Genetic Variant of DNAM-1 rs763361 C>T Is Associated with Ankylosing Spondylitis in a Mexican Population

DNAM-1 (CD226) is an activating receptor expressed in CD8+ T cells, NK cells, and monocytes. It has been reported that two SNPs in the DNAM-1 gene, rs763361 C>T and rs727088 G>A, have been associated with different autoimmune diseases; however, the role of DNAM-1 in ankylosing spondylitis has been less studied. For this reason, we focused on the study of these two SNPs in association with ankylosing spondylitis. For this, 34 patients and 70 controls were analyzed using endpoint PCR with allele-specific primers. Our results suggest that rs763361 C>T is involved as a possible protective factor under the CT co-dominant model (OR = 0.34, 95% CI = 0.13-0.88, p = 0.022) and the CT + TT dominant model (OR = 0.39, 95% CI = 0.17-0.90, p = 0.025), while rs727088 G>A did not show an association with the disease in any of the inheritance models. When analyzing the relationships of the haplotypes, we found that the T + A haplotype (OR = 0.31, 95% CI = 0.13-0.73, p = 0.0083) is a protective factor for developing the disease. In conclusion, the CT and CT + TT variants of rs763361 C>T and the T + A haplotype were considered as protective factors for developing ankylosing spondylitis.

Hematological indices as indicators of inflammation induced by exposure to pesticides

Pesticide toxicity, both acute and chronic, is a global public health concern. Pesticides are involved in abnormal inflammatory responses by interfering with the normal physiology and metabolic status of cells. In this regard, inflammatory indices aggregate index of systemic inflammation (AISI), monocyte-to-high-density lipoprotein ratio, monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte platelet ratio (NLPR), neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune inflammation index, and systemic inflammation response index (SIRI) have been used as predictive markers of inflammatory status in several diseases and also in acute poisoning events. This study aimed to determine systemic inflammation indices and their relationship with pesticide exposure from urban sprayers in 302 individuals categorized into three groups (reference group and moderate and high exposure groups). The data suggest that the AISI, MLR, NLPR, and SIRI indices were significantly higher in the exposed groups compared with the reference group. In conclusion, this study proposes that inflammation indices warrant further attention in order to assess their value as early biomarkers of acute and chronic pesticide intoxication.

Association Between MIR3117 and MIR612 Genes Polymorphisms with Childhood Acute Lymphoblastic Leukemia in the Mexican Population

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer in the world, which is associated with a wide spectrum of factors that play an important role in epidemiology, risk stratification, and therapeutic intervention. Several studies have shown the role of microRNAs (miRNAs) in the development of the disease. Genetic variations such as single-nucleotide polymorphisms (SNPs) in miRNAs can alter their function and lead to alter the expression of their target genes.

OBJECTIVE

The aim of this study was to evaluate the association of rs12402181 in MIR3117 and rs12803915 in MIR612 with the risk of childhood preB-ALL in Mexican population.

MATERIAL AND METHODS

DNA from 148 children (<18 years old) diagnosed with preB-ALL and 172 samples from participants in control group were included in the present study. Genotyping of the rs12402181 and rs12803915 polymorphisms was carried out by Real-Time PCR. To estimate the risk factor, the multiple genetic models co-dominant, dominant, and recessive were determined in both polymorphisms.

RESULTS

In dominant genetic model from rs12402181, a high risk of susceptibility to ALL was observed (OR = 2.03, 95% CI = 1.27-3.22, p = 0.003). In the analysis adjusted for gender, a significant increase in the risk of ALL was maintained (OR = 2.03, 95% CI = 1.28-3.24, p = 0.003). The rs12803915 polymorphism was no associated with the risk of susceptibility to preB-ALL in any of the genetic models using in this study.

CONCLUSIONS

Our data indicated that the A allele of the rs12402181 polymorphism may be considered as a genetic biomarker of preB-ALL susceptibility. Likewise, it was identified that the A allele of the rs12402181 polymorphism is an independent risk factor for ALL.

Particulate matter (PM10) induces in vitro activation of human neutrophils, and lung histopathological alterations in a mouse model

The epidemiological association between exposure to particulate matter (PM₁₀) and various respiratory and cardiovascular problems is well known, but the mechanisms driving these effects remain unclear. Neutrophils play an essential role in immune defense against foreign agents and also participate in the development of inflammatory responses. However, the role of these cells in the PM₁₀ induced inflammatory response is not yet fully established. Thus, this study aims to evaluate the effect of PM₁₀ on the neutrophil-mediated inflammatory response. For this, neutrophils from healthy adult human donors were in vitro exposed to different concentrations of PM₁₀. The cell viability and cytotoxic activity were evaluated by MTT. LDH, propidium iodide and reactive oxygen species (ROS) were quantified by flow cytometry. Interleukin 8 (IL-8) expression, peptidyl arginine deiminase 4 (PAD₄), myeloperoxidase (MPO), and neutrophil elastase (NE) expression were measured by RT-PCR. IL-8 was also quantified by ELISA. Fluorescence microscopy was used to evaluate neutrophil extracellular traps (NETs) release. The in vivo inflammatory responses were assessed in BALB/c mice exposed to PM₁₀ by histopathology and RT-PCR. The analysis shows that PM₁₀ exposure induced a cytotoxic effect on neutrophils, evidenced by necrosis and LDH release at high PM₁₀ concentrations. ROS production, IL-8, MPO, NE expression, and NETs release were increased at all PM₁₀ concentrations assessed. Neutrophil infiltration in bronchoalveolar lavage fluid (BALF), histopathological changes with inflammatory cell infiltration, and CXCL1 expression were observed in PM₁₀-treated mice. The results suggest that lung inflammation in response to PM₁₀ could be mediated by neutrophils activation. In this case, these cells migrate to the lungs and release pro-inflamatory mediators, including ROS, IL-8, and NETs. Thus, contributing to the exacerbation of respiratory pathologies, such as allergies, infectious and obstructive diseases.

Deleted genes associated with obesity in Mexican patients diagnosed with nonalcoholic fatty liver disease

AIM

Nonalcoholic fatty liver disease (NAFLD) is a complex metabolic condition in which both lifestyle and genetic factors have a pathogenic role. The LEP gene encodes leptin, which regulates appetite, body weight, and several metabolic functions. Proopiomelanocortin (POMC), regulates food intake and energy balance. The aim of the study was to determine partial or complete deletions of genes associated with obesity in patients diagnosed with NAFLD.

MATERIAL AND METHODS

Blood samples and DNA from 43 individuals diagnosed with NAFLD by ultrasonographic technique (Fibroscan) were obtained. The partial or complete deletions of genes were determined by MLPA (Multiplex Ligation-dependent Probe Amplification) using the SALSA probemix P220-B2 Obesity only on 43 individuals. Fifty blood samples from healthy individuals were included.

RESULTS

Eleven out of 43 individuals analyzed by MLPA presented some deletion of the genes analyzed: six were female and five were male. The partial or complete deletion of the LEPR and POMC genes was observed in eight patients (18.6%), SIM1 in six patients (13.9%), GRIK2 and SH2B1 in two patients (4.7%), SEZGL2 in four patients (9.3%), and MCR4 in one patient (2.3%).

CONCLUSION

Partial deletion was observed in LEPR, POMC, SIM1, GRIK2, SH2B1, SEZGL2, and MCR4 genes in 26% of the cases, and we suggest that these alterations probably has a potential relationship for the development of NAFLD.

The influence of the -94 Ins/Del ATTG polymorphism of NFkB on the anti-CCP antibody levels in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by an inflammatory process that affects mainly synovial tissue in joints, and by the production of cyclic citrullinated peptides (anti-CCP) antibodies. In the inflammatory process the regulation of the nuclear factor kappa B (NFkB) transcription factor activation is a key point in the production of inflammatory cytokines. On the other hand, polymorphisms in several genes could contribute to the promotion of the inflammatory process observed in RA, and the association of the rs28362491 polymorphism in the NFkB gene with RA has been studied in different population. Therefore, it could be one of the interest targets to analyze their association with RA in a Mexican population.This is a case-control study to determine the influence of rs28362491 in the NFkB gene on RA and on clinical features of this disease, such as anti-CCP antibody levels, Disease Activity Score, and Health Assessment Questionnaire-Disability Index.The genotype of rs28362491 in the NFkB gene was determined in 140 RA patients and 135 healthy controls using the polymerase chain reaction-restriction fragment length polymorphism method with the enzyme PflMI. The following clinical variables were also determined: anti-CCP levels, Disease Activity Score, and Spanish version of the Health Assessment Questionnaire Disability-Index.Although no association of the polymorphism as a risk/protection factor with RA was found, the RA patients who carried the Ins/Ins genotype showed higher anti-CCP levels, while those with the Del/Del genotype showed higher Spanish version of the Health Assessment Questionnaire-Disability Index levels, compared to the other genotypes.The NFkB -94 Ins/Del ATTG (rs28362491) polymorphism is, therefore, associated with higher levels of anti-CCP antibodies, though no significant association as a risk or protection factor in RA cases was identified.

High frequency of the risk allele of rs4132601 and rs11978267 from the IKZF1 gene in indigenous Mexican population

Background

IKZF1 is a relevant gene associated with the pathogenesis of acute lymphoblastic leukemia, and the rs4132601 (T>G) and rs11978267 (A>G) polymorphisms have been associated with the development of this disease in several populations. The aim of this study was to determine the allelic and genotypic frequencies of the rs4132601 and rs11978267 polymorphisms in two indigenous Mexican groups (Cora and Huichol) and Mestizo populations from Nayarit, Mexico, and compare them with the frequencies of both polymorphisms in other populations of the world.

Methods

One hundred, 116, and 100 subjects from the Mestizo, Huichol, and Cora populations, respectively, all of them residents of the state of Nayarit, Mexico, were analyzed. The frequencies of rs4132601 and rs11978267 were determined by allelic discrimination using TaqMan assays.

Results

The allelic frequencies of rs4132601 were as follows: Mestizo group T = 0.74, G = 0.26; Cora T = 0.745, G = 0.255; and Huichol T = 0.47, G = 0.53. In the case of the rs11978267 polymorphism, the allelic frequencies were Mestizo A = 0.745, G = 0.255; Cora A = 0.735, G = 0.265; and Huichol A = 0.457, G = 0.543. For each population, both polymorphisms were in Hardy–Weinberg equilibrium.

Conclusion

The Huichol population from Nayarit presented the highest frequencies of the risk allele reported to date in the whole world for both rs4132601 and rs11978267 polymorphisms.

Neutrophil extracellular traps and inflammatory response: Implications for the immunopathogenesis of ankylosing spondylitis

AIM

Ankylosing spondylitis (AS) pathogenesis has focused on the adaptive immune response; however, innate immune responses may also play a role in the inflammatory response of AS. Dysregulated neutrophil activation can induce tissue damage and contribute to the pathogenesis of immune-related diseases. Hence, the aim of this study was to assess the effect of immune complexes formed with the p30 of Salmonella typhimurium and anti-p30 antibodies present in the sera of AS patients and controls in inducing the release of neutrophil extracellular traps (NETs) and the secretion of pro-inflammatory cytokines.

METHODS

We collected polymorphonuclear leukocytes (PMNs) from healthy donors. The PMNs isolated were stimulated with p30 alone or in immunocomplexes formed with antibodies presents in sera of AS patients or control subjects. Then, the NETs were analyzed by fluorescence microscopy. Concentrations of interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β, IL-8 and IL-10, were determined using the Cytometric Bead Array kit.

RESULTS

Significant difference was observed in the release of NETs between the neutrophils stimulated with p30 + AS (70.52 ± 16.24) those unstimulated neutrophils (9.94 ± 12.12; P = .0095), stimulated with phorbol 12-myristate 13-acetate (39.78 ± 14.50; P = .0190), stimulated with control serum (CS) (10.85 ± 5.33; P = .0082) and serum of AS patient (10.28 ± 6.15; P = .0087). The stimulation of neutrophils with p30 alone induced a relatively low production of IL-6 (64.5 pg/mL), IL-8 (2658.3 pg/mL), IL-1β (31.11 pg/mL), and TNF-α (3.8 pg/mL), compared to p30 + AS and p30 + CS groups.

CONCLUSION

Our results show that neutrophils release NETs and pro-inflammatory cytokines in response to p30 in immunocomplexes. These findings could improve our understanding of the role of innate immunity in the initiation and/or maintenance of inflammatory responses, and in the progression of AS.

pirA- and pirB-like gene identification in Micrococcus luteus strains in Mexico

Acute hepatopancreatic necrosis disease (AHPND) was first reported in China in 2009 and afterwards in Mexico in 2013. AHPND is caused by Vibrio parahaemolyticus and affects Penaeus monodon and Litopenaeus vannamei shrimp cultures. The bacterium contains the pirA- and pirB-like genes in 69- to 70-Kb plasmids, which encode the toxins that produce the disease. The aim of this study was to determine whether pirA- and pirB-like genes existed in bacterial genera distinct from Vibrio before the first cases of AHPND were documented in Mexico. Two bacterial isolates were selected from shrimp farms in Nayarit in 2006 and analysed by nested-PCR to determine the presence of pirA- and pirB-like genes. The two isolates chosen did indeed show the presence of these genes, and those findings were confirmed by sequencing. Both strains matched to the bacterial species Micrococcus luteus. Results revealed two important situations: (a) the pirA- and pirB-like genes were present in a bacterial species that has not been reported previously (Micrococcus luteus); and (b) pirA- and pirB-like bacterial genes were present in Mexico before the first AHPND outbreak was reported in China.

Impaired neutrophil extracellular traps and inflammatory responses in the peritoneal fluid of patients with liver cirrhosis

Liver cirrhosis (LC) is an inflammatory process associated with impaired functions in adaptive and innate immune responses at both systemic and local levels, also referred as Cirrhosis-Associated Immune Dysfunction. In this study, we evaluated the functionality of neutrophils from ascitic fluid (AF) of patients with hepatic cirrhosis by testing their ability to generate neutrophil extracellular traps (NETs) in vitro. To further determine the activation state of neutrophils, expression of the activation markers CD66b, CD69, and CD80 on these cells was analysed by flow cytometry. The inflammatory environment in AF was assessed by measured concentration of pro- and anti-inflammatory cytokines. Samples were collected from 40 patients with LC, 20 of them with uncomplicated ascites (ASC) and 20 with spontaneous bacterial peritonitis (SBP). Peripheral blood (PB) neutrophils from healthy individuals were used as control (HC). Our results revealed a significant decrease in the release of NETs in neutrophils from the SBP group compared with HC. Low expression of CD69 and CD80 on neutrophils from AF of SBP patients was also observed. Comparisons of inflammatory cytokine levels in AF from the different study groups (SBP and ASC) revealed significant differences. In conclusion, we demonstrate that the development of complications, such as SBP, increases initially the inflammatory status, but chronically results in impaired neutrophil function as demonstrated by the decreased capability of NETs formation. There is also an increase in both pro-inflammatory and anti-inflammatory cytokines, thus predisposing for new episodes of SPB and increasing morbidity and mortality in cirrhotic patients.

STAT4 rs7574865 G/T polymorphism is associated with rheumatoid arthritis and disease activity, but not with anti-CCP antibody levels in a Mexican population

Rheumatoid arthritis (RA) is a systemic autoimmune disease in whose etiology genetic factors are known to play an important role. Among the genes associated with RA, STAT4 could be an important factor in conducting helper T cells toward the pro-inflammatory Th1 and Th17 lineages. The aim of this study is to determine the association of the STAT4 polymorphism rs7574865 with RA, disease activity, and anti-cyclic citrullinated peptide (CCP) antibody levels in a Mexican population. Genotyping was carried out using the Taqman® system from Applied Biosystems in 140 patients with RA and 150 healthy subjects. Disease activity was evaluated by a rheumatologist using the DAS28 and Spanish-HAQ-DI instruments. Anti-CCP levels were determined by ELISA. Associations of the genotypes of rs7574865 with DAS28, HAQ, and anti-CCP antibody levels with RA were determined. Findings showed that the GT and TT genotypes and the T allele from rs7574865 were all associated as risk factors for RA, independently of their anti-CCP status. An association with moderate-to-high disease activity (DAS28 ≥ 3.2) was also found. Additionally, patients with the GT or TT genotypes showed lower HAQ values than those who carried the GG genotype. No differences in anti-CCP antibody levels or DAS28 and genotypes were found. This work supports the association of the STAT4 rs7574865 polymorphism with RA and disease activity, but not with anti-CCP antibody levels in a Mexican population.

Genotyping WSSV isolates from northwestern Mexican shrimp farms affected by white spot disease outbreaks in 2010-2012

White spot disease (WSD) causes high mortality in cultured shrimp throughout the world. Its etiologic agent is the white spot syndrome virus (WSSV). The genomic repeat regions ORF 75, ORF 94, and ORF 125 have been used to classify WSSV isolates in epidemiological studies using PCR with specific primers and sequencing. The present study investigated the variation in nucleotide sequences from 107, 150, and 143 isolates of WSSV collected from Litopenaeus vannamei shrimp ponds with WSD outbreaks in northwestern Mexico during the period 2010-2012, in the genomic repeat regions ORFs 75, 94, and 125, respectively. The haplotypic nomenclature for each isolate was based on the number of repeat units and the position of single nucleotide polymorphisms on each ORF. We report finding 17, 43, and 66 haplotypes of ORFs 75, 94, and 125, respectively. The study found high haplotypic diversity in WSSV using the complete sequences of ORFs 94 and 125 as independent variables, but low haplotypic diversity for ORF 75. Different haplotypes of WSSV were found from region-to-region and year-to-year, though some individual haplotypes were found in different places and in more than one growing cycle. While these results suggest a high rate of mutation of the viral genome at these loci, or perhaps the introduction of new viral strains into the area, they are useful as a tool for epidemiological surveys. Two haplotypes from some of the ORFs in the same shrimp were encountered, suggesting the possibility of multiple infections.

Lymphoproliferative response to the 30-kDa protein and a crude lysate from Salmonella typhimurium in patients with ankylosing spondylitis

OBJECTIVES

To determine the lymphoproliferative response to the 30-kDa protein (p30) of Salmonella typhimurium in patients with ankylosing spondylitis (AS).

METHOD

Lymphoproliferative response was determined in peripheral blood mononuclear cells (PBMCs) from 30 patients with AS and 40 healthy subjects. Cells were cultured with concanavalin A (Con A), a crude lysate of S. typhimurium (StCL), or p30. Lymphoproliferation was measured by the MTT assay.

RESULTS

Our data show that the mitogenic response to Con A was similar in both groups studied; however, the lymphoproliferative response to StCL and p30 was statistically higher in AS patients than in healthy subjects.

CONCLUSIONS

Our data strongly suggest that S. typhimurium, and particularly p30, are associated with AS.

Characterization of the humoral immune response against Gnathostoma binucleatum in patients clinically diagnosed with gnathostomiasis

Gnathostomiasis is an emerging systemic parasitic disease acquired by consuming raw or uncooked fresh-water fish infected with the advanced third-stage larvae of Gnathostoma spp. This disease is endemic to the Pacific region of Mexico, and one of its etiologic agents has been identified as Gnathostoma binucleatum. We characterized the humoral immune response of patients clinically diagnosed with gnathostomiasis by detecting total IgM, IgE, and IgG class and subclasses against a crude extract of the parasite by Western blotting. Our results do not show differences in the antigens recognized by IgM and IgE. However, we found that the specific humoral immune response is caused mainly by IgG, specifically IgG4. We found that 43%, 65.2%, 54.1%, and 26.3% of the patients recognize the 37-kD, 33-kD, 31-kD, and 24-kDa antigens, suggesting that the 33-kD antigen is the immunodominant antigen of G. binucleatum.

IgG class antibodies to heat shock-induced streptococcal antigens in psoriatic patients

BACKGROUND

Psoriasis is a chronic inflammatory skin disease. Probably autoimmune in nature, and associated with streptococcal throat infections as a triggering factor. Although many groups have associated the disease with other pathogens, Streptococcus pyogenes seems to be the most important microorganism related to this disease. Therefore, it is necessary to identify the streptococcal antigens involved in the process.

METHODS

In this work IgG class antibodies to soluble antigens obtained from Staphyloccus aureus, Candica albicans or S. pyogenes before and after heat shock induction, were analyzed by ELISA in 28 psoriatic patients and 30 healthy donors.

RESULTS

In all cases, the patients and the controls had IgG class antibodies to the four antigens. Nevertheless, the IgG levels to the heat shock-induced S. pyognes were statistically different between the patients and the controls (P < 0.001). There was no difference between the groups when the IgG antibodies to the other antigens, including the noninduced streptococcal extract, were analyzed. Additionally, anti-streptolysin O titers and throat cultures were carried out in all patients and controls. No differences between ASO titers were found but the patients were more frequently colonized by pyogenes.

CONCLUSION

Results obtained in this study suggest that heat shock-induced proteins from S. pyogenes are associated with psoriasis.

Autoantibodies to autologous skin in guttate and plaque forms of psoriasis and cross-reaction of skin antigens with streptococcal antigens

BACKGROUND

Psoriasis is a chronic disease of the skin that appears to be of autoimmune nature. It has a strong association with throat streptococcal infections, as well as with stressful events. Although many groups consider psoriasis to be a T-cell-mediated autoimmune disease, autoantibodies could also play a role in the development of this process.

METHODS

In this work, we looked for autoantibodies to psoriatic skin in 21 psoriatic patients and four healthy donors (controls). The immunoperoxidase technique was used to look for autoantibodies in autologous sera in skin sections obtained from lesions or from healthy areas of the same patient, before and after immunoadsorption with a Streptococcus pyogenes extract. The skin biopsies were also analyzed with a pool of sera from mice immunized with the streptococcal extract.

RESULTS

We found that all psoriatic patients had autoantibodies to antigens present in keratinocytes, whereas healthy subjects did not. These antibodies did not recognize epitopes on healthy skin from the same psoriatic patients or controls. Immunoadsorption of autologous sera removed the reactivity to antigens in skin lesions in all cases. Mouse anti-streptococcal sera recognized epidermal antigens present in lesional psoriatic skin, but not in healthy skin from psoriatic patients or controls. Deposits of immunoglobulin G (IgG) were not detected in the lesions.

CONCLUSIONS

It seems that autoantibodies, although they do not appear to participate in the pathogenesis of psoriasis, are an important feature, and that skin antigens, which appear in lesional immature keratinocytes, cross-react with S. pyogenes and contribute to the autoimmune process in psoriasis.