Immunophenotyping in Adult Patients with Common Variable Immunodeficiency

Introduction Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by low antibody levels. Immunophenotyping is crucial for classifying CVID patients and predicting severe complications by analyzing lymphocyte subsets. Methods Retrospective cohort of patients who fulfilled the 2019 European Society for Immunodeficiencies criteria for CVID and had performed a flow cytometry immunophenotype treated at a referral center in Buenos Aires. Results We analyzed 19 patients, of whom 10 were male and 9 female with a mean age of 51 years (20-66 years). The median follow-up was 12 years (6-35 years). Key findings included profoundly low CD19+ B cells (84.2%), decreased natural killer cells (68.4%), and inverted CD4/CD8 ratio (73.7%). T cell subpopulations showed a decrease in naive CD4+ T cells in 15 patients (78.9%); T helper (Th) profiles demonstrated skewing toward a Th1 profile in 12/13 patients (92.3%), accompanied by a decrease in Th2 and Th17 populations. Naive CD8+ T lymphocytes were decreased in 15/18 patients (83.3%) and increased in 3/18 (16.7%); effector memory cells were decreased in 2 (11.1%) and increased in 3 (16.7%). Terminal effector cells were decreased in 9 patients (50%) and increased in 9 patients (50%). Immune dysregulation (autoimmune cytopenias, granulomatous-lymphocytic interstitial lung disease, enteropathy) affected 52.6% of patients, 9/10 showed increased transitional B cells, 8/10 increased CD21low B cells, 8/10 a skewing to a Th1 profile, and 7/10 had an inverted CD4/CD8 ratio. 6/10 had decreased regulatory T cells (Tregs). Lymphoproliferation was present in 57.9%. Notably, 15.8% of the total cohort developed non-Hodgkin's lymphoma. 10/10 showed increased transitional B cells, 8/10 increased CD21low B cells, 9/9 presented a skewing to a Th1 profile, and 9/10 had an inverted CD4/CD8 ratio. Conclusion Immunophenotyping including T cell subsets may be useful to characterize CVID patients at risk of complex noninfectious complications.