Primary immunodeficiencies

Carried by: MaRIH (CEREDIH reference center)

References:

Clinician(s): Isabelle PELLIER, Despina MOSHOUS, Vincent BARLOGIS, Coralie MALLEBRANCHE, Paul BASTARD

Biologist(s): Capucine PICARD, Charline MIOT, Jérémie ROSAIN, Maud TUSSEAU, Mathieu FUSARO

Presentation

Primary immune deficiencies (PID) are rare diseases that are clinically, biologically and genetically heterogeneous (more than 550 genes identified in 2026) with a genetic diagnosis rate of approximately 50% (CEREDIH registry):

> 80% in young children with PID,
< 13% in patients with common variable immunodeficiency (CVID) diagnosed after adolescence.

Whole-genome sequencing of patients with PID without a genetic diagnosis will enhance the potential identification of their genetic defect, improving knowledge on the pathophysiology of their disease, allow for the development of targeted treatment(s) and facilitate family genetic counselling.

Criteria before considering a discussion in MDM-FMG

Extended family tree, type of transmission considered, age of first clinical signs
Clinical: infection, autoimmunity, autoinflammation, allergy, haemophagocytosis, lymphoproliferation, granuloma, liver disease, cancer (lymphoma) and dysmorphia or other syndrome features
Lab tests: complete blood count, immunoglobulin levels (IgG, A, M), post-vaccination and post-infection serology
Lymphocyte phenotyping: Naïve/memory T, Naïve/memory B and NK),
EBV status

If available: evaluation of LT Vα7.2 by FACS
Genetics already performed (Sanger, panel)