The object of the study was to assess TRPM3 surface expression on NK and B lymphocytes from healthy controls, followed by a comparative investigation examining TRPM3 surface expression, and cytoplasmic and mitochondrial calcium influx in CD19+ B cells, CD56bright and CD56dim cell populations from CFS/ME patients. Here, TRPM3 is linked to myalgic encephalomeyelitis/chronic fatigue syndrome.