Andreia Bettencourt

The Protective Role of HLA-DRB1∗13 in Autoimmune Diseases

Autoimmune diseases (AIDs) are characterized by a multifactorial aetiology and a complex genetic background, with the MHC region playing a major role. We genotyped for HLA-DRB1 locus 1228 patients with AIDs-213 with Systemic Lupus Erythematosus (SLE), 166 with Psoriasis or Psoriatic Arthritis (Ps + PsA), 153 with Rheumatoid Arthritis (RA), 67 with Systemic Sclerosis (SSc), 536 with Multiple Sclerosis (MS), and 93 with Myasthenia Gravis (MG) and 282 unrelated controls. We confirmed previously established associations of HLA-DRB1∗15 (OR = 2.17) and HLA-DRB1∗03 (OR = 1.81) alleles with MS, HLA-DRB1∗03 with SLE (OR = 2.49), HLA-DRB1∗01 (OR = 1.79) and HLA-DRB1∗04 (OR = 2.81) with RA, HLA-DRB1∗07 with Ps + PsA (OR = 1.79), HLA-DRB1∗01 (OR = 2.28) and HLA-DRB1∗08 (OR = 3.01) with SSc, and HLA-DRB1∗03 with MG (OR = 2.98). We further observed a consistent negative association of HLA-DRB1∗13 allele with SLE, Ps + PsA, RA, and SSc (18.3%, 19.3%, 16.3%, and 11.9%, resp., versus 29.8% in controls). HLA-DRB1∗13 frequency in the AIDs group was 20.0% (OR = 0.58). Although different alleles were associated with particular AIDs, the same allele, HLA-DRB1∗13, was underrepresented in all of the six diseases analysed. This observation suggests that this allele may confer protection for AIDs, particularly for systemic and rheumatic disease. The protective effect of HLA-DRB1∗13 could be explained by a more proficient antigen presentation by these molecules, favouring efficient clonal deletion during thymic selection.

Association between vitamin D receptor (VDR) gene polymorphisms and systemic lupus erythematosus in Portuguese patients

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown origin, in which both genetic and environmental factors are involved. One such environmental factor is vitamin D, a vital hormone that plays a specific function in the immune system homeostasis, acting through a nuclear receptor (VDR) expressed in all immune cells. Several polymorphisms of the gene that encodes this receptor have been described. Though inconsistently, these polymorphisms have been associated with clinical manifestations and SLE development. The aim of this study was to determine the possible association between VDR gene polymorphisms (BsmI, ApaI, TaqI e FokI) and SLE susceptibility and severity, in a cohort of lupus patients from the north of Portugal. A total of 170 patients (F = 155, M = 15; age = 45 ± 13.4 years) with SLE (diagnosed according the American College of Rheumatology criteria) with at least five years of disease evolution and followed in the Autoimmune Disease Clinical Immunology Unit of Centro Hospitalar do Porto were studied. Patients and 192 ethnicity-matched controls were genotyped for BsmI (rs1544410), ApaI (rs7975232), TaqI (rs731236) and FokI (rs2228570) polymorphisms by TaqMan allelic discrimination assay. Disease severity was assessed by SLICC damage score, number of affected organs, number of severe flares and pharmacological history. SLE patients with the CT genotype of FokI polymorphism have a higher SLICC value (p = 0.031). The same result was observed for the group of patients with the TT genotype of TaqI polymorphism (p = 0.046). No differences were observed in VDR genotype between patients and controls. Also, we observed that the other clinical features analysed were not influenced by VDR polymorphisms. Our study confirms a possible role of VDR gene polymorphisms in SLE. A positive association was found between VDR polymorphisms and SLE severity (chronic damage). The presence of CT genotype of FokI and TT genotype of TaqI seems to confer a worse prognosis and may constitute a risk factor for higher long-term cumulative damage in SLE patients.

Cognitive reserve in multiple sclerosis: Protective effects of education.

Background: Recent data suggest that cognitive reserve modulates the adverse effects of multiple sclerosis (MS) pathology on cognitive functioning; however, the protective effects of education in MS are still unclear. Objective: To explore education as an indicator of cognitive reserve, while controlling for demographic, clinical and genetic features. Methods: A total of 419 MS patients and 159 healthy comparison (HC) subjects underwent a comprehensive neuropsychological (NP) assessment, and answered the Hospital Anxiety and Depression Scale. Based on the HC data, MS patients’ NP scores were adjusted for sex, age and education; and the estimated 5th percentile (or 95th percentile, when appropriate) was used to identify any deficits. Patients also performed the Mini-Mental State Examination (MMSE); and their human leucocyte antigen HLA-DRB1 and apolipoprotein E (ApoE) genotypes were investigated. Results: Patients with higher education were less likely (p < 0.05) to have cognitive deficits than those with lower education, even when controlling for other covariates. Other significant predictors of cognitive deficit were: age, Expanded Disability Status Scale (EDSS), Multiple Sclerosis Severity Scale (MSSS), and a progressive course. No significant association was found with the HLA-DRB1*15:01 or ApoE ε4 alleles. Conclusions: These results provide support to the use of education as a proxy of cognitive reserve in MS and stress the need to take into account education when approaching cognition in MS.

Olfactory dysfunction in multiple sclerosis: association with secondary progression

Objective: The Brief Smell Identification Test (B-SIT) was used to explore odour identification capacities in multiple sclerosis (MS). Methods: In total, 153 consecutive patients with MS and 165 healthy controls (HC) participated in the study. All participants were asked to answer the B-SIT and the Hospital Anxiety and Depression Scale (HADS). The Expanded Disability Status Scale (EDSS), the Multiple Sclerosis Severity Scale (MSSS), and the Mini-Mental State Examination (MMSE) were used for patients’ clinical and cognitive characterization. Results: Patients with MS (11.1%) were more impaired on the B-SIT than HC participants (3%). The frequency of impairment was higher for patients with secondary progressive (SPMS; 11/16, 68.8%) than relapsing–remitting (RRMS; 4/121, 3.3%) or primary progressive (2/16, 12.5%) courses. A threshold score of ≤ 8 on the B-SIT provided a sensitivity of 69% and a specificity of 97% in the identification of SPMS among patients with relapsing onset. The association between SPMS and impaired B-SIT remained statistically significant after adjusting for demographic (i.e. age and education), clinical (i.e. disease duration, EDSS, and MSSS), psychopathological (i.e. HADS anxiety and depression scores), and cognitive (i.e. MMSE) variables. Conclusions: A brief odour identification measure provided a good discrimination between SPMS and RRMS courses. A systematic assessment of olfactory functions may contribute to the development of clinical markers of SPMS.

HLA class II alleles as markers of tuberculosis susceptibility and resistance

BACKGROUND Not every individual exposed to Mycobacterium tuberculosis becomes infected. One host genetic factor, involved in modulating the immune response that has been studied in many ethnic groups is the association of human leukocyte antigens (HLA) with susceptibility to tuberculosis (TB). OBJECTIVE To investigate the association between TB, HLA-DRB1 and HLA-DQB1 alleles in a Portuguese population. METHODS HLA-DRB1 and HLA-DQB1 gene polymorphisms were analyzed by PCR-SSP in 92 TB patients, and 82 healthcare professionals without TB but exposed on a daily basis to infectious patients for more than two years (healthy exposed - HE). Tuberculin skin test reaction (TST), was positive in 69 individuals (all over 15 mm) in the HE group (HE+) and negative in thirteen (HE-). RESULTS HLA-DRB1*14 frequency is higher in the TB patients group (7 % vs. 0; p = 0.038) than in HE+. CONCLUSIONS No genetic marker clearly indicative of disease susceptibility or resistance was identified in this study. However, HLA-DRB1*14 was more frequent in TB patients suggesting that it may be involved in the evolution infection towards active TB in our population.

Cognitive Functioning in Behcet's Disease

The impact of Behçets disease on higher cognitive functions is still poorly understood. We proposed (1) to characterize the neuropsychological profile of Behçets disease patients with (Neuro‐BD) and without (BD) neurological manifestations; (2) to identify which clinical, psychopathological, and genetic variables are related to neuropsychological performance; and (3) to explore the association between cognitive functioning and neuroimaging findings in BD patients. Fifteen Neuro‐BD and 35 BD patients in the nonactive phase of their illness underwent a neurological examination, performed a comprehensive battery of neuropsychological tests, and answered the hospital anxiety and depression scale. Human leukocyte antigen (HLA)‐B*51 genotyping was also performed. Patients’ neuropsychological performances were compared to those of healthy demographically matched subjects. Within one month from the testing date, a subset of 20‐BD patients underwent a magnetic resonance imaging (MRI) scan. Fifty‐three percent of Neuro‐BD and 40% of BD patients were impaired at least on one neuropsychological measure (i.e., digit span–forward). Poorer cognitive functioning in Neuro‐BD was associated with parenchymal involvement, whereas in BD it was related to presence of white matter changes in the frontal lobes, history of headache complaints, or higher levels of anxiety and depression. Current prednisone intake had a positive impact on neuropsychological performance. Disease duration, time since onset of neurological manifestations, or presence of HLA‐B*51 allele had no significant influence. Our results indicate that Behçets disease may affect cognitive abilities in the absence of overt neurological symptoms. These findings point to an insidious course of neurological involvement.

Protective role of the HLA-A*02 allele in Portuguese patients with multiple sclerosis.

Background Multiple sclerosis (MS) is associated with human leukocyte antigen (HLA) HLA–DRB1*15. Recent evidence that CD8 T cells are implicated in MS suggests that HLA class I may also contribute. An association of HLA–A*02 and A*03 alleles has been described. Objectives We examined the influence of HLA–A*02 and HLA–A*03 in Portuguese patients with MS, independently of HLA–DRB1*15 using a logistic regression model. Conclusions DRB1*15 increased the risk of developing MS and HLA–A*02 decreased the risk. A*03 had no effect. To analyze if HLA–A*02 association was independent from DRB1*15, an interaction between these two alleles was introduced in the model; no significant interaction was found.

HLA in Portuguese systemic lupus erythematosus patients and their relation to clinical features.

Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease translating the different genetic and environmental factors involved. Polymorphisms at several loci, including the major histocompatibility complex (MHC), have been associated worldwide with SLE, although inconsistencies exist among these studies mainly due to genetic heterogeneity between populations and sample characteristics. The aim of the present study was to investigate in Portuguese SLE the association of HLA‐DRB1 alleles with clinical patterns of the disease and severity. Two hundred eighteen Portuguese patients with SLE—42% of whom had kidney involvement—were studied for HLA‐DRB1. Clinical and laboratory manifestations were correlated with HLA allele frequencies. HLA‐DRB1 * 03 allele frequency was significantly higher in SLE patients—as a whole and as either with or without renal involvement—compared to controls, while HLA‐DRB1 * 09 and DRB1 * 13 allele frequencies were decreased. Regarding the relationship with the presence or absence of specific clinical manifestations, it was only found that HLA‐DRB1 * 08 allele frequency was increased in patients with neurological involvement. No association with the presence or absence of anti‐dsDNA, anti‐sm or antiphospholipid antibodies, or antiphospholipid syndrome, was observed. These results were reproducible when analysis was repeated only with patients with more than 5 years of evolution. As in other populations HLA‐DRB1 * 03 is a susceptibility allele in Portuguese SLE patients, while HLA‐DRB1 * 09 and DRB1 * 13 alleles may be protective alleles, not only for the disease, but for the development of nephritis. No correlations with the different clinical manifestations were found, except with the neurological system.

New insights of HLA class I association to Behçet’s disease in Portuguese patients

Human leukocyte antigen (HLA)-B*51 is a well-known genetic factor associated with Behçets disease (BD). To analyse the influence of HLA-B*51 and other HLA class I alleles in BD susceptibility in a Portuguese population and its association with disease severity, we studied 78 BD patients and 208 healthy controls. The patients were classified into two severity groups as described by Gul et al. As expected, a higher frequency of HLA-B*51 was found. The frequency of HLA-Cw*16 alleles was significantly higher in patients. Regarding severity, HLA-B*27 frequency was higher in the severe group compared with controls and with the mild group. Thus, HLA-B*51 and HLA-Cw*16 seem to confer susceptibility to BD in this patients. HLA-B*27 may be important as a prognostic factor.

The role of KIR2DS1 in multiple sclerosis - KIR in Portuguese MS patients

Killer Immunoglobulin-like Receptor (KIR) genes may influence both resistance and susceptibility to different autoimmune diseases, but their role in the pathogenesis of Multiple Sclerosis (MS) is still unclear. We investigated the influence of KIR genes on MS susceptibility in 447 MS Portuguese patients, and also whether genetic interactions between specific KIR genes and their HLA class I ligands could contribute to the pathogenesis of MS. We observed a negative association between the activating KIR2DS1 gene and MS (adjusted OR=0.450, p=0.030) independently from the presence of HLA-DRB1*15 allele. The activating KIR2DS1 receptor seems to confer protection against MS most probably through modulation of autoreactive T cells by Natural Killer cells.