Human IgE(+) B cells are derived from T cell-dependent and T cell-independent pathways.
BACKGROUND
The prevalence of IgE-mediated diseases has been increasing worldwide, yet IgE-expressing B cells are poorly characterized, mainly because of their scarcity and low membrane IgE levels.


OBJECTIVE
We sought to study the immunobiology of human IgE-expressing B cells in healthy subjects and patients with allergic disease.


METHODS
We used a stepwise approach for flow cytometric detection and purification of human IgE-expressing B cells in control subjects, CD40 ligand-deficient patients, and patients with atopic dermatitis. Molecular analysis of replication histories, somatic hypermutation (SHM), and immunoglobulin class-switching was performed.


RESULTS
Using multicolor flow cytometry, we reliably detected IgE-expressing plasma cells and 2 IgE-expressing memory B-cell subsets. These IgE-expressing cells showed molecular and phenotypic signs of antigen responses. The replication history and SHM levels of IgE(+) plasma cells and CD27(+)IgE(+) memory B cells fitted with a germinal center (GC)-dependent pathway, often through an IgG intermediate, as evidenced from Sγ remnants in Sμ-Sε switch regions. CD27(-)IgE(+) cells showed limited proliferation and SHM and were present in CD40 ligand-deficient patients, indicating a GC-independent origin. Patients with atopic dermatitis had normal numbers of blood IgE(+) plasma cells and CD27(+)IgE(+) memory B cells but increased numbers of CD27(-)IgE(+) memory B cells with high SHM loads compared with those seen in healthy control subjects and patients with psoriasis.


CONCLUSIONS
We delineated GC-dependent and GC-independent IgE(+) B-cell responses in healthy subjects and indicated involvement of the GC-independent pathway in a human IgE-mediated disease. These findings provide new insights into the pathogenesis of IgE-mediated diseases and might contribute to accurate monitoring of IgE(+) B cells in patients with severe disease undergoing anti-IgE treatment.
Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
Magdalena A
MA
Berkowska
Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Pediatrics, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
Jorn J
JJ
Heeringa
Department of Dermatology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
Enes
E
Hajdarbegovic
Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
Mirjam
M
van der Burg
Department of Dermatology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
H Bing
HB
Thio
Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
P Martin
PM
van Hagen
Bioceros B.V., Utrecht, The Netherlands.
Louis
L
Boon
Centro de Investigación del Cáncer (IBMCC-CSIC/USAL Nucleus; IBSAL) and Service of Cytometry, Department of Medicine, University of Salamanca, Salamanca, Spain.
Alberto
A
Orfao
Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
Jacques J M
JJ
van Dongen
Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands. Electronic address: m.vanzelm@erasmusmc.nl.
Menno C
MC
van Zelm
D001402:B-Lymphocytes / Q000276:immunology*; D023201:CD40 Ligand / Q000235:genetics / Q000378:metabolism*; D002450:Cell Communication; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D018858:Germinal Center / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D017578:Immunoglobulin Class Switching; D007073:Immunoglobulin E / Q000378:metabolism*; D007156:Immunologic Memory; D027041:Somatic Hypermutation, Immunoglobulin; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000378:metabolism
D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D023201:CD40 Ligand; D007073:Immunoglobulin E
B cell; CD40 ligand; IgE; atopic dermatitis; plasma cell