Kalle Kisand

Chronic mucocutaneous candidiasis in APECED or thymoma patients correlates with autoimmunity to Th17-associated cytokines

Chronic mucocutaneous candidiasis (CMC) is frequently associated with T cell immunodeficiencies. Specifically, the proinflammatory IL-17A–producing Th17 subset is implicated in protection against fungi at epithelial surfaces. In autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED, or autoimmune polyendocrine syndrome 1), CMC is often the first sign, but the underlying immunodeficiency is a long-standing puzzle. In contrast, the subsequent endocrine features are clearly autoimmune, resulting from defects in thymic self-tolerance induction caused by mutations in the autoimmune regulator (AIRE). We report severely reduced IL-17F and IL-22 responses to both Candida albicans antigens and polyclonal stimulation in APECED patients with CMC. Surprisingly, these reductions are strongly associated with neutralizing autoantibodies to IL-17F and IL-22, whereas responses were normal and autoantibodies infrequent in APECED patients without CMC. Our multicenter survey revealed neutralizing autoantibodies against IL-17A (41%), IL-17F (75%), and/ or IL-22 (91%) in >150 APECED patients, especially those with CMC. We independently found autoantibodies against these Th17-produced cytokines in rare thymoma patients with CMC. The autoantibodies preceded the CMC in all informative cases. We conclude that IL-22 and IL-17F are key natural defenders against CMC and that the immunodeficiency underlying CMC in both patient groups has an autoimmune basis.

Genetic variation in the SMAD3 gene is associated with hip and knee osteoarthritis.

OBJECTIVE Smad3 (or, MADH3) is a key intracellular messenger in the transforming growth factor beta signaling pathway. In mice, Smad3 deficiency accelerates growth plate chondrocyte maturation and leads to an osteoarthritis (OA)-like disease. We undertook this study to investigate the role of genetic variation in SMAD3 in the risk of large-joint OA in humans. METHODS Ten tag single-nucleotide polymorphisms (SNPs) in the SMAD3 gene region were tested in a discovery set: 313 patients who had undergone total knee replacement, 214 patients who had undergone total hip replacement, and 520 controls from the UK. The SNP associated with both hip and knee OA was subsequently genotyped in 1,221 controls and 1,074 cases from 2 cohorts of patients with hip OA and 2,537 controls and 1,575 cases from 4 cohorts of patients with knee OA. RESULTS A SNP (rs12901499) mapping to intron 1 of SMAD3 was associated with both knee and hip OA (P < 0.0022 and P < 0.021, respectively) in the discovery set. In all study cohorts, the major allele (G) was increased among OA patients relative to controls. A meta-analysis for knee OA yielded an odds ratio (OR) of 1.22 (95% confidence interval [95% CI] 1.12-1.34), P < 7.5 x 10(-6). For hip OA, the OR was 1.22 (95% CI 1.09-1.36), P < 4.0 x 10(-4). No evidence for heterogeneity was found (I(2) = 0%). CONCLUSION Our data indicate that genetic variation in the SMAD3 gene is involved in the risk of both hip OA and knee OA in European populations, confirming the results from animal models on the potential importance of this molecule in the pathogenesis of OA.

The GDF5 rs143383 polymorphism is associated with osteoarthritis of the knee with genome-wide statistical significance

Osteoarthritis of the knee is a major cause of pain, disability and the use of healthcare resources among middle-aged and older people.1 Although osteoarthritis is multifactorial, it is known to have a significant genetic contribution and a number of studies have attempted to dissect such a contribution (see Valdes and Spector2 for review). The GDF5 gene encodes the growth differentiation factor 5, a bone morphogenetic protein involved in joint formation, expressed in different joint structures, which has been shown to ameliorate tendon, ligament and bone healing after trauma in mice.3 4 A promoter polymorphism (rs143383) in GDF5 has been found to be strongly associated with both hip and knee osteoarthritis in Asian individuals,4 and is the most widely replicated genetic association with knee osteoarthritis, although much less so for hip and hand osteoarthritis.5 This variant is functional, with the lower gene expression variant having increased genetic risk.4 A large-scale meta-analysis reported the association of the major (T) allele with knee osteoarthritis achieved OR 1.15 p=9.7×10−7 and achieved p=9×10−5 (OR 1.13, 95% CI 1.06 to 1.20) when Asian subjects were excluded.5 The genome-wide statistical significance level of p<5×10−8 is increasingly …

Meta-analysis of genome-wide association studies confirms a susceptibility locus for knee osteoarthritis on chromosome 7q22

Objectives Osteoarthritis (OA) is the most prevalent form of arthritis and accounts for substantial morbidity and disability, particularly in older people. It is characterised by changes in joint structure, including degeneration of the articular cartilage, and its aetiology is multifactorial with a strong postulated genetic component. Methods A meta-analysis was performed of four genome-wide association (GWA) studies of 2371 cases of knee OA and 35 909 controls in Caucasian populations. Replication of the top hits was attempted with data from 10 additional replication datasets. Results With a cumulative sample size of 6709 cases and 44 439 controls, one genome-wide significant locus was identified on chromosome 7q22 for knee OA (rs4730250, p=9.2×10−9), thereby confirming its role as a susceptibility locus for OA. Conclusion The associated signal is located within a large (500 kb) linkage disequilibrium block that contains six genes: PRKAR2B (protein kinase, cAMP-dependent, regulatory, type II, β), HPB1 (HMG-box transcription factor 1), COG5 (component of oligomeric golgi complex 5), GPR22 (G protein-coupled receptor 22), DUS4L (dihydrouridine synthase 4-like) and BCAP29 (B cell receptor-associated protein 29). Gene expression analyses of the (six) genes in primary cells derived from different joint tissues confirmed expression of all the genes in the joint environment.

LARGE SCALE META-ANALYSIS OF INTERLEUKIN-1 BETA AND INTERLEUKIN-1 RECEPTOR ANTAGONIST POLYMORPHISMS ON RISK OF RADIOGRAPHIC HIP AND KNEE OSTEOARTHRITIS AND SEVERITY OF KNEE OSTEOARTHRITIS

OBJECTIVE To clarify the role of common genetic variation in the Interleukin-1β (IL1B) and Interleukin-1R antagonist (IL1RN) genes on risk of knee and hip osteoarthritis (OA) and severity of knee OA by means of large-scale meta-analyses. METHODS We searched PubMed for articles assessing the role of IL1B and IL1RN polymorphisms/haplotypes on the risk of hip and/or knee OA. Novel data were included from eight unpublished studies. Meta-analyses were performed using fixed- and random-effects models with a total of 3595 hip OA and 5013 knee OA cases, and 6559 and 9132 controls respectively. The role of ILRN haplotypes on radiographic severity of knee OA was tested in 1918 cases with Kellgren-Lawrence (K/L) 1 or 2 compared to 199 cases with K/L 3 or 4. RESULTS The meta-analysis of six published studies retrieved from the literature search and eight unpublished studies showed no evidence of association between common genetic variation in the IL1B or IL1RN genes and risk of hip OA or knee OA (P>0.05 for rs16944, rs1143634, rs419598 and haplotype C-G-C (rs1143634, rs16944 and rs419598) previously implicated in risk of hip OA). The C-T-A haplotype formed by rs419598, rs315952 and rs9005, previously implicated in radiographic severity of knee OA, was associated with reduced severity of knee OA (odds ratio (OR)=0.71 95%CI 0.56-0.91; P=0.006, I(2)=74%), and achieved borderline statistical significance in a random-effects model (OR=0.61 95%CI 0.35-1.06 P=0.08). CONCLUSION Common genetic variation in the Interleukin-1 region is not associated with prevalence of hip or knee OA but our data suggest that IL1RN might have a role in severity of knee OA.

The follow-up of asymptomatic persons with antibodies to pyruvate dehydrogenase in adult population samples

Purpose. The presence of antimitochondrial antibodies (AMA), the hallmark of primary biliary cirrhosis (PBC), precedes the clinical manifestation of the disease for many years. The main mitochondrial autoantigen is the E2 component of the pyruvate dehydrogenase complex (PDC). The aim of this study was to identify anti-PDC-positive persons from two Estonian populations by different methodologies and to follow up the positive cases. Methods. Enzyme-linked immunosorbent assay (ELISA) tests for antibodies to native PDC and recombinant PDC-E2 fusion protein were performed in 1461 persons (age range, 15–95 years) from Karksi-Nuia (plus 104 volunteers from the neighborhood) and to native PDC in 497 persons (age range, 50–91 years) from Abja-Paluoja (plus 28 volunteers from that neighborhood). Positive cases were tested with an enzyme inhibition assay. Results. We identified 14 asymptomatic persons with antibodies to native PDC and/or recombinant PDC-E2 from these two population samples. Eight of the 14 were available for follow-up. Three of the 8 developed abnormal liver biochemical test results by the ninth year of follow-up. These persons also had, or developed, during the follow-up, a positive AMA immunofluorescence test, inhibitory antibodies to PDC, and anti-PDC of at least IgG and IgA class. Five of the 8 persons with low levels of anti-PDC, of only one immunoglobulin class reacting with only one PDC preparation, did not show any signs of cholestasis or changes in their immunoreactivity during follow-up. Conclusions. A significant number of asymptomatic patients found to have antibodies to PDC are at high risk of developing primary biliary cirrhosis.

Impact of cryopreservation on serum concentration of matrix metalloproteinases (MMP)-7, TIMP-1, vascular growth factors (VEGF) and VEGF-R2 in Biobank samples

Abstract Background: Blood biomarkers are subject to pre-analytical variability. In many cases, the stability of important new tissue biomarkers during freeze cycles and storage has not been studied sufficiently. Methods: To test the stability of matrix metalloproteinases-7 (MMP-7) and their tissue inhibitors (TIMP-1), vascular growth factors (VEGF) and VEGF-receptor, serum samples were frozen and then thawed up to six times. The impact of storage temperature was investigated using an accelerated stability testing protocol. Stability at –20°C and –75°C was calculated using the Arrhenius equation. Results: The average concentration of TIMP-1 was stable, even after six freeze/thaw cycles. One thawing did not change the concentration of MMP-7 and VEGF-receptor. However, repeated freeze/thaw cycles increased the measured values significantly. Decreases in VEGF concentrations were dramatic, even after the first freeze/thaw cycle. According to the Arrhenius calculation, MMP-7 showed excellent stability, at least 5 years at –20°C and several 100 years at –75°C. The VEGF-receptor maintains 90% of its initial concentration at –20°C over 3 months, and decades at –75°C. TIMP-1 and VEGF showed poor stability with cryopreservation, even at –75°C. Conclusions: The stability of MMP-7, TIMP-1, VEGF or VEGF-receptor in biobanking is highly variable, and this should be taken into account in the interpretation of results. A temperature –20°C is unsuitable for prolonged storage of the biomarkers investigated, and repeated thawing of sera is not recommended. VEGF is especially unstable and should be quantitated using serum that has never been frozen.

Type 1 diabetes is insulin -2221 MspI and CTLA-4 +49 A/G polymorphism dependent.

Background  Several studies have demonstrated an association of type 1 diabetes with specific alleles of HLA class II molecules, as with polymorphisms of insulin gene region. The aim of our study was to evaluate the interaction of insulin −2221 MspI polymorphism to type 1 diabetes susceptibility in connection with autoimmunity associated gene – CTLA‐4 polymorphism.

Association of CTLA4 but not ICOS polymorphisms with type 1 diabetes in two populations with different disease rates.

Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and inducible T-cell co-stimulator (ICOS) genes are important mediators of T-cell activation in autoimmune diseases. The aim of the current study was to assess the impact of CTLA-4 and ICOS genes on the susceptibility to type 1 diabetes among two populations with different disease incidence rates. Three single nucleotide polymorphisms (SNPs) within the CTLA-4 region (+49A/G, CT60A/G, CTBC217_1C/T) and two SNPs within the ICOS region (CTIC154_1 C/T, CTIC159 C/G) were genotyped in 955 control subjects and 574 diabetic patients of Estonian and Finnish descent. The current study confirms the involvement of the CTLA-4 but not the ICOS gene in susceptibility to type 1 diabetes. However, the risk alleles and the defined main risk haplotype were more common in the Finnish controls compared with the Estonians, indicating that this gene locus might also be one of the contributing factors to the higher disease incidence in Finland.

Missense single nucleotide polymorphism of the ADAM12 gene is associated with radiographic knee osteoarthritis in middle-aged Estonian cohort

OBJECTIVE One of the recognized candidate genes of osteoarthritis (OA) is the ADAM metallopeptidase domain 12 (meltrin alpha) gene. We investigated the potential role of two single nucleotide polymorphisms (SNP) of the ADAM12 gene in susceptibility to radiographic knee OA and its progression in an Estonian cohort. METHODS The rs3740199 and rs1871054 polymorphisms were genotyped according to restriction fragment polymorphism in a population-based cohort consisting of 189 subjects selected from the age group 32-55 years. The radiological features of OA were measured in the tibio- and patellofemoral joints (PFJ). The X-ray investigation was repeated 3 years later for estimation of OA progression. RESULTS We found statistically significant association between rs3740199 polymorphism and patellofemoral OA in male patients (P=0.014), genetic risk was mostly related to CC homozygosity. The same SNP also affected the presence of advanced grade (II+III) osteophytes in the whole group (P=0.042) and the occurrence of osteophytes on the patellar margins in the PFJ (P=0.046). In OA progression the most significant association was found between joint space narrowing of the tibiofemoral joint and rs3740199 SNP in women (P=0.018). The rs1871054 polymorphism was not related to OA susceptibility or to progression traits. In our study the haplotype GC (rs3740199/rs1871054) was associated with reduced risk for development of osteophytes in the PFJ (P=0.041). CONCLUSIONS We conclude that rs3740199 polymorphism may affect occurrence of knee OA and its progression. We also hypothesize that the genetic contribution of ADAM12 to OA is remarkably gender-dependent and anatomical site-specific.