anergy of T cells in an MLR. The existence of autoantibodies against CD28, which may have a T cell-stimulating function, has been shown. The data indicate that autoantibodies against CD28 could be a new immunological mechanism in allergic inflammation. Additionally, autoantibodies against CD28 could be an important new marker to discriminate between atopic diseases and other inflammatory skin diseases.

Evidence for unique association signals in SLE at the CD28-CTLA4-ICOS locus in a family-based study

CD28, CTLA4 (cytotoxic T lymphocyte-associated protein 4) and ICOS (inducible T cell co-stimulator) are good candidate genes for systemic lupus erythematosus (SLE) because of their role in regulating T cell activation. CTLA4 inhibits CD28-mediated T cell activation. CTLA4 is expressed on CD4+ and CD8+ activated T cells, and also B cells, but CD28 and ICOS are largely restricted to T cells. An interval encompassing the CD28-CTLA4-ICOS locus on chromosome 2q33 was linked to lupus in two genome-wide linkage scans. This large family-based association study in 532 UK SLE families represents the first high-density genetic screen of 80 SNPs at this locus. There are seven haplotype blocks across the locus. In CTLA4, the strongest signal comes from two variants, located 2.1 kb downstream from the 3'-UTR. These polymorphisms, rs231726 (SNP 43) and rs231726 (SNP 44), are in complete linkage disequilibrium (LD) (r(2)=1) and are associated with SLE P=0.0008 (GH) and P=0.01 (family-based association test). There is also a signal in the distal 3' flanking region of CTLA4/ICOS promoter (P=0.003). There was no confirmation of published associations for SLE in the promoter or coding region of CTLA4. These SLE risk alleles are more distal than those identified in Graves' disease and are in LD with Graves' disease protective alleles identified in both of these regions of CTLA4 (Ueda et al. 2003). These factors suggest an SLE-specific pattern of association. The functional consequences of the associated polymorphisms are likely to influence CTLA4 expression, although it is possible that genetically modulated ICOS expression is involved in SLE susceptibility.