McKeon, Andrew

AbstractBackgroundChronic gastrointestinal dysmotility greatly impacts the quality of life. Treatment options are limited and generally symptomatic. Neural autoimmunity is an under‐recognized etiology. We evaluated immunotherapy as an aid to diagnosing autoimmune gastrointestinal dysmotility (AGID).MethodsTwenty‐three subjects evaluated at the Mayo Clinic for suspected AGID (August 2006–February 2014) fulfilled the following criteria: (1) prominent symptoms of gastrointestinal dysmotility with abnormalities on scintigraphy–manometry; (2) serological evidence or personal/family history of autoimmune disease; (3) treated by immunotherapy on a trial basis, 6–12 weeks (intravenous immune globulin, 16; or methylprednisolone, 5; or both, 2). Response was defined subjectively (symptomatic improvement) and objectively (gastrointestinal scintigraphy/manometry studies).Key ResultsSymptoms at presentation: constipation, 18/23; nausea or vomiting, 18/23; weight loss, 17/23; bloating, 13/23; and early satiety, 4/23. Thirteen patients had personal/family history of autoimmunity. Sixteen had neural autoantibodies and 19 had extra‐intestinal autonomic testing abnormalities. Cancer was detected in three patients. Preimmunotherapy scintigraphy revealed slowed transit (19/21 evaluated; gastric, 11; small bowel, 12; colonic, 11); manometry studies were abnormal in 7/8. Postimmunotherapy, 17 (74%) had improvement (both symptomatic and scintigraphic, five; symptomatic alone, eight; scintigraphic alone, four). Nine responders re‐evaluated had scintigraphic evidence of improvement. The majority of responders who were re‐evaluated had improvement in autonomic testing (six of seven) or manometry (two of two).Conclusions & InferencesThis proof of principle study illustrates the importance of considering an autoimmune basis for idiopathic gastrointestinal dysmotility and supports the utility of a diagnostic trial of immunotherapy.

Abstract Purpose: Clustering of neural autoantibodies in patients with paraneoplastic neurologic disorders may predict tumor type. A mathematical analysis of neural autoantibody clusters was performed in 78,889 patients undergoing evaluation for a suspected paraneoplastic autoimmune neurologic disorder. Tumor predictive autoantibody profiles were confirmed in sera from patients with histologically proven tonsillar cancer, thymoma, and lung cancer. Patients and Methods: Of note, 78,889 patient sera were tested for 15 defined neural autoantibodies (1.2 million tests). The observed and hypothesized frequencies of autoantibody clusters were compared and their tumor associations defined. A tumor validation study comprised serum from 368 patients with a variety of tumors (thymoma, lung, or tonsil). Results: Informative oncological associations included (i) thymoma in 85% of patients with muscle striational, acetylcholine receptor antibodies plus CRMP5 autoantibodies; (ii) lung carcinoma in 80% with both P/Q-type and N-type calcium channel antibodies plus SOX1-IgG; and (iii) in men, prostate carcinoma frequency more than doubled when striational and muscle AChR specificities were accompanied by ganglionic AChR antibody. In women, amphiphysin-IgG alone was associated commonly with breast carcinoma, but amphiphysin-IgG, coexisting with antineuronal nuclear autoantibody-type 1 or CRMP5-IgG, was associated with lung cancer (P < 0.0001). In the validation cohorts, many tumor-associated profiles were encountered that matched the clusters identified in the screening study (e.g., 15% of thymoma patients had striational, acetylcholine receptor antibodies plus collapsin response-mediator protein-5 autoantibodies). Conclusions: Neural autoantibodies commonly coexist in specific clusters that are identifiable by comprehensive screening. Signature autoantibody clusters may predict a patient's cancer risk and type. Clin Cancer Res; 20(14); 3862–9. ©2014 AACR.