Early onset of polyglandular failure is associated with HLA-DRB1*03

DRB1 locus alleles of HLA class II are associated with modulation of the immune response in different serological profiles of HIV-1/Epstein-Barr virus coinfection in the Brazilian Amazon region

Background

Epstein-Barr virus (EBV) infection involves distinct clinical and serological profiles. We evaluated the frequency of alleles of locus DRB1 of HLA class II in different serological profiles of EBV infection among HIV-1 infected patients.

Methods

We recruited 19 patients with primary infection, 90 with serological transition and 467 with past infection by EBV, HIV-1 co-infection was 100% in primary infection and approximately 70% in other serological profiles. EBV viral load was quantified by real-time PCR, T lymphocyte quantification and cytokine level analysis were performed by flow cytometry, and HLA locus genotyping was performed by PCR-SSO.

Results

The DRB1*09 allele was associated with primary infection (p: 0.0477), and carriers of the allele showed changes in EBV viral load (p: 0.0485), CD8(+) T lymphocyte counts (p: 0.0206), double-positive T lymphocyte counts (p: 0.0093), IL-4 levels (p: 0.0464) and TNF levels (p: 0.0161). This allele was also frequent in HIV-coinfected individuals (p: 0.0023) and was related to the log10 HIV viral load (p: 0.0176) and CD8(+) T lymphocyte count (p: 0.0285). In primary infection, the log10 HIV viral load was high (p: 0.0060) and directly proportional to the EBV viral load (p: 0.0412). The DRB1*03 allele correlated with serological transition (p: 0.0477), EBV viral load (p: 0.0015), CD4(+) T lymphocyte count (p: 0.0112), CD8(+) T lymphocyte count (p: 0.0260), double-negative T lymphocyte count (p: 0.0540), IL-4 levels (p: 0.0478) and IL-6 levels (p: 0.0175). In the serological transition group, the log10 HIV viral load was high (p: 0.0060), but it was not associated with the EBV viral load (p: 0.1214). Past infection was related to the DRB1*16 allele (p: 0.0477), with carriers displaying IgG levels (p: 0.0020), CD4(+) T lymphocyte counts (p: 0.0116) and suggestive CD8(+) T count alterations (p: 0.0602). The DRB01*16 allele was also common in HIV-1 patients with past EBV infection (p: 0.0192); however, the allele was not associated with clinical markers of HIV-1 infection.

Conclusion

Our results suggest that HLA class II alleles may be associated with the modulation of the serological profiles of the immune response to Epstein-Barr virus infection in patients coinfected with HIV-1.

Analysis of the AIRE Gene Promoter in Patients Affected by Autoimmune Polyendocrine Syndromes

Autoimmune polyglandular syndromes (APS) are classified into four main categories, APS1-APS4. APS1 is caused by AIRE gene loss of function mutations, while the genetic background of the other APS remains to be clarified. Here, we investigated the potential association between AIRE gene promoter Single Nucleotide Polymorphisms (SNPs) and susceptibility to APS. We sequenced the AIRE gene promoter of 74 APS patients, also analyzing their clinical and autoantibody profile, and we further conducted molecular modeling studies on the identified SNPs. Overall, we found 6 SNPs (-230Y, -655R, -261M, -380S, -191M, -402S) of the AIRE promoter in patients' DNA. Interestingly, folding free energy calculations highlighted that all identified SNPs, except for -261M, modify the stability of the nucleic acid structure. A rather similar percentage of APS3 and APS4 patients had polymorphisms in the AIRE promoter. Conversely, there was no association between APS2 and AIRE promoter polymorphisms. Further AIRE promoter SNPs were found in 4 out of 5 patients with APS1 clinical diagnosis that did not harbor AIRE loss of function mutations. We hypothesize that AIRE promoter polymorphisms could contribute to APS predisposition, although this should be validated through genetic screening in larger patient cohorts and in vitro and in vivo functional studies.

Recurrence risk of autoimmune thyroid and endocrine diseases

BACKGROUND AND OBJECTIVE

The recurrence risk ratio (λ) expresses the risk ratio of index patients' first-degree relatives developing a disease as compared to the general population and is a quantitative measure of the genetic contribution to the disease. This paper offers the results of a specialized center as well as a review of the pertinent literature.

METHODS

Data from 3315 consecutive subjects followed at an ORPHAN academic tertiary referral expert center for endocrine autoimmunity as well as 419 unrelated German families were collected. λ was assessed based on 806 well-documented subjects, 299 index patients with autoimmune glandular (AIGD) and non-endocrine diseases and 507 of their first-degree relatives (328 children, 179 siblings).

RESULTS

As many as 36% of relatives of patients with autoimmune diseases (AID) were affected by various autoimmune conditions. Twenty-five percent and 23% of all relatives had an AIGD or an autoimmune thyroid disease (AITD), respectively. Furthermore, 29% and 25% of relatives of index cases with polyglandular (PGA) and monoglandular (MGA) autoimmunity were affected. The recurrence risk for AITD was increased 16-fold in both children and siblings compared to the general population (λ, 95% CI 16, 11-21 and 16, 12-19, respectively). Furthermore, λ for AITD/AIGD was 21.62 (95% CI 14.17-30.69)/17.57 (11.80-24.36) and 13.48 (8.42-20.52)/10.68 (6.76-16.02) for siblings of patients with PGA and MGA, respectively. Overall, a strong genetic component for AITD and AIGD with a significant genetic impact on the development of PGA was demonstrated.

CONCLUSION

These novel results strongly recommend the screening for AITD and AIGD in children and siblings of index patients with AITD.

Neuromyelitis optica is an HLA associated disease different from Multiple Sclerosis: a systematic review with meta-analysis

Neuromyelitis Optica and Multiple Sclerosis are idiopathic inflammatory demyelinating diseases of the central nervous system that currently are considered distinct autoimmune diseases, so differences in genetic susceptibility would be expected. This study aimed to investigate the HLA association with Neuromyelitis Optica by a systematic review with meta-analysis. The STROBE instrument guided research paper assessments. Thirteen papers published between 2009 and 2020 were eligible. 568 Neuromyelitis Optica patients, 41.4% Asians, 32.4% Latin Americans and 26.2% Europeans were analyzed. Only alleles of the DRB1 locus were genotyped in all studies. Neuromyelitis Optica patients have 2.46 more chances of having the DRB1*03 allelic group than controls. Ethnicity can influence genetic susceptibility. The main HLA association with Neuromyelitis Optica was the DRB1*03:01 allele in Western populations and with the DPB1*05:01 allele in Asia. Differences in the Multiple Sclerosis and Neuromyelitis Optica genetic susceptibility was confirmed in Afro descendants. The DRB1*03 allelic group associated with Neuromyelitis Optica has also been described in other systemic autoimmune diseases.

Type 1 Diabetes and Autoimmune Thyroid Disease-The Genetic Link

Type 1 diabetes (T1D) and autoimmune thyroid disease (AITD) are the most frequent chronic autoimmune diseases worldwide. Several autoimmune endocrine and non-endocrine disorders tend to occur together. T1D and AITD often cluster in individuals and families, seen in the formation of autoimmune polyendocrinopathy (AP). The close relationship between these two diseases is largely explained by sharing a common genetic background. The HLA antigens DQ2 (DQA1*0501-DQB1*0201) and DQ8 (DQA1*0301-DQB1*0302), tightly linked with DR3 and DR4, are the major common genetic predisposition. Moreover, functional single nucleotide polymorphisms (or rare variants) of various genes, such as the cytotoxic T-lymphocyte- associated antigen (CTLA4), the protein tyrosine phosphatase non-receptor type 22 (PTPN22), the interleukin-2 Receptor (IL2Ra), the Vitamin D receptor (VDR), and the tumor-necrosis-factor-α (TNF) that are involved in immune regulation have been identified to confer susceptibility to both T1D and AITD. Other genes including cluster of differentiation 40 (CD40), the forkhead box P3 (FOXP3), the MHC Class I Polypeptide-Related Sequence A (MICA), insulin variable number of tandem repeats (INS-VNTR), the C-Type Lectin Domain Containing 16A (CLEC16A), the Erb-B2 Receptor Tyrosine Kinase 3 (ERBB3) gene, the interferon-induced helicase C domain-containing protein 1 (IFIH1), and various cytokine genes are also under suspicion to increase susceptibility to T1D and AITD. Further, BTB domain and CNC homolog 2 (BACH2), C-C motif chemokine receptor 5 (CCR5), SH2B adaptor protein 3 (SH2B3), and Rac family small GTPase 2 (RAC2) are found to be associated with T1D and AITD by various independent genome wide association studies and overlap in our list, indicating a strong common genetic link for T1D and AITD. As several susceptibility genes and environmental factors contribute to the disease aetiology of both T1D and AITD and/or AP subtype III variant (T1D+AITD) simultaneously, all patients with T1D should be screened for AITD, and vice versa.

Amino Acid Polymorphisms in Hla Class II Differentiate Between Thyroid and Polyglandular Autoimmunity

CONTEXT

The structure of the human leucocyte antigen (HLA) peptide-binding clefts strongly contributes to monoglandular and polyglandular autoimmunity (AP).

OBJECTIVE

To investigate the impact of amino acid polymorphisms on the peptide-binding interactions within HLA class II and its association with AP.

DESIGN

Immunogenetic study.

SETTING

Tertiary referral center for autoimmune endocrine diseases.

SUBJECTS

587 subjects with AP, autoimmune thyroid disease (AITD), type 1 diabetes (T1D), and healthy unrelated controls were typed for HLA class II.

METHODS

Amino acids within the peptide binding cleft that are encoded by HLA class II exon 2 were listed for all codon positions in all subjects. Overall comparisons between disease and control groups with respect to allele distribution at a given locus were performed by assembling rare alleles applying an exact Freeman Halton contingency table test with Monte-Carlo P values based on 150 000 samples.

RESULTS

The Monte Carlo exact Fisher test demonstrated marked differences in all 3 loci, DQA1, DQB1, and DRB1 (P < .0001) between AP and both AITD and controls, as well as between AP type II (Addison's disease as a major endocrine component) and AP type III (T1D + AITD). Differences were also noted between AP and T1D pertaining to the DRB1 allele (P < .041). Seven amino acid positions, DRB1-13, DRB1-26, DRB1-71, DRB1-74, DQA1-47, DQA1-56, and DQB1-57, significantly contributed to AP. Five positions in DQA1 (11, 47, 50, 56, and 69) completely correlated (P < .0001).

CONCLUSION

Amino acid polymorphisms within HLA class II exon 2 mediate the AP risk and differentiate between thyroid and polyglandular autoimmunity.

Autoimmune Polyendocrinopathy

CONTEXT

This mini-review offers an update on the rare autoimmune polyendocrinopathy (AP) syndrome with a synopsis of recent developments.

DESIGN AND RESULTS

Systematic search for studies related to pathogenesis, immunogenetics, screening, diagnosis, clinical spectrum, and epidemiology of AP. AP (orphan code ORPHA 282196) is defined as the autoimmune-induced failure of at least two glands. AP is divided into the rare juvenile type I and the adult types II to IV. The prevalence is 1:100,000 and 1:20,000 for types I and types II to IV, respectively. Whereas type I (ORPHA 3453) is a monogenetic syndrome with an autosomal recessive transmission related to mutations in the autoimmune regulator (AIRE) gene, types II to IV are genetically complex multifactorial syndromes that are strongly associated with certain alleles of HLA genes within the major histocompatibility complex located on chromosome 6, as well as the cytotoxic T lymphocyte antigen 4 and the protein tyrosine phosphatase nonreceptor type 22 genes. Addison disease is the major endocrine component of type II (ORPHA 3143), whereas the coexistence of type 1 diabetes and autoimmune thyroid disease is characteristic for type III (ORPHA 227982). Genetic screening for the AIRE gene is useful in patients with suspected type I, whereas serological screening (i.e., diabetes/adrenal antibodies) is required in patients with monoglandular autoimmunity and suspected AP. If positive, functional endocrine testing of the antibody-positive patients as well as serological screening of their first-degree relatives is recommended.

CONCLUSION

Timely diagnosis, genetic counseling, and optimal long-term management of AP is best offered in specialized centers.

Thyroid Dysfunction and Diabetes Mellitus: Two Closely Associated Disorders

Thyroid dysfunction and diabetes mellitus are closely linked. Several studies have documented the increased prevalence of thyroid disorders in patients with diabetes mellitus and vice versa. This review critically discusses the different underlying mechanisms linking type 1 and 2 diabetes and thyroid dysfunction to demonstrate that the association of these two common disorders is unlikely a simple coincidence. We assess the current state of knowledge on the central and peripheral control of thyroid hormone on food intake and glucose and lipid metabolism in target tissues (such as liver, white and brown adipose tissue, pancreatic β cells, and skeletal muscle) to explain the mechanism linking overt and subclinical hypothyroidism to type 2 diabetes and metabolic syndrome. We also elucidate the common susceptibility genes and the pathogenetic mechanisms contributing to the autoimmune mechanism involved in the onset of type 1 diabetes mellitus and autoimmune thyroid disorders. An untreated thyroid dysfunction can impair the metabolic control of diabetic patients, and this association can have important repercussions on the outcome of both of these disorders. Therefore, we offer recommendations for the diagnosis, management, and screening of thyroid disorders in patients with diabetes mellitus, including the treatment of diabetic patients planning a pregnancy. We also discuss the major causes of failure to achieve an optimal management of thyroid dysfunction in diabetic patients and provide recommendations for assessing and treating these disorders during therapy with antidiabetic drugs. An algorithm for a correct approach of these disorders when linked is also provided.

Sex Alters the MHC Class I HLA-A Association With Polyglandular Autoimmunity

CONTEXT

The major histocompatibility complex (MHC) strongly contributes to the development of polyglandular autoimmunity (PGA).

OBJECTIVE

To evaluate the impact of sex on human leukocyte antigen (HLA) association with PGA for the first time.

DESIGN

Cross-sectional immunogenetic study.

SETTING

Academic tertiary referral Orphan Disease Center for PGA (ORPHA 282196) and immunogenetics laboratory.

SUBJECTS

Patients (158) with coexistent type 1 diabetes and autoimmune thyroid disease (adult type 3 PGA, ORPHA 227982) and 479 unrelated healthy controls.

INTERVENTIONS

All 637 white subjects were typed for HLA-A, -B, -DRB1, -DQA1, and -DQB1 alleles at a two-field level.

MAIN OUTCOME MEASURES

Modification of the gene-disease association by sex.

RESULTS

MHC class I HLA-A association was sex related to both the total white adult type 3 PGA collective (n = 158, P = 0.0065), as well as in PGA patients with autoimmune Hashimoto thyroiditis (n = 91, P = 0.010). Compared with HLA-A*02:01, A*11:01 was over-represented in male patients, yet under-represented in women (OR 1.49, 95% CI 0.55 to 3.88 vs 0.42, 0.12 to 1.17). A*24:02 was under-represented in male but not in female patients (OR 0.37, 95% CI 0.11 to 1.04 vs 1.19, 0.65 to 2.15). With the exclusion of the five most frequent alleles (A*01:01, A*02:01, A*03:01, A*11:01, and A*24:02), the sum of all other identified alleles was under-represented in male patients (OR 0.37, 0.18 to 0.72, P = 0.0046). The strong MHC HLA-B association with PGA (P < 0.0001) was not sex related (P = 0.55). Furthermore, no interaction with sex was observed for the MHC class II HLA-DRB1, -DQA1, and -DQB1 alleles.

CONCLUSION

MHC class I HLA-A association with type 3 PGA is significantly affected by sex.

HLA DQ2 HAPLOTYPE, EARLY ONSET OF GRAVES DISEASE, AND POSITIVE FAMILY HISTORY OF AUTOIMMUNE DISORDERS ARE RISK FACTORS FOR DEVELOPING CELIAC DISEASE IN PATIENTS WITH GRAVES DISEASE

OBJECTIVE

The diagnosis of celiac disease (CD) in patients with different autoimmune diseases including Graves disease (GD) remains a challenge. The aims of our study were to: (1) assess the prevalence of CD in Polish patients with GD and (2) evaluate the prevalence of CD in the subgroups of patients with GD divided on the basis of clinical and human leukocyte antigen (HLA) typing criteria.

METHODS

The prospective study was conducted at an academic referral center. The study groups consisted of consecutive, euthyroid patients with GD (n = 232) and healthy volunteers without autoimmune thyroid diseases (n = 122). The diagnosis of CD was based on elevated immunoglobulin A autoantibodies to the enzyme tissue transglutaminase (IgA-TTG) and small intestine biopsy findings.

RESULTS

CD was diagnosed in 8 patients with GD (3.4%) and 1 healthy volunteer (0.8%). The development of CD in patients with GD was strongly associated with HLA-DQ2 haplotype (as predicted from linkage disequilibria, 14.6% vs. 1.5%, P = .009; odds ratio [OR] = 11.3; 95% confidence interval [CI] 1.3-252.7): 6 patients with CD carried HLA-DRB1(*)03, 1 carried an HLA-DRB1(*)04 allele, and 1 had an HLA-DRB1(*)07/(*)11 genotype. Multivariate analysis showed independent associations between CD and early GD onset (P = .014, OR = 9.6), autoimmunity in family (P = .029, OR = 6.3) and gastroenterologic symptoms (P = .031, OR = 8.1).

CONCLUSIONS

The results of our study suggest that serologic screening for CD may be considered in GD patients (1) with the HLA alleles typical for CD, (2) with an early onset of GD, or (3) a family history of autoimmunity. Moreover, the diagnosis of CD should be explored in euthyroid GD patients with nonspecific gastrointestinal symptoms.

HLA class II haplotypes differentiate between the adult autoimmune polyglandular syndrome types II and III

BACKGROUND

Genetics of the adult autoimmune polyglandular syndrome (APS) is poorly understood.

AIM

The aim of this study was to gain further insight into the genetics of the adult APS types. SITE: The study was conducted at a university referral center.

METHODS

The human leukocyte antigen (HLA) class II alleles, haplotypes, and genotypes were determined in a large cohort of patients with APS, autoimmune thyroid disease (AITD), and type 1 diabetes and in healthy controls by the consistent application of high-resolution typing at a four-digit level.

RESULTS

Comparison of the allele and haplotype frequencies significantly discriminated patients with APS vs AITD and controls. The HLA class II alleles DRB1*03:01 *04:01, DQA1*03:01, *05:01, DQB1*02:01, and *03:02 were observed more frequently (P<.001) in APS than in AITD and controls, whereas the alleles DRB1*15:01, DQB1*03:01, and *06:02 were underrepresented in APS vs AITD (Pc<.001) and controls (Pc<.01), respectively. The DRB1*03:01-DQA1*05:01-DQB1*02:01 (DR3-DQ2) and DRB1*04:01-DQA1*03:01:DQB1*03:02 (DRB1*04:01-DQ8) haplotypes were overrepresented in APS (Pc<.001). Combination of both haplotypes to a genotype was highly prevalent in APS vs AITD and controls (Pc<.001). Dividing the APS collective into those with Addison's disease (APS type II) and those without Addison's disease but including type 1 diabetes and AITD (APS type III) demonstrated DR3-DQ2/DRB1*04:01-DQ8 as a susceptibility genotype in APS III (Pc<.001), whereas the DR3-DQ2/DRB1*04:04-DQ8 genotype correlated with APS II (Pc<.001). The haplotypes DRB1*11:01-DQA1*05:05-DQB1*03:01 and DRB1*15:01-DQA1*01:02-DQB1*06:02 are protective in APS III but not in type II (Pc<.01).

CONCLUSIONS

HLA class II haplotypes differentiate between the adult APS types II and III. Susceptible haplotypes favor the development of polyglandular autoimmunity in patients with AITD.

Thyroid disorders and diabetes mellitus

Studies have found that diabetes and thyroid disorders tend to coexist in patients. Both conditions involve a dysfunction of the endocrine system. Thyroid disorders can have a major impact on glucose control, and untreated thyroid disorders affect the management of diabetes in patients. Consequently, a systematic approach to thyroid testing in patients with diabetes is recommended.

Autoimmune polyglandular syndrome type 2 shows the same HLA class II pattern as type 1 diabetes

Autoimmune polyglandular syndrome (APS) type 2 is defined by the manifestation of at least two autoimmune endocrine diseases. Only few data exist on genetic associations of APS type 2. In this controlled study, 98 patients with APS type 2, 96 patients with type 1 diabetes (T1D), and 92 patients with autoimmune thyroid disease, both as a single autoimmune endocrinopathy, were tested for association with alleles of the human leukocyte antigen (HLA) class II loci DRB1, DQA1, and DQB1. Patients with APS type 2 had significantly more often the alleles DRB1*03 (P(c) < 0.0001), DRB1*04 (P(c) < 0.000005), DQA1*03 (P(c) < 0.0001), and DQB1*02 (P(c) < 0.05), when compared with controls. Less frequent in APS were DRB1*15 (P(c) < 0.05), DQA1*01 (P(c) < 0.0005), and DQB1*05 (P(c) < 0.005). With regard to frequency and linkage of these alleles, the susceptible haplotypes DRB1*0301-DQA1*0501-DQB1*0201 and DRB1*0401/04-DQA1*0301-DQB1*0302 were deduced. Protective haplotypes in this study were DRB1*1501-DQA1*0102-DQB1*0602 and DRB1*0101-DQA1*0101-DQB1*0501. Comparing APS patients with vs without AD, no significant differences regarding HLA class II alleles were noted in our collective. Patients with T1D as a singular disease had the same susceptible and protective HLA alleles and haplotypes. The prevalence of DRB1*03 and DRB1*04 in APS patients was not because of the presence of diabetes, as the APS type 2 patients without diabetes had the same allele distribution. In conclusion, these data suggest a common immunogenetic pathomechanism for T1D and APS type 2, which might be different from the immunogenetic pathomechanism of other autoimmune endocrine disease.

Shared molecular amino acid signature in the HLA-DR peptide binding pocket predisposes to both autoimmune diabetes and thyroiditis

There is strong genetic association between type 1A diabetes (T1D) and autoimmune thyroid disease (AITD). T1D and AITD frequently occur together in the same individual, a condition classified as a variant of the autoimmune polyglandular syndrome type 3 (APS3). Because T1D and AITD are individually strongly associated with different HLA class II sequences, we asked which HLA class II pocket sequence and structure confer joint susceptibility to both T1D and AITD in the same individual (APS3v). We sequenced the HLA-DR gene in 105 APS3v patients and 153 controls, and identified a pocket amino acid signature, DRβ-Tyr-26, DRβ-Leu-67, DRβ-Lys-71, and DRβ-Arg-74, that was strongly associated with APS3v (P = 5.4 × 10(-14), odds ratio = 8.38). Logistic regression analysis demonstrated that DRβ-Leu-67 (P = 9.4 × 10(-13)) and DRβ-Arg-74 (P = 1.21 × 10(-13)) gave strong independent effects on disease susceptibility. Structural modeling studies demonstrated that pocket 4 was critical for the development of T1D+AITD; all disease-associated amino acids were linked to areas of the pocket that interact directly with the peptide and, therefore, influence peptide binding. The disease-susceptible HLA-DR pocket was more positively charged (Lys-71, Arg-74) compared with the protective pocket (Ala-71, Gln-74). We conclude that a specific pocket amino acid signature confers joint susceptibility to T1D+AITD in the same individual by causing significant structural changes in the MHC II peptide binding pocket and influencing peptide binding and presentation. Moreover, Arg-74 is a major amino acid position for the development of several autoimmune diseases. These findings suggest that blocking the critical Arg-74 pocket might offer a method for treating certain autoimmune conditions.

Genetics of the autoimmune polyglandular syndrome type 3 variant

BACKGROUND

Autoimmune thyroid diseases (AITD) and type 1 diabetes (T1D) are the most common autoimmune endocrine disorders. They occur frequently together in the same individual. This disease combination is denominated as autoimmune polyglandular syndrome type 3 variant (APS3v). This review aims to describe the genetic and pathological background of the syndrome. The joint susceptibility genes for AITD and T1D as well as the underlying pathogenetic mechanisms contributing to the development of autoimmunity are summarized.

SUMMARY

Family and population studies showed that the APS3v syndrome has a strong genetic background. Whole genome and candidate gene approaches identified several gene variations that are present in both AITD and T1D. Most important common disease susceptibility genes are human leucocyte antigen (chromosome 6), cytotoxic T-lymphocyte-associated antigen 4 (chromosome 2), protein tyrosine phosphatase nonreceptor type 22 (chromosome 1), forkhead box P3 (X chromosome), and the interleukin-2 receptor alpha/CD25 gene region (chromosome 10), all of which contributing to the susceptibility to APS3v. With respect to the underlying pathogenetic mechanisms, these genes are altogether involved in the immune regulation, in particular in the immunological synapse and T-cell activation. In addition to these common genes, there are further candidate genes with joint risk for AITD and T1D, in particular the v-erb-b2 erythroblastic leukemia viral oncogene homolog 3 gene (chromosome 12) and C-type lectin domain family 16 member A gene (chromosome 16). The latter one might be involved in pathogen recognition.

CONCLUSIONS

AITD and T1D share common susceptibility gene variants that possibly act pleiotropically as risk factors for the development of autoimmunity in APS3v. The functional consequences of the genetic variants as well as their interactions should be explored in greater detail. In particular, the functional consequences of the variants of forkhead box P3 predisposing to APS3v need to be elucidated. Finally, further large-scale genome-wide associations studies of single-nucleotide polymorphism variations capturing many thousand individual genetic profiles are warranted to identify further genes that are linked to the etiology of APS3v.

[Associations of autoimmune disorders in endocrine diseases]

Increasing data are known for dialogue between neuroendocrine and immune systems recently. Results of molecular genetic studies provided evidences for common languages of these systems by various signals including neurotransmitters, hormones, cytokines. It is proved the immune system is able to produce neurotransmitters and hormones and endocrine organs can even result in cytokines. This new integrative approach allows to investigate the physiologic events and diseases as interactions between the psycho-neuro-endocrine-immune systems. The autoimmune polyendocrine syndromes constitute a heterogeneous group of disorders characterized by loss of immune tolerance to self-antigens. In spite of distinct clinical pictures, molecular genetic studies revealed a common molecular mechanism in the associations of organ-specific diseases. Autoimmune polyendocrine syndrome-1 is characterized by associations at least two out of three cardinal signs: Addison's disease, autoimmune hypoparathyroidism and mucocutaneous candidiasis. This is a rare autosomal recessive syndrome induced by mutations in autoimmune regulator gene. Autoimmune polyendocrine syndrome-2 occurs more frequently and defined as the coexistence of Addison's disease, autoimmune thyroid disease and/or type-1 diabetes mellitus. Autoimmune polyendocrine syndrome-3 is characterized by association of autoimmune thyroid disease and type-1 diabetes mellitus. The HLA and other genes proved to be important in associations of the syndrome-2 and 3 in contrast to autoimmune polyendocrine syndrome-1. Identification of predisposing genetic helps to understand the common mechanisms and provide possibility for early therapy and prevention as well.

The protein tyrosine phosphatase non-receptor type 22 C1858T polymorphism is a joint susceptibility locus for immunthyroiditis and autoimmune diabetes

BACKGROUND

The lymphoid tyrosine phosphatase (LYP) encoded by the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene is a strong inhibitor of T cells. The single nucleotide polymorphism (SNP) C1858T within the PTPN22 gene was recently associated with autoimmune thyroid disease (AITD) and type I diabetes (T1D). The purpose of this study was to examine the joint association of this polymorphism with the co-occurrence of AITD and T1D.

METHODS

In this association study, 310 white subjects were genotyped for the C1858T polymorphism. The study population included 70 patients with both AITD and T1D (AITD+T1D), 70 patients with AITD only, 70 patients with T1D only, and 100 healthy controls. Patients with both AITD and T1D, and controls were also typed for HLA-DRB1. PTPN22 C1858T genotyping was performed by minisequencing. For HLA-DRB1 typing, polymerase chain reaction (PCR) sequence-specific oligonucleotide probes were used.

RESULTS

The PTPN22 1858 minor T-allele frequency was strongly increased in patients with AITD+T1D (23.6%) compared with controls (8.0%, pc<0.001), with patients with AITD only (8.6%, pc=0.006), or with T1D only (10.7%, pc=0.028). T-allele carriers were also more frequently present in the group with AITD+T1D versus controls (41.4% vs. 14.0%, OR=4.35, 95% CI=2.08-9.09), AITD (17.1%, OR=3.42, 95% CI=1.56-7.48), and T1D (21.4%, OR=2.59, 95% CI=1.23-5.45). Especially in subjects with Hashimoto's thyroiditis (HT)+T1D, T-allele carriers were mostly frequent (50% vs. 14%, OR=6.14, 95% CI=2.62-14.38, pc<0.001). Considering all included patients with AITD, T-allele carriers were 29.3% vs. 14.0% in controls (p=0.008, OR=2.54, 95% CI=1.30-4.98). Patients carrying the PTPN22 1858 T allele had a twofold increased frequency of the HLA-DRB1*03 allele (64.7% vs. 37.3%, pc=0.034).

CONCLUSION

The PTPN22 gene is a joint susceptibility locus for AITD (especially HT) and T1D.

Allergy and autoimmunity: parallels and dissimilarity: the yin and yang of immunopathology

The etiopathogenesis of allergy and autoimmune diseases is caused by genetic and acquired (environmental) factors, which might be common to both immunopathologies. Genetic factors play an important role in the development and process of immunopathological diseases. Several studies suggest a close relation between gene polymorphism of HLA and cytokines and development of autoimmunity and allergy. Certain gene polymorphisms act as risk or as protective factors. The infection also plays an important role in the induction of allergy and autoimmunity--as a trigger or as a protective factor. Moreover, similar clinical manifestations of both immunopathologies could result in diagnostic problems. This review summarizes the linkage of mechanisms of etiopathogenesis, clinical manifestations and therapeutic strategy between allergic and autoimmune diseases.

Joint genetic susceptibility to type 1 diabetes and autoimmune thyroiditis: from epidemiology to mechanisms

Type 1 diabetes (T1D) and autoimmune thyroid diseases (AITD) frequently occur together within families and in the same individual. The co-occurrence of T1D and AITD in the same patient is one of the variants of the autoimmune polyglandular syndrome type 3 [APS3 variant (APS3v)]. Epidemiological data point to a strong genetic influence on the shared susceptibility to T1D and AITD. Recently, significant progress has been made in our understanding of the genetic association between T1D and AITD. At least three genes have been confirmed as major joint susceptibility genes for T1D and AITD: human leukocyte antigen class II, cytotoxic T-lymphocyte antigen 4 (CTLA-4), and protein tyrosine phosphatase non-receptor type 22. Moreover, the first whole genome linkage study has been recently completed, and additional genes will soon be identified. Not unexpectedly, all the joint genes for T1D and AITD identified so far are involved in immune regulation, specifically in the presentation of antigenic peptides to T cells. One of the lessons learned from the analysis of the joint susceptibility genes for T1D and AITD is that subset analysis is a key to dissecting the etiology of complex diseases. One of the best demonstrations of the power of subset analysis is the CTLA-4 gene in T1D. Although CTLA-4 showed very weak association with T1D, when analyzed in the subset of patients with both T1D and AITD, the genetic effect of CTLA-4 was significantly stronger. Gene-gene and genetic-epigenetic interactions most likely play a role in the shared genetic susceptibility to T1D and AITD. Dissecting these mechanisms will lead to a better understanding of the etiology of T1D and AITD, as well as autoimmunity in general.