Islet, thyroid and transglutaminase antibodies in adult Bulgarian patients with type 1 diabetes

Prevalence of Various Systemic and Organ-Specific Autoimmune Markers in Addison's Disease Patients Compared to Healthy Controls

Background: Addison's disease (AD) is a rare disorder that often develops in the context of autoimmune polyglandular syndromes. However, the prevalence of rheumatological autoimmune diseases and corresponding autoimmune markers in AD is poorly investigated. Therefore, the present study aims to explore systemic and organ-specific immune markers in a cohort of AD patients from a single tertiary endocrine center. Material and methods: In total, 43 adult AD patients and 31 controls were included in the study. 21-hydroxylase autoantibodies (21OHAb), glutamic acid decarboxylase autoantibodies (GADAbs), zinc transporter-8 autoantibodies (ZnT8Abs), antibodies against nuclear antigens (ANAs), autoantibodies against cyclic citrullinated peptides (CCPAbs), rheumatoid factors (RFs), IgG autoantibodies against cardiolipin (ACLAbs), and autoantibodies against beta-2-Glycoprotein I (β2-GPIAbs) were measured in all participants. Results: An increased prevalence of antibodies against RFs (27.91% vs. 0%, p < 0.001) and ANAs (13.95% vs. 0%, p = 0.037) was found in AD patients compared to controls. Moreover, the titers of 21-hydroxylase and RF antibodies correlated positively (r = +0.269, p = 0.020). The AD patients tended to show an increased prevalence of subthreshold ACL antibody reactivity compared to controls. All patients diagnosed with type 1 diabetes mellitus were GADAb- but not ZnT8Ab-positive. Conclusions: The results show an increased prevalence of ANA and RF positivity in AD patients compared to controls and a significant association between 21-OHAb and RF positivity. ZnT8Ab positivity was not typical for adult AD patients from our ethnic group, while GADAbs were an essential marker for autoimmune diabetes mellitus. Extensive studies in different ethnic groups are needed to establish the clinical significance of various immunological markers for AD comorbidity and the appropriate follow-up protocols for patients with different antibody positivity.

Polymorphism in BACH2 gene is a marker of polyglandular autoimmunity

PURPOSE

Genetically predisposed individuals may develop several autoimmune diseases-autoimmune polyendocrine syndromes (APS). APS types 2-4, are complex disorders, which combine various organ-specific autoimmune conditions. Recent reports support the considerable role of the BACH2 gene in immune cell differentiation and shifting the T-cell balance towards regulatory T-cells. BACH2 polymorphisms are associated with autoimmune disorders, including Addison's disease (AD), Graves' disease (GD), and probably type 1 diabetes (T1D). Our study was aimed to investigate the BACH2 variant, rs3757247, in endocrine autoimmunity in the Polish population.

METHODS

The analysis comprised 346 individuals with APS, 387 with T1D only, and 568 controls. Genotyping was performed using TaqMan chemistry.

RESULTS

APS type 2 was found in 219 individuals, type 3 in 102, and type 4 in 25 subjects. Overall, AD was diagnosed in 244 subjects, Hashimoto's thyroiditis-in 238, T1D-in 127, GD-in 58, vitiligo and chronic gastritis each in 40 patients, celiac disease-in 28, premature menopause in 18, and alopecia in 4 patients. Minor T allele at rs3757247 was found in 56.4% APS vs. 44.1% control alleles (OR 1.59; 95%CI: 1.30-1.95, p < 0.0001). The distribution of genotypes revealed excess TT homozygotes in the APS cohort (33.2 vs. 20.1% in controls, p < 0.0001). The frequencies of rs3757247 alleles and genotypes in T1D patients did not present significant differences vs. controls (p-values > 0.05).

CONCLUSIONS

These results provide evidence of the association between BACH2 polymorphism and polyglandular autoimmunity. Since carriers of rs3757247 display increased risk for additional autoimmune conditions, this variant could identify individuals prone to develop APS.