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Age-related alterations of the CD19 complex and memory B cells in children with Down syndrome

Ayse Nazli Seckin1, Hulya Ozdemir1, Ayca Ceylan1

  • 1Department of Pediatric Immunology and Allergy, Selcuk University Medical Faculty, Alaeddin Keykubat Kampusu, 42131, Konya, Turkey.

Clinical and Experimental Medicine
|February 16, 2017
PubMed

Insights

Children with Down syndrome (DS) exhibit immune dysfunction, characterized by lower B cell counts and altered CD19, CD21, and CD81 expression. These B cell defects may explain their increased susceptibility to infections.

Area of Science:

  • Immunology
  • Pediatrics

Background:

  • Children with Down syndrome (DS) frequently experience recurrent respiratory infections, leukemia, and autoimmune disorders, indicating underlying immune system dysfunction.
  • The specific immunological defects contributing to this vulnerability are not fully understood, particularly concerning B cell populations.

Purpose of the Study:

  • To investigate the role of the CD19 complex and memory B cells in the immunodeficiency observed in children with Down syndrome.
  • To analyze the expression levels of key B cell surface molecules (CD19, CD21, CD81) and memory B cell subsets in children with DS.

Main Methods:

  • Flow cytometry was used to measure the expression of CD19, CD21, and CD81 on B cells and memory B cell subsets.
  • A cohort of 37 children with DS (29 with congenital heart disease) and 39 healthy controls were studied across different age groups.

Main Results:

  • Children with DS showed significantly lower B cell counts across all age groups compared to controls.
  • Reduced CD19 expression was observed in all age groups, while CD21 expression increased in those over 2 years, and CD81 expression increased in those over 6 years.
  • A reduced frequency of natural effector B cells (CD27+IgD+IgM+) was found in children with DS hospitalized for infections.

Conclusions:

  • Intrinsic defects in B cells, including altered cell counts and surface molecule expression, are present in children with Down syndrome.
  • These B cell abnormalities likely contribute to the increased susceptibility to severe respiratory tract infections in this population.

Keywords:
CD19 complexDown syndromeMemory B cells

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