title: IgG4-related disease and lymphocyte-variant hypereosinophilic syndrome: A comparative case series.
abstract: OBJECTIVE
  To compare the clinical and laboratory features of IgG4-related disease (IgG4-RD) and lymphocyte-variant hypereosinophilic syndrome (L-HES), two rare diseases that often present with lymphadenopathy, gastrointestinal symptoms, eosinophilia, and elevated immunoglobulins/IgE.
  
  
  METHODS
  Comparative case series of 31 patients with IgG4-RD and 13 patients with L-HES.
  
  
  RESULTS
  Peripheral blood eosinophilia was present in eight of 31 patients with IgG4-RD compared to 13 of 13 patients with L-HES (median eosinophils 0.4 vs 7.0 giga/L, P=.001) and 12 of 20 patients with IgG4-RD had increased serum IgE compared to eight of 13 patients with L-HES, P=.930. Twenty-seven of 30 patients with IgG4-RD had elevated serum IgG4 compared to five of 12 patients with L-HES (median IgG4 9.6 g/L vs 0.80 g/L, P=.002). Flow cytometry demonstrated an aberrant T-cell phenotype in 7 of 23 patients with IgG4-RD and 13 of 13 patients with L-HES (P<.001). T-cell clonality by PCR was positive in 12 of 23 patients with IgG4-RD vs 10 of 13 patients with L-HES (P=.143). Patients in both groups received corticosteroids as first-line therapy. For refractory disease in IgG4-RD, rituximab was the most common steroid-sparing agent, whereas in L-HES, it was pegylated interferon-α-2a.
  
  
  CONCLUSIONS
  The overlapping features of these two diseases with divergent treatment options demonstrate the importance of familiarity with both entities to optimize diagnosis and treatment.
authors.affiliation: Division of Rheumatology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Mollie N
authors.initials: MN
authors.lastname: Carruthers
authors.affiliation: Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Sujin
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.|Department of Pathology, Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Graham W
authors.initials: GW
authors.lastname: Slack
authors.affiliation: Division of Laboratory Hematology, Vancouver General Hospital, Vancouver, BC, Canada.
authors.forename: Bakul I
authors.initials: BI
authors.lastname: Dalal
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.|Department of Pathology, Centre for Lymphoid Cancer, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: Brian F
authors.initials: BF
authors.lastname: Skinnider
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: David F
authors.initials: DF
authors.lastname: Schaeffer
authors.affiliation: Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Jan P
authors.initials: JP
authors.lastname: Dutz
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD, USA.
authors.forename: Joanna K
authors.initials: JK
authors.lastname: Law
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Fergal
authors.initials: F
authors.lastname: Donnellan
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Marquez
authors.affiliation: Department of Pathology and Laboratory Medicine, Providence Healthcare, Vancouver, BC, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Seidman
authors.affiliation: Department of Pathology and Laboratory Medicine, Richmond Hospital, Richmond, BC, Canada.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Wong
authors.affiliation: Adult Metabolic Disease Clinic, Vancouver General Hospital, Vancouver, BC, Canada.
authors.forename: Andre
authors.initials: A
authors.lastname: Mattman
authors.affiliation: Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Luke Y C
authors.initials: LY
authors.lastname: Chen
mesh_terms: D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D007074:Immunoglobulin G / Q000097:blood*; D016898:Interferon-alpha / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D011994:Recombinant Proteins / Q000008:administration & dosage; D000069283:Rituximab / Q000008:administration & dosage*; D013601:T-Lymphocytes
chemical_list: D000305:Adrenal Cortex Hormones; D007074:Immunoglobulin G; D016898:Interferon-alpha; D011994:Recombinant Proteins; D011092:Polyethylene Glycols; D000069283:Rituximab; C100416:peginterferon alfa-2a
keywords: IgG4; IgG4-related disease; eosinophil; hypereosinophilic syndrome; hypergammaglobulinemia