The complex HLA-E-nonapeptide in Behçet disease

Introduction

The knowledge of the aetiology of Behçet disease (BD), an immune-mediated vasculitis, is limited. HLA-B, mainly HLA-B51, and HLA-A molecules are associated with disease, but the ultimate cause of this association remains obscure. There is evidence that NK cells participate in the etiopathology of BD. NK cells have activator and inhibitor surface receptors, like the KIR and the NKG2 families. Classical HLA-class I molecules (A, B and C) are keys in the activity control of the NK because they are KIR ligands. Most NKG2 receptors bind HLA-E, which presents only nonapeptides derived from the signal peptide of other class-I molecules.

Objective

This study investigates the contribution of the pair HLA-E and ligand, nonapeptide derived from the 3-11 sequence of the signal peptides of class I classical molecules, to the susceptibility to BD.

Methods

We analyzed the frequency of the HLA-derivated nonapeptide forms in 466 BD patients and 444 controls and an HLA-E functional dimorphism in a subgroup of patients and controls. Results: In B51 negative patients, the frequency of VMAPRTLLL was lower (70.4% versus 80.0% in controls; P=0.006, Pc=0.04, OR=0.60, 95%CI 0.41-0.86), and the frequency of VMAPRTLVL was higher (81.6% versus 71.4% in controls; P=0.004, Pc=0.03, OR=1.78, 95%CI 1.20-2.63). In homozygosity, VMAPRTLLL is protective, and VMAPRTLVL confers risk. The heterozygous condition is neutral. There were no significant differences in the distribution of the HLA-E dimorphism.

Discussion

Our results explain the association of BD with diverse HLA-A molecules, reinforce the hypothesis of the involvement of the NK cells in the disease and do not suggest a significant contribution of the HLA-E polymorphism to disease susceptibility.

Monitoring of kinetics and exhaustion markers of circulating CAR-T cells as early predictive factors in patients with B-cell malignancies

Purpose

CAR-T cell therapy has proven to be a disruptive treatment in the hematology field, however, less than 50% of patients maintain long-term response and early predictors of outcome are still inconsistently defined. Here, we aimed to optimize the detection of CD19 CAR-T cells in blood and to identify phenotypic features as early biomarkers associated with toxicity and outcomes.

Experimental design

In this study, monitoring by flow cytometry and digital PCR (dPCR), and immunophenotypic characterization of circulating CAR-T cells from 48 patients treated with Tisa-cel or Axi-cel was performed.

Results

Validation of the flow cytometry reagent for the detection of CAR-T cells in blood revealed CD19 protein conjugated with streptavidin as the optimal detection method. Kinetics of CAR-T cell expansion in blood confirmed median day of peak expansion at seven days post-infusion by both flow cytometry and digital PCR. Circulating CAR-T cells showed an activated, proliferative, and exhausted phenotype at the time of peak expansion. Patients with increased expansion showed more severe CRS and ICANs. Immunophenotypic characterization of CAR-T cells at the peak expansion identified the increased expression of co-inhibitory molecules PD1 and LAG3 and reduced levels of the cytotoxicity marker CD107a as predictors of a better long-term disease control.

Conclusions

These data show the importance of CAR-T cells in vivo monitoring and identify the expression of PD1LAG3 and CD107a as early biomarkers of long-term disease control after CAR-T cell therapy.

Association of Functional Polymorphisms of KIR3DL1/DS1 With Behçet's Disease

Behçet's disease (BD) is an immune-mediated vasculitis related to imbalances between the innate and adaptive immune response. Infectious agents or environmental factors may trigger the disease in genetically predisposed individuals. HLA-B51 is the genetic factor stronger associated with the disease, although the bases of this association remain elusive. NK cells have also been implicated in the etiopathogenesis of BD. A family of NK receptors, Killer-cell Immunoglobulin-like Receptor (KIR), with a very complex organization, is very important in the education and control of the NK cells by the union to their ligands, most of them, HLA class I molecules. This study aimed to investigate the contribution of certain KIR functional polymorphisms to the susceptibility to BD. A total of 466 BD patients and 444 healthy individuals were genotyped in HLA class I (A, B, and C). The set of KIR genes and the functional variants of KIR3DL1/DS1 and KIR2DS4 were also determined. Frequency of KIR3DL1^*004 was lower in patients than in controls (0.15 vs. 0.20, P = 0.005, Pc = 0.015; OR = 0.70; 95% CI 0.54–0.90) in both B51 positive and negative individuals. KIR3DL1^*004, which encodes a misfolded protein, is included in a common telomeric haplotype with only one functional KIR gene, KIR3DL2. Both, KIR3DL1 and KIR3DL2 sense pathogen-associated molecular patterns but they have different capacities to eliminate them. The education of the NK cells depending on the HLA, the balance of KIR3DL1/KIR3DL2 licensed NK cells and the different capacities of these receptors to eliminate pathogens could be involved in the etiopathogenesis of BD.

Behçet's disease and genetic interactions between HLA-B*51 and variants in genes of autoinflammatory syndromes

Behçet’s disease (BD) is an immune-mediated systemic disorder with a well-established genetic base. In a previous study, using a next generation sequencing approach, we found many rare variants and some functional polymorphisms in genes related to autoinflammatory syndromes (AID): CECR1, MEFV, MVK, NLRP3, NOD2, PSTPIP1 and TNFRSF1A in our BD cohort. Our strategy did not allow us to establish either number of patients with variants, proportion of individuals accumulating them or relationship with other genetic factors. With the goal to answer these questions, the individual samples were sequenced. Additionally, three functional polymorphisms: NLRP3 p.Gln703Lys, NOD2 p.Arg702Trp and p.Val955Ile were genotyped using TaqMan assays. A total of 98 patients (27.6%) carried at least one rare variant and 13 of them (3.7%) accumulated two or three. Functional regression model analysis suggests epistatic interaction between B51 and MEFV (P = 0.003). A suggestive protective association of the minor allele of NOD2 p.Arg702Trp (P = 0.01) was found in both, B51 positive and negative individuals. Therefore, a high percentage of patients with BD have rare variants in AID genes. Our results suggest that the association of MEFV with BD could be modulated by the HLA molecules; whereas the protective effect of NOD2 p.Arg702Trp would be independent of HLA.

Genetic variations in the TLR3 locus are associated with eosinophilic esophagitis

Background

Eosinophilic esophagitis (EoE) is an antigen-driven disease mediated by an abnormal immune Th2 response.

Objective

The objective of this article is to investigate genes associated with regulating immune responses leading to disease susceptibility.

Methods

Twenty-seven tag single nucleotide polymorphisms (tSNPs) selected in five candidate genes (TLR3, TLR4, FOXP3, FLG and TSLP) were genotyped in 218 EoE patients and 376 controls. Skin prick tests were carried out in EoE patients with a panel of 17 aeroallergens and 22 plant- and animal-derived foods.

Results

Five tSNPs located in the TSLP locus and one tSNP located in the TLR3 locus were significantly associated with EoE. The interactions between TLR3 and TSLP loci were analyzed. TLR3+/TSLP- and TLR3-/TSLP+ individuals showed a significantly reduced susceptibility to EoE compared to TLR3-/TSLP- individuals (OR = 0.66, p = 0.036 and OR = 0.23, p = 0.00014, respectively). Likewise, TLR3+/TSLP+ individuals showed the most decreased susceptibility of developing EoE (OR = 0.16, p = 0.0001). However, the interaction gain attributed to the combination of both genes was negative (IG = -4.52%), which indicated redundancy or independent effect. Additionally, TLR3 locus was found to be associated with aeroallergen and food sensitization in EoE patients (OR = 9.67, p_c = 0.025 and OR = 0.53, p_c = 0.048, respectively).

Conclusion

TLR3 constitutes a novel genetic susceptibility locus for developing EoE, and the effects would be independent of TSLP.

Mutational profile of rare variants in inflammasome-related genes in Behçet disease: A Next Generation Sequencing approach

Behçet's disease (BD) is an immune-mediated systemic disorder with a well-established association with HLA class I and other genes. BD has clinical overlap with many autoinflammatory diseases (AIDs). The aim of this study was to investigate the role of rare variants in seven genes involved in AIDs: CECR1, MEFV, MVK, NLRP3, NOD2, PSTPIP1 and TNFRSF1A using a next generation sequencing (NGS) approach in 355 BD patients. To check global association of each gene, 4 tests: SKAT, CollapseBt, C(α) and weighted KBAC were used. Databases: 1000 Genomes Project Phase 3, Infevers, HGMD and ClinVar and algorithms: PolyPhen2 and SIFT were consulted to collect information of the 62 variants found. All the genes resulted associated using SKAT but only 3 (MVK, NOD2 and PSTPIP1) with C(α) and weighted KBAC. When all the genes are considered, 40 variants were associated to AIDs in clinical databases and 25 were predicted as pathogenic at least by one of the algorithms. Including only MVK, NOD2 and PSTPIP1, the associated to AIDs variants found in BD were 20 and the predicted as pathogenic, 12. The maxima contribution corresponds to NOD2. This study supports influence of rare variants in genes involved in AIDs in the pathogenesis of BD.

PTPN22 is not associated with Behçet's disease. Study spanning the complete gene region in the Spanish population and meta-analysis of the functional variant R620W

OBJECTIVES

The functional variant R620W of the protein tyrosine phosphatase non receptor-22 (PTPN22) gene plays an important role in susceptibility to several immuno-mediated pathologies. Behçet's disease (BD) is a complex disease related to the immune system with a demonstrated genetic base. The HLA class I genes are the most important genetic factors in BD although other genes are also involved in the susceptibility to this disease. The PTPN22 has been proposed as a candidate gene in BD but this association has not been clearly demonstrated yet. The aim of this study was to assess the association of PTPN22 with BD.

METHODS

A cohort composed of 404 Spanish BD patients and 1517 unrelated healthy individuals ethnically matched was genotyped in rs2476601 (R620W). Five tag SNPs: rs1217412, rs2476599, rs3789607, rs3765598 and rs1217419 (spanning a 57 Kb region between 3'UTR and 5'UTR) and rs2488457 (located at the promoter region) were also studied in order to perform a screening of the complete gene. Genotyping was performed using TaqMan® assays. The rs2476601 data were included in a meta-analysis together with those published till the date. The rest of SNPs were used in a case-control study.

RESULTS

No evidence of the association of rs2476601 with BD in the meta-analysis (P = 0.504 in the model of alleles) was found. In the case-control study, no statistically significant differences were observed when comparing the distribution of variants in patients and controls.

CONCLUSIONS

Our results do not support a major role of the PTPN22 gene in BD.

Genetic Analysis with the Immunochip Platform in Behçet Disease. Identification of Residues Associated in the HLA Class I Region and New Susceptibility Loci

Behcet's disease (BD) is an immuno-mediated vasculitis in which knowledge of its etiology and genetic basis is limited. To improve the current knowledge, a genetic analysis performed with the Immunochip platform was carried out in a population from Spain. A discovery cohort comprising 278 BD cases and 1,517 unaffected controls were genotyped using the Immunochip platform. The validation step was performed on an independent replication cohort composed of 130 BD cases and 600 additional controls. The strongest association signals were observed in the HLA class I region, being HLA-B*51 the highest peak (overall P = 6.82E-32, OR = 3.82). A step-wise conditional logistic regression with classical alleles identified HLA-B*57 and HLA-A*03 as additional independent markers. The amino acid model that best explained the association, includes the position 97 of the HLA-B molecule and the position 66 of the HLA-A. Among the non-HLA loci, the most significant in the discovery analysis were: IL23R (rs10889664: P = 3.81E-12, OR = 2.00), the JRKL/CNTN5 region (rs2848479: P = 5.00E-08, OR = 1.68) and IL12A (rs1874886: P = 6.67E-08, OR = 1.72), which were confirmed in the validation phase (JRKL/CNTN5 rs2848479: P = 3.29E-10, OR = 1.66; IL12A rs1874886: P = 1.62E-08, OR = 1.61). Our results confirm HLA-B*51 as a primary-association marker in predisposition to BD and suggest additional independent signals within the class I region, specifically in the genes HLA-A and HLA-B. Regarding the non-HLA genes, in addition to IL-23R, previously reported in our population; IL12A, described in other populations, was found to be a BD susceptibility factor also in Spaniards; finally, a new associated locus was found in the JRKL/CNTN5 region.

Lymphomagenesis-related gene expression in B cells from sustained virological responders with occult hepatitis C virus infection

The expression of activation-induced cytidine deaminase, B-aggressive lymphoma, cyclin D1 and serine/threonine kinase 15 genes, among others, is increased in B cells from patients with chronic hepatitis C virus (HCV) infection. It is unknown whether the level of expression of these genes in B cells is increased in patients with hepatitis C who have achieved a sustained virological response (SVR) but who have persistent, detectable HCV RNA, so-called occult infection. Eighty-three patients who achieved and SVR, 27 with detectable HCV and 56 without detectable HCV RNA, 28 chronic hepatitis C patients and 32 healthy controls were studied. RNA was extracted from B cells, and gene expression levels were measured by RT-PCR. Patients with chronic HCV and those who achieved an SVR (with and without persistent low-level HCV RNA) showed a statistically significant higher expression compared to healthy controls, of activation-induced cytidine deaminase (P = 0.004, P < 0.001 and P = 0.002, respectively), B-aggressive lymphoma (P < 0.001, P = 0.001 and P = 0.006) and cyclin D1 (P = 0.026, P = 0.001; P = 0.038). For activation-induced cytidine deaminase patients with an SVR and 'occult infection' had a statistically significantly higher expression level than patients with and SVR without 'occult infection' (P = 0.014). The higher expression levels found for activation-induced cytidine deaminase, together with other genes indicates that these B lymphomagenesis-related genes are upregulated following HCV therapy and this is more marked when HCV can be detected in PBMCs.

Association of haplotypes of the TLR8 locus with susceptibility to Crohn's and Behçet's diseases

OBJECTIVES

The aim of this study was to investigate the role of the TLR8, a mediator of innate inflammatory response, in susceptibility to two immune-mediated disorders characterised by dysregulation of the immune response, Crohn's and Behçet's diseases (CD and BD).

METHODS

A total of 844 CD, 371 BD patients and 1385 controls were genotyped in 8 tag single nucleotide polymorphisms (tSNPs) in the locus TLR8 (chromosome X). All these tSNPs have a minor allele frequency greater than 0.05 in the Caucasian population.

RESULTS

The rs2407992 and the rs5744067 were associated with susceptibility to BD and CD, respectively (OR=1.34, 95%CI=1.10-1.62, p=0.0025 and OR=0.82, 95%CI=0.68-0.99, p=0.045, respectively). Although after stratification by gender, statistically significant differences in the distribution of the aforementioned SNPs were only observed in the females groups (BD OR=1.31, 95%CI=1.06-1.64, p=0.012 and CD OR=0.84, 95%CI=0.72-0.98, p=0.044) the trend was similar among males. Since the rs5744067 and rs2407992 are located in the same linkage disequilibrium block, we performed a haplotypic analysis by combination of the tSNPs. One haplotype (H1) was identified as a protective factor in BD (OR=0.75, 95%CI=0.62-0.90, p=0.0027) and another (H2) as a protective factor in CD (OR=0.78, 95%CI=0.64-094, p=0.0102). No statistically significant differences in the mean of the levels of expression attributable to the haplotype variants were found in the in silico analysis performed.

CONCLUSIONS

Our results suggest a relationship between the TLR8 and the susceptibility to CD and BD. Nevertheless, these differences could not be imputed to the levels of expression.

NUP98-HOXA9 bearing therapy-related myeloid neoplasm involves myeloid-committed cell and induces HOXA5, EVI1, FLT3, and MEIS1 expression

INTRODUCTION

Chromosomal rearrangements involving NUP98 gene have been associated with human leukemias such as de novo AML, therapy-related AML (t-AML), myelodysplastic syndrome (MDS), and chronic myeloid leukemia (CML). Genetic fusion NUP98-HOXA9, caused by t(7;11)(p15;p15), is a recurrent cytogenetic alteration in de novo acute myeloid leukemia (AML) usually found in young Asian patients and its description in therapy-related myeloid neoplasms (t-MN) is rare. Only one Asian case with molecular demonstration of the NUP98-HOXA9 fusion has been reported in therapy-related leukemia. NUP98-HOXA9 leukemogenic mechanism is derived from the transcription factor activity of the chimeric protein, which enhances the expression of genes related to cellular differentiation arrest and proliferation.

PATIENTS AND METHODS

We studied a Caucasian woman with a therapy-related acute myeloid leukemia after Ewing's sarcoma. Molecular demonstration of the genetic fusion NUP98-HOXA9 was performed by RT-PCR, and gene expression was analyzed by real-time PCR, including four AML patients with MLL rearrangements for comparative analysis. Cytologic and flow cytometric analysis was also carried out.

RESULTS

After cytologic and flow cytometric analysis diagnostics was therapy-related myeloid neoplasm (t-MN). The major component of blasts in the acute leukemia was with neutrophilic differentiation, but 13% erythroid lineage blasts were also found. Cytogenetic and FISH analysis revealed t(7;11)(p15;p15) and NUP98-HOXA9 fusion gene was demonstrated. Gene expression analysis showed upregulation of EVI1 and MEIS1 in the index patient, both of them previously related to a worst outcome.

CONCLUSION

In this work, we include a detailed molecular, clinical, cytological, and cytometric study of the second t-AML bearing NUP98-HOXA9 genetic fusion.

Variants of the IFI16 gene affecting the levels of expression of mRNA are associated with susceptibility to Behçet disease

OBJECTIVE

Behçet disease (BD) is a multifactorial disease in which infectious agents have been proposed as triggers in genetically predisposed individuals. The aim of our study was to investigate the role of innate immunity receptors, specifically the nucleic acid sensors, in susceptibility to BD.

METHODS

Seventy-four tag single nucleotide polymorphisms (tSNP) selected in 9 candidate genes (DDX58, IFIH1, TLR3, TLR7, TLR8, AIM2, IFI16, ZBP1, and TLR9) were genotyped in 371 patients and 854 controls. Assays of mRNA expression and allele-specific transcript quantification (ASTQ) were performed in 110 and 50 controls, respectively.

RESULTS

Patients and controls were genotyped and 2 tSNP (rs6940 in IFI16 and rs855873 in AIM2) were associated with BD. To confirm this association, these tSNP were genotyped in 850 additional controls, and the total cohort was randomly divided into 2 cohorts. The association of these 2 tSNP with the disease remained in both cohorts. One haplotype (rs6940T-rs855873G) was identified as a risk factor (OR 1.41, 95% CI 1.06-1.86, p = 0.015), and another (rs6940A-rs855873A) as a protective factor (OR 0.65, 95% CI 0.47-0.90, p = 0.009). Samples with the risk haplotype had lower IFI16 expression levels than samples with the protective (0.99 ± 0.29 vs 1.23 ± 0.50, p = 0.022). Consistently, in the ASTQ assays performed with the nonsynonymous rs6940 SNP, the risk allele had lower IFI16 expression levels than the protective (p = 0.027).

CONCLUSION

Our findings suggest association of IFI16, a cytosolic sensor of dsDNA and mediator of the AIM2 inflammasome-dependent pathway, in susceptibility to BD. Differences genetically determined in the levels of this molecule could be the cause of this association.

Association of the AIRE gene with susceptibility to rheumatoid arthritis in a European population: a case control study

INTRODUCTION

AIRE is a transcriptional regulator playing a functional role in thymocyte education and negative selection by controlling the expression of peripheral antigens in the thymus. Recently, the AIRE gene was identified as a genetic risk factor for rheumatoid arthritis (RA) in genome wide association (GWA) studies performed in the Japanese population. According to the available data this association is restricted to the Asian population. However, different facts could influence the lack of association in Caucasian populations. The aim of this study was to further investigate the possible role of the AIRE gene in susceptibility to RA in a Caucasian population.

METHODS

A total of 472 Spanish Caucasian RA patients and 475 ethnically matched controls were included in the study. Three single-nucleotide polymorphisms (SNPs) (rs2776377, rs878081 and rs1055311) with a minor allele frequency>0.05 in the Caucasian population which were not included in the high-throughput platforms used in the GWA studies performed in susceptibility to RA, and two SNPs (rs2075876 and rs1800520) associated with RA in the Japanese population, were selected and genotyped using TaqMan assays.

RESULTS

No significant differences in the distribution of the alleles of rs2776377, rs2075876, rs1055311 and rs1800520 SNPs between RA patients and controls were observed. Nevertheless, the frequency of the C allele of rs878081 was significantly higher among RA patients (80.5% vs. 74.6% in the control group, pc=0.012, OR=1.41, 95%CI 1.13-1.75). Regarding the distribution of the rs878081 genotypes, a higher frequency of CC homozygous individuals was found in the RA patient group (65.56% vs. 56.47% in the control group, pc=0.013, OR=1.47, 95%CI 1.12-1.93). The in silico analysis predicted lower affinity to the binding-site of a motif of the transcription NF-κB family and lower transcription levels of AIRE gene for the rs878081C risk variant

CONCLUSIONS

Our findings suggest that the AIRE gene is associated with susceptibility to RA in the Spanish population. Probably, this association has not been detected in the European population in the GWA studies because the earliest high-throughput platforms did not include SNP suitable markers (e.g. rs878081).

Insulin resistance predicts sustained virological response to treatment of chronic hepatitis C independently of the IL28b rs12979860 polymorphism

BACKGROUND

Insulin resistance has been strongly associated with the attainment of sustained viral response (SVR) in hepatitis C patients.

AIM

To determine, in a cohort of Spanish patients with chronic hepatitis C treated with peginterferon plus ribavirin (P+R), whether insulin resistance predicts SVR independently of interleukin-28B rs12979860 polymorphism.

METHODS

Insulin resistance was measured as [HOMA-IR = Insulin (IU/mL)*glucose (mmol/L)/22.5]. Genotype, viral load and histological fibrosis using Scheuer score were also measured. Binary logistic regression analysis was used for statistical purposes.

RESULTS

In a cohort of 240 patients [78% genotype 1, 24% showing advanced fibrosis, 71% high viral load (≥800 000 IU/mL), 31% IL28b genotype CC and 50% with HOMA >2] treated with P+R, 126 (53%) reached SVR. HOMA-IR index (HOMA <2: 63% vs. HOMA >2: 42%; P = 0.001 and IL28b (genotype CC: 68% vs. genotype CT/TT: 45%; P = 0.002) were significantly associated with SVR. In multivariable logistic regression analysis in the overall cohort, variables independently associated were: viral genotype OR: 0.29 (95% CI: 0.11-0.78), P = 0.01; fibrosis OR: 1.62 (95% CI: 1.22-2.16), P = 0.001; HOMA-IR OR: 1.22 (95% CI: 1.02-1.47), P = 0.03; and IL28B genotype OR: 2.43 (95% CI: 1.45-4.07), P = 0.001. The analyses also showed that degree of steatosis, HOMA-IR >2, mild fibrosis and IL28B CC genotype were significantly related to SVR in patients infected with HCV genotypes 1&4, but not in those with genotypes 2&3. No differences were seen in glucose, insulin level or HOMA-IR index segregated according to IL28B genotypes.

CONCLUSION

Our results suggest that insulin resistance, fibrosis stage and IL28B polymorphisms were independent variables associated with sustained viral response.

Cellular immune responses and occult infection in seronegative heterosexual partners of chronic hepatitis C patients

It is unknown whether hepatitis C virus (HCV)-specific cellular immune responses can develop in seronegative sexual partners of chronically HCV-infected patients and whether they have occult infection. Thirty-one heterosexual partners of patients with chronic HCV were studied, fifteen of them with HCV transmission risks. Ten healthy individuals and 17 anti-HCV seropositive patients, without viremia, were used as controls. Virus-specific CD4+ and CD8+ T-cell responses were measured by flow cytometry against six HCV peptides, situated within the nonstructural (NS) proteins NS3, NS4 and NS5, through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) production and CD69 expression. Sexual partners had a higher production of IFN-γ and IL-4 by CD4+ cells against NS3-p124 (P = 0.003), NS5b-p257 (P = 0.005) and NS5b-p294 (P = 0.012), and CD8+ cells against NS3-p124 (P = 0.002), NS4b-p177 (P = 0.001) and NS3-p294 (P = 0.004) as compared with healthy controls. We observed elevated IFN-γ production by CD4+ T cells against NS5b-p257 (P = 0.042) and NS5b-p294 (P = 0.009) in the sexual partners with HCV transmission risks (sexual, professional and familial altogether) than in those without risks. RNA was extracted from peripheral blood mononuclear cells (PBMC), and detection of HCV-RNA positive and replicative (negative) strands was performed by strand-specific real-time PCR. In four sexual partners, the presence of positive and negative HCV- RNA strands in PBMC was confirmed. Hence, we found an HCV-specific cellular immune response as well as occult HCV infection in seronegative and aviremic sexual partners of chronically HCV-infected patients.

Association of Toll-like receptor 10 and susceptibility to Crohn's disease independent of NOD2

Impaired innate inflammatory response has a key role in the Crohn's disease (CD) pathogenesis. The aim of this study was to investigate the possible role of the TLR10-TLR1-TLR6 gene cluster in CD susceptibility. A total of 508 CD patients (284, cohort 1 and 224, cohort 2) and 576 controls were included. TLR10-TLR1-TLR6 cluster single-nucleotide polymorphisms genotyping, NOD2 mutations and TLR10 mRNA quantification were performed using TaqMan assays. Nucleotide-binding oligomerization domain containing 2 (NOD2) and Toll-like receptor (TLR) loci interaction was analyzed by logistic regression and multifactor-dimensionality reduction (MDR). Entropy-based analysis was used to interpret combination effects. One TLR10 haplotype (TLR10(GGGG)) was found associated with CD susceptibility in both cohorts, individuals with two copies had approximately twofold more risk of CD susceptibility than individuals having no copies (odds ratio=1.89, P-value=0.0002). No differences in the mRNA levels were observed among the genotypes. The strongest model for predicting CD risk according to the MDR analysis was a two-locus model including NOD2 mutations and TLR10(GGGG) haplotype (P(c)<0.0001). The interaction gain attributed to the combination of both genes was negative (IG=-2.36%), indicating redundancy or independent effects. Our results support association of the TLR10 gene with CD susceptibility. The effect of TLR10 would be independent of NOD2, suggesting different signaling pathways for both genes.

Correlation between cytokines and anxious-depressive symptoms in patients with fibromyalgia

OBJECTIVE

To establish the influence of cytokines on anxious-depressive manifestations in fibromyalgia (FM) patients.

MATERIAL AND METHOD

The study comprised 56 women (50.5±7.8 years) with FM and 32 healthy female controls (39.65±9.24 years). Psychiatric symptoms were analyzed using the Hamilton Depression Rating Scale (HDRS) and the Hamilton Anxiety Rating Scale (HARS), while pain was assessed by means of a Visual Analog Scale (VAS). Proinflammatory cytokines IL-6, IL-8, IL-10, and TNFα were assayed in serum using the Luminex-xMAP method. The statistical analysis was carried out using the SSPS statistical package.

RESULTS

IL-8 values were significantly lower (p=.013) in patients than in controls. No differences were observed among IL-6, IL-10, and TNFα levels. When comparing cytokine levels with patient age, we observed a significant reduction in IL-6, IL-8, and TNFα in older patients. The values of these cytokines showed no relationship to the anxious-depressive symptoms.

CONCLUSIONS

In our series no differences in serum cytokines were seen between patients with FM and controls, with the exception of a reduction in IL-8 among patients with FM, and which could be attributed to the older age of these patients.

Caspase 7 influences susceptibility to rheumatoid arthritis

OBJECTIVE

The aim of this study was to investigate the possible role of the caspase 7 (CASP7) in susceptibility to rheumatoid arthritis (RA).

METHODS

Genotyping of three single nucleotide polymorphisms (SNPs) of the CASP7 gene: rs11593766 (G/ T), rs2227310 (C/G) and rs2227309 (G/A) was performed in a total of 906 RA patients and 528 matched healthy controls using TaqMan assays. All the subjects were of Spanish Caucasian origin. A relative quantification of mRNA encoding the non-functional variant of procaspase 7 (isoform beta) vs functional isoforms was performed in total RNA from 32 healthy individuals using real-time PCR.

RESULTS

Only the rs2227309 SNP was found to be associated with susceptibility to RA. Frequency of the G allele was significantly higher among RA patients [overall frequency of the G allele 74.0% in cases vs 68.4% in controls, P = 0.001, Odds ratio (OR) = 1.32, 95% Confidence intervals (95% CI) 1.11-1.56] and a higher frequency of GG homozygous individuals was found in the RA patient group (overall frequency of GG genotype 56.0% in cases and 46.4% in controls, P = 0.0005, OR = 1.47, 95%CI 1.18-1.83). A statistically significant deviation was observed to compare the relative expression of the procaspase 7 isoform beta in samples from individuals stratified according their rs2227309 genotypes (AA + AG: 1.36 +/- 0.55, n = 19, vs GG: 2.35 +/- 0.74, n = 13; P = 0.0002).

CONCLUSION

Our results support involvement of the CASP7 gene in the susceptibility to RA. The higher production of the no functional variant of CASP7 by individuals with a particular genotype could be the basis of this association.

Asporin repeat polymorphism in rheumatoid arthritis

BACKGROUND

Asporin belongs to a family of proteins associated with the cartilage matrix.

OBJECTIVE

To investigate the role of the functional polymorphism consisting of an aspartic acid (D) repeat polymorphism located in the ASPN gene in the susceptibility to and clinical outcome of rheumatoid arthritis.

METHODS

A total of 803 Spanish Caucasian patients with rheumatoid arthritis and 904 controls of the same ethnic origin and matched for age and sex were included in the study. The asporin D repeat polymorphism was genotyped using polymerase chain reaction with a fluorescent primer.

RESULTS

No significant differences were detected in the distribution of the 10 alleles found in our population on comparing patients with rheumatoid arthritis with control groups. Nevertheless, individuals bearing D14 produced rheumatoid factor more often than the rest (85.7% v 72.1%, p = 0.006, odds ratio (OR) = 2.35, 95% confidence interval 1.21 to 4.50), and the mean (SD) onset age was higher in the group of individuals bearing D13 (50.09 (13.94)) compared with the rest (47.21 (14.31)), although the difference did not reach significance (p = 0.06).

CONCLUSION

The results do not support a major role for asporin D repeat polymorphism in the susceptibility to rheumatoid arthritis. Nevertheless, they support the influence of this gene on the outcome of the disease.

The spectrum of mutations in Southern Spanish patients with hemophilia A and identification of 28 novel mutations

The aim of this study was to analyze the mutation pattern causing hemophilia A in a population from Southern Spain. Mutation analysis identified the mutation in 99 of the 109 unrelated patients enrolled in the Hemophilia Registry from Andalusia. About 54% of non-inversion mutations identified were previously unreported.

APC Germ-Line Mutations in Southern Spanish Patients with Familial Adenomatous Polyposis: Genotype–Phenotype Correlations and Identification of Eight Novel Mutations

Familial adenomatous polyposis (FAP) is a disease characterized by the presence of hundreds of adenomatous polyps in the colon and rectum which, if not treated, develop into colorectal cancer. FAP is an autosomal dominantly inherited disorder caused by mutation in the APC gene. The aim of this study was to search for germ-line mutations of the APC gene in unrelated FAP families from southern Spain. By direct sequencing of all APC gene exons, we found the mutation in 13 of 15 unrelated FAP families studied. We identified eight novel mutations: 707delA (exon6), 730_731delAG (exon7), 1787C-->G and 1946_1947insG (exon14), 2496delC, 2838_2839delAT, 2977A-->T, and 3224dupA (exon15). Two patients presented de novo germ-line mutations. Genotype-phenotype correlations for extraintestinal and extracolonic manifestations were studied. Intrafamilial phenotypic variability was observed in two families with mutations in exon/intron boundary, probably due to alternative splicing.

Antibodies against glutathione S-transferase T1 (GSTT1) in patients with de novo immune hepatitis following liver transplantation

Four patients of 283 liver-transplant recipients (1.4%) developed de novo immune-mediated hepatitis approximately 2 years after transplantation. Antibodies showing an unusual liver/kidney cytoplasmic staining pattern were detected in the sera of all four patients and one of them was used to screen a human liver cDNA expression library with the aim of identifying the antigenic target of these newly developed antibodies. After cloning and sequencing the gene, it was identified as the gene encoding the glutathion-S-transferase T1 (GSTT1), a 29-kD molecular weight protein, expressed abundantly in liver and kidney. Sera from the other three patients also contained anti-GSTT1 antibodies, two of them demonstrated by immunoblot analysis against the recombinant antigen and the other, which was negative by immunoblot, gave a positive reaction when used directly to screen the same library, suggesting it to be directed to a conformational epitope. The GSTT1 enzyme is the product of a single polymorphic gene that is absent from 20% of the Caucasian population. When we analysed the GSTT1 genotype of the four patients described above, we found that this gene is absent from all of them. Three donor paraffin embedded DNA samples were available and were shown to be positive for GSSTT1 genotype. In accordance with these results, we suggest that this form of post-transplant de novo immune hepatitis, that has been reported as autoimmune hepatitis by others, could be the result of an antigraft reaction in individuals lacking the GSTT1 phenotype, in which the immune system recognizes the GSTT1 protein as a non-self antigen, being the graft dysfunction not the result of an autoimmune reaction, but the consequence of an alo-reactive immune response.

Mitochondrial DNA point mutation in the COI gene in a patient with McArdle's disease

We studied a 57-year-old female patient with clinical and biochemical evidences of McArdle's disease. Her muscle biopsy also revealed signs of mitochondrial proliferation, scattered RRF, and a deficit in complex I of the respiratory chain. Molecular genetic analysis showed that the patient was heterozygous for the most common mutation at codon 49 in the myophosphorylase gene. Mitochondrial DNA analysis of muscle tissue revealed an additional G-to-A transition at nucleotide position 7444 in the cytochrome c oxidase subunit I (COI) gene.

[The effect of polymorphisms of the angiotensin-converting enzyme and angiotensinogen genes on the phenotypic expression of Spanish patients with hypertrophic cardiomyopathy]

BACKGROUND

Hypertrophic cardiomyopathy (HCM) has a great variability in its morphofunctional expression. This study analyzes whether angiotensin-converting enzyme (ACE) and angiotensinogen (AGT) gene polymorphisms modulate the phenotypic expression in Spanish patients with HCM.

PATIENTS AND METHODS

Forty Spanish HCM patients were studied. Twenty-six out of these 40 patients belonged to 7 families with familial HCM, and the remaining 14 patients had either a sporadic HCM or a HCM with unknown family incidence. A group of 269 healthy subjects was included as control for the genotype study. Maximal wall thickness, ventricular mass and several diastolic function indexes were measured in each patient by Doppler-echocardiography. The insertion/deletion (I/D) polymorphism of ACE gene and the M235T polymorphism of AGT gene were studied in both patients and healthy subjects.

RESULTS

A higher frequency in patients than in controls was found for D allele (0.79 vs 0.64; p = 0.02) and for DD genotype (62.5 vs 41.2%; p = 0.02). Conversely, no difference was observed in M235T polymorphism between both groups. Neither DD genotype of ACE, nor TT genotype of AGT determined a greater degree of ventricular hypertrophy or a worse diastolic function in patients with HCM.

CONCLUSIONS

D allele and DD genotype are predisposing factors to express HCM. In this series of Spanish patients, I/D polymorphism of ACE and M235T polymorphism of AGT do not modify phenotypic expression of HCM.

Detection of anti-PL-12 autoantibodies by ELISA using a recombinant antigen; study of the immunoreactive region

Autoantibodies to aminoacyl-tRNA synthetases are highly associated with myositis and detection is important in clinical diagnosis; however, current methods of screening limit its clinical utility. In the present study, alanyl-tRNA synthetase (PL-12) recombinant protein was obtained by immunological screening of a HeLa expression library and used in an ELISA with 22 anti-PL-12 sera, 200 autoimmune sera negative for PL-12 and 100 healthy individual sera. Sensitivity of the method was 95% (21/22) and specificity 100%. Mapping of the immunoreactive region was carried out using three anti-PL-12 sera and different recombinant protein-derived peptides. Results show that the same conformational epitope located within amino acids 730-951 of the PL-12 antigen outside the catalytic region was recognized by the three anti-PL-12 sera tested. We conclude that ELISA using recombinant protein is an effective and useful method for routine screening for anti-PL-12 autoantibodies.

Association of HLA-B51 subtypes and Behçet's disease in Spain

We have studied the distribution of the different HLA-B51* alleles among patients with Behçet's disease (BD) and ethnically matched healthy controls in a Spanish population. The serological B51 specificity was increased in BD patients (37.5% versus 15.5% in controls). Among the B51-associated alleles, the frequencies of B*5101 (32%) and 5108 (5.5%) were increased in BD patients with respect to the control frequencies (13% and 1.2% respectively). The fact that different HLA-B51 subtypes are associated with BD could suggest that common motifs shared by HLA-B51-related alleles are involved in the susceptibility to BD or, in the light of recent studies, that a mutation causing the susceptibility to BD occurred in the B*5101 haplotype, close to HLA-B gene, before the divergence of B*5108 from the B*5101 allele.

Human lymphocytotoxic monoclonal autoantibodies from a highly sensitized renal dialysis patient

A panel of 5 human monoclonal autolymphocytotoxic antibodies (IRM-3, IRM-4, IRM-7, IRM-8, and IRM-10) of the IgM class was established from a highly sensitized renal dialysis patient (IRM), by the generation of mouse-human heterohybridomas. This panel was screened for reactivity against foreign and autoantigens by ELISA, and for reactivity against different tissue sections and HEp-2 slide preparations by indirect immunofluorescence. Cytotoxicity screening of heterohybridoma supernatants gave broad panel reactivity profiles, being cytotoxic against B cells from patient IRM and also against most B cells tested and less reactive with chronic lymphocytic leukemia B cells; T cells were the least sensitive target. Immunoblotting showed that monoclonal IRM displayed some heterogeneity in their binding profiles, although all of them recognized a cellular structure of 26 kDa. None of the heterohybridoma cell lines exhibited cytoplasmic nor surface staining with an anti-CD5 mAb. Results obtained showed that all the autolymphocytotoxic mAbs generated were also able to react against certain nuclear and cytoplasmic self-structures as well as foreign compounds. Monoclonal antibody IRM-7 and, to a lesser degree, IRM-10 exhibited multispecific properties similar to those observed for polyreactive or natural antibodies.

TAP polymorphism in patients with Behçet's disease

OBJECTIVE

To determine if susceptibility to Behçet's disease (BD) is associated with polymorphism of HLA-DRB1, HLA-DQB1, DQB1, and TAP1 and TAP2 genes.

METHODS

Fifty eight Spanish BD patients and 116 ethnically matched unrelated healthy subjects were typed at the HLA-DRB1 and HLA-DQB1 loci using polymerase chain reaction/sequence specific oligotyping (PCR/SSO). TAP1 and TAP2 alleles were assigned using amplification refractory mutation system-PCR.

RESULTS

TAP1C was absent in BD patients, but was found in 12.1% of control subjects (pcorr < 0.05; relative risk = 0.06). Additionally, a linkage disequilibrium between HLA-DQB1*0501 and TAP2B was observed in BD patients (delta = 0.095, pcorr < 0.02), but not in the control group (delta = -0.0031, p > 0.05).

CONCLUSIONS

The complete absence of TAP1C alleles in BD patients may indicate that TAP1 polymorphism is not without some significance in the development of BD. Furthermore, the existence of a linkage disequilibrium between HLA-DQB1*0501 and TAP2B in our patients suggests that the gene conferring susceptibility for BD is inherited as an extended haplotype in the population studied.

Frequency of HLA-DPB1 alleles in a Spanish population: their contribution to rheumatoid arthritis susceptibility

HLA-DPB1 allele frequencies in 181 unrelated control individuals and 70 rheumatoid factor-positive RA patients from Seville (Spain) were determined using oligonucleotide typing methods. All frequencies shown concern the percentage of individuals positive for a certain allele. HLA-DPB1*0401 was the most common DPB1 allele in the healthy individuals, possessed by 65.7% of them. In addition to HLA-DPB1*0401, only the following alleles were found in normal subjects at frequencies greater than 10%: DPB1*0101 (15.5%), DPB1*0201 (12.2%), DPB1*0301 (16.6), and DPB1*0402 (29.3%). When HLA-DPB1 allelic frequencies were compared between seropositive RA patients and controls, a negative association for DPB1*0301 and DPB1*0401 was found in RA patients, although it failed to reach statistical significance after correction for the number of comparisons made. The other DPB1 alleles exhibited almost identical frequencies in both groups. However, when only DR4+ patients and controls were considered, the decrease in the frequency of the DPB1*0301 and DPB1*0401 alleles lacked statistical significance. On the other hand, when DR4- RA patients and controls were compared, the frequency of DPB1*0301 was found decreased significantly again, even more than in the whole group of patients.

Distribution of HLA-A*28 alleles in a Spanish population

DNA oligotyping was used to determine HLA-A28 subtypes in 25 unrelated Caucasian individuals living in or around Seville, Spain. Results showed that HLA-A*6802 was the most frequent allele, found in 14 individuals (53.8%), followed by HLA-68.3, which was present in eight subjects (30.8%), and both combined represented 84.6% of A28+ individuals in the area. The HLA-A*6801 allele was found in three individuals (11.5%), whereas HLA-A*6901 was present in one subject only (3.8%). Results indicate that the distribution of HLA-A28 alleles can vary among different Caucasoid populations. In this way, the high frequency obtained for A*6802 supports previous studies suggesting that the HLA-A*6802 allele was prevalent in people of the Mediterranean basin, in contrast to A*6801, prevalent in northern European populations.

A human monoclonal antibody reacting against HLA-DQ1-, DQ4-, and a subset of DQ7-bearing cells

Human mAb 2A2 recognizes an epitope present in the HLA-DQ1 + 4 specifications and also on several DQ7-positive cells. We have investigated the extra reactions of this monoclonal reagent on a wider panel of DQ1-, DQ4-negative/DQ7-positive B-cell lines. The results obtained support the existence of two subtypes of the HLA-DQ7 specificity on the basis of their reactivity with human mAb 2A2; the DQ7/2A2-positive variant has been found in 12 of 29 BCLs positive for the DR11 antigen, and in four of eight BCLs bearing DR4-DQ7 haplotypes. It has also been detected in the DR12-positive cells assayed and in several unusual DR/DQ7 combinations not commonly found in Caucasoid populations, including the DR13-DwHAG and DR14-Dw16 haplotypes. Results from competition binding assays between 2A2 and well-characterized murine anti-DQ polymorphic mAbs suggest that the epitope recognized by human mAb 2A2 on DQ1- or DQ4-bearing haplotypes is located on the DQ beta chains of such specificities, being amino acid residues 54-55, the potential binding site of antibody 2A2, whereas the binding site on DQ7 antigens cannot be explained on the basis of known amino acid sequences.

Application of the MAILA technique to the study of human anti-HLA monoclonal antibody specificity

The monoclonal antibody-specific immobilization of lymphocyte antigens (MAILA) assay was developed to detect antibodies present in human alloantisera against antigens of different major histocompatibility complex loci, particularly of class II specificity. The MAILA assay has been used in our laboratory to the determination of the type of HLA molecule recognized by human monoclonal antibodies 91C2 (anti-A2 + 28), 34F11 (anti-DQ1), and 2A2 (anti-DQ1 + 4 + short DQ7), using well characterized monomorphic as well as polymorphic murine monoclonals for the specific immobilization of HLA molecules. Results obtained show that the MAILA assay is also a valuable tool for the determination of specific human MHC locus products recognized by human monoclonal antibodies.