Immune profile in relation to sex steroid cyclicity in healthy women and women with multiple sclerosis

•Systemic in vivo immunological effects of sex hormones in healthy women and female MS patients.•In healthy women, high hormone level phases were associated with increases in TBX21 and GATA3 expression, as well as CXCL13, while CTLA-4 was decreased.•Our data indicate immune activating properties in vivo of high steroid sex hormone levels during both CHC and normal menstrual cyclicity. To prospectively study systemic in vivo immunological effects of sex hormones, using different phases of oral combined hormonal contraceptives (CHC), and the natural menstrual cycles in both healthy women and in women with multiple sclerosis (MS), blood samples from sixty female MS patients and healthy controls with and without CHC were drawn in high and low estrogenic/progestogenic phases. Expression of Th-associated genes in blood cells was determined by qPCR and a panel of cytokines and chemokines was measured in plasma. High hormone level phases were associated with increases in Th1 (TBX21) and Th2 (GATA3) associated markers, as well as the B cell-associated chemokine CXCL13, while the inhibitory regulator CTLA-4 was decreased. These changes were not observed in MS patients, of whom most were treated with immunomodulatory drugs. Our data indicate immune activating properties in vivo of high steroid sex hormone levels during both CHC and normal menstrual cyclicity.