Flow cytometric immunophenotyping in the diagnosis and follow-up of immunodeficient children

Abstract

From time to time, paediatricians are confronted with children who might suer from a primary immunode®ciency disease. For practical purposes, these children can be divided into four main clinical categories: (1) a relatively large group of children with recurrent ear-nose and throat and lower respiratory tract infections, in some cases caused by de®ciencies of antibodies or complement; (2) children with failure to thrive, intractable diarrhoea or an opportunistic infection which can be caused by a T-lymphocyte or combined immunode®ciency; (3) children with infections with pyogenic bacteria or fungi as seen in case of granulocyte/ monocyte function de®ciency; and (4) a small heterogeneous group of children with recurrence of particular infections. Also, acquired immunode®ciency becomes a more common problem in paediatric practice. Flow cytometric immunophenotyping of leucocytes appears to be an ecient and rapid tool in the diagnosis and followup of immunode®cient patients, supporting early recognition, before serious infections have compromised the child's general condition. This technique can now be performed in many hospitals. In this review, we give directions for the use of¯ow cytometric immunophenotyping of leucocytes in the diagnosis and follow-up of immunode®cient children according to the four main clinical categories. Keywords Flow cytometry á Immunode®ciency á ImmunophenotypingAbbreviations AID activation-induced cytidine deaminase á BTK Bruton tyrosine kinase á CD40L CD40 ligand á ENT ear-nose and throat á FSC forward scatter á HIV human immunode®ciency virus á IFN interferon á IL interleukin á LWB lysed whole blood á McAb monoclonal antibody á SCID severe combined immunode®ciency á SSC side scatter á TCR T-cell receptor á ICF immunode®ciency-centromeric instability-facial dysmorphism

Mutations in genes required for T-cell development:IL7R, CD45, IL2RG, JAK3, RAG1, RAG2, ARTEMIS, and ADA and severe combined immunodeficiency: HuGE review

“…Lymphocyte profiles are determined by subset analysis using flow cytometry. 46 Patients with B ϩ forms of SCID often have normal or elevated levels of nonfunctional B cells. These lymphocyte profiles may be altered by the presence of maternal lymphocytes that cross the placenta during gestation.…”

“…Subset analysis by flow cytometry is therefore necessary to enumerate T, B, and NK cells. 46 Diagnostic tests analyze T-cell function by using in vitro responses of peripheral blood lymphocytes to phytomitogens and common antigens. B-cell function is measured by looking at serum immunoglobulins and specific antibodies.…”

“…47 Subset analysis by flow cytometry would be necessary to enumerate T, B, and NK cells. 46 This test could not be done on DBS.…”

Development of a standardized flow cytometric method to conduct longitudinal analyses of intracellular CD3ζ expression in patients with head and neck cancer

“…Advances in flow cytometer designs and novel fluorochromes for the chemical conjugation of antibodies have facilitated robust, multi-parametric analysis at a single cell level. The technology has been widely used in basic research (8), clinical analysis of patient immune responses (9), hematological malignancies and minimal residue disease (10)(11)(12), and enumeration of lymphocyte populations in immunodeficient diseases and cancer (13,14).…”

Characterization of B-Lymphocytes

“…On this basis, fluorochrome-conjugated antibodies and flow cytometry represent an excellent tool to identify defects and malignancies of the Bcell system [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”