Implications of serum calcitonin gene-related peptide and type I interferon in systemic lupus erythematosus-associated headaches

Objective Headache is a common neurological symptom in patients with systemic lupus erythematosus (SLE). Calcitonin gene-related peptide (CGRP) is a potential chemical mediator of headaches, while type I interferon (IFN) plays a pivotal role in the immune system of SLE. This study investigated the implications of CGRP and type I IFNs as headache biomarkers in patients with SLE. Methods We used clinical information and serum samples from 144 patients with SLE from a Japanese multicenter cohort and a biobank. Serum CGRP, IFN-α, and IFN-β levels, which were measured using enzyme-linked immunoassay, were compared among patients with headache, those without headache, and 20 healthy controls (HC). These levels were compared based on the severity of daily disability caused by headaches as determined using the Migraine Disability Assessment. Results Of the 144 patients, 60 had headache (median age, 42 years; 56 women) and were significantly younger than patients without headache (median age, 49 years; 77 women) ( p < .005). Both groups had a median SLE Disease Activity Index 2000 score of 4.0, which was not significantly different, whereas photosensitivity was significantly more prevalent in patients with headache than in those without headache ( p < .05). Serum CGRP and IFN-α levels were not significantly different between patients with headache, those without headache, and HC. Serum IFN-β levels were significantly higher in patients with headache than in those without headache ( p < .005), while being significantly lower in both patients with and without headache than in HC ( p < .005). No significant differences in serum CGRP, IFN-α and IFN-β levels were observed based on the severity of daily disability related to headaches. Conclusion Serum CGRP and type I IFNs levels may not be involved in SLE-associated headaches.