An observational study in Kawasaki Disease and Macrophage Activation Syndrome (MAS), sponsored by Meyer Children's Hospital IRCCS. Not yet recruiting at 1 site in Italy. Open to participants aged 4 Weeks to 17 Years. Per ClinicalTrials.gov, last updated 2026-03-25.
Sponsored by Meyer Children's Hospital IRCCS · Observational
Kawasaki Disease (KD) is one of the most common vasculitides in childhood and represents a leading cause of acquired heart disease in developed countries. Macrophage Activation Syndrome (MAS) is a potentially life threatening hyperinflammatory condition belonging to the spectrum of hemophagocytic lymphohistiocytosis (HLH), and it can complicate various rheumatologic diseases. Awareness of MAS in the context of KD has recently increased, supporting the hypothesis that it is an underdiagnosed complication. The study aims to define the epidemiology, clinical characteristics, management, and therapeutic strategies of MAS in patients with KD, through a multicenter data collection in Europe.
KD most frequently affects young children under the age of 5. Its epidemiology varies by geographical location and season. The course of KD can be complicated by the development of MAS.
Clinical similarities between KD-especially refractory KD-and MAS, combined with the lack of specific diagnostic criteria, may hinder accurate and timely identification of MAS in KD, complicating treatment decisions and worsening clinical outcomes. Given that MAS is associated with a significant risk of multi-organ failure (MOF), patient prognosis may be severely compromised, with increased morbidity and mortality. Therefore, early recognition of MAS is crucial in order to implement targeted therapeutic strategies as promptly as possible.
In this retrospective-prospective, observational, descriptive, international multicenter study, we aim to:
The study will include international pediatric rheumatology centers affiliated with the PReS network.
62 studies on the registry are indexed under Mucocutaneous Lymph Node Syndrome; 17 are open to participants now.
This study's planned enrollment of 150 is below the median of 284 across 24 observational studies indexed under Mucocutaneous Lymph Node Syndrome.
Browse Mucocutaneous Lymph Node Syndrome studies →Meyer Children's Hospital IRCCS is the lead sponsor of 78 studies on the registry; 55 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Since no validated or universally accepted diagnostic criteria currently exist for MAS occurring in the context of KD, the diagnosis of MAS will be based on the clinical judgment of the treating physician.
To minimize the risk of misdiagnosis, all cases will be independently and critically reviewed by three experienced pediatric rheumatologists.
Control groups will consist of age- and sex-matched patients, divided as follows:
The goal is to include at least 30 MAS-KD patients, along with 60 KD-resistant controls and 60 KD-responsive controls.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients with diagnosis of KD made according to the 2024 AHA guidelines.
Patients with KD resistant to first-line therapy
Patients with KD responsive to first-line therapy.
MAS-KD population
Definition of the proportion of patients with KD who develop MAS in the study population.
Time frame: From the study initiation date onward for 36 months
Clinical and laboratory features of MAS KD patients
Adjusted Odds ratios of clinical and laboratory risk factors
Time frame: From the study initiation date onward for 36 months
Applicability and diagnostic performance of currently available MAS classification criteria
Evaluation of diagnostic performance metrics (sensitivity, specificity, positive predictive value, negative predictive value) of existing MAS criteria when applied to KD patients.
Time frame: From the study initiation date onward for 36 months
Heterogeneity of MAS KD population
Differences in clinical course based on e.g., intensive care unit admission (present/absent, days), duration of fever (days), coronary involvement (present/absent,) among three groups of Patients: patients with KD complicated by MAS; patients with KD resistant to first-line therapy; patients with KD responsive to first-line therapy.
Time frame: From the study initiation date onward for 36 months
Applicability and diagnostic performance of currently available MAS classification criteria
Evaluation of diagnostic performance metrics (sensitivity, specificity, positive predictive value, negative predictive value) of existing MAS criteria when applied to KD patients.
Time frame: From the study initiation date onward for 36 months
MAS diagnosis
Time from KD onset to MAS diagnosis and its correlation with clinical outcomes;
Time frame: From the study initiation date onward for 36 months
Treatment and clinical response of MAS KD patients
Description of treatments used for MAS (e.g., corticosteroids, IVIG, biologics) and the corresponding clinical response.
Time frame: From the study initiation date onward for 36 months
Heterogeneity of MAS KD population
Differences in treatment strategies based on e.g., intensive care unit admission (present/absent, days), duration of fever (days), coronary involvement (present/absent,) among three groups of Patients: patients with KD complicated by MAS; patients with KD resistant to first-line therapy; patients with KD responsive to first-line therapy.
Time frame: From the study initiation date onward for 36 months
Heterogeneity of MAS KD population
Differences in outcomes based on e.g., intensive care unit admission (present/absent, days), duration of fever (days), coronary involvement (present/absent,) among three groups of Patients: patients with KD complicated by MAS; patients with KD resistant to first-line therapy; patients with KD responsive to first-line therapy.
Time frame: From the study initiation date onward for 36 months
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Feb 2026; primary completion for Nov 2027, 21 months later.
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This study is not yet recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Mucocutaneous Lymph Node Syndrome →
Meyer Children's Hospital IRCCS