Genetic polymorphism in IL17RA induces susceptibility to Toxoplasma gondii infection in Brazilian pregnant women.

Congenital toxoplasmosis is a parasitic disease caused by Toxoplasma gondii, an obligate intracellular parasite which can cause fetal death/abortion and can induce damage in the brain and eyes of the infected babies. The environmental and genetic factors associated with T. gondii and the maternal immune response, drive part of the pathogenesis of congenital toxoplasmosis. Thus, in this study, we aimed to investigate the allelic and genotypic frequencies of specific single nucleotide polymorphisms (SNPs) in the IL17A and IL17RA genes, as well as the production of IL-17A, IL-33, and CCL2 in pregnant women, from the State of Rio Grande do Norte, Brazil, further relating these along with the clinical parameters, to the toxoplasmosis infection. Through PCR-RFLP techniques, two SNPs implicated in Th17 immune response, IL17A rs2275913 (G> A) and IL17RA rs4819554 (A> G) modulation were evaluated in pregnant women, either infected or not infected by T. gondii. These women were also evaluated in terms of plasma release of CCL2, IL-33, and IL-17A which relate to hypertension, number of abortions, and ethnic pattern. The results showed that the G-allele of the SNP rs2275913 (IL17A) appeared to be protective in this population, while the rs4819554 (IL17RA) SNP G allele was associated with greater susceptibility to T. gondii infection [ρ value = 0.025; OR = 2.815 (1.118-7.089); CI = 95%]. None of the cytokines had any influence on the analyzed parameters (abortion and hypertension). In conclusion, our data suggest an immunogenic evidence of susceptibility to T. gondii infection driven by the rs4819554 (IL17RA) SNP G allele in Brazilian pregnant women. Further studies are needed to reinforce this trial marker in populations from distinct geographical areas as well as to confirm the protective pattern related to the G-allele of the SNP rs2275913 (IL17A) in pregnant women.

Immunohistochemical evaluation of HLA-G and FoxP3+ T regulatory cells in oral cavity and lower lip squamous cell carcinomas.

Human Leukocyte Antigen G (HLA-G) is a molecule involved in the tumor immunosuppression and also in the generation of regulatory T (Treg) cells, thus leading to evasion to the immune system host, and consequently, contributing to tumor progression in several cancers. The aim of this study was to evaluate the immunoexpression of HLA-G by tumor cells and FoxP3+ Treg cells in 25 oral tongue squamous cell carcinomas (SCCs) and 25 lower lip SCCs and analyze their relationship with clinical parameters. HLA-G expression was higher in oral tongue SCCs than in lower lip SCCs. In oral tongue SCCs and lower lip SCCs, no association between HLA-G expression and clinical parameters (tumor size, lymph node status, distant metastasis, and clinical stage) was verified (P>0.05). FoxP3+ Treg cells were detected along the tumor invasive front in all cases of oral tongue and lower lip SCCs. In oral tongue SCC cases, the number of Treg cells tended to be higher in smaller tumors, tumors without regional lymph node metastasis, and tumors in early clinical stages, but the difference was not statistically significant (P>0.05). A significant positive correlation was found between the expression of HLA-G by neoplastic cells and Treg cells in lower lip SCCs (p = 0.008). Our findings suggest the involvement of HLA-G and Treg cells in the modulation of immune responses in oral tongue and lower lip SCCs. This interaction between HLA-G and Treg cells may represent an evasion mechanism in these malignancies.

Immune response and evasion mechanisms in lip carcinogenesis: An immunohistochemical study.

OBJECTIVES: Programmed death ligand-1 (PD-L1) and human leukocyte antigen-G (HLA-G) are considered immune checkpoint molecules that inhibit T-cell effectiveness, contributing to tumor immune escape. This study investigated PD-L1, HLA-G, CD8, and granzyme B (GrB) expression at different stages of lip carcinogenesis. DESIGN AND RESULTS: Forty cases of lip squamous cell carcinoma (LSCC), 55 actinic cheilitis (AC), and 10 healthy lip mucosa (HLM) were submitted to immunohistochemistry. Semiquantitative (PD-L1, HLA-G), and quantitative (CD8, GrB) analysis were performed. PD-L1 and HLA-G expression in neoplastic cells/keratinocytes and stroma/connective tissue was significantly higher in LSCC and AC, compared to HLM (p<0.05). PD-L1 was not associated with clinicopathological features of the lesions. HLA-G expression by malignant cells was significantly higher in LSCCs with distant metastasis (p = 0.041).CD8+ and GrB+ cell numbers progressively increased from HLMs to LSCC, with AC exhibiting intermediate numbers (p<0.01). Most LSCCs showed coexistence of PD-L1+ and CD8+ cells (72.5%). PD-L1 was directly correlated to CD8+ and GrB+ lymphocytic infiltration in LSCCs (p<0.05). Low cytotoxic immune response was associated with lymph node metastasis in LSCC (p<0.05). CONCLUSIONS: PD-L1 and HLA-G-mediated immune evasion mechanisms are likely to occur from early pre-malignant to advanced malignant stages of lip carcinogenesis, which might provide a rationale for therapeutic blockade of these pathways. PD-L1 expression in LSCCs was correlated with the cytotoxic markers, suggesting that PD-L1 may appear as an escape mechanism in response to an active antitumor response.

Immunohistochemical evaluation of HLA-G and FoxP3+ T regulatory cells in oral cavity and lower lip squamous cell carcinomas

Abstract: Human Leukocyte Antigen G (HLA-G) is a molecule involved in the tumor immunosuppression and also in the generation of regulatory T (Treg) cells, thus leading to evasion to the immune system host, and consequently, contributing to tumor progression in several cancers. The aim of this study was to evaluate the immunoexpression of HLA-G by tumor cells and FoxP3+ Treg cells in 25 oral tongue squamous cell carcinomas (SCCs) and 25 lower lip SCCs and analyze their relationship with clinical parameters. HLA-G expression was higher in oral tongue SCCs than in lower lip SCCs. In oral tongue SCCs and lower lip SCCs, no association between HLA-G expression and clinical parameters (tumor size, lymph node status, distant metastasis, and clinical stage) was verified (P>0.05). FoxP3+ Treg cells were detected along the tumor invasive front in all cases of oral tongue and lower lip SCCs. In oral tongue SCC cases, the number of Treg cells tended to be higher in smaller tumors, tumors without regional lymph node metastasis, and tumors in early clinical stages, but the difference was not statistically significant (P>0.05). A significant positive correlation was found between the expression of HLA-G by neoplastic cells and Treg cells in lower lip SCCs (p = 0.008). Our findings suggest the involvement of HLA-G and Treg cells in the modulation of immune responses in oral tongue and lower lip SCCs. This interaction between HLA-G and Treg cells may represent an evasion mechanism in these malignancies.

Patients with systemic sclerosis present increased DNA damage differentially associated with DNA repair gene polymorphisms.

OBJECTIVE: Patients with systemic sclerosis (SSc) exhibit increased toxicity when exposed to genotoxic agents. In our study, we evaluated DNA damage and polymorphic sites in 2 DNA repair genes (XRCC1 Arg399Gln and XRCC4 Ile401Thr) in patients with SSc. METHODS: A total of 177 patients were studied for DNA repair gene polymorphisms. Fifty-six of them were also evaluated for DNA damage in peripheral blood cells using the comet assay. RESULTS: Compared to controls, the patients as a whole or stratified into major clinical variants (limited or diffuse skin involvement), irrespective of the underlying treatment schedule, exhibited increased DNA damage. XRCC1 (rs: 25487) and XRCC4 (rs: 28360135) allele and genotype frequencies observed in patients with SSc were not significantly different from those observed in controls; however, the XRCC1 Arg399Gln allele was associated with increased DNA damage only in healthy controls and the XRCC4 Ile401Thr allele was associated with increased DNA damage in both patients and controls. Further, the XRCC1 Arg399Gln allele was associated with the presence of antinuclear antibody and anticentromere antibody. No association was observed between these DNA repair gene polymorphic sites and clinical features of patients with SSc. CONCLUSION: These results corroborate the presence of genomic instability in SSc peripheral blood cells, as evaluated by increased DNA damage, and show that polymorphic sites of the XRCC1 and XRCC4 DNA repair genes may differentially influence DNA damage and the development of autoantibodies.

The variant of CD11b, rs1143679 within ITGAM, is associated with systemic lupus erythematosus and clinical manifestations in Brazilian patients.

BACKGROUND/AIMS: Immune responses mediated by complement receptors (CR) are impaired in patients with systemic lupus erythematosus (SLE). Regarding CR3 (CD11b/CD18), the CD11b subunit is encoded by the ITGAM gene and a single nucleotide polymorphism (G230A; rs1143679) in ITGAM changes an arginine to a histidine at position 77 (R77H). We assessed whether the variant R77H, rs1143679 within ITGAM, is associated with the risk to developing SLE and the clinical manifestations of Brazilian SLE patients. METHODS: The rs1143679 was genotyped by SSP-PCR in 157 patients with SLE and 147 healthy individuals. Clinical and laboratorial manifestations were obtained from the official medical records according the criteria of the American College of Rheumatology. RESULTS: The 77H variant was associated with susceptibility to SLE (OR=1.8); the frequencies of the minor allele A were 0.25 (SLE) and 0.15 (healthy) (p<0.01). In addition, the minor allele A was associated with lupus nephritis (p=0.02) and antiphospholipid antibodies (p=0.04). CONCLUSION: These results showed that the rs1143679 variant is also associated with the risk to SLE in our population and with the risk to specific clinical manifestations, as nephritis and presence of antiphospholipid antibodies. These results may have implications for discussing the association of this polymorphism with the IC deposition in SLE.

HLA-G expression in the skin of patients with systemic sclerosis.

OBJECTIVE: To determine HLA-G expression in skin biopsies from patients with systemic sclerosis (SSc), and its association with epidemiological, clinical, and laboratory variables and survival. METHODS: Paraffin-embedded skin biopsies obtained from 21 SSc patients (14 limited SSc, 7 diffuse SSc) and from 28 healthy controls were studied. HLA-G expression was evaluated by immunohistochemistry. RESULTS: HLA-G molecules were detected in 57% of skin biopsies from patients with SSc (9 from limited SSc, 3 from diffuse SSc), whereas no control sample expressed HLA-G (p=0.000004). In patients, HLA-G molecules were consistently observed within epidermal and some dermal cells. HLA-G expression was associated with a lower frequency of vascular cutaneous ulcers (p=0.0004), telangiectasias (p=0.008), and inflammatory polyarthralgia (p=0.02). After a 15-year followup, SSc patients who exhibited HLA-G survived longer than patients who did not. CONCLUSION: HLA-G is expressed in skin biopsies from patients with SSc, and this is associated with a better disease prognosis. This suggests a modulatory role of HLA-G in SSc, as observed in other skin disorders.