KIT D816V mutation-positive cell fractions in lesional skin biopsies from adults with systemic mastocytosis.

BACKGROUND

Most adults with systemic mastocytosis (SM) carry the somatic KIT D816V mutation, but the occurrence of the mutation in lesional skin remains to be characterized.

OBJECTIVE

To assess the distribution and fraction of KIT D816V mutation-positive cells in lesional skin.

METHODS

Lesional skin biopsies from 29 adults with SM were analysed using sensitive and quantitative qPCR KIT D816V mutation analysis.

RESULTS

The KIT D816V mutation was detected in skin in all cases. Highly similar mutation levels were observed in all patients with a median of 5% mutation-positive cells in the skin (range 1-23%).

CONCLUSION

The KIT D816V mutation is consistently present in lesional skin in adults with SM. The low variation in mutation levels detected in lesional skin contrasts blood and bone marrow where mast cell (MC) progenitor and non-MC lineage involvement causes the mutation-positive cell fraction to be highly variable.