IFNA1 and neuromyelitis optica: A higher frequency of detectable IFN-α in serum was observed in the SLE patients (16/24) compared to NMO, OR = 6; 95% CI (1.69–21.87, P = 0.0029) and compared to the MS group, OR = 39; 95% CI (6.60–381.47, P < 0.0001).