Among 15 individual MS patients, the RAs of IgGs from CSFs at a fixed concentration of MBP (0.5 mg/ml) were very different (the specific RAs varied in a range 3.5–368 nmole MBP per hour per mg of Abs, while apparent kcat = V/[IgG] in the range 0.009–0.93 min−1); the average RA values were 175.0±94.5 nM MBP per hour per mg of Abs (average apparent kcat 0.4±0.26 min−1) (Table 3). The gene discussed is DDX41; the disease is myeloid sarcoma.