A genome-wide association study of asthma hospitalizations in adults.

BACKGROUND: Little is known about the genetic determinants of severe asthma exacerbations. OBJECTIVES: We aimed to identify genetic variants associated with asthma hospitalizations. METHODS: We conducted a genome-wide association study of asthma hospitalizations in 34,167 white British adults with asthma, 1,658 of whom had at least 1 asthma-related hospitalization. This analysis was conducted by using logistic regression under an additive genetic model with adjustment for age, sex, body mass index, smoking status, and the first 5 principal components derived from genotypic data. We then analyzed data from 2 cohorts of Latino children and adolescents for replication and conducted quantitative trait locus and functional annotation analyses. RESULTS: At the chromosome 6p21.3 locus, the single-nucleotide polymorphism (SNP) rs56151658 (8 kb from the promoter of HLA-DQB1) was most significantly associated with asthma hospitalizations (for test allele A, odds ratio = 1.36 [95% CI = 1.22-1.52]; P = 3.11 × 10-8); 21 additional SNPs in this locus were associated with asthma hospitalizations at a P value less than 1 × 10-6. In the replication cohorts, multiple SNPs in strong linkage disequilibrium with rs56151658 were associated with severe asthma exacerbations at a P value of .01 or less in the same direction of association as in the discovery cohort. Three HLA genes (HLA-DQA2, HLA-DRB6, and HLA-DOB) were also shown to mediate the estimated effects of the SNPs associated with asthma hospitalizations through effects on gene expression in lung tissue. CONCLUSIONS: We identified strong candidate genes for asthma hospitalizations in adults in the region for class II HLA genes through genomic, quantitative trait locus, and summary data-based mendelian randomization analyses.

Plasmodium vivax Pv12 B-cell epitopes and HLA-DRß1*-dependent T-cell epitopes in vitro antigenicity.

Malaria is an infectious disease caused by parasites from the genus Plasmodium (P. falciparum and P. vivax are responsible for 90% of all clinical cases); it is widely distributed throughout the world's tropical and subtropical regions. The P. vivax Pv12 protein is involved in invasion, is expressed on merozoite surface and has been recognised by antibodies from individuals exposed to the disease. In this study, B- and T-cell epitopes from Pv12 were predicted and characterised to advance in the design of a peptide-based vaccine against malaria. For evaluating the humoral response of individuals exposed to natural P. vivax infection from two endemic areas in Colombia, BepiPred-1.0 software was used for selecting B-cell epitopes. B-cell epitope 39038 displayed the greatest recognition by naturally-acquired antibodies and induced an IgG2/IgG4 response. NetMHCIIpan-3.1 prediction software was used for selecting peptides having high affinity binding for HLA-DRß1* allele lineages and this was confirmed by in-vitro binding assays. T-epitopes 39113 and 39117 triggered a memory T-cell response (Stimulation Index≥2) and significant cytokine production. Combining in-silico, in-vitro and functional assays, two Pv12 protein regions (containing peptides 39038, 39040, 39113 and 39117) have thus been characterised as promising vaccine candidates against P. vivax malaria.

TCR-contacting residues orientation and HLA-DRß* binding preference determine long-lasting protective immunity against malaria.

Fully-protective, long-lasting, immunological (FPLLI) memory against Plasmodium falciparum malaria regarding immune protection-inducing protein structures (IMPIPS) vaccinated into monkeys previously challenged and re-challenged 60 days later with a lethal Aotus monkey-adapted P. falciparum strain was found to be associated with preferential high binding capacity to HLA-DRß1* allelic molecules of the major histocompatibility class II (MHC-II), rather than HLA-DRß3*, ß4*, ß5* alleles. Complete PPIIL 3D structure, a longer distance (26.5 Å ± 1.5 Å) between residues perfectly fitting into HLA-DRß1*PBR pockets 1 and 9, a gauche(-) rotamer orientation in p8 TCR-contacting polar residue and a larger volume of polar p2 residues was also found. This data, in association with previously-described p3 and p7 apolar residues having gauche(+) orientation to form a perfect MHC-II-peptide-TCR complex, determines the stereo-electronic and topochemical characteristics associated with FPLLI immunological memory.

Gauche(+) side-chain orientation as a key factor in the search for an immunogenic peptide mixture leading to a complete fully protective vaccine.

Topological and stereo-electron characteristics are essential in major histocompability class II-peptide-T-cell receptor (MHC-p-TCR) complex formation for inducing an appropriate immune response. Modified high activity binding peptides (mHABPs) were synthesised for complete full protection antimalarial vaccine development producing a large panel of individually fully protection-inducing protein structures (FPIPS) and very high long-lasting antibody-inducing (VHLLAI) mHABPs. Most of those which did not interfere, compete, inhibit or suppress their individual VHLLAI or FPIPS activity contained or displayed a polyproline II-like (PPIIL) structure when mixed. Here we show that amino acid side-chains located in peptide binding region (PBR) positions p3 and p7 displayed specific electron charges and side-chain gauche(+) orientation for interacting with the TCR. Based on the above, and previously described physicochemical principles, non-interfering, long-lasting, full protection-inducing, multi-epitope, multistage, minimal subunit-based chemically synthesised mHABP mixtures can be designed for developing vaccines against diseases scourging humankind, malaria being one of them.

The high immunogenicity induced by modified sporozoites' malarial peptides depends on their phi (ϕ) and psi (ψ) angles.

The importance of CSP- and STARP-derived ϕ and ψ dihedral angles in mHABP structure was analysed by (1)H NMR in the search for molecules which can be included as components of a first-line-of-defence Plasmodium falciparum sporozoite multi-epitope vaccine against the most lethal form of human malaria. Most of the aforementioned dihedral angles were left-hand-like polyproline type II (PPII(L)) structures whilst others had right-hand-like α-helix (α(R)), thus allowing mHABPS to fit better into MHCII molecules and thereby form an appropriate pMHCII complex and also establish the H-bonds which stabilise such complex and by this means induce an appropriate immune response. This information has great implications for vaccine development, malaria being one of them.

Phi (Φ) and psi (Ψ) angles involved in malarial peptide bonds determine sterile protective immunity.

Modified HABP (mHABP) regions interacting with HLA-DRß1(∗) molecules have a more restricted conformation and/or sequence than other mHABPs which do not fit perfectly into their peptide binding regions (PBR) and do not induce an acceptable immune response due to the critical role of their Φ and Ψ torsion angles. These angle's critical role was determined in such highly immunogenic, protection-inducing response against experimental malaria using the conformers (mHABPs) obtained by (1)H-NMR and superimposed into HLA-DRß1(∗)-like Aotus monkey molecules; their phi (Φ) and psi (Ψ) angles were measured and the H-bond formation between these molecules was evaluated. The aforementioned mHABP propensity to assume a regular conformation similar to a left-handed polyproline type II helix (PPII(L)) led to suggesting that favouring these conformations according to their amino acid sequence would lead to high antibody titre production and sterile protective immunity induction against malaria, thereby adding new principles or rules for vaccine development, malaria being one of them.

Antinuclear antibodies and HLA class II alleles in Jamaican patients with systemic lupus erythematosus.

OBJECTIVE: The relationship between human leukocyte antigens class II (HLA) and antinuclear antibodies was investigated in Jamaican patients with Systemic Lupus Erythematosus (SLE). METHODS: Samples of blood of 82 patients with SLE and 75 healthy controls were tested for antinuclear antibodies using the fluorescent antinuclear antibody (FANA) test, counterimmunoelectrophoresis (CIEP) and the Crithidia luciliae immunofluorescence test (CL-IFT). A DNA-based HLA typing method was used to determine the frequencies of alleles of HLA-DRB1, DRB3, DRB4 and DRB5 in patients and healthy controls. RESULTS: The FANA test was positive in all of the sera from patients with SLE. Anti-dsDNA antibodies were present in 49% (40/82), anti-Sm/RNP 44% (36/82) and anti-Ro/La 43% (35/82) of the sera from SLE patients. The frequency of HLA-DR4 was significantly lower in SLE patients than in healthy controls (2/82, 2% vs 15/75, 20%; RR = 0.12; p = 0.0004; CP = 0.005) but no other HLA-DRB1 SLE associations were found. A positive HLA-DR3 anti-Ro/La antibody association was found in the patients with SLE (9/21, 43% vs 5/55, 9%; odds ratio (OR) = 7.5; CP = 0.01). In contrast, possession of HLA-DR6 was negatively associated with the absence of anti-dsDNA antibodies (9/32, 28% vs 27/44, 61%; OR = 0.2; CP = 0.05). CONCLUSION: The HLA-DR6 allele is associated with the absence of antinuclear antibodies and HLA-DR3 with the presence of anti-Ro/La antibodies in Jamaican patients with SLE. However, these results and those of previous studies of Jamaican patients suggest that the HLA-DR3 association with the development of SLE reported in other populations might in fact reflect the association of HLA-DR3 with anti-Ro/La antibodies. Further investigations are needed to determine whether HLA-DRB antinuclear antibody associations define clinical subsets of SLE in Jamaican patients.