Thyroid function and antithyroid autoantibodies in patients with connective tissue diseases

Abstract

Autoimmune thyroid disease (ATD) has been described in patients with connective tissue diseases (CTD). The aim of this study was to estimate and compare the prevalence of ATD in a group of 91 CTD patients, and in their subgroups: 53 systemic lupus erythematosus (SLE), 24 rheumatoid arthritis (RA), 7 primary Sjogren’s syndrome (SSy) and 7 progressive systemic sclerosis (SSc) patients. A control group of 34 healthy blood volunteers was used for comparison. Serum levels of free thyroxine (FT4), thyroid stimulating hormone (TSH), as well as thyroid autoantibodies (Abs) specific of thyroperoxidase (TPO) and thyroglobulin (TG) were examined. CTD patients, in general, as well as SLE and RA subgroups, had significantly higher number of thyroid dysfunction than the control group (p lt 0.05). The most prominent thyroid dysfunction was subclinical hypothyroidism, with a higher prevalence in all subgroups of patients when compared to the control. Anti-TPO Abs were detected in a significant number of CTD patients, especially in SLE subgroup when compared to the control group. It was also found that a higher number of CTD patients, SLE and RA subgroups, had positive anti-Tg Abs, when compared to the control subjects. In conclusion, the prevalence of ATD in CTD patients was more frequent than in the control group. The patients with anti-TPO Abs and anti-Tg Abs at the time when they were analyzed, had hyperthyroidism, hypothyroidism or were clinically and biochemically euthyroid. The prevalence of hypothyroidism was greater than the prevalence of hyperthyroidism in all subgroups of patients.

Autoimunske bolesti štitaste žlezde (AITD) opisane su kod bolesnika sa sistemskim bolestima vezivnog tkiva (SBVT). Cilj ovog rada bio je da se ispita prevalencija AITD u grupi od 91 bolesnika sa SBVT, koja je uključila 53 bolesnika sa sistemskim eritemskim lupusom (SLE), 24 obolelih sa reumatoidnim artritisom (RA) i po 7 obolelih od primarnog Sjogrenovog sindroma (SSy) i progresivne sistemske skleroze (SSc). Kontrolnu grupu ispitanika činila su 34 dobrovoljna davaoca krvi. Kod svih učesnika u studiji merene su serumske koncentracije slobodnog tiroksina (FT4), tireostimulišućeg hormona (TSH), kao i autoantitela specifičnih za tireoperoksidazu (anti-TPO At) i tireoglobulin (anti-Tg At). U grupi bolesnika sa SBVT, kao i u podgrupama obolelih od SLE i RA, nađena je statistički značajno veća učestalost poremećaja funkcije štitaste žlezde u odnosu na kontrolnu grupu (p lt 0.05), a od svih poremećaja funkcije štitaste žlezde najčečće je detektovana subklinička hipotireoza. Anti-TPO At nađena su kod značajno većeg broja bolesnika sa SBVT i SLE, u odnosu na kontrolnu grupu. Isto tako, i anti-Tg At su detektovana kod većeg broja ispitanika u grupi SBVT, i podgrupama SLE i RA, nego kod zdravih osoba. U zaključku, prevalencija AITD kod obolelih od SBVT veća je nego u kontrolnoj grupi. Bolesnici sa anti- TPO At i anti-Tg At u vreme kada su analizirani, imali su subkliničku ili klinički manifestnu hipotireozu ili hipertireozu, ili su još bili u stadijumu bolesti u kome se ne može detektovati poremećaj funkcije štitaste žlezde. Prevalencija hipotireoze bila je veća od prevalencije hipertireoze u svim podgrupama bolesnika sa SBVT.