The IgM seroprevalence was about 6 times higher in MS patients (7.3%; 9/124; 95% CL 3.7–12.8%) than in the blood of healthy donors (1.3%; 2/150; 95% CL 0.3–4.2%) (χ22 = 6.49, p = 0.039) (Table 1; Fig. 1A). The gene discussed is CD40LG; the disease is myeloid sarcoma.