title: Common variable immunodeficiency and idiopathic primary hypogammaglobulinemia: two different conditions within the same disease spectrum.
abstract: Patients with hypogammaglobulinemia who do not fulfill all the classical diagnostic criteria for common variable immunodeficiency (reduction of two immunoglobulin isotypes and a reduced response to vaccination) constitute a diagnostic and therapeutic dilemma, because information concerning the clinical and immunological characteristics of these patients with idiopathic primary hypogammaglobulinemia is not available. In 44 common variable immunodeficiency and 21 idiopathic primary hypogammaglobulinemia patients we determined the clinical phenotypes and performed flow cytometric immunophenotyping to assess the pathophysiological B-cell patterns and memory B-cell subset counts. Age-matched B-cell subset reference values of 130 healthy donors were generated. Severe pneumonia and bronchiectasis occurred at similar frequencies in idiopathic primary hypogammaglobulinemia and common variable immunodeficiency. Although IgG levels were only moderately reduced compared to common variable immunodeficiency, 12 of 21 idiopathic primary hypogammaglobulinemia patients required immunoglobulin replacement. Non-infectious disease-related clinical phenotypes (autoimmune cytopenia, polyclonal lymphocytic proliferation and persistent unexplained enteropathy) were exclusively observed in common variable immunodeficiency and were associated with early peripheral B-cell maturation defects or B-cell survival defects. T-cell dependent memory B-cell formation was more severely affected in common variable immunodeficiency. Furthermore, 14 of 21 idiopathic primary hypogammaglobulinemia patients showed normal peripheral B-cell subset counts, suggestive for a plasma cell defect. In conclusion, idiopathic primary hypogammaglobulinemia patients who do not fulfill all diagnostic criteria of common variable immunodeficiency have moderately decreased immunoglobulin levels and often a normal peripheral B-cell subset distribution, but still suffer from serious infectious complications.
authors.affiliation: m.vanderburg@erasmusmc.nl.
authors.forename: Gertjan J
authors.initials: GJ
authors.lastname: Driessen
authors.forename: Virgil A S H
authors.initials: VA
authors.lastname: Dalm
authors.forename: P Martin
authors.initials: PM
authors.lastname: van Hagen
authors.forename: H Anne
authors.initials: HA
authors.lastname: Grashoff
authors.forename: Nico G
authors.initials: NG
authors.lastname: Hartwig
authors.forename: Annemarie M C
authors.initials: AM
authors.lastname: van Rossum
authors.forename: Adilia
authors.initials: A
authors.lastname: Warris
authors.forename: Esther
authors.initials: E
authors.lastname: de Vries
authors.forename: Barbara H
authors.initials: BH
authors.lastname: Barendregt
authors.forename: Ingrid
authors.initials: I
authors.lastname: Pico
authors.forename: Sandra
authors.initials: S
authors.lastname: Posthumus
authors.forename: Menno C
authors.initials: MC
authors.lastname: van Zelm
authors.forename: Jacques J M
authors.initials: JJ
authors.lastname: van Dongen
authors.forename: Mirjam
authors.initials: M
authors.lastname: van der Burg
mesh_terms: D000293:Adolescent; D000328:Adult; D000361:Agammaglobulinemia / Q000175:diagnosis* / Q000276:immunology*; D000368:Aged; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D017074:Common Variable Immunodeficiency / Q000175:diagnosis* / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult