Heterogeneous immune cell composition in patients with combined immunodeficiency

Area of Science:

• Immunology
• Genetics
• Cell Biology

Background:

• Combined immunodeficiencies (CIDs) are severe inborn errors of immunity with T cell defects.
• CID immunological heterogeneity is not fully understood.
• Understanding CID immune cell landscapes is crucial for diagnosis and treatment.

Purpose of the Study:

• To characterize the immune cell landscape in CID patients with mutations in different genes.
• To identify specific immunophenotypic patterns associated with distinct genetic defects.
• To explore the immunological heterogeneity within CIDs.

Main Methods:

• Mass cytometry analysis of peripheral blood immune cells from four CID patients (ARPC1B, EZR, BCL10, IRF4 mutations) and healthy controls.
• Unbiased computational approaches for profiling immune populations and subsets.
• Comparative analysis of immune cell frequencies and phenotypes.

Main Results:

• All patients showed altered immune cell frequencies compared to controls.
• EZR and ARPC1B deficiency led to reduced T cell frequencies.
• BCL10 deficiency resulted in near absence of NK cells.
• T cell subset analysis revealed impaired activation/memory formation (BCL10, IRF4) or thymic output defects (ARPC1B).
• Consistent B cell abnormalities included increased naïve and decreased memory B cells, and diminished plasmablasts.

Conclusions:

• CID patients exhibit significant immunological heterogeneity based on specific genetic defects.
• Disease-causing gene mutations dictate distinct immune cell alterations, revealing CID complexity.
• Comprehensive immunophenotyping provides insights into CID pathophysiology and aids in developing tailored therapies.