Lymphocyte Subgroups and KREC Numbers in Common Variable Immunodeficiency: A Single Center Study.

Area of Science:

• Immunology
• Genetics

Background:

• Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency, characterized by impaired B cell differentiation and antibody production.
• Understanding the immunological markers associated with CVID is crucial for accurate diagnosis and management.

Purpose of the Study:

• To investigate the relationship between B cell subsets, kappa-deleting recombination excision circle (KREC) copy numbers, and clinical/immunological data in CVID patients.
• To assess the diagnostic utility of KREC copy numbers in CVID, considering available classification systems.

Main Methods:

• Quantitative real-time polymerase chain reaction was used for KREC analysis.
• Flow cytometry was employed to measure B cell subgroups.
• Correlations were analyzed between B cell counts, KREC levels, and patient clinical data.

Main Results:

• CD19+ B cell counts and KREC copy numbers were significantly lower in CVID patients compared to healthy controls.
• A positive correlation was observed between CD19+ cell counts and KREC copy numbers in both CVID patients and controls.
• Low KREC copy numbers suggest B cell deficiency, but elevated KREC levels do not exclude a CVID diagnosis.

Conclusions:

• KREC copy numbers serve as quantitative indicators of B cell defects in CVID.
• The heterogeneity of CVID etiology is highlighted by findings of low CD4+ cells and lymphopenia in some patients.
• While low KREC levels are indicative of B cell deficiency, their presence alone is insufficient to confirm or rule out CVID.