Thyroid autoantibodies in autoimmune diseases

August 4, 2004

Medicina (B Aires). 2004;64(3):227-30.

Thyroid autoantibodies in autoimmune diseases.

Innocencio RM, Romaldini JH, Ward LS.

Department of Medicine, Faculdade de Ciencias Medicas/UNICAMP, Campinas,

Sao o, Brazil. reginain@...

Abnormalities in the thyroid function and thyroid autoantibodies have

been frequently described in patients with autoimmune diseases but seldom in

antiphospholipid syndrome patients. In order to determine the prevalence of

thyroid function and autoimmune abnormalities, we compared serum thyrotropin

(TSH, serum free thyroxine (T4) levels, thyroid antithyroglobulin (TgAb) and

antithyroperoxidase (TPOAb) levels of 25 patients with systemic sclerosis,

25 patients with rheumatoid arthritis and 13 patients with antiphospholipid

syndrome to a control group of 113 healthy individuals. Evaluation included

a thorough clinical examination with particular attention to thyroid disease

and a serologic immune profile including rheumatoid factor, antinuclear and

anticardiolipin antibody measurements. Subclinical hypothyroidism

(4.2<TSH<10 mU/L) was diagnosed in five patients (8%), and subclinical

hyperthyroidism (undetectable<TSH<0.34 mU/L) in four patients (6%).

Anti-thyroglobulin (TgAb) and/or anti-thyroperoxidase (tPOAb) antibodies

were present in 21/63 (33%) of our patients: 13/25 (52%) of the systemic

sclerosis cases, 8/25 (32%) of the rheumatoid arthritis patients, but 0

(0/13) of the antiphospholipid syndrome patients. In conclusion, our data

confirm a high prevalence of silent autoimmune thyroid diseases in

association with systemic sclerosis and rheumatoid arthritis (p<0.02), but

not with antiphospholipid syndrome. Elevated antibody titres may reflect an

epiphenomenon of the underlying autoimmune disorders and play an additive

role in the development of the euthyroid sick syndrome in these patients,

but our data suggest that the antiphospholipid syndrome presents a different

pattern of response. Subclinical thyroid diseases should be considered when

evaluating patients with autoimmune diseases.

PMID: 15239536 [PubMed - in process]

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