Routine KIT p.D816V screening identifies clonal mast cell disease in patients with Hymenoptera allergy regularly missed using baseline tryptase levels alone.
Anaphylaxis
KIT p.D816V
hereditary α-tryptasemia
mast cells
tryptase
venom
Journal
The Journal of allergy and clinical immunology
ISSN: 1097-6825
Titre abrégé: J Allergy Clin Immunol
Pays: United States
ID NLM: 1275002
Informations de publication
Date de publication:
08 2021
08 2021
Historique:
received:
12
10
2020
revised:
15
01
2021
accepted:
16
02
2021
pubmed:
24
3
2021
medline:
21
10
2021
entrez:
23
3
2021
Statut:
ppublish
Résumé
Clonal mast cell disorders and elevated basal serum tryptase (BST) levels with unknown cause(s) are associated with severe Hymenoptera venom-triggered anaphylaxis (HVA). However, some individuals with clonal disease have a normal BST level (<11.4 ng/mL). Our aim was to evaluate whether screening for KIT p.D816V in the blood is a useful clinical tool to risk-stratify patients with venom allergy. We prospectively recruited 374 patients with Hymenoptera allergy and no overt signs of mastocytosis who were referred to our center during the years 2018 and 2019. KIT p.D816V was determined in their peripheral blood by quantitative PCR, and tryptase genotyping was performed by droplet digital PCR. In all, 351 patients (93.9%) had normal levels of BST, and KIT p.D816V was detected in 8% of patients (28 of 351), predominantly in patients with the most severe Mueller grade IV anaphylaxis (18.2% [24 of 132] vs 1.8% in patients with lower grades [4 of 88 with grade III and 0 of 131 with other grades]; P < .001). In grade IV patients with a normal BST level, KIT p.D816V was associated with more severe symptoms, including a significantly higher frequency of loss of consciousness (58.3% [14 of 24] vs 34.3% [37 of 108]; P = .03) and absence of skin symptoms (41.7% [10 of 24] vs 15.7% [17 of 108]; P = .004). Among patients with a normal BST level, KIT p.D816V (OR = 10.25 [95% CI = 3.75-36.14]; P < .0001) was the major risk factor associated with severe HVA. Hereditary α-tryptasemia (HαT) due to increased germline copies of TPSAB1 encoding α-tryptase was the most common cause (65.2% [15 of 23]) of elevated BST level in patients with HVA, and together with KIT p.D816V, it accounted for 90% of BST level elevations (20 of 23) in patients with HVA. These results indicate that routine KIT p.D816V screening identifies clonal disease in high-risk patients with HVA who are regularly missed when BST level is used alone.
Sections du résumé
BACKGROUND
Clonal mast cell disorders and elevated basal serum tryptase (BST) levels with unknown cause(s) are associated with severe Hymenoptera venom-triggered anaphylaxis (HVA). However, some individuals with clonal disease have a normal BST level (<11.4 ng/mL).
OBJECTIVE
Our aim was to evaluate whether screening for KIT p.D816V in the blood is a useful clinical tool to risk-stratify patients with venom allergy.
METHODS
We prospectively recruited 374 patients with Hymenoptera allergy and no overt signs of mastocytosis who were referred to our center during the years 2018 and 2019. KIT p.D816V was determined in their peripheral blood by quantitative PCR, and tryptase genotyping was performed by droplet digital PCR.
RESULTS
In all, 351 patients (93.9%) had normal levels of BST, and KIT p.D816V was detected in 8% of patients (28 of 351), predominantly in patients with the most severe Mueller grade IV anaphylaxis (18.2% [24 of 132] vs 1.8% in patients with lower grades [4 of 88 with grade III and 0 of 131 with other grades]; P < .001). In grade IV patients with a normal BST level, KIT p.D816V was associated with more severe symptoms, including a significantly higher frequency of loss of consciousness (58.3% [14 of 24] vs 34.3% [37 of 108]; P = .03) and absence of skin symptoms (41.7% [10 of 24] vs 15.7% [17 of 108]; P = .004). Among patients with a normal BST level, KIT p.D816V (OR = 10.25 [95% CI = 3.75-36.14]; P < .0001) was the major risk factor associated with severe HVA. Hereditary α-tryptasemia (HαT) due to increased germline copies of TPSAB1 encoding α-tryptase was the most common cause (65.2% [15 of 23]) of elevated BST level in patients with HVA, and together with KIT p.D816V, it accounted for 90% of BST level elevations (20 of 23) in patients with HVA.
CONCLUSION
These results indicate that routine KIT p.D816V screening identifies clonal disease in high-risk patients with HVA who are regularly missed when BST level is used alone.
Identifiants
pubmed: 33753098
pii: S0091-6749(21)00423-1
doi: 10.1016/j.jaci.2021.02.043
pii:
doi:
Substances chimiques
Arthropod Venoms
0
KIT protein, human
EC 2.7.10.1
Proto-Oncogene Proteins c-kit
EC 2.7.10.1
Tryptases
EC 3.4.21.59
Types de publication
Journal Article
Research Support, N.I.H., Intramural
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
621-626.e7Informations de copyright
Copyright © 2021 American Academy of Allergy, Asthma & Immunology. All rights reserved.