Hammer, Christian

[["dc.bibliographiccitation.firstpage","1143"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Molecular Psychiatry"],["dc.bibliographiccitation.lastpage","1149"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Hammer, Christian"],["dc.contributor.author","Stepniak, Beata"],["dc.contributor.author","Schneider, Anja"],["dc.contributor.author","Papiol, Sergi"],["dc.contributor.author","Tantra, Martesa"],["dc.contributor.author","Begemann, Martin"],["dc.contributor.author","Sirén, Anna-Leena"],["dc.contributor.author","Pardo, Luis A."],["dc.contributor.author","Sperling, Swetlana"],["dc.contributor.author","Mohd Jofrry, Sue"],["dc.contributor.author","Gurvich, Artem"],["dc.contributor.author","Jensen, Niels"],["dc.contributor.author","Ostmeier, Katrin"],["dc.contributor.author","Lühder, F."],["dc.contributor.author","Probst, Christian"],["dc.contributor.author","Martens, Henrik"],["dc.contributor.author","Gillis, M."],["dc.contributor.author","Saher, Gesine"],["dc.contributor.author","Assogna, F."],["dc.contributor.author","Spalletta, Gianfranco"],["dc.contributor.author","Stöcker, W."],["dc.contributor.author","Schulz, Thomas F."],["dc.contributor.author","Nave, Klaus-Armin"],["dc.contributor.author","Ehrenreich, Hannelore"],["dc.date.accessioned","2017-09-07T11:46:37Z"],["dc.date.available","2017-09-07T11:46:37Z"],["dc.date.issued","2014"],["dc.description.abstract","In 2007, a multifaceted syndrome, associated with anti-NMDA receptor autoantibodies (NMDAR-AB) of immunoglobulin-G isotype, has been described, which variably consists of psychosis, epilepsy, cognitive decline and extrapyramidal symptoms. Prevalence and significance of NMDAR-AB in complex neuropsychiatric disease versus health, however, have remained unclear. We tested sera of 2817 subjects (1325 healthy, 1081 schizophrenic, 263 Parkinson and 148 affective-disorder subjects) for presence of NMDAR-AB, conducted a genome-wide genetic association study, comparing AB carriers versus non-carriers, and assessed their influenza AB status. For mechanistic insight and documentation of AB functionality, in vivo experiments involving mice with deficient blood-brain barrier (ApoE(-/-)) and in vitro endocytosis assays in primary cortical neurons were performed. In 10.5% of subjects, NMDAR-AB (NR1 subunit) of any immunoglobulin isotype were detected, with no difference in seroprevalence, titer or in vitro functionality between patients and healthy controls. Administration of extracted human serum to mice influenced basal and MK-801-induced activity in the open field only in ApoE(-/-) mice injected with NMDAR-AB-positive serum but not in respective controls. Seropositive schizophrenic patients with a history of neurotrauma or birth complications, indicating an at least temporarily compromised blood-brain barrier, had more neurological abnormalities than seronegative patients with comparable history. A common genetic variant (rs524991, P=6.15E-08) as well as past influenza A (P=0.024) or B (P=0.006) infection were identified as predisposing factors for NMDAR-AB seropositivity. The >10% overall seroprevalence of NMDAR-AB of both healthy individuals and patients is unexpectedly high. Clinical significance, however, apparently depends on association with past or present perturbations of blood-brain barrier function."],["dc.identifier.doi","10.1038/mp.2013.110"],["dc.identifier.gro","3150565"],["dc.identifier.pmid","23999527"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/7339"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Neuropsychiatric disease relevance of circulating anti-NMDA receptor autoantibodies depends on blood-brain barrier integrity"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","82"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Annals of Neurology"],["dc.bibliographiccitation.lastpage","94"],["dc.bibliographiccitation.volume","76"],["dc.contributor.author","Dahm, Liane"],["dc.contributor.author","Ott, Christoph"],["dc.contributor.author","Steiner, Johann"],["dc.contributor.author","Stepniak, Beata"],["dc.contributor.author","Teegen, Bianca"],["dc.contributor.author","Saschenbrecker, Sandra"],["dc.contributor.author","Hammer, Christian"],["dc.contributor.author","Borowski, Kathrin"],["dc.contributor.author","Begemann, Martin"],["dc.contributor.author","Lemke, Sandra"],["dc.contributor.author","Rentzsch, Kristin"],["dc.contributor.author","Probst, Christian"],["dc.contributor.author","Martens, Henrik"],["dc.contributor.author","Wienands, Jürgen"],["dc.contributor.author","Spalletta, Gianfranco"],["dc.contributor.author","Weißenborn, Karin"],["dc.contributor.author","Stöcker, Winfried"],["dc.contributor.author","Ehrenreich, Hannelore"],["dc.date.accessioned","2017-09-07T11:46:34Z"],["dc.date.available","2017-09-07T11:46:34Z"],["dc.date.issued","2014"],["dc.description.abstract","ObjectiveWe previously reported an unexpectedly high seroprevalence (∼10%) of N-methyl-D-aspartate-receptor subunit-NR1 (NMDAR1) autoantibodies (AB) in healthy and neuropsychiatrically ill subjects (N = 2,817). This finding challenges an unambiguous causal relationship of serum AB with brain disease. To test whether similar results would be obtained for other brain antigen-directed AB previously connected with pathological conditions, we systematically screened serum samples of 4,236 individuals.MethodsSerum samples of healthy (n = 1,703) versus neuropsychiatrically ill subjects (schizophrenia, affective disorders, stroke, Parkinson disease, amyotrophic lateral sclerosis, personality disorder; total n = 2,533) were tested. For analysis based on indirect immunofluorescence, we used biochip mosaics of frozen brain sections (rat, monkey) and transfected HEK293 cells expressing respective recombinant target antigens.ResultsSeroprevalence of all screened AB was comparable in healthy and ill individuals. None of them, however, reached the abundance of NMDAR1 AB (again ∼10%; immunoglobulin [Ig] G ∼1%). Appreciable frequency was noted for AB against amphiphysin (2.0%), ARHGAP26 (1.3%), CASPR2 (0.9%), MOG (0.8%), GAD65 (0.5%), Ma2 (0.5%), Yo (0.4%), and Ma1 (0.4%), with titers and Ig class distribution similar among groups. All other AB were found in ≤0.1% of individuals (anti–AMPAR-1/2, AQP4, CV2, Tr/DNER, DPPX-IF1, GABAR-B1/B2, GAD67, GLRA1b, GRM1, GRM5, Hu, LGl1, recoverin, Ri, ZIC4). The predominant Ig class depended on antigen location, with intracellular epitopes predisposing to IgG (chi-square = 218.91, p = 2.8 × 10−48).InterpretationTo conclude, the brain antigen-directed AB tested here are comparably detectable in healthy subjects and the disease groups studied here, thus questioning an upfront pathological role of these serum AB."],["dc.identifier.doi","10.1002/ana.24189"],["dc.identifier.gro","3150539"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/7312"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Seroprevalence of autoantibodies against brain antigens in health and disease"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]