Migraine is a frequent and debilitating neurologic disorder. It is more frequent in women, and more prevalent in patients with autoimmune and/or inflammatory diseases such as multiple sclerosis (MS), rheumatoid arthritis (RA), Crohn's disease (CD), systemic lupus erythematosus (SLE) and endometriosis, whereas patients with long standing type 1 diabetes mellitus (T1DM) - an autoimmune but non inflammatory disease - seem to be less affected compared to the general population. Despite new migraine prevention treatments, a large number of patients remain unresponsive to currently available anti-migraine therapy and migraine pathophysiology remains unclear. Several peptides (calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating peptide-38 (PACAP-38), vasoactive intestinal polypeptide (VIP)) and hormones (estrogens, prolactin) and the immune system play an important role in migraine pathophysiology. Among T lymphocytes, regulatory T (Treg) cells suppress inflammation. Studies have evidenced higher levels of inflammatory molecules (cytokines) in migraine patients and have suggested decreased proportions of Treg cells in migraine, as well as in MS, RA, CD and SLE, whereas inflammation declines and Treg levels seem increased in long-standing T1DM. Inflammation, which participates in migraine pain, seems to be a common factor for migraine and these diseases. However, these studies display conflicting results and further investigation is required to better understand the mechanisms behind migraine. In this study, the investigators will compare Treg levels, as well as identify Treg subpopulations and measure cytokine levels in migraine and migraine-free participants with and without an autoimmune/inflammatory disorder (MS, RA, CD, SLE, T1DM and endometriosis).