Altered activation of peripheral CD8+ T cells in pediatric Crohn's disease

•In CD treated with standard therapy calcium response during activation was elevated.•This was not affected by the inhibition of Kv1.3 or IKCa1 potassium channels.•Infliximab normalized potassium channel function of CD8+ lymphocytes in severe CD.

AimAlthough Crohn's disease (CD) is an extensively investigated autoimmune condition, knowledge on early phase activation of lymphocytes, especially CD8+ Tc cells is scarce. Our aim was to investigate the calcium influx characteristics of CD8+ cells upon activation as well as the expression and function of Kv1.3 and IKCa1 lymphocyte potassium channels.MethodsWe took peripheral blood from 12 healthy controls, 23 CD children on conventional therapy and 6 severe CD children before and after infliximab therapy. Intracellular calcium levels were monitored in CD8+ lymphocytes using flow cytometry.ResultsIn CD treated with standard therapy calcium response during activation was elevated. This was not affected by the inhibition of Kv1.3 or IKCa1 potassium channels. After the switch to infliximab potassium channel function and expression of CD8+ lymphocytes were comparable to healthy controls in severe CD.ConclusionCalcium handling of CD8+ lymphocytes is altered in pediatric CD, which is normalized by infliximab therapy.