B-cell activation with CD40L or CpG measures the function of B-cell subsets and identifies specific defects in immunodeficient patients

• Around 65% of primary immunodeficiencies are antibody deficiencies. Functional tests are useful tools to study B-cell functions in vitro. However, no accepted guidelines for performing and evaluating functional tests have been issued yet. Here, we report our experience on the study of B-cell functions in infancy and throughout childhood. We show that T-independent stimulation with CpG measures proliferation and differentiation potential of memory B cells. Switched memory B cells respond better than IgM memory B cells. On the other hand, CD40L, a T-dependent stimulus, does not induce plasma cell differentiation, but causes proliferation of naive and memory B cells. During childhood, the production of plasmablasts in response to CpG increases with age mirroring the development of memory B cells. The response to CD40L does not change with age. In patients with selective IgA deficiency (SIgAD), we observed that switched memory B cells are reduced due to the absence of IgA memory B cells. In agreement, IgA plasma cells are not generated in response to CpG. Unexpectedly, B cells from SIgAD patients show a reduced proliferative response to CD40L. Our results demonstrate that functional tests are an important tool to assess the functions of the humoral immune system.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Reumatologi och inflammation (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Rheumatology and Autoimmunity (hsv//eng)

Nyckelord

Adolescent

Adult

Age Factors

Antigens

CD40/metabolism

B-Lymphocyte Subsets/*immunology/*metabolism

Biomarkers

CD40 Ligand/*immunology

Cells

Cultured

Child

Child

Preschool

Humans

Immunoglobulin A/blood/immunology

Immunoglobulin Class Switching

Immunoglobulin M/blood/immunology

Immunologic Deficiency Syndromes/blood/*immunology/*metabolism

Immunologic Memory

Immunophenotyping

Infant

Lymphocyte Activation/*immunology

Oligodeoxyribonucleotides/*immunology

Phenotype

Protein Binding

Receptors

Antigen

B-Cell/metabolism

Young Adult

B cells

Functional tests

Immunodeficiency

Pediatric immunology

Selective IgA deficiency

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)