Diagnostic significance of immunophenotyping of peripheral blood lymphocytes in pediatric patients from the Autonomous Province of Vojvodina, Republic of Serbia

Introduction/Objective Although lymphocyte immunophenotyping based on flow cytometry is a powerful tool in the diagnosis of many primary immunodeficiences (PID), there has been an increasing awareness of associated costs and the need for its reassessment as a screening tool. We present the results and diagnostic impact of immunophenotyping performed by flow cytometry in the University Children's Hospital, Belgrade, in a series of patients referred from the Institute for Child and Youth Health Care of Vojvodina from July 2008 to July 2018.Methods We reviewed the laboratory reports on numbers of B lymphocytes (CD19+), T lymphocytes (CD3+), natural killer cells (CD3-CD16/CD56+) and activated T cells (CD3+HLA-DR+), as well as CD4+ and CD8+ T cells in 198 children.Results Patients were grouped by stated indication into the following eight categories: hypogamma-globulinemia (34), selective IgA deficiency and/or IgG subclass deficiency (43), various infections with no immunoglobulin deficiencies (67), asthma and/or allergies with no immunoglobulin deficiencies or infections (23), known or suspected autoimmune disorders (24), and miscellaneous diagnoses not ac-companied by infections (7). In total, 159 (80.3%) findings were either completely within the respective reference range or exhibited only minimal aberrations. Four patients were diagnosed with Bruton's disease and one with Artemis immunodeficiency. Nineteen patients were given immunoglobulin substitution to control infections and/or maintain immunoglobulin G levels. Conclusion Lymphocyte immunophenotyping aids the diagnosis of PID in selected patients. We venture some thoughts on how the usefulness of this laboratory method could be improved in real-life tertiary care pediatric hospital settings.