PLP1 and myeloid sarcoma: The percentage of MS patients who had isotype-switched anti-PLP antibodies to any IgG subtype (83.9%) was highly significantly different from that of healthy controls (11.1%; P = 1.8 × 10−9) and that of OND patients (18.8%; P = 2.0 × 10−7) by χ2 with Yates' correction.