Demographic, clinical and laboratory characteristics of ISM patients grouped according to the pattern of changes in sBT levels (sBT slope) after 48 months of follow-up.

Results expressed as number of cases from total cases in the group and percentage between brackets or *as median values and range between brackets.ASM, aggressive systemic mastocytosis; BM, bone marrow; ISM, indolent systemic mastocytosis; NS, not statistically significant; MC, mast cells; sBT, serum baseline tryptase; SSM, smouldering systemic mastocytosis.†Assessed by flow cytometry.‡Splenomegaly.§Hepatomegaly in one case, hepatomegaly plus splenomegaly in the other 2 patients.∣∣Splenomegaly in one case, hepatomegaly plus splenomegaly in the other 5 patients.