title: Acquired Immunoglobulin G deficiency in stroke patients and experimental brain ischemia.
abstract: OBJECTIVE
  Acute brain injuries induce a systemic immune depression syndrome (SIDS) that predisposes patients to bacterial infections. While cellular compartments of this syndrome have been well characterized, the contribution of humoral immune mechanisms and particularly immunoglobulins to SIDS has not been investigated so far.
  
  
  METHODS
  We determined serum immunoglobulin levels and infectious complications at several time points in 159 ischemic and hemorrhagic stroke patients. Additionally, findings were verified in a transient middle cerebral artery occlusion model. A novel immunoassay was established to analyze the IgG excretion ratio in mice.
  
  
  RESULTS
  We identified a transient IgG reduction in patients suffering from substantial ischemic or hemorrhagic brain injuries. The IgG-reduction was associated with subsequent bacterial infections. Similarly, transient hypogammaglobulinemia was detected in a murine stroke model. We then used this animal model to further distinguish the mechanism of the IgG reduction by an IgG transfer paradigm. Excretional loss rather than deficient production of IgG was demonstrated to underlay hypogammaglobulinemia.
  
  
  CONCLUSIONS
  This is the first report of transient hypogammaglobulinemia after ischemic and hemorrhagic stroke suggesting involvement in infectious complications. These findings pave the road for further studies investigating post-stroke hypogammaglobulinemia as a druggable target for stroke-induced complications.
authors.affiliation: Institute for Stroke and Dementia Research, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Germany; Department of Neurology, University Heidelberg, Germany. Electronic address: Arthur.Liesz@med.uni-muenchen.de.
authors.forename: Arthur
authors.initials: A
authors.lastname: Liesz
authors.affiliation: Institute for Stroke and Dementia Research, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Roth
authors.affiliation: Department of Internal Medicine, University Heidelberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Zorn
authors.affiliation: Department of Neurology, University Heidelberg, Germany.
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.affiliation: Institute for Stroke and Dementia Research, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hofmann
authors.affiliation: Department of Neurology, University Heidelberg, Germany; Division of Brain Sciences, Imperial College London, UK.
authors.forename: Roland
authors.initials: R
authors.lastname: Veltkamp
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000818:Animals; D019921:Biotinylation; D001930:Brain Injuries / Q000097:blood / Q000209:etiology; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D017099:IgG Deficiency / Q000209:etiology*; D007074:Immunoglobulin G / Q000097:blood*; D002546:Ischemic Attack, Transient / Q000097:blood / Q000150:complications; D008163:Luminescent Measurements; D008297:Male; D051379:Mice; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D020521:Stroke / Q000097:blood* / Q000150:complications* / Q000473:pathology; D013997:Time Factors
chemical_list: D007074:Immunoglobulin G
keywords: IgG deficiency; Immunosuppression; Post-stroke infection; Stroke; Translational research