Figure 2From: Natural killer cell dysfunction is a distinguishing feature of systemic onset juvenile rheumatoid arthritis and macrophage activation syndromeFlow cytometric analysis of CD56bright and CD56dim natural killer cells. (a) In healthy individuals, most circulating NK cells are CD56dim (about 90%) and express high levels of perforin. In contrast, CD56bright NK cells comprise about 10% of all human NK cells and express low levels of perforin. (b, c) Two distinct patterns of CD56 staining observed in patients with systemic juvenile rheumatoid arthritis (sJRA): (b) normal pattern (observed in 17 of 20 patients with sJRA as well as in all controls, and all other JRA patients); (c) almost complete disappearance of CD56bright subset of NK cells (observed in 3 of 20 patients with sJRA only).Back to article page