CTLA-4 gene polymorphisms and natural soluble CTLA-4 protein in psoriasis vulgaris

sCD163, sCD28, sCD80, and sCTLA-4 as soluble marker candidates for detecting immunosenescence

BACKGROUND

Inflammaging, the characteristics of immunosenescence, characterized by continuous chronic inflammation that could not be resolved. It is not only affect older people but can also occur in young individuals, especially those suffering from chronic inflammatory conditions such as autoimmune disease, malignancy, or chronic infection. This condition led to altered immune function and as consequent immune function is reduced. Detection of immunosenescence has been done by examining the immune risk profile (IRP), which uses flow cytometry. These tests are not always available in health facilities, especially in developing countries and require fresh whole blood samples. Therefore, it is necessary to find biomarkers that can be tested using stored serum to make it easier to refer to the examination. Here we proposed an insight for soluble biomarkers which represented immune cells activities and exhaustion, namely sCD163, sCD28, sCD80, and sCTLA-4. Those markers were reported to be elevated in chronic diseases that caused early aging and easily detected from serum samples using ELISA method, unlike IRP. Therefore, we conclude these soluble markers are beneficial to predict pathological condition of immunosenescence.

AIM

To identify soluble biomarkers that could replace IRP for detecting immunosenescence.

CONCLUSION

Soluble costimulatory molecule suchsCD163, sCD28, sCD80, and sCTLA-4 are potential biomarkers for detecting immunosenescence.

The Role of Co-Signaling Molecules in Psoriasis and Their Implications for Targeted Treatment

Psoriasis is a chronic, systemic immune-mediated inflammatory disease manifesting in the skin, joint or both. Co-signaling molecules are essential for determining the magnitude of the T cell response to the antigen. According to the function of co-signaling molecules, they can be divided into co-stimulatory molecules and co-inhibitory molecules. The role of co-signaling molecules in psoriasis is recognized, mainly including the co-stimulatory molecules CD28, CD40, OX40, CD27, DR3, LFA-1, and LFA-3 and the co-inhibitory molecules CTLA-4, PD-1, and TIM-3. They impact the pathological process of psoriasis by modulating the immune strength of T cells, regulating the production of cytokines or the differentiation of Tregs. In recent years, immunotherapies targeting co-signaling molecules have made significant progress and shown broad application prospects in psoriasis. This review aims to outline the possible role of co-signaling molecules in the pathogenesis of psoriasis and their potential application for the treatment of psoriasis.

Association of Cytotoxic T Lymphocyte Antigen-4 Gene Polymorphisms with Psoriasis Vulgaris: A Case-Control Study in Turkish Population

Psoriasis is a common, chronic, and autoimmune skin disease in which dysregulation of immune cells, particularly T cells, is thought to play an important role in the pathogenesis. Cytotoxic T lymphocyte antigen-4 (CTLA-4) expressed only on activated T cells is an immunoregulatory molecule and plays a role in the pathogenesis of autoimmune disorders. We aimed to determine whether CTLA-4 gene polymorphisms are associated with development and/or clinical features of psoriasis vulgaris (Pv). Genotyping of SNPs (−318C>T, +49A>G, and CT60A>G) in CTLA-4 gene was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 103 Pv patients and 102 controls. No statistically significant associations were detected in any of the investigated genetic models for the −318C>T polymorphism. The genotype distributions of +49A>G and CT60A>G were associated with Pv development. In haplotype analysis, while frequency of CAA haplotype was significantly higher in the control group, frequencies of CGG and CAG haplotype were significantly higher among the patients. However, all of CTLA-4 polymorphisms and haplotypes do not have an effect on severity and onset age of Pv. In conclusion, the +49A>G and CT60A>G polymorphisms may be risk factors for Pv development. Furthermore, CGG and CAG haplotypes may contribute to Pv development, while CAA haplotype may be protective against Pv.

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.

The expression of mCTLA-4 in skin lesion inversely correlates with the severity of psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory disease characterized by epidermal hyperplasia and increased T cell infiltration. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is a key factor that affects T cell function and immune response. However, whether the expression of CTLA-4 affects the severity of psoriasis is still unknown.

OBJECTIVE

The aim of the project was to investigate the correlation between the expression of CTLA-4 and the severity of psoriasis.

METHODS

The plasma soluble CTLA-4 levels and membrane CTLA-4 expression were measured by enzyme-linked immunosorbent assay and immunohistochemistry analysis in mild, moderate and severe psoriasis patients, respectively. Imiquimod-induced mouse model of psoriasis was treated with CTLA-4 immunoglobulin fusion protein (CTLA-4 Ig) or anti-CTLA-4 antibody. Epidermal thickness and infiltrating CD3+ T cell counts were evaluated.

RESULTS

The plasma soluble CTLA-4 levels had no significant difference among mild, moderate, and severe patients (p > 0.05). However, the membrane CTLA-4 expression in skin was significantly higher in mild psoriasis patients compared to moderate and severe psoriasis patients (17652.86 ± 18095.66 vs 6901.36 ± 4400.77 vs 3970.24 ± 5509.15, p < 0.001). Furthermore, in imiquimod-induced mouse model of psoriasis, the results showed that mimicking CTLA-4 function improved the skin phenotype and reduced epidermal thickness (172.87 ± 28.25 vs 245.87 ± 36.61 μm, n = 6, p < 0.01) as well as infiltrating CD3+ T cell counts (5.09 ± 3.45 vs 13.45 ± 4.70, p < 0.01) compared to control group. However, blocking CTLA-4 function aggregated the skin phenotype including enhanced epidermal thickness and infiltrating CD3+ T cell counts compared to control group.

CONCLUSION

These results indicated that the expression of mCTLA-4 in skin lesion inversely correlated with the severity of psoriasis and CTLA-4 might play a critical role in the disease severity of psoriasis.

Lack of association between cytotoxic T-lymphocyte antigen-4+49A/G polymorphism and psoriasis and vitiligo: A meta-analysis of case-control studies

BACKGROUND

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a critical negative regulator of T-cell activation and proliferation. Several studies have assessed the association between CTLA-4+49A/G polymorphism and psoriasis and vitiligo, but the results are inconsistent.

AIMS

This study was conducted to examine the association between CTLA-4+49A/G polymorphism and psoriasis and vitiligo susceptibility.

METHODS

The PubMed, Embase, and China National Knowledge Infrastructure (CNKI) databases were searched according to predefined criteria for all relevant studies published prior to July 3, 2014. Odds ratios (ORs) with 95% confidence intervals (CIs), and heterogeneity and publication bias tests were performed to estimate the strength of the association.

RESULTS

Fourteen studies comprising six on psoriasis (700 cases, 781 controls) and eight on vitiligo (1514 cases, 2049 controls) were included. Overall, no significant association was detected between CTLA-4+49A/G polymorphism and psoriasis. There was still no significant relationship when the studies were limited to ethnicity (Asian and Caucasian), HWE or heterogeneity, except the limitation to heterogeneity in the dominant (OR=0.69, 95% CI=0.51-0.93, I(2)=0.0%) and additive (OR=0.69, 95% CI=0.48-0.98, I(2)=0.0%) models, and the limitation to both heterogeneity and HWE in the dominant model (OR=0.68, 95% CI=0.48-0.98, I(2)=0.0%). Both overall and subgroup analyses based on ethnicity, genotype frequencies, and heterogeneity also failed to demonstrate an association between CTLA-4+49A/G polymorphism and vitiligo.

CONCLUSION

CTLA-4+49A/G polymorphism may not contribute to psoriasis and vitiligo susceptibility, but further well-designed studies with large sample size are warranted to confirm this conclusion.

Genetics of psoriasis and pharmacogenetics of biological drugs

Psoriasis is a chronic inflammatory disease of the skin. The causes of psoriasis are unknown, although family and twin studies have shown genetic factors to play a key role in its development. The many genes associated with psoriasis and the immune response include TNFα, IL23, and IL12. Advances in knowledge of the pathogenesis of psoriasis have enabled the development of new drugs that target cytokines (e.g., etanercept, adalimumab, and infliximab, which target TNFα, and ustekinumab, which targets the p40 subunit of IL23 and IL12). These drugs have improved the safety and efficacy of treatment in comparison with previous therapies. However, not all patients respond equally to treatment, possibly owing to interindividual genetic variability. In this review, we describe the genes associated with psoriasis and the immune response, the biological drugs used to treat chronic severe plaque psoriasis, new drugs in phase II and III trials, and current knowledge on the implications of pharmacogenomics in predicting response to these treatments.

CTLA4 and CD86 gene polymorphisms and susceptibility to chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) may be related to chronic inflammation and immune-mediated conditions, and its pathogenesis involves T-cell activation and proliferation. Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and costimulatory molecules (CD80/CD86) genes are important mediators of T-cell activation in the immune response. The aim of this study was to investigate whether +2379G/C (rs17281995) and +1057G/A (rs1129055) in CD86 and -318C/T (rs5742909) and +49A/G (rs231775) in CTLA-4 genes single nucleotide polymorphisms (SNPs) are associated with COPD in a Chinese population. The four polymorphisms were identified in 396 COPD patients and 400 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The frequency of the T allele of the -318C/T in CTLA-4 and the A allele of the +1057G/A in CD86 polymorphisms showed significant association with COPD when compared with controls (T allele: p < 0.0001; A allele: p = 0.009). Comparison of genotype frequencies showed that -318CT, +1057GA, and +1057AA genotype was overrepresented in the COPD group, respectively (-318CT: 50.8% vs 28.5%, p < 0.0001; +1057GA: 58.6% vs 54.2%, p = 0.002; +1057AA: 30.1% vs 25.8%, p = 0.002). However, we failed to find any association between the four SNPs and COPD when cases were classified by smoking status or clinical stages (p > 0.05). The results indicate that the polymorphisms of CTLA-4 (-318C/T) and CD86 (+1057G/A) may be important genetic factor associated with risk or protection for COPD in Chinese population.

Biochemical analysis of CTLA-4 immunoreactive material from human blood

Background

CTLA-4 was initially described as a membrane-bound molecule that inhibited lymphocyte activation by interacting with B7.1 and B7.2 molecules on antigen presenting cells. Alternative splicing of mRNA encoding the CTLA-4 receptor leads to the production of a molecule (sCTLA-4) that lacks a membrane anchor and is therefore secreted into the extracellular space. Despite studies finding that people with autoimmune disease more frequently express high levels of sCTLA-4 in their blood than apparently healthy people, the significance of these findings is unclear.

Methods

Molecules isolated from blood using CTLA-4 specific antibodies were analyzed with ligand binding assays, mass spectroscopy, and biochemical fractionation in an effort to increase our understanding of CTLA-4 immunoreactive material.

Results

Mass spectroscopy analysis of the molecules recognized by multiple CTLA-4-specific antibodies failed to identify any CTLA-4 protein. Even though these molecules bind to the CTLA-4 receptors B7.1 and B7.2, they also exhibit properties common to immunoglobulins.

Conclusion

We have identified molecules in blood that are recognized by CTLA-4 specific antibodies but also exhibit properties of immunoglobulins. Our data indicates that what has been called sCTLA-4 is not a direct product of the CTLA-4 gene, and that the CTLA-4 protein is not part of this molecule. These results may explain why the relationship of sCTLA-4 to immune system activity has been difficult to elucidate.

Lack of association between sCTLA-4 levels in human plasma and common CTLA-4 polymorphisms

BACKGROUND

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an important downregulatory molecule expressed on both T and B lymphocytes. Numerous population genetics studies have documented significant associations between autoimmune diseases and single nucleotide polymorphisms (SNPs) within and around the CTLA-4 region of chromosome 2 in man. Furthermore, circulating levels of a soluble form of CTLA-4 (sCTLA-4) have been reported in a variety of autoimmune mediated diseases. Despite these findings, the relationship between levels of sCTLA-4 protein, mRNA transcript levels, and SNPs within the CTLA-4 region have not been clearly defined. In order to further clarify this relationship, we have tested four different SNPs within the CTLA-4 region among subjects whom are negative (n = 53) versus positive (n = 28) for sCTLA-4.

RESULTS

Our data do not support a clear association between sCTLA-4 levels and any of the four SNPs tested.

CONCLUSION

The variation in the SNPs tested does not appear to effect sCTLA-4 protein levels, despite reports that they affect sCTLA-4 mRNA.

Lack of association between the G-2548A polymorphism of the leptin gene and psoriasis in a Turkish population

BACKGROUND

Psoriasis is a multifactorial disease in which genetic and inflammatory factors play important roles. Leptin is classified as a cytokine and plays an important role in the regulation of the T-helper response. A common polymorphism in the promoter of the human leptin gene (G-2548A) may have a role in the pathogenesis of psoriasis.

AIM

To investigate the association between psoriasis and leptin gene polymorphism (G-2548A).

METHODS

The study involved 109 patients with psoriasis and 125 healthy controls. Analyses of G-2548A polymorphism of the leptin gene were made by the polymerase chain reaction-restriction fragment length polymorphism technique. The genotypes (GG, GA, and AA of leptin gene G-2548A) and alleles (G and A) were scored and the frequencies were estimated. The frequencies of alleles and genotypes in patients and controls were compared. The relationship between leptin gene polymorphism and the clinical features of the patients was analyzed.

RESULTS

Both genotype [odds ratio (OR), 0.921; 95% confidence interval (CI), 0.501-1.694; P = 0.792] and allele (OR, 0.864; 95% CI, 0.600-1.242; P = 0.429) frequencies were not significantly different between patient and control groups. In addition, there was no significant association between genotype and allele frequencies and the clinical characteristics of psoriasis.

CONCLUSION

In this case-control study, no evidence of association between the G-2548A variant of the leptin gene and psoriasis was found.

Distribution of the CTLA-4 single nucleotide polymorphisms CT60G>A and +49A>G in psoriasis vulgaris patients and control individuals from a Polish Caucasian population

Psoriasis vulgaris is a multifactorial disease with an autoimmune component, and T lymphocytes seem to be involved in its aetiology. CTLA-4 molecule is an important down-regulator of T-lymphocyte activation, and several polymorphisms of the CTLA-4 gene were found to be associated with some autoimmune diseases. We examined whether single nucleotide polymorphisms (SNPs) in the CTLA-4 gene, CT60A>G and +49A>G, are associated with psoriasis vulgaris. Alleles of these two SNPs were determined by the polymerase chain reaction-restriction fragment length polymorphism method. Both the CT60G>A and the +49A>G alleles and genotypes were distributed similarly in patients and controls. Although the two SNPs studied here in Poles were in linkage disequilibrium, all four possible two-locus haplotypes were found, one of them rare; of the remaining three, the haplotype +49G, CT60G was significantly (P = 0.019, OR = 0.58, 95%CI = 0.37-0.91) less frequent in the patient group with disease onset between the ages of 21 and 40 years than in controls and the other patient groups, whereas the frequencies of the other haplotypes were similar in patients and controls. To the authors' knowledge, this is the first study on CTLA-4 CT60 allele frequencies in psoriasis.