When PBMCs were cultured for 18 h in the absence of exogenous stimulation and the frequency of IL-10-expressing B-cells compared with levels of SCFAs, the percentage of both naïve and IgMhi MZ-like B-cells that expressed IL-10 correlated positively with the concentration of butyrate in serum samples from patients with CIS/MS (Fig. 4a,e). The gene discussed is IL10; the disease is myeloid sarcoma.