title: Immunoglobulin E deficiency: a forgotten clue pointing to possible immunodeficiency?
abstract: BACKGROUND
  Patients with primary antibody deficiency often have delayed diagnosis. Very low IgE, found during investigations for allergy, may be a marker for other immunodeficiency.
  
  
  METHODS
  We introduced a new laboratory policy of testing cases with very low IgE levels for possible linked antibody deficiency. The data represent an audit of routine results collected over two years.
  
  
  RESULTS
  Very low IgE (≤2 IU/mL) was identified in 85/2622 (3.2%) routine patient samples. Two children and four adult patients were found to have one or more classes of immunoglobulin below the reference range for age. In 2/6, the initiative of the laboratory led to a new unsuspected diagnosis of antibody immunodeficiency.
  
  
  CONCLUSIONS
  Common variable immunodeficiency continues to be overlooked as a primary cause of lung disease in adults. Very low serum IgE should trigger appropriate investigation (immunoglobulin quantification and serum electrophoresis).
authors: Immunology and Immunogenetics, Blood Sciences Laboratory, North Bristol NHS Trust, Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB, UK. joe.unsworth@nbt.nhs.uk
authors: David J
authors: DJ
authors: Unsworth
authors: Paul F
authors: PF
authors: Virgo
authors: Robert J
authors: RJ
authors: Lock
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D017074:Common Variable Immunodeficiency / Q000097:blood / Q000175:diagnosis; D004406:Dysgammaglobulinemia / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000172:deficiency*; D007223:Infant; D008875:Middle Aged
chemical_list: D007073:Immunoglobulin E