Serum Basal Tryptase Levels in Healthy Children (KID-Tryp)

Evaluation of Basal Tryptasemia According to Age in a Pediatric Control Population

The National REference Center for MASTocytosis (CEREMAST), located at the Necker-Enfants Malades Hospital, is particularly interested in two groups of rare diseases whose common point is excessive activation of mast cells: mastocytosis and mast cell activation syndromes (MCAS). Unlike MCAS, whose symptoms result solely from this aberrant mast cell activation, in mastocytosis there is, in addition, an expansion and a clonal accumulation of mast cells in different target organs. These two diseases are heterogeneous in their clinical presentation and can begin in early childhood. While the diagnostic criteria for mastocytosis are well established, those for MCAS are unclear, causing major diagnostic error and therefore poor patient care.

To date, there is no study evaluating tryptase standards in children less than 18 years of age.

The research focuses on the dosage of tryptase in a control population of children aged 0 to 18 years.

Each patient receiving a complete blood count (CBC) in a surgery department of the Necker-Enfants Malades hospital will be selected to participate in the study. After the CBC analysis, the rest of the sample will be kept for this research instead of being discarded.

Knowing the norms of tryptase according to age would be an important tool for dermatologists, allergists and pediatricians caring for patients suspected of MCAS or mastocytosis. A blood test could thus avoid a few years of diagnostic wandering in the MCAS and mastocytosis.

Study Overview

• Status: Completed
• Conditions: Basal Tryptasemia
• Intervention / Treatment: Other: Tryptase dosage

Detailed Description

The National REference Center for MASTocytosis (CEREMAST), located at the Necker-Enfants Malades Hospital, is particularly interested in two groups of rare diseases whose common point is excessive activation of mast cells: mastocytosis and mast cell activation syndromes (MCAS). Unlike MCAS, whose symptoms result solely from this aberrant mast cell activation, in mastocytosis there is, in addition, an expansion and a clonal accumulation of mast cells in different target organs. These two diseases are heterogeneous in their clinical presentation and can begin in early childhood. While the diagnostic criteria for mastocytosis are well established, those for MCAS are unclear, causing major diagnostic error and therefore poor patient care.

At CEREMAST, for the pediatric branch, just over 700 children with mastocytosis and 150 with MCAS are followed. For each patient, a tryptase assay is performed. Over the years, CEREMAST is able to confirm that the standard of tryptase currently given as <11.4µg/L is not valid in children and clearly objectify that the level of normal tryptase increases with age in the child. Several patients with MCAS with hereditary hyper-alpha-tryptasemia (HAT) are followed at CEREMAST with diagnostic delays of 4 years on average. The knowledge among the doctors who took care of these patients that a tryptase at 7µg/L can be pathological in children could have avoided this wandering, and allowed the faster implementation of an effective antihistamine treatment.

Recent studies have shown that familial hypertryptasemia or hereditary hyper-alpha-tryptasemia (HAT) of autosomal dominant transmission was associated with an increase in the number of copies of the TPSAB1 gene, coding for tryptase alpha 1 and beta. By now systematically looking for amplifications of the TPSAB1 gene in all CEREMAST patients, it has been noted that a duplication may be associated with a tryptase at 6 μg/L, considered normal in children.

To date, there is no study evaluating tryptase standards in children less than 18 years of age.

The research focuses on the dosage of tryptase in a control population of children aged 0 to 18 years.

Each patient receiving a complete blood count (CBC) in a surgery department of the Necker-Enfants Malades hospital will be selected to participate in the study. After the CBC analysis, the rest of the sample will be kept for this research instead of being discarded.

Knowing the norms of tryptase according to age would be an important tool for dermatologists, allergists and pediatricians caring for patients suspected of MCAS or mastocytosis. A blood test could thus avoid a few years of diagnostic wandering in the MCASs and mastocytosis.

• Study Type: Observational
• Enrollment (Actual): 402

Contacts and Locations

Study Locations

• France
  • Paris, France, 75015
    • Hôpital Necker-Enfants Malades

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: No older than 17 years (Child)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients for whom a complete blood count (CBC) is carried out for their care in a surgery department (orthopedic, visceral, maxillofacial, neurology, cardiology surgery) at the Necker-Enfants Malades hospital, in order to have a control pediatric population with no excess of chronic inflammatory or allergic disease compared to the general French population.

Description

Inclusion Criteria:

• Minor patients aged 0-18
• Patient for whom a complete blood count (CBC) is carried out for their care in a surgery department (orthopedic, visceral, maxillofacial, neurology, cardiology surgery) at the Necker-Enfants Malades hospital
• Information and non-opposition of the subjects and of holders of parental authority subjects

Exclusion Criteria:

- Patients hospitalized in departments other than surgery at Necker-Enfants Malades Hospital

Study Plan

How is the study designed?

Design Details

• Observational Models: Other
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Subjects; Control pediatric population: no excess of chronic inflammatory or allergic disease compared to the general French population.	Other: Tryptase dosage; Collection of biological waste from a blood test for complete blood count (CBC) of care. Centrifugation to recover the plasma, then dosage of the tryptase.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum basal tryptase levels according to age	Basal tryptasemia according to age in a pediatric control population.	8 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum basal tryptasemia levels according to sex	Basal tryptasemia according to sex in a pediatric control population.	8 months

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Collaborators: URC Necker Cochin, France
• Investigators: Principal Investigator: Laura Polivka, MD, Assistance Publique - Hôpitaux de Paris; Study Director: Luc de Chaisemartin, MD, Assistance Publique - Hôpitaux de Paris

Publications and helpful links

General Publications

• Puel M, Rossignol J, Devin C, Madrange M, Diep A, Roland PN, Chollet-Martin S, Husson J, Hermine O, Bodemer C, Brouzes C, De Chaisemartin L, Polivka L; CEREMAST network. Redefining tryptase norms in the pediatric population reveals sex-based differences: Clinical implications. Allergy. 2025 Jan;80(1):335-338. doi: 10.1111/all.16365. Epub 2024 Oct 19. No abstract available.

Study record dates

Study Major Dates

• Study Start (Actual): April 21, 2022
• Primary Completion (Actual): October 24, 2022
• Study Completion (Actual): October 24, 2022

Study Registration Dates

• First Submitted: April 4, 2022
• First Submitted That Met QC Criteria: April 4, 2022
• First Posted (Actual): April 12, 2022

Study Record Updates

• Last Update Posted (Estimated): September 12, 2025
• Last Update Submitted That Met QC Criteria: September 5, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Mastocytosis; Serum basal tryptase levels; Pediatric control population; Basal tryptasemia according to age; Basal tryptasemia according to sex; Mast cell activation syndromes (MCAS)
• Additional Relevant MeSH Terms: Mast Cell Activation Disorders; Neoplasms; Immune System Diseases; Neoplasms by Histologic Type; Neoplasms, Connective and Soft Tissue; Neoplasms, Connective Tissue; Mast Cell Activation Syndrome; Mastocytosis
• Other Study ID Numbers: APHP220353

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No