If, however, we consider the mean Ab-titer of the MAP positive MS subjects (n = 9), the interferon-beta-treated patients (n = 5) did not have a statistically significant difference compared to the drug-free ones (n = 4) (6574 ± 747 AU/mL vs 5811 ± 520 AU/mL, p = 0.13), probably because interferon-beta treatment causes a Th1 to Th2 shift or class switching. The gene discussed is IFNB1; the disease is myeloid sarcoma.