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Background: Antibodies targeting the N-methyl-D-aspartate receptor (NMDAR) have been detected in patients with psychosis. However, studies measuring the IgG subclass in serum have provided variable estimates of prevalence, and it is unclear whether these antibodies are more common in patients than controls. Because these inconsistencies could be due to methodological approaches and patient characteristics, we aimed to investigate the effect of these factors on heterogeneity., Methods: We searched Web of Science and Ovid (MEDLINE and PsycINFO) for cross-sectional and case-control studies published between Jan 1, 2000, and May 5, 2019, that reported NMDAR IgG antibody seropositivity in patients with psychosis. Pooled proportions and odds ratios (ORs) were derived using random-effects models. We estimated between-study variance (τ 2 ) and the proportion of observed variance due to heterogeneity (I 2 ). We then used univariable random-effects meta-regression analysis to investigate the effect of study factors on heterogeneity of proportions and ORs. Our protocol was registered on PROSPERO (CRD42018099874)., Findings: Of 1276 articles in the initial search, 28 studies were eligible for inclusion, including 14 cross-sectional studies and 14 case-control studies. In cross-sectional studies, NMDAR IgG antibodies were detected in 0·73% (95% CI 0·09-1·38; I 2 56%; p=0·026) of patients with psychosis, and in case-control studies, patients with psychosis were not significantly more likely to be seropositive than healthy individuals (OR 1·57, 95% CI 0·78-3·16; I 2 15%; p=0·20). Meta-regression analyses indicated that heterogeneity was significantly associated with assay type across both study designs, illness stage in cross-sectional studies, and study quality in case-control studies. Compared with studies using a fixed cell-based assay, cross-sectional and case-control studies using the live method yielded higher pooled prevalence estimates (0·36% [95% CI -0·23 to 0·95] vs 2·97% [0·70 to 5·25]) and higher ORs (0·65 [0·33 to 1·29] vs 4·43 [1·73 to 11·36]). In cross-sectional studies, the prevalence was higher in exclusively first-episode samples than in multi-episode or mixed samples (2·18% [0·25 to 4·12] vs 0·16% [-0·31 to 0·63]), and in case-control studies, higher ORs were reported in low-quality studies than in high-quality studies (3·80 [1·47 to 9·83] vs 0·72 [0·36 to 1·42])., Interpretation: Higher estimates of NMDAR IgG antibody prevalence have been obtained with the live cell-based assay, and studies using this method find that seropositivity is more common in patients with psychosis than in controls. The effects of illness stage and study quality on heterogeneity were not consistent across study designs, and we provide clear recommendations for clinicians and researchers regarding interpreting these findings., Funding: None., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Infantile myofibromatosis, the most common fibrous tumor of infancy, is classified in 2 forms; as a solitary nodule or as numerous, widely-distributed multicentric lesions with or without visceral involvement. Although benign, multicentric myofibromas are still associated with a high incidence of morbidity and mortality due to the infiltration of critical structures. Herein, we present a case of an infant with aggressive PDGFRB and NOTCH3 mutation-negative myofibromas distributed throughout the vascular, respiratory, and gastrointestinal systems. The extensive disease resulted in pulmonary hypertension, respiratory failure and gastrointestinal obstruction refractory to chemotherapy and unamenable to surgical resection. Despite the presence of numerous highly invasive myofibromas, multiple imaging modalities largely underestimated, or even missed, tumors found at autopsy. This case demonstrates the limitations of radiographic imaging to assess disease burden in multicentric infantile myofibromatosis. The postmortem findings of extensive disease far exceeding what was demonstrated by multiple imaging modalities suggests that pediatricians should have a high index of suspicion for undetected tumors if clinical deterioration is otherwise unexplained., (© 2020 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)

Background: Psychosis is a common presenting feature in antibody-mediated encephalitis, for which prompt recognition and treatment usually leads to remission. We aimed to investigate whether people with circumscribed schizophrenia-like illnesses have such antibodies-especially antibodies against the N-methyl-D-aspartate receptor (NMDAR)-more commonly than do healthy controls., Methods: We recruited patients aged 14-35 years presenting to any of 35 mental health services sites across England with first-episode psychosis, less than 6 weeks of treatment with antipsychotic medication, and a score of 4 or more on at least one selected Positive and Negative Syndrome Scale (PANSS) item. Patients and controls provided venous blood samples. We completed standardised symptom rating scales (PANSS, ACE-III, GAF) at baseline, and tested serum samples for antibodies against NMDAR, LGI1, CASPR2, the GABA A receptor, and the AMPA receptor using live cell-based assays. Treating clinicians assessed outcomes of ICD diagnosis and functioning (GAF) at 6 months. We included healthy controls from the general population, recruited as part of another study in Cambridge, UK., Findings: Between Feb 1, 2013, and Aug 31, 2014, we enrolled 228 patients with first-episode psychosis and 105 healthy controls. 20 (9%) of 228 patients had serum antibodies against one or more of the neuronal cell surface antibodies compared with four (4%) of 105 controls (unadjusted odds ratio 2·4, 95% CI 0·8-7·3). These associations remained non-significant when adjusted for current cigarette smoking, alcohol consumption, and illicit drug use. Seven (3%) patients had NMDAR antibodies compared with no controls (p=0·0204). The other antibodies did not differ between groups. Antibody-positive patients had lower PANSS positive, PANSS total, and catatonia scores than did antibody-negative patients. Patients had comparable scores on other PANSS items, ACE-III, and GAF at baseline, with no difference in outcomes at 6 months., Interpretation: Some patients with first-episode psychosis had antibodies against NMDAR that might be relevant to their illness, but did not differ from patients without NMDAR antibodies in clinical characteristics. Our study suggests that the only way to detect patients with these potentially pathogenic antibodies is to screen all patients with first-episode psychosis at first presentation., Funding: Medical Research Council., (Copyright © 2017 Elsevier Ltd. All rights reserved.)