In children with autoimmune thyroiditis CTLA4 and FCRL3 genes--but not PTPN22--are overexpressed when compared to adults.

Wojciechowska-Durczynska K, Krawczyk-Rusiecka K, Zygmunt A, Stawerska R, Lewinski A.
  Vol. 37 (1) 2016 Neuro endocrinology letters Comparative Study   2016; 37(1): 65-69 PubMed PMID:  26994388    Citation  Keywords:  Adolescent, Adult, Aged, Case-Control Studies, Child, Female, Genetic Predisposition to Disease, Genotype, Humans, Male, Membrane Transport Proteins:genetics, Middle Aged, Protein Tyrosine Phosphatase, Non-Receptor Type 22:genetics, Receptors, Immunologic.   

BACKGROUND: Numerous genetic studies revealed several susceptibility genes of autoimmune thyroid diseases (AITD), including CTLA4, PTPN22 and FCRL3. These immune-modulating genes are involved in genetic background of AITD among children and adult patients. However, possible age-related differences in overexpression of these genes remain unclear.

PURPOSE: The goal of this single centre cohort study was evaluation of expression levels of three (3) genes CTLA4, PTPN22 and FCRL3 in adult patients and children with autoimmune thyroiditis.

METHODS: A total of 47 patients--24 adults (mean age--47.7 years) and 23 children (mean age--12.4 years) with autoimmune thyroiditis were assessed for the level of expression of CTLA4, PTPN22 and FCRL3 genes, utilizing ABI PRISM' 7500 Sequence Detection System (Applied Biosystem, Foster City, CA, USA).

RESULTS: The overexpression of PTPN22 (mean RQ = 2.988) and FCRL3 (mean RQ = 2.544) genes were confirmed in adult patients with autoimmune thyroiditis, at the same time the expression level of CTLA4 gene was significantly decreased (mean RQ = 0.899) (p < 0.05). Similar discrepancies were not observed in children with autoimmune thyroiditis in whom overexpression of all three genes--CTLA4, PTPN22 and FCRL3--was observed. Differences in CTLA4 and FCRL3 genes expression levels in patients with autoimmune thyroiditis were found depending on the age, with increased expression levels of CTLA4 (mean RQ = 3.45 1) and FCRL3 (mean RQ = 7.410) in children when compared to adults (p < 0.05) (Mann-Whitney's U-test). There were moderate negative linear correlations between two genes in question (CTLA4 and FCRL3) expression level and patients' age [correlation coefficient (r) = -0.529 (p < 0.0002) and -0.423 (p < 0.0032), respectively; Spearman's rank correlation test].

CONCLUSION: Our results are consistent with the hypothesis that there are few age-dependent genetic differences as regards autoimmune thyroiditis in adults and children. Accordingly, CTLA4 and FCRL3 genes overexpression may play an important role in children suffering from autoimmune thyroiditis.

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