Navarro‐Navarro P, Alvarez‐Twose I, Pérez‐Pons A, Henriques A, Mayado A, García‐Montero AC, Sanchez‐Muñoz L, González‐López O, Matito A, Caldas C, Jara‐Acevedo M, Orfao A.
KIT
D816V
mutation in blood for the diagnostic screening of systemic mastocytosis and mast cell activation syndromes
KIT
D816V
in blood of mastocytosis and
MCAS.
Allergy 2022;
78:1347-1359. [PMID:
36385619 DOI:
10.1111/all.15584]
[Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/06/2022] [Accepted: 10/11/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND
Current diagnostic algorithms for systemic mastocytosis (SM) rely on the detection of KITD816V in blood to trigger subsequent bone marrow (BM) investigations.
METHODS
Here, we correlated the KITD816V mutational status of paired blood and BM samples from 368 adults diagnosed with mast cell activation syndrome (MCAS) and mastocytosis and determined the potential utility of investigating KITD816V in genomic DNA from blood-purified myeloid cell populations to increase diagnostic sensitivity. In a subset of 69 patients, we further evaluated the kinetics of the KITD816V cell burden during follow-up and its association with disease outcome.
RESULTS
Our results showed a high correlation (P < .0001) between the KITD816V mutation burden in blood and BM (74% concordant samples), but with a lower mean of KITD816V-mutated cells in blood (P = .0004) and a high rate of discordant BM+ /blood- samples particularly among clonal MCAS (73%) and BM mastocytosis (51%), but also in cutaneous mastocytosis (9%), indolent SM (15%), and well-differentiated variants of indolent SM (7%). Purification of different compartments of blood-derived myeloid cells was done in 28 patients who were BM mast cell (MC)+ /blood- for KITD816V, revealing KITD816V-mutated eosinophils (56%), basophils (25%), neutrophils (29%), and/or monocytes (31%) in most (61%) patients. Prognostically, the presence of ≥3.5% KITD816V-mutated cells (P < .0001) and an unstable KITD816V mutation cell burden (P < .0001) in blood and/or BM were both associated with a significantly shortened progression-free survival (PFS).
CONCLUSIONS
These results confirm the high specificity but limited sensitivity of KITD816V analysis in whole blood for the diagnostic screening of SM and other primary MCAS, which might be overcome by assessing the mutation in blood-purified myeloid cell populations.
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