The functional genetic variation in the PTPN22 gene has a negligible effect on the susceptibility to develop inflammatory bowel disease

The aim of this study was to assess the possible association between the protein tyrosine phosphatase non-receptor 22 (PTPN22) gene 1858C-->T (rs2476601, encoding R620W) polymorphism and inflammatory bowel disease (IBD). Our study population consisted of 1113 IBD [544 ulcerative colitis (UC) and 569 Crohn's disease (CD)] patients and 812 healthy subjects. All the individuals were of Spanish white origin. Genotyping of the PTPN22 gene 1858C-->T polymorphism was performed by real time polymerase chain reaction technology, using TaqMan 5'-allelic discrimination assay. The frequency of the PTPN22 1858T allele in healthy subjects was 6.2% compared with 6.7% in the UC patients and 5.1% in Crohn's patients. No statistically significant differences were observed when the PTPN22 1858C-->T allele and genotype distribution among CD patients, UC patients and healthy controls were compared. These results indicate that the PTPN22 1858C-->T polymorphism does not appear to play a major role in IBD predisposition in our population.     

Association analysis of the PTPN22 gene in childhood-onset systemic lupus erythematosus in Mexican population

Several studies have identified a functional single nucleotide polymorphism 1858C/T in the PTPN22 gene to be associated with several autoimmune diseases. Association studies of this polymorphism with familial and sporadic systemic lupus erythematosus (SLE) have shown some discrepancies. To our knowledge, this is the first study that includes only pediatric-onset SLE patients. We performed a case-control association study in 250 unrelated Mexican patients with childhood-onset SLE consisting of 228 cases with sporadic SLE and 22 cases with familial SLE and 355 healthy controls. We observed a statistically significant difference in the frequency of the PTPN22 1858T allele between SLE patients (3.4%) and healthy controls (1.1%) (P=0.0062, odds ratio (OR) 3.09 (95% confidence interval 1.32-7.21)). The association was also observed when only sporadic cases were analyzed (OR=3.19). Our results support the association of the PTPN22 1858T allele with sporadic childhood-onset SLE in Mexican population.     

Association study of PTPN22 C1858T polymorphism in Trypanosoma cruzi infection

In this study we investigated a possible role for the single nucleotide polymorphism C1858T of the PTPN22 (protein tyrosine phosphatase nonreceptor 22) gene in determining the susceptibility to Trypanosoma cruzi infection, as well as in development of chagasic heart disease. This study included 316 patients with Chagas' disease and 520 healthy individuals from Colombia and Peru. Genotyping of PTPN22 was performed by the real-time polymerase chain reaction technology, using the TaqMan 5' allelic discrimination assay. No statistically significant differences in the frequency of PTPN22 C1858T gene polymorphism between chagasic patients and controls or between asymptomatic and cardiomyopathic individuals were observed. Our findings suggest that the PTPN22 polymorphism analyzed does not play a major role in the development of Chagas' disease in the Colombian and Peruvian populations.     

The association of lymphoid protein tyrosine phosphatase non-receptor 22 (PTPN22) gene polymorphism with Egyptian immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is an autoimmune syndrome involving platelets destruction and suppression of platelet production that may predispose to bleeding. Protein tyrosine phosphatase non-receptor 22 gene (PTPN22) is an important negative regulator of signal transduction through the T-cell receptors (TCR). A single nucleotide polymorphism (SNP) 1858C?>?T within this gene was reported to be associated with increased risk of autoimmune diseases. The aim of the work was to study the frequency of the 1858C?>?T single nucleotide polymorphism in the PTPN22 gene in Egyptian ITP patients. After full clinical and laboratory examination of our subjects, the expression of the PTPN22 (1858C?>?T) gene polymorphism was analyzed in 60 ITP patients—40 childhood ITP (26 acute and 14 chronic) and 20 adulthood ITP (eight acute and 12 chronic)—and 100 healthy controls using a polymerase chain reaction-restriction fragment length polymorphism assay [PCR-RFLP]. The PTPN22 1858C?>?T SNP was significantly overrepresented in ITP patients than controls. It was detected in 11 childhood ITP (27.5%) and five adulthood ITP (25.0%) compared to 8.0% in controls (p?=?0.002, p?=?0.02) when comparing childhood ITP and adulthood ITP to controls, respectively. The T allele was significantly higher in ITP patients than controls. It was 20% for childhood ITP, 15% in adulthood ITP and 4% in controls (p?=?0.002, p?=?0.05) when comparing childhood ITP and adulthood ITP to controls, respectively. From this study we concluded that the PTPN22 1858C?>?T polymorphism is more prevalent in ITP patients; thus, it may be considered as a genetic risk factor in development of ITP in Egyptian patients.     

The 1858T PTPN22 gene variant contributes to a genetic risk of type 1 diabetes in a Ukrainian population

The 1858T variant of the protein tyrosine phosphatase gene, PTPN22, is associated with an increased risk of several autoimmune diseases. The aim of this study has been to investigate the possible association of 1858C-->T PTPN22 polymorphism and type 1 diabetes (T1D) in Caucasians from Ukraine. Overall, the distribution of 1858 PTPN22 genotypes differed significantly between the T1D patient group (n = 296) and the control group (n = 242) (P = 0.0036). When both groups were classified according to sex, the TT genotype and T allele showed a statistically significant higher frequency in T1D female patients (5.9 and 22.8%, respectively) in comparison with the female controls (0 and 11.9%) (P = 0.008 for both analyses). The patients with the TT genotype were significantly younger at the onset of T1D compared with those with genotypes TC and CC (P = 0.035 and 0.019, respectively). In our Ukrainian Caucasian cohort, we confirmed the association between T1D and the PTPN22,1858T allele.     

Association of PTPN22 single nucleotide polymorphism with rheumatoid arthritis but not with allergic asthma

PTPN22 gene encodes a lymphoid tyrosine phosphatase (LYP), an important negative regulator of T-cell responses. The 1858C>T (Arg620Trp) single nucleotide polymorphism (rs2476601) was found associated with autoimmune diseases, including rheumatoid arthritis (RA). Allergic diseases are similar to autoimmune diseases, by an exaggerated immune response to an antigen (allergen in this case) normally not invoking such response in healthy individuals. We investigated whether polymorphism 1858C>T in PTPN22 gene is associated with susceptibility to allergic asthma and RA in a Polish population. PTPN22 was genotyped in 173 patients with RA, in 198 patients with allergic asthma, and in 543 controls using PCR-RFLP. The patients with RA differed from healthy controls in frequencies of PTPN22 1858C>T alleles (P=0.0004; odds ratio (OR), 1.8; 95% CI, 1.33-2.55) and genotypes (P=0.0009). Strong associations of 1858T allele with RA limited to joints (0.21 vs 0.12, P=0.0002; OR, 2.1; 95% CI, 1.44-3.00), with erosive disease (0.20 vs 0.12, P=0.0003; OR, 1.92; 95% CI, 1.34-2.71), with a lack of rheumatoid factor (RF; 0.23 vs 0.12, P=0.0008; OR, 2.29; 95% CI, 1.44-3.63), and weak association with the presence of RF (0.17 vs 0.12, P=0.02; OR, 1.6; 95% CI, 1.10-2.40) in comparison with healthy controls were observed. Very strong association of 1858T allele (P<0.0001; OR, 2.72; 95% CI, 1.9-3.9) and T phenotype (P<0001; OR, 3.2; 95% CI, 2.1-4.9) with antibodies to cyclic citrullinated peptide (CCP) was found. When patients with allergic asthma were typed for PTPN22 1858C>T polymorphism, no difference with control was found. Subdivision of patients into those with mild, moderate, or severe asthma did not reveal any associations. In conclusion, we confirmed associations between several clinical manifestations of RA and PTPN22 1858T allele. However, no association with 1858C>T polymorphism was found for susceptibility to allergic asthma or for severity of the disease.     

Protein tyrosine phosphatase non-receptor type 22 gene variants at position 1858 are associated with type 1 and type 2 diabetes in Estonian population

Protein tyrosine phosphatase non-receptor type 22 (PTPN22) is considered an important regulator of T-cell activation. Polymorphisms within the PTPN22 gene have been suggested to confer susceptibility to autoimmune endocrine disorders. To evaluate the impact of a functional variation in the PTPN22 gene in type 1 (T1D) and type 2 diabetes (T2D), the PTPN22 C1858T single nucleotide polymorphism (SNP) was studied in the population of Estonian origin, including 170 T1D patients, 244 T2D patients and 230 controls. Using two methods for PTPN22 C1858T detection in parallel, we found that not only T1D but also T2D is associated with the PTPN22 1858T allele. The role of PTPN22 gene in the pathogenesis of T2D is yet unclear and needs further investigation.     

The PTPN22 1858T variant is not associated with primary biliary cirrhosis

The minor allele of a single nucleotide polymorphism (SNP) in the PTPN22 gene (1858T) encoding the Lyp-tyrosine phosphatase has been recently associated with multiple autoimmune disorders, raising the possibility that this variant may also represent a risk allele for primary biliary cirrhosis (PBC). We therefore investigated the possible association of the PTPN22(1858T) variant with PBC in a Canadian population. We studied 160 Caucasian patients with biopsy and antimitochondrial antibodies (AMA)-proven PBC who were genotyped for the PTPN22(C1858T) SNP using a single-base primer extension assay and mass spectrometry. The frequency of the PTPN22(1858T) allele was then compared between the patients and 290 healthy controls. No association was detected between the PTPN22(1858T) allele and PBC, the frequency of this variant being similar in patients with PBC (7.5%) and controls (8.4%). Restricting the analysis to patients with PBC with any second autoimmune condition or specifically with sicca syndrome or autoimmune thyroid disease also revealed no association with this variant. Thus the PTPN22(1858T) variant is not associated with PBC or with the combination of PBC and a second autoimmune disease. These data suggest that this variant does not confer risk for PBC and does not account for the frequent presence of other autoimmune diseases in patients with PBC.     

No evidence for association between 1858 C/T single-nucleotide polymorphism of PTPN22 gene and primary Sjögren's syndrome

One-third of first-degree relatives of patients with primary Sj?gren's syndrome (pSS) suffer from other autoimmune diseases, including type I diabetes, systemic lupus erythematosus and autoimmune thyroiditis. Recently, 1858 C/T polymorphism of PTPN22 gene was reported to predispose to these autoimmune diseases. We decided to investigate whether PTPN22 gene polymorphism was also involved in the genetic predisposition to pSS in a case-control study, including 183 patients with pSS and 172 healthy controls. No significant differences in allele (T allele frequency: 7.7% in patients with pSS vs 7.8% in controls, P=0.9) and genotype frequencies of PTPN22 polymorphism were detected between patients with pSS and controls. PTPN 22 gene polymorphism was not associated with a specific pattern of autoantibody secretion either. Thus, 1858 C/T polymorphism of PTPN22 gene is not involved in genetic predisposition to pSS.     

Association of the PTPN22 gene polymorphism with autoantibody positivity in Turkish rheumatoid arthritis patients

The PTPN22 C1858T gene polymorphism has been recently reported to be associated with rheumatoid arthritis (RA) in European and North American ancestry. In contrast, the frequency of PTPN22 C1858T polymorphism is extremely rare in Asian and African populations. As the genetic heterogeneity between populations is clearly present in RA, we wanted to investigate whether the PTPN22 C1858T polymorphism is associated with RA in Turkey and with autoantibody positivity. A total of 323 RA patients and 426 healthy controls were genotyped by polymerase chain reaction restriction fragment length polymorphism for the PTPN22 C1858T polymorphism (rs2476601). The frequencies of heterozygote genotype (CT) were 8.4% in RA patients and 5.4% in the healthy controls, respectively [odds ratio (OR): 1.6, P = 0.14]. The homozygote genotype (T/T) was absent in both RA patients and the healthy controls. When compared with the healthy controls, we found the significant associations between the frequency of PTPN22 heterozygote (CT) polymorphism and RA patients with RF positivity and anti-CCP positivity, respectively (OR: 2.05, P = 0.04 and OR: 2.1, P = 0.03, respectively). Our study suggests that the PTPN22 C1858T polymorphism acts as a susceptibility gene for autoantibody-positive RA in Turkey.     

The PTPN22 promoter polymorphism -1123G>C association cannot be distinguished from the 1858C>T association in a Norwegian rheumatoid arthritis material

The protein tyrosine phosphatase nonreceptor 22 (PTPN22) gene has, during the last 2 years, been recognized as a susceptibility gene for numerous autoimmune diseases, including rheumatoid arthritis (RA) and type 1 diabetes. An association between the exonic 1858C>T single nucleotide polymorphism (SNP) and RA has repeatedly been replicated in several Caucasian populations. The SNP is not associated with autoimmune diseases in Asian populations, as the 1858T allele is almost absent. Recently, a promoter polymorphism -1123G>C was proposed to be associated with acute-onset type 1 diabetes in Japanese and Korean populations. Furthermore, in Caucasian populations, the presence of additional PTPN22 risk variants has been suggested, indicating that the 1858C>T risk variant cannot explain the entire disease association observed in the region. In this study, we wanted to jointly address and integrate these separate findings to further elucidate the association between the PTPN22 gene and RA in a Norwegian material of 861 RA patients and 559 healthy controls. Our results revealed that the strength of the association with the PTPN22 promoter polymorphism, -1123G>C, is analogous to that observed for 1858C>T. As the -1123G>C variant is also polymorphic in Asian populations, our data underpin the need to further explore the association between this variant and autoimmune diseases in different populations.     

Association of the single nucleotide polymorphism C1858T of the PTPN22 gene with type 1 diabetes

The PTPN22 (protein tyrosine phosphatase N22) gene encodes the protein tyrosine phosphatase Lyp. One function of Lyp is downregulation of T-cell signaling through its interaction with the negative regulatory kinase C-terminal Src tyrosine kinase (Csk). A single nucleotide polymorphism in the PTPN22 gene, C1858T, encodes products with different Csk binding affinities. Disease association of the PTPN22 1858T allele has been reported in case-control studies of three different autoimmune disorders: type 1 diabetes (T1D), rheumatoid arthritis, and systemic lupus erythematosus. In this study, a set of 341 white, multiplex T1D families were genotyped for the C1858T single nucleotide polymorphism of PTPN22, and transmission disequilibrium test analysis revealed significant association (p = 0.005) of the T allele with T1D. No effects of parent of origin, sex of patient, or human leukocyte antigen genotype (high-risk human leukocyte antigen DR3/DR4 vs non-DR3/DR4) were observed. However, transmission of the T allele was significantly increased in the subset of patients who also carried at least one copy of the TCF7 883A allele, another allele that is important in regulating T-cell responses and that is associated with T1D. These results are consistent with the hypothesis that individuals lacking the C allele of PTPN22 may have reduced capacity to downregulate T-cell responses and may therefore be more susceptible to autoimmunity.     

Differential association of the PTPN22 coding variant with autoimmune diseases in a Dutch population

Protein tyrosine phosphatase PTPN22 is involved in the negative regulation of T-cell responsiveness. Recently, the association of a coding variant of the PTPN22 gene-R620W(1858C>T) with a number of autoimmune diseases has been described. Therefore, we tested the association of PTPN22 1858*T allele in Dutch early onset type 1 diabetes (T1D) and rheumatoid arthritis (RA) patients, as well as celiac disease (CD) patients, for which no previous study of PTPN22 has been reported. The PTPN22 variant was strongly associated with T1D in cases vs controls (P=2 x 10(-7), OR=2.3, 95% CI=1.7-3.1) as well as in a transmission disequilibrium test in nuclear trio's (P=9 x 10(-9), OR=3.3, CI=2.1-5.0), RA (case/control: P=0.003, OR=1.8 CI =1.2-2.6), but not CD, in spite of a trend of increased homozygosity (P=0.05) and early age at onset (P=0.01). PTPN22 is not generally associated with T-cell mediated autoimmune diseases, although it might play a role in the CD patients with early clinical manifestation.     

Autoimmunity and atherosclerosis: functional polymorphism of PTPN22 is associated with phenotypes related to the risk of atherosclerosis. The Cardiovascular Risk in Young Finns Study

There is a growing body of evidence attesting the significance of inflammation in the pathogenesis of atherosclerosis. Protein tyrosine phosphate PTPN22 C/T single nucleotide polymorphism (SNP) at + 1858 has been identified recently as a susceptibility factor for various inflammatory autoimmune diseases. We hypothesized that data on the genetic polymorphism of the PTPN22 enzyme associated with an increased risk of autoimmunity could also provide insight into the possible role of autoimmunity in the pathogenesis of atherosclerosis. Therefore we analysed the PTPN22 + 1858 C/T polymorphism in a population of young Finnish adults (n = 2268) for whom data on carotid artery intima-media thickness (IMT), a presymptomatic predictor of atherosclerosis, and risk factors for atherosclerosis were available. In males carriage of the T allele of PTPN22 + 1858 was associated significantly with IMT in univariate and multivariate analyses, while in females it was associated with several risk factors for atherosclerosis (BMI, waist circumference, waist-to-hip ratio, serum concentrations of C-reactive protein and triglycerides) but not with IMT. Our results indicate that the genetic polymorphism of PTPN22 + 1858 known to predispose to autoimmunity also enhances the development of atherosclerosis and thereby links the genetics of autoimmunity and atherosclerosis.     

PTPN22基因多态性与自身免疫甲状腺病的相关性

目的:检测PTPN22基因的单核苷酸多态性(SNP)及其与中国人自身免疫甲状腺病(AITD)的相关性, 并研究CTLA- 4基因SNP与PTPN22 SNP的相互关系.方法:采用PCR-RFLP技术分析231例AITD患者, 其中Graves'病(GD)149例, 桥本甲状腺炎(HT)82例和131例健康对照者PTPN22基因 1858 C>T及CTLA- 4基因49A>G位点的基因型.采用SASP-PCR技术分析PTPN22基因启动子-1123G>C的基因型.结果:(1)PTPN22基因的 1858C>T位点不存在多态性;(2)PTPN22基因-1123G>C SNP的等位基因和基因型分布频率在GD组与正常对照组间的差异有统计学意义(P值分别为0.040和0.013, OR值分别为1.44和2.33);(3) CTLA- 4基因 49A>G位点的等位基因和基因型分布频率在AITD组与正常组间有明显差异;(4)与携带PTPN22的G等位基因及CTLA- 4的AA基因型者相比, 携带PTPN22CC基因型与CTLA- 4 AG或GG基因型者发生GD的OR值=3.31(95%CI: 2.69-8.89).结论:PTPN22基因启动子-1123G>C SNP与GD的发生相关, 其CC基因型与CTLA- 4基因的G 等位基因对GD的发生起协同作用.     

PTPN22 Polymorphism is Related to Autoimmune Disease Risk in Patients with Turner Syndrome

Individuals with Turner syndrome (TS) clearly have an increased risk for autoimmune diseases. Recently, an allelic variation (C1858T) of the PTPN22 gene was revealed to be associated with the development of autoimmunity. Thus, the aim of this study was to determine the frequency of the PTPN22 C1858T polymorphism in women with Turner syndrome (TS) compared to controls. Case–control study comprises 142 women with TS (cases) and 180 healthy and fertile women without a history of autoimmune disease (controls). Detection of the PTPN22 C1858T polymorphism (rs2476601) was performed by TaqMan real‐time PCR. The chi‐square test was used to compare allele and genotype frequencies between groups and to estimate the Hardy–Weinberg equilibrium. All P‐values were two‐tailed, and 95% confidence intervals (CIs) were calculated. A P‐value <0.05 was considered statistically significant. Genotypes CC, CT and TT of the PTPN22 C1858T polymorphism presented frequencies of, respectively, 67.6%, 28.2% and 4.2% in the TS, and 82.8%, 16.1% and 1.1% in the control group (P = 0.0043). Alleles C and T were present in, respectively, 81.7% and 18.3% of the patients with TS (P = 0.001, OR = 2.22, 95% CI = 1.39‐3.54) and in 90.8% and 9.2%, respectively, of the controls. The data suggest that in Brazilian patients with TS, the PTPN22 C1858T polymorphism may be an important genetic factor predisposing to autoimmune disease risk.     

Association of PTPN22 C1858T polymorphism and type 1 diabetes: a meta-analysis

Recently, protein tyrosine phosphatase nonreceptor 22 (PTPN22) C1858T polymorphism has been identified as a susceptibile gene for type 1 diabetes (T1D), but studies are inconsistence, In order to assess the association between PTPN22C1858T polymorphism and T1D based on different ethnicities, a meta-analysis was performed, including 26 studies, total of 16,240 patients and 17,997 controls. Meta-analysis was performed on T versus C, T/T+T/C versus C/C (dominant model) and T/T versus T/C+C/C (recessive model) in a fixed/random effects model. The results indicated an association between the PTPN22 C1858T polymorphism and T1D in all subjects. The overall odds ratio (OR) of T versus C using the fixed effects model was 1.948 (95% CI = 1.859～2.041, P < 0.001). After stratification by ethnicity, analysis revealed that the PTPN22 C1858T polymorphism T allele was significantly associated with T1D in Europeans, Americans (OR = 1.946, 95% CI = 1.852~2.045, P < 0.001; OR = 1.946, 95% CI = 1.690~2.242, P < 0.001, respectively). Meta-analysis of the T/T+T/C genotype and the T/T genotypes showed the same results as that shown by the PTPN22 C1858T polymorphism T allele. This meta-analysis suggests a possible association between the PTPN22 C1858T polymorphism and T1D, especially in European and American populations.     

Association of PTPN22 gene functional variants with development of pulmonary tuberculosis in Moroccan population

Mycobacterium tuberculosis , the causal agent of pulmonary tuberculosis (TB), remains a major health problem throughout the world causing high mortality in humans. Previous studies showed that several genes may play crucial roles in susceptibility to TB. The PTPN22 gene encodes the lymphoid tyrosine phosphatase that has an important regulatory effect on T- and B-cell activation in immune response. The purpose of this study was to investigate the role of two functional missense single nucleotide polymorphisms (SNPs) of the PTPN22 gene region (R620W and R263Q) in the susceptibility to TB in the Moroccan population. A case–control association study was performed including 123 pulmonary TB patients and 155 healthy controls. All subjects were genotyped by TaqMan SNP genotyping assays. Regarding the PTPN22 R620W (C1858T) SNP, we observed a statistically significant difference in the distribution of the PTPN22 1885T allele between pulmonary TB patients and healthy controls (0.41% vs 3.2%, P  = 0.01, odds ratio (OR) = 0.14, 95% confidence interval (CI) = 0.01–0.93). With respect to the PTPN22 R263Q (G788A), we observed an increase of 788A allele frequencies in TB patients compared with those in healthy controls (3.65% vs 0.65%, P  = 0.01, OR = 5.85, 95% CI = 1.17–39.55). These results suggest that PTPN22 gene variants may affect susceptibility to TB in the Moroccan population.     

A general autoimmunity gene (PTPN22) is not associated with inflammatory bowel disease in a British population

A single-nucleotide polymorphism (C1858T) causing an amino acid substitution (R620W) in the lymphoid protein tyrosine phosphatase gene PTPN22 has been implicated in type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, Graves' disease, juvenile idiopathic arthritis and Hashimoto's thyroiditis, thus revealing a general role for this gene in autoimmune disease. We investigated the association of the C1858T variant in an additional autoimmune disease population by performing a case-control study of 514 British individuals with inflammatory bowel disease (IBD) [294 with Crohn's disease (CD) and 220 with ulcerative colitis (UC)] and 374 normal controls. No significant differences in genotype or allele frequencies were observed between IBD, CD or UC and controls, indicating that PTPN22 does not influence risk of IBD.     

Mutation screening of PTPN22: association of the 1858T-allele with Addison's disease

The tyrosine-protein phosphatase non-receptor type 22 (PTPN22) gene was recently identified as an important genetic susceptibility factor in several autoimmune diseases. The increased risk has been broadly explained by the 1858T-allele (rs2476601). As two smaller studies on Addison's disease (AD) have shown diverging results, we aimed to elucidate the predisposing effect of the single-nucleotide polymorphism (SNP) 1858CT in a larger population of AD patients, especially focusing on the AD patients with known autoimmune etiology. We also screened for unknown rare or common variants in the PTPN22 gene that could predispose for AD. The case-control study of Norwegian AD patients (n=332) and controls (n=990) showed a significant association between autoimmune AD (n=302) and the PTPN22 1858T risk allele (P=0.016). The association of AD with 1858T was supported by a meta-analysis combining our genotype data with that of others published previously (P=0.003). The mutation screening of PTPN22 in AD patients (n=332) and controls (n=112) revealed eight missense variants, five of which have not been reported previously. In conclusion, the 1858T-allele is a PTPN22 genetic susceptibility factor for autoimmune AD. Other rare variants in PTPN22 do occur, and may also be involved in the pathogenesis.