Tiago Degani Veit

Association of the HLA-G 14 bp polymorphism with systemic lupus erythematosus:

Human leukocyte antigen-G (HLA-G) is a nonclassical class I major histocompatibility complex molecule which is induced at the course of inflammatory pathologies, and its expression has been suggested as a possible mechanism of tissue protection against autoimmune inflammatory responses, therefore acting as a mechanism of immune surveillance. We investigated the influence of the 14 bp polymorphism of the HLA-G gene on systemic lupus erythematosus (SLE) by analyzing 293 patients with SLE and 460 healthy controls. The patient’s group was not in Hardy–Weinberg equilibrium, presenting an excess of heterozygotes (P = 0.014). The heterozygote group exhibited lower systemic lupus erythematosus disease activity indexes than the homozygous deletion group and the homozygous insertion group (mean value = 2.29 against 2.97 and 3.4, respectively, P = 0.035). Photosensitive patients showed a higher frequency of heterozygotes and an equivalent lower frequency of homozygotes for deletion; on the other hand, patients without arthritis presented a higher frequency of heterozygotes than the arthritis group and also a lower frequency of the del/del genotype. Overall, our results support the idea of a role of the HLA-G insertion/deletion polymorphism and therefore a role for the HLA-G molecule, on the pathology of SLE.

Association of the HLA-G 14-bp insertion/deletion polymorphism with juvenile idiopathic arthritis and rheumatoid arthritis

We tested the possible association of the 14-bp polymorphism of the HLA-G gene in the course of two inflammatory diseases, rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). Patients and controls were genotyped for the 14-bp polymorphism by polymerase chain reaction with specific primers for the exon 8 of the human leukocyte antigen (HLA)-G gene and the amplified fragment was visualized in a 6% polyacrylamide gel. A total of 106 JIA patients, 265 RA patients, 356 healthy adults and 85 healthy children were genotyped for the 14-bp polymorphism. Female JIA patients presented a higher frequency of the -14 bp allele when compared with female healthy children (0.743 and 0.500, corrected P=0.003), which reflected in the JIA group as a whole. This increased frequency of the -14-bp allele was observed in all JIA subtypes. In RA patients, no differences in allelic and genotypic frequencies were observed between patients and controls. No correlations were observed among genotype and disease severity or clinical manifestations. Our data suggest that the HLA-G -14 bp allele is probably a risk factor for JIA, mainly in females. Considering the differences observed in relation to gender, we suggest that hormonal differences can interfere with the development of JIA. Considering the RA patients, our data agree with results from the literature and highlight the differences in the etiology of RA and JIA.

Systemic lupus erythematosus: Association with KIR and SLC11A1 polymorphisms, ethnic predisposition and influence in clinical manifestations at onset revealed by ancestry genetic markers in an urban Brazilian population

Systemic lupus erythematosus (SLE) is an autoimmune disorder of the connective tissue with a wide and heterogeneous spectrum of manifestations, with renal and neurological involvement usually related to worse prognosis. SLE more frequently affects females of reproductive age, and a high prevalence and renal manifestation seem to be associated with non-European ethnicity. The present study aims to investigate candidate loci to SLE predisposition and evaluate the influence of ethnic ancestry in the disease risk and clinical phenotypic heterogeneity of lupus at onset. Samples represented by 111 patients and 345 controls, originated from the city of Belém, located in the Northern Region of Brazil, were investigated for polymorphisms in HLA-G, HLA-C, SLC11A1, MTHFR, CASP8 and 15 KIR genes, in addition to 89 Amerindian samples genotyped for SLC11A1. We also investigated 48 insertion/deletion ancestry markers to characterize individual African, European and Amerindian ancestry proportions in the samples. Predisposition to SLE was associated with GTGT deletion at the SLC11A1 3’UTR, presence of KIR2DS2 +/KIR2DS5 +/KIR3DS1 + profile, increased number of stimulatory KIR genes, and European and Amerindian ancestries. The ancestry analysis ruled out ethnic differences between controls and patients as the source of the observed associations. Moreover, the African ancestry was associated with renal manifestations.

O papel do gene e da molécula HLA-G na expressão clínica das doenças reumatológicas

Human leukocyte antigen G (HLA-G) is a non-classic class I major histocompatibility complex (MHC) molecule characterized by low polymorphism in its coding region, a limited tissue distribution pattern in physiologic conditions, and expression through soluble isoforms and isoforms bound to surface membranes through alternative splicing. HLA-G is fairly known since it is involved in induction and maintenance of tolerance between the maternal immunologic system and the semi-allogeneic fetus at the level of the fetal-placental interface. Besides, several studies have indicated a wider immunoregulatory role of this molecule. In this context, the expression of HLA-G in inflammatory and rheumatologic diseases is a relatively recent research area. The first studies described the expression of HLA-G in several inflammatory myopathies, atopic dermatitis, and cutaneous psoriasis. Based on the findings that HLA-G could divert T helper responses to the Th2 type, it was hypothesized that HLA-G would be a protective molecule in inflammatory responses. In this article, we review the potential roles of the HLA-G molecule in the immune system and in several rheumatologic diseases, such as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and others.

Mannose-binding Lectin Gene Polymorphisms in Brazilian Patients with Rheumatoid Arthritis

Objective. Rheumatoid arthritis (RA) is a disease with unknown etiology but it is probably multifactorial. RA susceptibility is related to genetic, hormonal, immunologic, and environmental factors. Mannose-binding lectin (MBL) is an important protein of the human innate immune system, encoded by the MBL2 gene. Polymorphisms in MBL2 were associated with several diseases, and may be an important factor in RA susceptibility. We analyzed 3 MBL2 gene polymorphisms in 322 Brazilian patients with RA and 345 ethnically matched healthy controls. Methods. MBL2 gene variants were analyzed through polymerase chain reaction sequencing. Results. Considering MBL2 B, C, and D alleles separately, a significant difference in both genotypic and allelic frequencies, particularly concerning frequency of the C allele, was observed comparing European-derived and African-derived individuals (European-derived patients 0.022 vs African-derived patients 0.205; European-derived controls 0.029 vs African-derived controls 0.144; both p < 0.001). We also analyzed MBL2 genotype in relation to extraarticular manifestations. Considering MBL2 variants together, we found an increased frequency of the OO genotype among patients with rheumatoid nodules (p = 0.031), although this association lost significance after Bonferroni correction. Conclusion. Our findings suggest an association of MBL2 genotypes with some clinical manifestations of RA, but more studies are needed to clarify the actual role of MBL in RA.

CCR5delta32 in systemic lupus erythematosus: implications for disease susceptibility and outcome in a Brazilian population

The aim of this study was to analyze the allelic and genotypic frequencies of the CCR5delta32 polymorphism in systemic lupus erythematosus (SLE) patients and to investigate a possible association of this allele with SLE susceptibility and clinical outcome. A total of 367 SLE patients and 435 healthy controls were genotyped for the CCR5delta32 polymorphism. We observed that, in European-derived individuals, the frequency of the CCR5delta32 allele was smaller in patients than in controls (2.7% vs. 7.5%, OR 0.34, 95% CI 0.17–0.65, p Bonf = 0.002), suggesting that this allele could be considered a protective factor for the disease. Regarding clinical manifestations, we observed that CCR5delta32 female African-derived carrier patients presented a higher predisposition to class IV nephritis when compared with absent nephritis/other class group (13.8% vs. 3.8%, OR 37.1, 95% CI 2.8–1854.7, p Bonf = 0.030). A multivariate analysis including all female patients and controlling for the presence or absence of anti-dsDNA antibodies, ethnicity and age at diagnosis showed an increased relative risk of 3.9 times for patients carrying the CCR5delta32 allele to develop class IV nephritis as compared with noncarriers. Our data suggest that the CCR5delta32 allele is a protective factor for the disease in European-derived patients and a susceptibility factor to class IV nephritis in African-derived female patients.

New evidence for balancing selection at the HLA-G locus in South Amerindians

HLA-G is a non-classical HLA (Human Leukocyte Antigen) molecule characterized by limited tissue distribution under normal physiological conditions and low variability at both DNA and protein levels. Several studies suggest that HLA-G could play a role, as an immunoregulatory molecule, in situations as diverse as transplantation, cancer, viral infections and inflammatory diseases. A total of 237 individuals from 21 South American tribes speaking nine different linguistic families were studied in relation to the 14 bp insertion/deletion polymorphism at the HLA-G gene. A consistent (seven in nine) excess of heterozygosity in samples classified by language was obtained. Our data supply evidences for balancing selection acting at the HLA-G 14 bp INDEL region. Enhanced fetal survival in a pathogen-rich environment may account for these findings.

The paradox of high availability and low recognition of soluble HLA-G by LILRB1 receptor in rheumatoid arthritis patients

HLA-G is a regulatory molecule involved in immunologic tolerance. Growing evidence indicates that HLA-G plays a role in the regulation of inflammatory processes and autoimmune diseases. This study aimed at a systematic evaluation of soluble HLA-G (sHLA-G) in plasma of rheumatoid arthritis (RA) patients with long-lasting chronic inflammation. RA patients (n=68) and healthy controls (n=26) had their plasmatic sHLA-G measured by ELISA whereas the binding capability of sHLA-G to its cognate LILRB1 receptor was measured by a Luminex-based assay. All subjects were PCR-genotyped for HLA-G 14bp polymorphism (rs66554220). Significantly higher sHLA-G levels were observed in patients (p<0.001), however no significant differences were observed in LILRB1 binding capacity between RA patients and controls. Remarkably, the proportion of patients presenting specific binding of sHLA-G to LILRB1 was significantly decreased as compared to controls (56% vs. 81%, p=0.027). Patients without rheumatoid factor (RF-) were significantly overrepresented in the group of patients positive for LILRB1 binding as compared to patients without LILRB1 binding (31% vs 10%, p=0.033). Furthermore, methotrexate treated patients (n=58) revealed significantly lower LILRB1 binding to sHLA-G molecules than non-treated patients (medians: 12.2 vs. 67.7 units/ml, p=0.031). Unlike in controls, no significant differences in sHLA-G levels were observed among patients grouped by 14pb genotype. Thus, in a substantial number of late RA patients, the circulating sHLA-G molecules are impaired regarding LILRB1 recognition, meaning that although increased levels are observed; these molecules are not qualified to exert their protective functions against inflammation. Our findings offer new insights into the immunopathology of RA patients with long-lasting anti-RA-treatment and highlight the importance to also measure the binding capability of sHLA-G to LILRB1.

Aspectos clínico-patológicos e controle da paratuberculose em rebanho bovino leiteiro

Paratuberculosis (Johnes disease) is a granulomatous enteritis of ruminants caused by Mycobacterium avium subsp. paratuberculosis. Epidemiology, clinic-pathological and laboratorial aspects of paratuberculosis in a dairy cattle herd are described. The disease was diagnosed from 2006 to 2009 in eight cows that presented chronic-intermittent diarrhea and chronic weight loss, in the Rio Claro municipality, Rio de Janeiro. At necropsy, the subserosal lymphatic vessels were proeminent and dilated, mesenteric nodes were enlarged and intestinal mucosa was corrugated, thickened and of microgranular aspect. From duodenum to the rectum, histopathology revealed severe and diffuse granulomatous inflammation of the lamina propria and submucosa, broadened and distorted villi, dilatation of the lymphatic vessels in their apex, lymphangioectasia and granulomatous lymphangitis in the submucosa. Ziehl-Neelsen stain showed variable amounts of acid-fast bacilli in macrophages, in Langhans giant cells and freely in the mucosa and submucosa of the small intestine, colon and lymphnodes. In some cows, the lamina propria presented severe hypertrophy, mainly in the jejunum and ileum. Mycobacterium avium subsp. paratuberculosis was isolated through bacterial cultivation of samples taken from feces, intestinal mucosa and milk, and identified through IS900 PCR. From 298 cows older than three years, the percentage of reactive animals was 40% by indirect ELISA test. The diagnosis of paratuberculosis was based on clinic-epidemiological data, serology, bacterial isolation in Herrold egg yolk medium with micobactin and on IS900 PCR. After the adoption of control measures, as slaughter of cows with clinical signs, selective slaughter of seropositive cows, removal of the calf from the dam at birth, and use of the colostrum bank, we observed a reduction from six clinical cases to only one case per year, in the last three years of the study.

The CCR5Δ32 polymorphism as a pre-eclampsia susceptibility marker: an evaluation in Brazilian women.

a cluster with other chemokine receptor genes [5]. the CCr5Δ32 (rs333) is an allelic variant of which 32 bp were deleted in the coding region resulting in a nonfunctional receptor. First described as a co-receptor for hIV-1 virus infection, this variant was also associated to several inflam-matory conditions (see Vargas et al. for a review). homozy-gous individuals for CCr5Δ32 do not express a functional protein, while heterozygous may express low amounts of the functional receptor when compared to the wild-type homozygous individuals.Pre-eclampsia, for instance, is one of the most common pregnancy complications and along with other hyperten-sive disorders, is a major contributor to maternal mortal-ity worldwide [6]. Despite its severity, the etiology of Pe is not fully elucidated, affecting 5–10% of all pregnan -cies globally. In Brazil, this disease accounts for more than 7 % of maternal–fetal mortality. thus, the understanding of such phenomenon is of great importance to elucidate the immunological mechanisms involved during the gesta-tional period. Pe is characterized, among others symptoms, by the occurrence of hypertension (diastolic blood pres-sure of ≥90 mm hg), edema and substantial proteinuria (≥300 mg in 24 h) at or after 20 weeks of gestation [7]. 6, Furthermore, Pe is characterized by events of endothelial dysfunction and excessive inflammation, mainly in the first trimester of pregnancy [6]. One of the pathophysiologi-cal mechanisms of Pe is a failure to develop an adequate blood supply to the placenta, leading to placental oxidative stress and excessive release of placental factors in mater-nal circulation. In addition, an inadequate trophoblast inva-sion results in an incomplete remodeling of uterine spiral arteries, being the main cause of placental ischemia in PeImmunogenetics laboratory, Department of[8, 9]. It is known that genetic factors play a role in pre-eclampsia. Also, an immune unbalance in pre-eclampsia has been reported. Altered cytokine production and marked Dear Sir,We read with interest the manuscript by Gurdol et al. [1] that suggested a protective effect of the CCr5Δ32 poly-morphic variant of the CCr5 gene in inflammation asso-ciated to pre-eclampsia (Pturkish women. e) in the CCr5Δ32 allelic variant was observed in a lower fre-quency among pre-eclamptic women as compared to con-trols, and therefore the authors suggested that its presence conferred protection against this disease. As it is well-estab-lished, chemokines are chemotactic cytokines involved in several cellular processes including innate immunity, cellu-lar recruitment, cell activation, induction of adhesion mol-ecules expression and inflammation [2]. Chemokine recep-tors (CCr) are members of the G protein-coupled receptors and present seven transmembrane domains, being con-sidered as important determinants of early inflammatory responses [2]. Different works already evaluated the asso-ciation of CCr genes polymorphisms as well as cytokine levels and the inflammatory state and pathogenesis of pre-eclampsia [3, 4]. CCr5 is a member of the CC chemokine receptors mainly expressed in immune system cells, such as macrophages and t lymphocytes. CCr5 plays an impor-tant role in migration of immune cells to inflammatory sites. It has been shown that chemokines are essential for the regulation of immune responses, being crucial in patho-genesis of both autoimmune and hypersensitivity-based diseases [2t]. he gene encoding CCr5 (