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Two-colour flow cytometry study of lymphocyte subpopulations in patients with primary immunodeficiencies
A V Filatov1, V V Shcherbukhin, P S Bachurin
1Institute of Immunology, Ministry of Health of the USSR, Moscow.
Insights
Abnormal CD5 and CD7 antigen distribution was found in children with primary immunodeficiency syndromes, particularly antibody deficiencies. This finding was absent in healthy controls, suggesting a link to immune system disorders.
Area of Science:
- Immunology
- Flow Cytometry
- Primary Immunodeficiency
Background:
- Primary immunodeficiency syndromes (PIDs) are a group of genetic disorders affecting the immune system.
- Flow cytometry is a crucial technique for immunophenotyping immune cells.
Purpose of the Study:
- To investigate the distribution of CD5 and CD7 antigens in children with PIDs.
- To identify potential correlations between antigen distribution abnormalities and specific PID types.
Main Methods:
- Immunofluorescent flow cytometry was used to analyze peripheral blood samples.
- One hundred and eighty-five children with various PIDs and sixty-nine healthy controls were studied.
- Two-color flow immunofluorescence was employed to assess co-expression of CD4, CD5, CD7, and CD8 antigens.
Main Results:
- A bimodal distribution of CD5 and CD7 antigens was observed in 26 cases (14% of PID patients).
- This abnormality was most frequent in total antibody deficiencies, including common variable hypogammaglobulinaemia and congenital agammaglobulinaemia.
- Abnormal CD7+ excess over CD5+ cells was noted in ataxia-telangiectasia and Wiskott-Aldrich syndrome.
Conclusions:
- The bimodal CD5/CD7 antigen distribution is a potential indicator of certain primary immunodeficiency syndromes, especially antibody deficiencies.
- Specific antigen expression patterns may aid in the diagnosis and classification of PIDs.
- Further research is warranted to elucidate the functional implications of these observed antigen abnormalities.
Abstract:
Immunofluorescent flow cytometric examination of one hundred and eighty-five children with different primary immunodeficiency syndromes and sixty-nine control patients revealed twenty-six cases with a bimodal distribution of antigens CD5 and CD7. Such abnormalities were most frequently found in patients with total antibody deficiency, namely those with common variable hypogammaglobulinaemia (10/24 patients) and congenital agammaglobulinaemia with lack of B cells (10/40), but were never seen in normal controls. Two-colour flow immunofluorescence demonstrated that antigen CD4 was expressed only on intensely fluorescent CD5+ cells, irrespective of the immunodeficiency state. Antigen CD4 was detected on cells with both high and low expression of antigen CD7, but a small percentage (2%-5%) of CD4+ lymphocytes did not belong to the CD7+ population. Antigen CD8 was found equally on intensely and weakly fluorescent CD5+ and CD7+ cells. In some immunodeficient patients suffering from ataxia-telangiectasia (12/36) and in some with Wiskott-Aldrich syndrome (2/6) there was a significant excess (greater than 20%) of CD7+ over CD5+ cells. In these patients a considerable number of the CD8+ cells were not part of the CD5+ population, but were always part of the CD7+ population. Cell populations with the phenotype CD5-, CD7+ consisted mainly of lymphocytes showing weak expression of antigen CD8.