Ivana Shawkatová

High susceptibility to pemphigus vulgaris due to HLA-DRB1*14:54 in the Slovak population

The current work describes an association between pemphigus vulgaris (PV) and class II HLA alleles in the Slovak population, the first such study in Slovakia on the ‘high‐resolution level’. This work takes into account the new HLA allele nomenclature, officially adopted in 2010. In particular, we have focused on the associations between PV and DRB1*14:54 and DRB1*14:01. This case–control study was performed in a cohort of 43 PV Caucasian patients and 113 Caucasian control subjects from Slovakia. HLA typing was performed using PCR‐SSP (polymerase chain reaction with sequence‐specific primers). We found significantly positive associations between PV and the HLA alleles DRB1*04:02, DRB1*04:04, DRB1*14:54, DRB1*14:04, DRB1*14:05, DQB1*03:02 and DQB1*05:03. In contrast, HLA‐DQB1*06, DRB1*07 and DRB1*13 were negatively associated with PV. Importantly, 93% of PV patients possessed at least one of two HLA haplotypes, DRB1*04–DQB1*03 or HLA‐DRB1*14–DQB1*05. We confirmed the previously reported associations between HLA class II alleles and PV and described a new association between PV and DRB1*14:54. This allele was first described in 2005, and there has been only one report of its association with PV to date.

Characterization of MICA gene polymorphism of HLA complex in the Slovak population

Background: The function of the MHC class I polypeptide-related sequence A (MICA) gene, which belongs to the MHC class I chain-related genes, is to trigger cytolysis of target cells mediated by NKG2D receptor recognition in NK (Natural Killer) cells and CD8 T-lymphocytes. The MICA gene has a high degree of polymorphism, especially observed in exons 2–5. MICA allelic diversity has been reported in association with some autoimmune diseases such Behcets disease, psoriasis and diabetes, as well as with organ rejections. Aim: The aim of this study was to analyse MICA gene polymorphism in the Slovak population, to establish frequencies of MICA alleles and to compare the results with those found in other Western Eurasian populations. No such study has been performed previously in the Slovak population. Subjects and methods: This study examined DNA samples from 124 unrelated Slovak individuals (51 women and 73 men with an average age of 40.3 years) using direct sequencing of MICA exons 2–5. Allele and genotype frequencies were calculated by direct counting and statistical analysis was carried out using Arlequin software. Results: This study identified 15 out of 71 MICA alleles. The most frequent allele was MICA*008 (37.1%) followed by alleles MICA*002 (16.5%) and MICA*009 (11.3%). The rarest alleles were MICA*027, MICA*006 (both 0.8%) and MICA*057 (0.4%), respectively. The most frequent genotypes were 008/008 and 008/002, both with a frequency of 13.7%. Exon 5 microsatellite polymorphism screening revealed five MICA alleles, namely A4, A5, A5.1, A6 and A9. The most frequent was allele A5.1 (37.1%) and the rarest A5 (8.1%). Finally it was found that haplotype MICA*008 A5.1 was the most frequent (37.1%). Conclusion: A comparison of these results with those reported in the literature revealed similarity in MICA polymorphism to that found in other Western Eurasian populations. The data will be useful for further association studies on MICA polymorphism and its function.

Gestational choriocarcinoma analyzed by polymerase chain reaction amplification of polymorphic VNTR and human leukocyte antigen regions

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Donor non-specific MICA antibodies in renal transplant recipients

Despite recent advances in solid organ transplantations, an antibody mediated rejection caused by donor specific antibodies is still a major problem in kidney graft survival. Besides HLA-induced humoral response, antibodies against MICA antigens have recently attracted attention because of their possible role in graft rejection. The aim of our study was to establish whether renal recipients produce antibodies against MICA molecules due to the transplantation and if they are specific for MICA antigens of the donors. MICA antibody screening was performed in 124 kidney recipient sera. 22 sera, that were found to be MICA antibody positive, were further examined for MICA antibody profiles and compared with donor MICA alleles. The analysis of MICA antibody positive sera showed mostly more complex reactivity patterns. A significant fraction of patient sera (59%) reacted not only with the donor MICA antigens, but also with other MICA patterns. A match between antibody specificities and MICA antigens was observed in 41% of renal recipients only. On the other hand, as much as in 36% of recipient sera were detected antibodies against their own MICA molecules. We did not prove a complete correlation between the recipient MICA antibody specificities and MICA antigens of the donor. We assume that MICA antibody induction occurs not only due to the allogeneic stimulation itself but also due to other factors that need to be elucidated.

The +190 G/A (rs1799864) polymorphism in the C-C chemokine receptor 2 (CCR2) gene is associated with susceptibility to multiple sclerosis in HLA-DRB1*15:01-negative individuals.

C-C chemokine receptor 2 (CCR2) is one of the key players involved in the transmigration of mononuclear cells into the central nervous system (CNS) and subsequent development of multiple sclerosis (MS). The aim of the current study was to analyse the association of CCR2 +190 G/A (rs1799864) polymorphism with susceptibility to MS and its influence on the age at onset, severity and neurological disability in MS. CCR2 genotyping was carried out by a polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) in 301 MS patients and 342 healthy controls. Logistic regression analysis suggested a marginally significant association between MS and rs1799864 A allele (AA+GA vs. GG, P=0.047, OR=1.50, 95% CI=1.00-2.25), however, after stratification of study groups for the presence of HLA-DRB1*15:01 risk allele, this association could be found in HLA-DRB1*15:01-negative individuals only (AA+GA vs. GG, P=0.014, OR=1.84, 95% CI=1.13-2.98). Furthermore, there was no association between CCR2 polymorphism and clinical features of MS. In conclusion, our results suggest that CCR2 +190 G/A polymorphism may increase the susceptibility to MS, but its action seems to be restricted to individuals who do not possess the major risk allele HLA-DRB1*15:01.

Role of HLA-G and other immune mechanisms in pregnancy

Pregnancy loss (abortion) and pre-eclampsia represent the most common disorders in pregnant women. Besides infection, there are anatomical, endocrinological, genetic and immunological factors that can induce pregnancy disorders. Because the exact mechanisms of physiological pregnancy maintenance are still not clearly understood, the search for genes and proteins fulfilling this role is still in progress. One of the immune molecules that plays a beneficial role in pregnancy is the nonclassical HLA-G molecule. The molecule is mainly expressed on trophoblast cells in the foetal placenta and induces the immune tolerance of the foetus via its interaction with inhibitory receptors on maternal NK cells and CD8+ T lymphocytes. In relation to pregnancy disorders, associations between HLA-G polymorphism, HLA-G level and HLA-G function were described. Thus, the HLA-G molecule can be used as a new diagnostic marker and, potentially, for the future therapy of pregnancy disorders.

A Novel Association of Polymorphism in the ITGA4 Gene Encoding the VLA-4 α4 Subunit with Increased Risk of Alzheimer’s Disease

Alzheimers disease (AD) is the most prevalent cause of dementia in elderly people worldwide. Many studies support the hypothesis that the inflammation of the CNS contributes to the neurodegeneration and disease progression. The integrin molecule α4β1, also known as very late antigen 4 (VLA-4), belongs to adhesion molecules that activate the inflammatory process through the migration of immune cells into the CNS. Therefore, the objective of our study was to analyze the association between two polymorphisms located in the ITGA4 gene encoding the α4 subunit of VLA-4 and the risk of AD. 104 late-onset AD patients and 206 control subjects from Slovakia were genotyped for ITGA4 gene SNP polymorphism rs113276800 (−269C/A) and rs1143676 (+3061A/G). The same study cohorts were also genotyped for the APOE-ε4, which is a known genetic factor associated with increased risk of AD developing. ITGA4 polymorphism analysis revealed significantly higher frequency of the +3061AG carriers in AD group compared to the controls (P ≤ 0.05). Following the APOE-ε4 stratification of study groups, the association remained significant only in APOE-ε4 noncarriers. Our study suggests a novel association of ITGA4 +3061A/G polymorphism with AD and its possible contribution to the disease pathology.

TNFRSF1A polymorphisms and their role in multiple sclerosis susceptibility and severity in the Slovak population

Tumour necrosis factor (TNF)‐mediated signalling plays a key role in inflammatory and neurodegenerative processes leading to the development of multiple sclerosis (MS). Recent studies have highlighted the role of tumour necrosis factor receptor superfamily member 1A (TNFRSF1A) gene encoding the type 1 TNF receptor in the genetic predisposition to MS. This study aimed to validate the association of TNFRSF1A rs1800693 and rs4149584 polymorphisms with susceptibility to MS in the Slovak population and analyse their influence on age at disease onset, severity, and disability progression. Polymerase chain reaction–restriction fragment length polymorphism method was used to genotype both TNFRSF1A polymorphisms in 541 MS patients and 724 healthy controls. Logistic regression analysis revealed a significantly increased risk of developing MS for the carriers of rs1800693 C allele (TC + CC vs. TT: pcorr = 0.005; OR = 1.61; 95% CI = 1.23–2.12), irrespective of sex and carriage of the major MS risk allele HLA‐DRB1*15:01. On the other hand, no association could be found between rs4149584 and MS risk (GA + AA vs. GG: pcorr = 1.00; OR = 1.25; 95% CI = 0.71–2.21). Moreover, neither polymorphism was significantly associated with age at disease onset, MS Severity Score (MSSS) or MS Progression Index (PI) in any of the inheritance models. In conclusion, our results provide support for a sex‐ and HLA‐DRB1*15:01‐independent association of TNFRSF1A rs1800693 SNP with MS susceptibility, but not with age at disease onset, severity or rate of disability accumulation.