The Impact of Contraceptives on Immune Responses to TB Infection
Medroxyprogesterone aceate (MPA), also known as Depo Provera is the most commonly used contraceptive in South Africa and other developing countries. Unlike other synthetic progestins, MPA possesses selective glucocorticoid activity and it is well known that glucocorticoids cause reactivation of latent TB. Given that over 60% of woman using contraceptives choose MPA in our study cohort where the TB incidence is 948/100 000, we are investigating the impact of MPA use on immune responses to TB. Ultimately we would like to elucidate whether MPA compared to other contraceptives affects susceptibility to TB, disease severity or response to TB treatment.
The Interplay between the Endocrine and the Immune System during TB Infection
There is increasing evidence that the immune system and the endocrine system influence each other. Cytokines produced during an immune response feedback to the hypothalamus and alter the secretion of hormones such as those involved in the hypothalamic-pituitary-adrenal and the hypothalamus-pituitary-gonadal axes. In turn, steroid hormones as well as metabolic hormones, are able to bind to their respective receptors on immune cells and affects the secretion of cytokines and chemokines. We are studying how TB influences the hormonal balance, and are trying to identify the underlying molecular mechanisms of the interplay between the immune and endocrine systems.