Application of Flow Cytometry in Primary Immunodeficiencies: Experience From India

Abstract

Primary immunodeficiency diseases (PID) are a clinically and immunologically heterogeneous group of disorders of immune system. Diagnosis of these disorders is often challenging and requires identification of underlying genetic defects, complemented by a comprehensive evaluation of immune system. Flow cytometry, with its advances in the last few decades, has emerged as an indispensable tool for enumeration as well as characterization of immune cells. Flow cytometric evaluation of the immune system not only provides clues to underlying genetic defects in certain PIDs and helps in functional validation of novel genetic defects, but is also useful in monitoring immune responses following specific therapies. India has witnessed significant progress in the field of flow cytometry as well as PID over last one decade. Currently, there are seven Federation of Primary Immunodeficiency Diseases (FPID) recognized centers across India, including two Indian Council of Medical research (ICMR) funded centers of excellence for diagnosis, and management of PIDs. These centers offer comprehensive care for PIDs including flow cytometry based evaluation. The key question which always remains is how one selects from the wide array of flow cytometry based tests available, and whether all these tests should be performed before or after the identification of genetic defects. This becomes crucial, especially when resources are limited and patients have to pay for the investigations. In this review, we will share some of our experiences based on evaluation of a large cohort of hemophagocytic lymphohistiocytosis, severe combined immunodeficiency, and chronic granulomatous disease, and the lessons learned for optimum use of this powerful technology for diagnosis of these disorders.

Clinical, Immunological, and Molecular Features of Severe Combined Immune Deficiency: A Multi-Institutional Experience From India

“…PGIMER, Chandigarh, North India, and NIIH, Mumbai, West India) have the wherewithal to perform functional studies. Both the centers have performed flow cytometry tests for samples received from other centers, however, timely transportation of viable blood samples from far off places, especially during hot summers remains a significant problem ( 11 , 12 ). Lack of state-of-the-art facilities to do functional assays in all patients with SCID is one of the limitations of our study.…”

“…Analysis of lymphocyte subsets by flow cytometry had been carried out in most patients. Methodology for laboratory assay of lymphocyte subsets, naïve, memory T cells, HLA-DR expression, CD132 expression, CD127 expression, and lymphocyte proliferation assays at Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh and National Institute of Immunohematology (NIIH), Mumbai have been previously described ( 11 , 12 ). Other centers performed conventional lymphocyte subsets (CD3, CD19, CD4, CD8, CD56) by flow cytometry in private laboratories.…”

Multicenter Outcome of Hematopoietic Stem Cell Transplantation for Primary Immune Deficiency Disorders in India

“…However, a significant number remain undiagnosed and would contribute to the infant and childhood mortality data. The Indian Society for Primary Immune Deficiency (ISPID) was established by a team of physicians involved in children’s care in this field in March 2011 ( 3 ). Each year, awareness programs have been arranged systematically across the country through ISPID and International collaborators like Foundation for Primary Immunodeficiency Diseases (FPID) to train pediatricians to recognize PID’s ten warning signs ( 4 ).…”

Primary Immunodeficiency Disorders: Where Do We Stand?

“…Although the former is foolproof, it is expensive, not easily available and associated with longer turnaround time. Flow cytometry acts as a bridge between basic laboratory tests and genetic diagnosis [5]. It helps in the diagnosis of several PIDs by evaluation of specific cell populations or subpopulations as in X-linked agammaglobulinemia (XLA) and severe combined immunodeficiency (SCID), various cellular proteins as in LAD, biologic effects associated with immune defects as in Common Variable Immune Deficiency (CVID) and functional immune defects as in CGD.…”

“…Similarly, leucopenia and lymphopenia in an infant with severe sepsis does not always mean SCID. Percentage of naïve T cells may be useful in such a situation [5].…”