HLA-DR and DQB1 gene polymorphism in the North-western Colombian population

Leishmania spp Epitopes in Humans Naturally Resistant to the Disease: Working Toward a Synthetic Vaccine

Vaccines are one of the most effective strategies to fight infectious diseases. Reverse vaccinology strategies provide tools to perform in silico screening and a rational selection of potential candidates on a large scale before reaching in vitro and in vivo evaluations. Leishmania infection in humans produces clinical symptoms in some individuals, while another part of the population is naturally resistant (asymptomatic course) to the disease, and therefore their immune response controls parasite replication. By the identification of epitopes directly in humans, especially in those resistant to the disease, the probabilities of designing an effective vaccine are higher. The aim of this work was the identification of Leishmania epitopes in resistant humans. To achieve that, 11 peptide sequences (from Leishmania antigenic proteins) were selected using epitope prediction tools, and then, peripheral blood mononuclear cells (PBMCs) were isolated from human volunteers who were previously divided into four clinical groups: susceptible, resistant, exposed and not exposed to the parasite. The induction of inflammatory cytokines and lymphoproliferation was assessed using monocyte-derived dendritic cells (moDCs) as antigen-presenting cells (APCs). The response was evaluated after exposing volunteers’ cells to each peptide. As a result, we learned that STI41 and STI46 peptides induced IL-8 and IL-12 in moDCs and lymphoproliferation and low levels of IL-10 in lymphocytes differentially in resistant volunteers, similar behavior to that observed in those individuals to L. panamensis lysate antigens. We conclude that, in silico analysis allowed for the identification of natural Leishmania epitopes in humans, and also STI41 and STI46 peptides could be epitopes that lead to a cellular immune response directed at parasite control.

Patient HLA-DRB1* and -DQB1* allele and haplotype association with hepatitis C virus persistence and clearance

Hepatitis C virus (HCV) infection is prevalent throughout the world and interferon (IFN)-based treatments are currently the only therapeutic option. However, depending upon variations in their human leukocyte antigen (HLA), some patients do not respond well to IFN therapy. The current study evaluated the HLA allele and haplotype distribution of 204 HCV-seropositive individuals from Islamabad, Pakistan, who were receiving standard IFN therapy. In this cohort, 150 patients (74%) showed a sustained virological response to IFN therapy, whereas 54 (26%) did not. In addition to the HCV patients, 102 unrelated healthy volunteers were used as controls. DNA was isolated from the blood of the patients and controls for HLA-DRB1 and HLA-DQB1 allele typing, whilst plasma was used for HCV detection and genotyping. HLA-DRB1*04 was found to impart a significant protective advantage [Bonferroni-corrected P value (pc)=0.047] against HCV infection. In patients on IFN therapy, HLA-DRB1*11 and -DQB1*0301 (pc=0.044) were found to be associated with viral clearance. In contrast, HLA-DRB1*07 (pc=0.008) individually or in combination with HLA-DQB1*02 was found to be associated with viral persistence. These associations of HLA with HCV persistence or clearance will be beneficial in deciding the therapeutic regimen for Pakistani patients infected with HCV genotype 3a.

TIRAP (MAL) S180L polymorphism is a common protective factor against developing tuberculosis and systemic lupus erythematosus

BACKGROUND AND AIM

The involvement of Toll-like receptor (TLR)-mediated pathways in infectious and autoimmunity has been suggested. The MyD88 adaptor-like (Mal) protein, also known as the TIR domain-containing adaptor protein (TIRAP), is implicated in the TLR2- and TLR4-mediated MyD88-dependent signaling pathway. The aim of this study was to investigate the influence of the functional TIRAP (MAL) S180L polymorphism on tuberculosis (TB) and four autoimmune diseases namely: rheumatoid arthritis (RA), primary Sjögren's syndrome (pSS), systemic lupus erythematosus (SLE) and type 1 diabetes mellitus (T1D).

METHODS

This was a case-control and family based association study in which 1325 individuals from a well-defined Colombian population were involved. TIRAP (MAL) S180L genotyping was done by using a polymerase chain reaction-restriction fragment length polymorphism technique and by direct sequencing.

RESULTS

Leu180 allele was found to be a protective factor against developing TB (odd ratio (OR): 0.53, 95% confidence interval (CI): 0.29-0.97) and SLE (OR: 0.29, 95% CI: 0.14-0.61) while no significant influence on RA, pSS and T1D was observed.

CONCLUSION

These results support the influence of TIRAP (MAL) S180L polymorphism on TB and indicate that TB and SLE might share a common immunogenetic pathway in the innate immune response.

The IkappaBL gene polymorphism influences risk of acquiring systemic lupus erythematosus and Sjögren's syndrome

The human inhibitory kappaB-like gene (IkappaBL) maps to a chromosomal region approximately 25 kb telomeric of the TNF gene at 6p21.3. IkappaBL encodes a protein related to IkappaBalpha that may interact with members of the NF-kappaB/Rel family. We evaluated the role of IkappaBL gene polymorphism in systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS). Genomic DNA isolated from individuals with SLE (n = 134), pSS (n = 67) and from individuals matched for age, sex, and ethnicity (n = 423) was genotyped for Delta-473, -62T/A and +738T/C polymorphisms. The -62A allele was associated with a decrease in the risk of acquiring SLE in a recessive manner; whereas the +738C allele was associated with a more than twofold and threefold increase in the risk of SLE and pSS respectively, relative to the +738T allele. Four haplotypes were observed for the IkappaBL polymorphisms. Haplotype -62A+738T (AT) was associated with a 37% decrease in the risk of SLE, whereas AC tended to increase the risk of developing pSS. Using previously reported TNF data, an almost twofold increased in the risk of SLE was observed between haplotypes IKBL-62T+738T/TNF-308G-238G (TTGG) and TTAG because of linkage disequilibrium between IKBL-62T and TNF-308A. Our findings indicate that the IkappaBL gene influences the risk of developing SLE and pSS.

CCL3L1 gene-containing segmental duplications and polymorphisms in CCR5 affect risk of systemic lupus erythaematosus

OBJECTIVES

There is an enrichment of immune response genes that are subject to copy number variations (CNVs). However, there is limited understanding of their impact on susceptibility to human diseases. CC chemokine ligand 3 like-1 (CCL3L1) is a potent ligand for the HIV coreceptor, CC chemokine receptor 5 (CCR5), and we have demonstrated previously an association between CCL3L1-gene containing segmental duplications and polymorphisms in CCR5 and HIV/AIDS susceptibility. Here, we determined the association between these genetic variations and risk of developing systemic lupus erythaematosus (SLE), differential recruitment of CD3+ and CD68+ leukocytes to the kidney, clinical severity of SLE reflected by autoantibody titres and the risk of renal complications in SLE.

METHODS

We genotyped 1084 subjects (469 cases of SLE and 615 matched controls with no autoimmune disease) from three geographically distinct cohorts for variations in CCL3L1 and CCR5.

RESULTS

Deviation from the average copy number of CCL3L1 found in European populations increased the risk of SLE and modified the SLE-influencing effects of CCR5 haplotypes. The CCR5 human haplogroup (HH)E and CCR5-Delta32-bearing HHG*2 haplotypes were associated with an increased risk of developing SLE. An individual's CCL3L1-CCR5 genotype strongly predicted the overall risk of SLE, high autoantibody titres, and lupus nephritis as well as the differential recruitment of leukocytes in subjects with lupus nephritis. The CCR5 HHE/HHG*2 genotype was associated with the maximal risk of developing SLE.

CONCLUSION

CCR5 haplotypes HHE and HHG*2 strongly influence the risk of SLE. The copy number of CCL3L1 influences risk of SLE and modifies the SLE-influencing effects associated with CCR5 genotypes. These findings implicate a key role of the CCL3L1-CCR5 axis in the pathogenesis of SLE.

Association of HLA subtype DRB1*0407 in Colombian patients with actinic prurigo

BACKGROUND

Human leukocyte antigen (HLA) DRB1*0407 had been associated with actinic prurigo in different populations. This class II HLA-DR subtype had not been studied in Colombia.

OBJECTIVE

The objective of this study was to establish whether there was an association of actinic prurigo with HLA DR in a Colombian population.

MATERIALS AND METHODS

Forty patients with a clinical diagnosis of actinic prurigo and 40 healthy subjects, paired by age, sex and birthplace, were studied. HLA typing for HLA DRB1 and DRB1*04, if necessary, was performed by the PCR-SSP method using blood samples.

RESULTS

A high frequency of HLA DRB1*0407 was found in the patients (97.5% vs. 30%; P<0.00001). The allelic frequency of HLA DRB1*0407 was 63.8% in the case group, and 14.5% in the controls (P<0.00001). In the control group, there was a higher frequency of the alleles DRB1*01 (14.5% vs. 1.25%; P=0.0027) and DRB1*13 (23.7% vs. 2.5%; P=0.00013).

LIMITATIONS

The small number of controls does not allow us to drive conclusions about other HLA alleles.

CONCLUSIONS

HLA subtype DRB1*0407, found in actinic prurigo patients in studies conducted in England, Scotland, Ireland and Mexico, was also associated in Colombian patients. This finding, concordant in patients from different ethnic groups, could be helpful in the diagnosis of this disease and probably important in its pathogenesis. DRB1*01 and DRB1*13 alleles were more frequent in controls than in patients; we do not know whether they play any role in the resistance to the disease.

Familial clustering of autoimmune diseases in patients with type 1 diabetes mellitus

We investigated the familial aggregation of autoimmune diseases (AIDs) among first-degree relatives (FDR) of patients with type 1 diabetes mellitus (T1D). Relatives of 98 T1D patients defined according to the guidelines diagnosis of the American Diabetes Association and 113 matched controls without any AID, were interviewed using a questionnaire that sought information about demographic and medical characteristics including a list of 18 AIDs. Genetic analysis was performed using the program ASSOC and by calculating recurrent risk ratios. In cases, 25.5% of the families had at least one member having an AID, while in controls there were 9% (odds ratio [OR]: 3.96, 95% confidence interval [CI]=1.74-9.0, p=0.0006). An AID was registered in 8.3% of 312 FDR of patients as compared with 2.4% of 362 FDR in controls (OR: 3.56, 95% CI=1.64-7.73, p=0.0008). The most frequent AIDs registered in FDR of cases were autoimmune thyroid disease (AITD) and T1D, which disclosed coefficients of aggregation. These results indicate that AIDs cluster within families of T1D patients adding further evidence to consider that clinically different autoimmune phenotypes may share common susceptibility gene variants, which may act pleiotropically as risk factors for autoimmunity.

Interleukin-1beta polymorphisms in Colombian patients with autoimmune rheumatic diseases

Interleukin-1 beta (IL-1beta) exerts a range of inflammatory and immunomodulatory activities that are important in host defense and autoimmune response. The IL-1beta gene, located on chromosome 2 (2q13), is polymorphic. The influence of its polymorphism on 355 patients with autoimmune rheumatic diseases was examined. To this effect, 172 patients with rheumatoid arthritis (RA), 114 with systemic lupus erythematosus (SLE), and 69 with primary Sjogren's syndrome (pSS) were studied. The control group consisted of 392 matched healthy individuals. Genotyping of IL-1beta single-nucleotide polymorphisms (SNPs) at positions -511 (C/T) and + 3953 (C/T) was performed by the polymerase chain reaction-restriction fragment length polymorphism technique. In addition, levels of IL-1beta were measured by immunoassay in supernatants of lipopolysaccharide (LPS)-stimulated and nonstimulated peripheral blood monocytes (PBM) obtained from 19 homozygous individuals for the three most common IL-1beta likely haplotypes, all belonging to the control group. Allele + 3953T was protective for SLE (odds ratio (OR) = 0.57, 95% confidence intervals (CI) = 0.34-0.88, P = 0.01) as was the haplotype -511C + 3953T (OR = 0.43, 95%CI = 0.25-0.74, pc = 0.006). The latter was associated with a lower LPS-stimulated-PBM IL-1beta secretion. Results suggest that IL-1beta polymorphism influences the susceptibility to acquire SLE in our population. The protective association might be explained by the observed inhibitory effect of IL-1beta + 3953T allele on the secretion of IL-1beta under inflammatory circumstances.

The Impact of Disease Activity on the Quality of Life, Mental Health Status, and Family Dysfunction in Colombian Patients With Rheumatoid Arthritis

This study investigated the relationship between activity of disease, mental health status, quality of life, and family dysfunction in northwestern Colombian patients with rheumatoid arthritis (RA). Seventy-nine patients completed a 2-phase study that included physical examination (objective measurement of disease activity according to adapted American College of Rheumatology criteria) and a pretested questionnaire that sought information on helplessness, disability, depression, anxiety, quality of life, arthritis self-efficacy for pain, and other symptoms, as well as family dysfunction and socioeconomic status. Nineteen patients (24%) had active RA, 48 (61%) had moderately active RA, and 12 (15%) were in remission. Symptoms of depression, helplessness, disability, pain, anxiety, lower quality of life, and self-efficacy were associated with RA activity regardless of age, sex, and duration of the disease. Symptoms of depression were directly correlated with anxiety, helplessness, pain, and disability and inversely correlated with quality of life and self-efficacy. Although family dysfunction was present in 39% of patients, no associations between family dysfunction, activity of RA, mental health variables, socioeconomical status or quality of life were observed. These results indicate that RA activity significantly influences mental health status and quality of life in this population. Accordingly, a holistic conception of therapy should guide the treatment of patients with RA.