Under baseline ex vivo conditions, blood monocytes from SM patients showed a significantly (P < 0.001) increased (vs. HD) spontaneous production of IL1β, IL6, IL8, TNFα, and to a less extent also IL10 (P = 0.036), with higher numbers of cytokine‐producing monocytes (Figure 1A,B). This evidence concerns the gene IL1B and systemic mastocytosis.