Flow Cytometry Contributions for the Diagnosis and Immunopathological Characterization of Primary Immunodeficiency Diseases With Immune Dysregulation

Abstract

Almost 70 years after establishing the concept of primary immunodeficiency disorders (PIDs), more than 320 monogenic inborn errors of immunity have been identified thanks to the remarkable contribution of high-throughput genetic screening in the last decade. Approximately 40 of these PIDs present with autoimmune or auto-inflammatory symptoms as the primary clinical manifestation instead of infections. These PIDs are now recognized as diseases of immune dysregulation. Loss-of function mutations in genes such as FOXP3, CD25, LRBA, IL-10, IL10RA, and IL10RB, as well as heterozygous gain-of-function mutations in JAK1 and STAT3 have been reported as causative of these disorders. Identifying these syndromes has considerably contributed to expanding our knowledge on the mechanisms of immune regulation and tolerance. Although whole exome and whole genome sequencing have been extremely useful in identifying novel causative genes underlying new phenotypes, these approaches are time-consuming and expensive. Patients with monogenic syndromes associated with autoimmunity require faster diagnostic tools to delineate therapeutic strategies and avoid organ damage. Since these PIDs present with severe life-threatening phenotypes, the need for a precise diagnosis in order to initiate appropriate patient management is necessary. More traditional approaches such as flow cytometry are therefore a valid option. Here, we review the application of flow cytometry and discuss the relevance of this powerful technique in diagnosing patients with PIDs presenting with immune dysregulation. In addition, flow cytometry represents a fast, robust, and sensitive approach that efficiently uncovers new immunopathological mechanisms underlying monogenic PIDs.

Immunity and Genetics at the Revolving Doors of Diagnostics in Primary Immunodeficiencies

“…Thus, clinical, immunological, and genomic investigations remain reciprocally necessary for a reliable diagnostic process. Flow cytometry investigations to assess PIDs with immune-dysregulation have been recently reviewed by Cabral-Marques et al [ 98 ].…”

Case Report: Extensive Phosphorylation of Interleukin-1 Receptor-Associated Kinase 4 in a Patient With Schnitzler Syndrome

“…However, trials to establish IRAK-4 inhibitors as a new therapy in rheumatoid arthritis are underway ( 23 ), which underlines the possible value of this target. Analysis of phosphorylated signaling proteins by flow cytometry has been reported in various conditions, like cancer and HIV infection ( 24 ), in multiple sclerosis ( 25 ) and for the immunopathological characterization of primary immunodeficiency diseases ( 26 , 27 ). Further studies are needed to test the reliability of pIRAK-4 measurements in different diseases and larger patient cohorts.…”

How to evaluate for immunodeficiency in patients with autoimmune cytopenias: laboratory evaluation for the diagnosis of inborn errors of immunity associated with immune dysregulation

“…36 §Gifford et al 63 ||Ammann et al 64 Lab diagnosis of monogenic autoimmune cytopenias | 665 36 §Gifford et al 63 ||Ammann et al 64 Flow cytometry is a tremendously valuable tool in the diagnosis of IEIs and can be used for immunophenotyping, protein expression, and functional assessment. 13 Lymphocyte subset quantitation of T, B, and natural killer (NK) cells in blood is useful in "global binning" of patients, based on whether they have numerical deficits in one or more lymphocyte subsets. However, additional immunophenotyping, particularly of the T-cell (CD4 + and CD8 + ) and B-cell compartments is also often necessary because there can be quantitative and functional dysregulation in differentiation of the adaptive immune system, which may not be apparent by a global lymphocyte subset analysis.…”