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Adiponectin, a hormone secreted by adipose tissue, plays a complex role in regulating metabolic homeostasis and has also garnered attention for its potential involvement in the pathogenesis of late-onset Alzheimer's disease (LOAD). The objective of this study was to investigate the association of ADIPOQ variants with plasma adiponectin levels and LOAD risk in subjects from the Slovak Caucasian population. For this purpose, 385 LOAD patients and 533 controls without cognitive impairment were recruited and genotyped for a total of eighteen ADIPOQ single nucleotide polymorphisms (SNPs). Both single-locus and haplotype-based logistic regression analyses were employed to assess the association of SNPs with LOAD risk, while linear regression analysis was used to explore their influence on adiponectin levels in LOAD patients. ADIPOQ variants rs822395 and rs2036373 in intron 1 were found to significantly elevate total adiponectin levels after accounting for several potential confounders. Additional SNPs in the 5' region and intron 1 exhibited a non-significant trend of association with adiponectin. However, none of the ADIPOQ SNPs showed an association with LOAD risk, neither in the whole-group analysis nor in subgroup analyses after stratification for sex or the APOE ε4 allele, a well-established LOAD risk factor. In summary, while adiponectin has emerged as a potential contributor to the development of LOAD, this study did not unveil any significant involvement of its gene variants in susceptibility to the disease.

Polymorphisms in genes encoding receptors that modulate the activity of microglia and macrophages are attractive candidates for participation in genetic susceptibility to multiple sclerosis (MS). The aims of the study were to (1) investigate the association between Alzheimer’s disease-linked variant rs3865444:C>A in the CD33 gene and MS risk, (2) assess the effect of the strongest MS risk allele HLA-DRB1*15:01 on this association, and (3) analyze the correlation of rs3865444 with selected clinical phenotypes, i.e., age of onset and disease severity. CD33 rs3865444 was genotyped in a cohort of 579 patients and 1145 controls and its association with MS risk and clinical phenotypes was analyzed by logistic and linear regression analysis, respectively. Statistical evaluation revealed that rs3865444 reduces the risk of MS in the HLA-DRB1*15:01-positive subpopulation but not in the cohort negative for HLA-DRB1*15:01. A significant antagonistic epistasis between rs3865444 A and HLA-DRB1*15:01 alleles in the context of MS risk was detected by the interaction synergy factor analysis. Comparison of allele and genotype distribution between relapsing-remitting MS, secondary progressive MS, and control groups revealed that rs3865444 C to A substitution may also be associated with a decreased risk of transition of MS to its secondary progressive form, irrespective of the HLA-DRB1*15:01 carrier status. On the other hand, no correlation could be found between rs3865444 and the age of disease onset or MS severity score. Future studies are required to shed more light on the role of CD33 in MS pathogenesis.

CD33 rs3865444:C>A single nucleotide polymorphism (SNP) has been previously associated with the risk of late-onset Alzheimer's disease (LOAD); however, the results have been inconsistent across different populations. CD33 is a transmembrane receptor that plays an important role in AD pathogenesis by inhibiting amyloid β42 uptake by microglial cells. In this study, we aimed to validate the association between rs3865444 and LOAD risk in the Slovak population and to evaluate whether it was affected by the carrier status of the major LOAD risk allele apolipoprotein (APOE) ε4. CD33 rs3865444 and APOE variants were genotyped in 206 LOAD patients and 487 control subjects using the polymerase chain reaction-restriction fragment length polymorphism method and direct sequencing, respectively. Logistic regression analysis revealed a significant association of rs3865444 A allele with a reduced LOAD risk that was only present in APOE ε4 allele carriers (AA + CA versus CC: p = .0085; OR = 0.45; 95% CI = 0.25-0.82). On the other hand, no such association was found in subjects without the APOE ε4 (p = .75; OR = 0.93; 95% CI = 0.61-1.42). Moreover, regression analysis detected a significant interaction between CD33 rs3865444 A and APOE ε4 alleles (p = .021 for APOE ε4 allele dosage and p = .051 for APOE ε4 carriage status), with synergy factor (SF) value of 0.49 indicating an antagonistic effect between the two alleles in LOAD risk. In conclusion, our results suggest that CD33 rs3865444:C˃A substitution may reduce the risk of LOAD in Slovaks by antagonizing the effect conferred by the major susceptibility allele APOE ε4., (© 2020 John Wiley & Sons Ltd.)

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., (© 2018 John Wiley & Sons Ltd.)

Infiltration of immune cells into CNS is one of the essential events in multiple sclerosis (MS) development. Adhesion molecules like the intercellular adhesion molecule 1 (ICAM-1) play critical role in this process. Therefore, the ICAM1 gene containing two important single-nucleotide polymorphisms (SNPs) belongs to candidate loci with possible involvement in MS susceptibility and/or severity. The objective of our case-control study was to analyze the association of two functional ICAM1 polymorphisms rs1799969 (or G241R) and rs5498 (or K469E) with susceptibility to MS and evaluate their influence on the age at disease onset, severity, neurological disability and progression rate. Two hundred forty-eight MS subjects (mean 39.2 years) and 208 age-matched controls (mean 35.6 years) were involved in the study. Genotyping of ICAM1 rs1799969 and rs5498 SNPs was performed by PCR-RFLP. Presence of the rs3135388 polymorphism tagging the major MS risk allele HLA-DRB1*15:01 allele was determined as well. Our analysis revealed no statistically significant association of ICAM1 polymorphisms with risk of MS development in the Slovak population. Stratification of study cohorts by gender, age at onset and presence of the HLA-DRB1*15:01 risk allele showed only moderate changes. Correlation of clinical findings as age at onset, Kurtzke Expanded Disability Status Scale, Multiple Sclerosis Severity Score and progression index with ICAM1 genotypes in MS patients revealed no significant association; however, patients with earlier onset of MS showed slightly higher frequencies of the homozygous G allele at rs5498 in comparison to other genotypes (P = 0.04), suggesting that GG carriers tend to induce MS at an earlier age.

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., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Objective: The aim of the present study was to assess the association between HLA-DRB1 and -DQB1 allele groups with the genetic predisposition to multiple sclerosis (MS) in the Caucasian Central European Slovak population., Methods: A total of 282 unrelated patients with sporadic MS were enrolled in this case-control study. HLA-DRB1 and HLA-DQB1 allele groups were genotyped using a polymerase chain reaction with sequence-specific primers. The DRB1 and DQB1 allele carrier frequencies, genotypes and haplotype frequencies were compared between MS cases and healthy controls., Results: Positive association with MS was found for alleles HLA-DRB1*15 (OR = 3.64; Pcor = 6.9x10-11), DRB1*03 (after elimination of carriers of DRB1*15, OR = 2.8; Pcor = 0.0029), DQB1*06 (OR = 1.99; Pcor = 7.0x10-4), genotypes HLA-DRB1*15/*15 (OR = 7.6; Pcor = 0.001) and DQB1*06/*06 (OR = 3.81; Pcor = 4.0x10-4) and for haplotype DRB1*15-DQB1*06 (OR = 3.03; Pcor = 0.001). Carriage of alleles DRB1*07 (OR = 0.53; Pcor = 0.04), DRB1*13 (OR = 0.39; Pcor = 4.0x10-4), DQB1*03 (OR = 0.46; Pcor = 1.0x10-4), genotypes HLA-DRB1*13/*11 (OR = 0.12; Pcor = 0.004), DQB1*05/*03 (OR = 0.39; Pcor = 0.035), DQB1*03/*03 (OR = 0.38; Pcor = 0.029) and haplotypes DRB1*13-DQB1*06 (OR = 0.47; Pcor = 0.0128) and DRB1*11-DQB1*03 (OR = 0.58; Pcor = 0.0352) was found to be protective against MS development., Discussion: This is the first study performed to analyse the association of HLA-DRB1/DQB1 with susceptibility to MS in Slovakia. The results of our study confirm that HLA class II alleles, genotypes and haplotypes are associated with MS risk.

Psoriasis vulgaris is a complex chronic skin disease with immunological and genetic background. The most important predisposing genetic factors in psoriasis are genes of the human leukocyte antigen (HLA) region. Accumulative evidence has shown that several HLA alleles are closely associated with psoriasis; however, they tend to vary in different racial and ethnic backgrounds. One hundred forty-seven unrelated Slovak patients with psoriasis vulgaris (average age at onset 28 ± 14 years) were genotyped for the HLA-C, DQB1 and DRB1 alleles by the polymerase chain reaction using sequence-specific primers. Allele frequencies observed in the group of psoriatic patients were compared to those obtained in the ethnically matched control group comprising 194 subjects with no history of psoriasis. Susceptibility to psoriasis vulgaris in our study group is significantly associated with HLA-C*06 (odds ratio (OR) = 3.85), DRB1*07 (OR = 2.56) and DQB1*02 (OR = 1.09), respectively, whereas DRB*01 (OR = 0.05) is associated negatively. Hereby, we provide the first report on the association of HLA-C, DRB1 and DQB1 alleles with psoriasis in the Slovak population. Our findings confirm HLA-C*06 and DRB1*07 as the most important genetic risk factors for psoriasis. However, the role of HLA genes as causative in the pathogenesis of the disease remains unclear. Identification of genetic factors that increase the risk of psoriasis is a precondition that helps to elucidate the pathogenesis of this troubling disease and identify targets for a more specific and effective therapy.

Clinical and immunopathological evidence support a potential role of inflammatory cytokines in Alzheimer's disease (AD). However, studies examining the association between cytokine gene polymorphisms and risk of developing AD yielded conflicting results. The objective of our study was to evaluate the association between the functional polymorphisms in the TNF-alpha, TGF-beta1, IL-10, IL-6 and IFN-gamma genes, respectively and the risk of AD in Slovak individuals. Fifty sporadic AD patients and 140 non-demented age-matched control subjects were genotyped in our case-control study. The observed allele and genotype frequencies in AD patients and controls did not reveal any statistically significant differences. In conclusion, our data suggest that there is no involvement of cytokine gene genetic variance in the development of AD in the Slovak population.