CD19 and myalgic encephalomeyelitis/chronic fatigue syndrome: In addition to the high cell number, a later study showed that a subset of B-cells in ME/CFS patients have impaired cell signalling function as indicated by lower expression of transient receptor potential melastatin-3 (TRPM3) cation channels on CD19+ B-cells in 17 ME/CFS patients, as compared to 19 healthy controls [68, 70].