Human immunology and immunotherapy: main achievements and challenges.

The immune system is a fascinating world of cells, soluble factors, interacting cells, and tissues, all of which are interconnected. The highly complex nature of the immune system makes it difficult to view it as a whole, but researchers are now trying to put all the pieces of the puzzle together to obtain a more complete picture. The development of new specialized equipment and immunological techniques, genetic approaches, animal models, and a long list of monoclonal antibodies, among many other factors, are improving our knowledge of this sophisticated system. The different types of cell subsets, soluble factors, membrane molecules, and cell functionalities are some aspects that we are starting to understand, together with their roles in health, aging, and illness. This knowledge is filling many of the gaps, and in some cases, it has led to changes in our previous assumptions; e.g., adaptive immune cells were previously thought to be unique memory cells until trained innate immunity was observed, and several innate immune cells with features similar to those of cytokine-secreting T cells have been discovered. Moreover, we have improved our knowledge not only regarding immune-mediated illnesses and how the immune system works and interacts with other systems and components (such as the microbiome) but also in terms of ways to manipulate this system through immunotherapy. The development of different types of immunotherapies, including vaccines (prophylactic and therapeutic), and the use of pathogens, monoclonal antibodies, recombinant proteins, cytokines, and cellular immunotherapies, are changing the way in which we approach many diseases, especially cancer.

Novel genetic loci associated HLA-B*08:01 positive myasthenia gravis.

OBJECTIVE: To identify potential causative markers involved in the development of early-onset myasthenia gravis (EOMG) in the MHC and non-MHC regions that may interact with the HLA-B*08:01 allele. METHODS: We analyzed 583 MG patients and identified 5 patients homozygous for the disease-associated ancestral haplotype 8.1 (HLA-A*01:01, B*08:01, DRB1*03:01, DQB1*02:01). We also analyzed more than 9000 controls and selected 24 for further investigation. We subsequently conducted a fine mapping analysis through high-throughput sequencing of the MHC region (from upstream of the GPα5 gene to downstream of the ZBTB9 gene). For the interaction analysis we analyzed a total of 150,090 SNPs equally distributed throughout the genome in the individuals that were homozygous for the main susceptibility HLA allele HLA-B*08:01 and investigated the expression of the genes located close to the observed susceptibility variants. RESULTS: The overall coverage of the 4.79 Mb MHC region ranged between 96.57% and 97.41%. We identified 705 new variants in the MHC region (673 SNPs and 32 InDels). However, no significant differences were found between patients and controls within the MHC region of the ancestral 8.1 haplotype. As the susceptibility gene is considered to be located close to the HLA-B locus, complete sequencing of the surrounding 200 kb was carried out in the 5 patients and 24 controls. No significant differences where observed, suggesting that the HLA-B molecule itself is the susceptibility factor for EOMG. We also observed two new susceptibility loci specific for MG HLA*08:01 patients (P < 3.33 × 10-7). These loci map to an intronic OVCH1 variant (rs10492374; P = 1.90 × 10-8) and a 5' downstream CNPY2 variant (rs10783780; P = 3.33 × 10-7) on chromosome 12. Individuals heterozygous for GA*rs10492374 showed an increased expression of the OVCH1 gene. The rs10783780 genotypes were not associated with CNPY2 mRNA levels, but the MG HLA*08:01 patients present a lower expression of this gene than the healthy controls. CONCLUSION: Our results showed that when we control for the influence of the ancestral haplotype 8.1, no polymorphism was demonstrated to be associated with EOMG development within the MHC region suggesting that the HLA-B*08:01 allele is the unique genetic factor within the HLA region responsible for EOMG development in patients who carry the ancestral haplotype 8.1. Our study also identified two novel polymorphisms as risk factors for MG HLA-B*08:01 positive patients which regulate the expression of the OVCH1 and CNYP2 genes.

A functional variant that affects exon-skipping and protein expression of SP140 as genetic mechanism predisposing to multiple sclerosis.

Several variants in strong linkage disequilibrium (LD) at the SP140 locus have been associated with multiple sclerosis (MS), Crohn's disease (CD) and chronic lymphocytic leukemia (CLL). To determine the causal polymorphism, we have integrated high-density data sets of expression quantitative trait loci (eQTL), using GEUVADIS RNA sequences and 1000 Genomes genotypes, with MS-risk variants of the high-density Immunochip array performed by the International Multiple Sclerosis Genetic Consortium (IMSGC). The variants most associated with MS were also correlated with a decreased expression of the full-length RNA isoform of SP140 and an increase of an isoform lacking exon 7. By exon splicing assay, we have demonstrated that the rs28445040 variant was the causal factor for skipping of exon 7. Western blots of peripheral blood mononuclear cells from MS patients showed a significant allele-dependent reduction of the SP140 protein expression. To confirm the association of this functional variant with MS and to compare it with the best-associated variant previously reported by GWAS (rs10201872), a case-control study including 4384 MS patients and 3197 controls was performed. Both variants, in strong LD (r(2) = 0.93), were found similarly associated with MS [P-values, odds ratios: 1.9E-9, OR = 1.35 (1.22-1.49) and 4.9E-10, OR = 1.37 (1.24-1.51), respectively]. In conclusion, our data uncover the causal variant for the SP140 locus and the molecular mechanism associated with MS risk. In addition, this study and others previously reported strongly suggest that this functional variant may be shared with other immune-mediated diseases as CD and CLL.

Candidate gene study of TRAIL and TRAIL receptors: association with response to interferon beta therapy in multiple sclerosis patients.

TRAIL and TRAIL Receptor genes have been implicated in Multiple Sclerosis pathology as well as in the response to IFN beta therapy. The objective of our study was to evaluate the association of these genes in relation to the age at disease onset (AAO) and to the clinical response upon IFN beta treatment in Spanish MS patients. We carried out a candidate gene study of TRAIL, TRAILR-1, TRAILR-2, TRAILR-3 and TRAILR-4 genes. A total of 54 SNPs were analysed in 509 MS patients under IFN beta treatment, and an additional cohort of 226 MS patients was used to validate the results. Associations of rs1047275 in TRAILR-2 and rs7011559 in TRAILR-4 genes with AAO under an additive model did not withstand Bonferroni correction. In contrast, patients with the TRAILR-1 rs20576-CC genotype showed a better clinical response to IFN beta therapy compared with patients carrying the A-allele (recessive model: p = 8.88×10(-4), pc = 0.048, OR = 0.30). This SNP resulted in a non synonymous substitution of Glutamic acid to Alanine in position 228 (E228A), a change previously associated with susceptibility to different cancer types and risk of metastases, suggesting a lack of functionality of TRAILR-1. In order to unravel how this amino acid change in TRAILR-1 would affect to death signal, we performed a molecular modelling with both alleles. Neither TRAIL binding sites in the receptor nor the expression levels of TRAILR-1 in peripheral blood mononuclear cell subsets (monocytes, CD4+ and CD8+ T cells) were modified, suggesting that this SNP may be altering the death signal by some other mechanism. These findings show a role for TRAILR-1 gene variations in the clinical outcome of IFN beta therapy that might have relevance as a biomarker to predict the response to IFN beta in MS.

Alternative splicing and proteolytic rupture contribute to the generation of soluble IL-6 receptors (sIL-6R) in rheumatoid arthritis.

OBJECTIVE: To describe the relationship between the two mechanisms involved in sIL6R generation in rheumatoid arthritis (RA). METHOD: RA patients were selected from a group of subjects genotyped for the rs8192284 SNP, located at the proteolytic cleavage site of IL-6R. sIL6R and protease levels (ADAM17) were measured and the contribution of alternative splicing in the generation of sIL-6R was evaluated through qRT-PCR. RESULT: Increased sIL-6R plasma levels and expression of spliced isoform generating sIL-6R are genotype dependent. ADAM17 concentrations were independent of the genotype studied. CONCLUSION: Alternative splicing and proteolytic cleavage participate in sIL-6R generation in RA. The rs8192284 polymorphism determines the sIL-6R plasma level through differential proteolytic rupture controlled by ADAM17.

Replication study of 10 genes showing evidence for association with multiple sclerosis: validation of TMEM39A, IL12B and CBLB [correction of CLBL] genes.

BACKGROUND AND OBJECTIVES: Ten genes previously showing different evidence of association with multiple sclerosis have been selected to validate. METHODS: Eleven polymorphisms were genotyped with the iPLEX™ Sequenom in a well-powered collection of Spanish origin including 2863 multiple sclerosis cases and 2930 controls. RESULTS: Replication extended to the following polymorphisms: PKN2 (rs305217), GTF2B (rs7538427), EPHA4 (rs1517440), YTHDF3 (rs12115114), ANKFN1 (rs17758761) and PTPRM (rs4798571), which did not reach the threshold of significance in a follow-up of the first genome-wide association study (GWAS) conducted in multiple sclerosis; TMEM39A (rs1132200), which appeared as a newly identified susceptibility gene in the same study; a gene previously reaching GWAS significance in Italy, CBLB (rs9657904); IL12B (rs6887695, rs10045431), a susceptibility gene shared by diverse autoimmune diseases and, finally, another gene showing inconclusive association with multiple sclerosis, CNR1 (rs1049353). CONCLUSIONS: Pooled analysis corroborated the effect on MS predisposition of three genes: TMEM39A [rs1132200: p(M-H)=0.001; OR(M-H) (95% CI)= 0.84 (0.75-0.93)], IL12B [rs6887695: p(M-H)=0.03; OR(M-H) (95% CI)= 1.09 (1.01-1.17)] and CBLB [rs9657904: p(M-H)=0.01; OR(M-H) (95% CI)= 0.89 (0.81-0.97)].

TRAIL/TRAIL receptor system and susceptibility to multiple sclerosis.

The TNF-related apoptosis inducing ligand (TRAIL)/TRAIL receptor system participates in crucial steps in immune cell activation or differentiation. It is able to inhibit proliferation and activation of T cells and to induce apoptosis of neurons and oligodendrocytes, and seems to be implicated in autoimmune diseases. Thus, TRAIL and TRAIL receptor genes are potential candidates for involvement in susceptibility to multiple sclerosis (MS). To test whether single-nucleotide polymorphisms (SNPs) in the human genes encoding TRAIL, TRAILR-1, TRAILR-2, TRAILR-3 and TRAILR-4 are associated with MS susceptibility, we performed a candidate gene case-control study in the Spanish population. 59 SNPs in the TRAIL and TRAIL receptor genes were analysed in 628 MS patients and 660 controls, and validated in an additional cohort of 295 MS patients and 233 controls. Despite none of the SNPs withstood the highly conservative Bonferroni correction, three SNPs showing uncorrected p values<0.05 were successfully replicated: rs4894559 in TRAIL gene, p = 9.8×10(-4), OR = 1.34; rs4872077, in TRAILR-1 gene, p = 0.005, OR = 1.72; and rs1001793 in TRAILR-2 gene, p = 0.012, OR = 0.84. The combination of the alleles G/T/A in these SNPs appears to be associated with a reduced risk of developing MS (p = 2.12×10(-5), OR = 0.59). These results suggest that genes of the TRAIL/TRAIL receptor system exerts a genetic influence on MS.

Plasma soluble IL-6 receptor concentration in rheumatoid arthritis: associations with the rs8192284 IL6R polymorphism and with disease activity.

Soluble interleukin-6 receptor α subunit (sIL-6R) is primarily generated by shedding of the membrane-bound form. This process is influenced by the single nucleotide polymorphism rs8192284 (A > C) resulting in an aspartic acid to alanine substitution (D358A) at the proteolytic cleavage site. The aim of this study was to determine whether plasma levels of sIL6R are influenced by the rs8192284 polymorphism in patients with rheumatoid arthritis and to assess the association between plasma sIL-6R levels and disease activity as reflected by anti-CCP status. Thirty-nine patients were randomly selected from a cohort of patients with RA of Spanish descent. Plasma sIL-6R concentrations were measured using sandwich ELISA. Genotyping of the rs8192284 (A > C) polymorphism was done using a Fast Real-Time PCR System. DAS 28 scores were used to assess disease activity. Plasma sIL-6R levels were positively associated with the number of C alleles (AA: 35.27 (3.50) ng/ml, AC: 45.50 (4.58) ng/ml, CC: 52.55 (3.18) ng/ml, P = 0.0001). DAS28 and plasma sIL-6R levels were positively associated in the anti-CCP-positive subgroup (r (2) = 0.45, P = 0.0336) and negatively associated in the anti-CCP-negative subgroup (r (2) = -0.45, P = 0.0825). No association between anti-CCP status and sIL-6R level was found. Our findings show that the rs8192284 polymorphism is operative in patients with RA. The presence of anti-CCP antibodies determines the relationship between sIL-6R concentration and disease activity.

Specific association of a CLEC16A/KIAA0350 polymorphism with NOD2/CARD15(-) Crohn's disease patients.

Independent genome-wide association studies highlighted the function of CLEC16A/KIAA0350 polymorphisms modifying the risk to either multiple sclerosis (rs6498169) or type 1 diabetes (rs2903692). This C-type lectin gene maps to a linkage disequilibrium block at 16p13 and a functional role of this gene could be envisaged for other immune-related conditions, such as inflammatory bowel disease (IBD). The present study, aimed at investigating the association of those two polymorphisms with IBD, included 720 IBD patients and 550 ethnically matched healthy controls. The effect of rs2903692 previously described in diabetes was observed specifically for Crohn's disease (CD) patients lacking the main susceptibility factor described to date, that is, three polymorphisms within another pattern recognition gene, NOD2/CARD15 (NOD2(-) vs NOD2(+) CD patients, G vs A: P=0.008; OR (95% CI)=1.54 (1.10-2.15); NOD2(-) CD patients vs controls: P=0.008; OR (95% CI)=1.37 (1.08-1.73)). Replication of these findings was performed in independent Spanish cohorts of 544 IBD patients and 340 controls and the combined data yielded significant differences (405 NOD2(-) vs 204 NOD2(+) CD patients, G vs A: P=0.0012; OR(M-H) (95% CI)=1.49 (1.17-1.90); NOD2(-) CD patients vs controls: P=0.0007; OR(M-H) (95% CI)=1.35 (1.13-1.60)). The pooled analysis of the ulcerative colitis patients vs controls also yielded a significant risk (P=0.0005; OR (95% CI)=1.52 (1.19-1.93)). These data would suggest that microbial recognition through different pathways seems to converge in the development of these polygenic bowel diseases.

Polymorphisms in the selenoprotein S gene: lack of association with autoimmune inflammatory diseases.

BACKGROUND: Selenoprotein S (SelS) protects the functional integrity of the endoplasmic reticulum against the deleterious effects of metabolic stress. SEPS1/SelS polymorphisms have been involved in the increased release of pro-inflammatory cytokines interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha and IL-6 in macrophages. We aimed at investigating the role of the SEPS1 variants previously associated with higher plasma levels of these cytokines and of the SEPS1 haplotypes in the susceptibility to develop immune-mediated diseases characterized by an inflammatory component. RESULTS: Six polymorphisms distributed through the SEPS1 gene (rs11327127, rs28665122, rs4965814, rs12917258, rs4965373 and rs2101171) were genotyped in more than two thousand patients suffering from type 1 diabetes, rheumatoid arthritis or inflammatory bowel diseases and 550 healthy controls included in the case-control study. CONCLUSION: Lack of association of SEPS1 polymorphisms or haplotypes precludes a major role of this gene increasing predisposition to these inflammatory diseases.

Role of the MHC2TA gene in autoimmune diseases.

OBJECTIVES: Expression of major histocompatibility complex (MHC) class II genes is almost exclusively regulated by the class II transactivator. A promoter polymorphism (-168A/G, rs3087456) in the MHC2TA gene was associated with increased susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction in a northern European population. However, no evidence of association of this MHC2TA variant with the two autoimmune diseases could be subsequently detected in independent cohorts. AIM: To test the aforementioned single nucleotide polymorphism and another G-->C change (nt1614 from coding sequence, rs4774) to analyse the haplotype pattern in this MHC2TA gene. METHODS: A case-control study was performed with 350 patients with rheumatoid arthritis, 396 patients with multiple sclerosis, 663 patients with inflammatory bowel disease (IBD) and 519 healthy controls from Madrid. Genotyping was ascertained by using TaqMan assays-on-demand on a 7900HT analyser, following the manufacturer's suggestions (Applied Biosystems, Foster City, California, USA). Haplotypes were inferred with the expectation-maximisation algorithm implemented by the Arlequin software. RESULTS: No independent association with these autoimmune diseases was found for either polymorphism in the Spanish cohorts tested. However, when haplotypes were compared between patients with rheumatoid arthritis and controls, a significant difference in their overall frequency distribution was observed, evidencing a protective haplotype (-168A/1614C, p = 0.006; odds ratio (OR) 0.7) and a risk haplotype (-168G/1614C, p = 0.019; OR 1.6). Patients with multiple sclerosis mirrored these results, but no effect on IBD was identified. CONCLUSIONS: The MHC2TA gene influences predisposition to rheumatoid arthritis and multiple sclerosis, but not to IBD. The -168G allele is not an aetiological variant in itself, but a genetic marker of susceptibility/protection haplotypes.

Analysis of the essential oil composition from the different parts of Eryngiumglaciale Boiss. from Spain.

The essential oil from the different parts (inflorescences, stems + leaves and roots) of Eryngium glaciale Boiss. gathered in Sierra Nevada (Spain) has been extracted by steam distillation and analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative but not qualitative differences have been found between the analysed parts. The principal compounds from the inflorescences oil were found to be phyllocladene isomer (43.5%), (E)-caryophyllene (15.2%) and valencene (11.5%), while the oil from stems and leaves only showed phyllocladene isomer (41.3%) as main one. The oil from the roots presented phyllocladene isomer (49.4%) and linalool (19.1%) as major constituents. This is the first report on the chemical composition of this species.