Thyroid dysfunction in African trypanosomiasis: a possible role for inflammatory cytokines

Area of Science:

• Endocrinology
• Infectious Diseases
• Immunology

Background:

• Sleeping sickness, or African trypanosomiasis, is a tsetse fly-transmitted disease.
• Experimental models show Trypanosoma brucei infection causes pituitary and thyroid lesions, leading to hypothyroidism.
• The impact of sleeping sickness on the hypothalamic-pituitary-thyroid axis in humans requires further investigation.

Purpose of the Study:

• To assess the functional integrity of the hypothalamic-pituitary-thyroid axis in patients with African trypanosomiasis.
• To evaluate thyroid function before, during, and after specific antiparasitic therapy.
• To explore the relationship between thyroid function, disease activity, and inflammatory cytokines.

Main Methods:

• A prospective, controlled, cross-sectional study involving 65 sleeping sickness patients and 13 controls.
• Thyroid function tests (TSH, fT3, fT4, rT3) and cytokine levels (TNF-alpha, IL-1, IL-6) were measured.
• TRH stimulation tests were performed, with blood samples collected at multiple time points relative to treatment.

Main Results:

• Unmedicated patients showed elevated TSH and low fT3/fT4 levels, indicative of primary hypothyroidism.
• Thyroid hormone levels normalized during and after treatment with suramin and/or melarsoprol.
• Elevated TNF-alpha and IL-6 levels correlated with impaired thyroid function and decreased with therapy.

Conclusions:

• Unmedicated sleeping sickness is associated with significant thyroid dysfunction, characterized by primary hypothyroidism.
• Specific antiparasitic therapy effectively reverses thyroid function impairment.
• Elevated cytokines may contribute to thyroid dysfunction, or parasitic thyroiditis could be involved.