Sex bias of regulatory T cells in thymus and blood

Abstract

Background: At least three percent of the human population suffer from autoimmune diseases. There are differences between the sexes in the prevalence of auto immune diseases. Women generally have a higher prevalence. The reason to this sex bias in not known. One cell type of interest is the regulatory T cells that functions to regulate the immune response to prevent autoimmunity. The proportion between the sexes of regulatory T cells in thymus is not known. Aim: To examine if there are sex differences in regulatory T in the thymus. And if so, explore in which stages of regulatory T cell development the sex bias is present. Method: Antibodies attached to specific markers on the cells were used to analyze the samples in the flow cytometer for quantity and proportion of the different markers. The files were analyzed with the software FlowJo. Results: No statistical significant difference of regulatory T cells in thymus between the sexes was found. This project shows the tendency of boys having higher proportion of regulatory T cells in peripheral blood and quite the opposite in the thymus, with a tendency towards higher proportion of regulatory T cells in females. This is not significant. Conclusion: The results suggest that there may be a sex bias in regulatory T cells in thymus. Further studies are needed with more individuals included. It would especially be interesting to investigate children older than two months, the difference seen is perhaps related to the androgen peak boys get at 12 weeks of age. This is the first study to examine the proportion of regulatory T cells in the thymus with flow cytometry. Flow cytometry is a good method to further examine the underlaying causes to the sex bias seen in autoimmune diseases on cellular level