In contrast, lower levels of CCL2 were found in plasma of ISM versus both BMM and ASM (P ≤ 0.042) (Figure 2B in Supplementary Information), together with increased cell surface expression of its CD192 receptor on monocytes (P = 0.037) of SM patients, regardless of the subtype of the disease. Here, CCL2 is linked to systemic mastocytosis.