Principal component analysis (PCA) including linked PGN and transcript (NFKB1, RIPK1 and IL-12A) expression as first (69% of variance) and second components (17% of variance) revealed clustering of nonMS white matter samples (Fig. 4D) while MS samples were scattered, reflecting the heterogeneity of disease severity. The gene discussed is IL12A; the disease is myeloid sarcoma.