title: Comparison of immunoglobulin G subclass concentrations in severe community-acquired pneumonia and severe pandemic 2009 influenza A (H1N1) infection.
abstract: We compared immunoglobulin G (IgG) subclasses in patients with severe noninfluenza community-acquired pneumonia (CAP) to those in patients with severe pandemic 2009 influenza (H1N1) virus infection. Low IgG1 and IgG2 levels occurred often in the CAP group; however, H1N1 patients had lower IgG1 and IgG2 levels (5.4 versus 3.3 g/liter [P = 0.008] and 2.5 versus 1.2 g/liter [P < 0.001], respectively). Low IgG2 levels may be specifically linked to severe H1N1; however, it is not clear whether this association is related to H1N1 or to other features of severity.
authors.affiliation: Department of Infectious Diseases, Austin Health, Melbourne, Australia.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Gordon
authors.forename: Natasha E
authors.initials: NE
authors.lastname: Holmes
authors.forename: M Lindsay
authors.initials: ML
authors.lastname: Grayson
authors.forename: Joseph
authors.initials: J
authors.lastname: Torresi
authors.forename: Paul D R
authors.initials: PD
authors.lastname: Johnson
authors.forename: Allen C
authors.initials: AC
authors.lastname: Cheng
authors.forename: Patrick G P
authors.initials: PG
authors.lastname: Charles
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017714:Community-Acquired Infections / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000145:classification*; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification; D007251:Influenza, Human / Q000276:immunology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000276:immunology*; D044967:Serum / Q000276:immunology; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G