Chemokine/chemokine receptor interactions in extramedullary leukaemia of the skin in childhood AML: Differential roles for CCR2, CCR5, CXCR4 and CXCR7

Chemokine receptor/ligand interactions orchestrate the migration of cells to peripheral tissues such as the skin. We analysed chemokine receptor expression by acute myeloid leukaemic (AML) cells present in peripheral blood (n = 7), bone marrow (n = 6), or skin (n = 11) obtained from 15 paediatric AML patients with skin involvement and in 10 AML patients without skin involvement. High percentages of circulating CCR2(pos) AML cells were only detected in patients with extramedullary disease. Skin-residing AML cells displayed a different set of receptors in situ, namely: CCR5, CXCR4, CXCR7 and CX3CR1. These results suggest the involvement of different chemokine/chemokine receptor interactions in homing and retention of AML blasts in the skin.