High Seroconversion Rate Against Severe Acute Respiratory Syndrome Coronavirus 2 in Symptomatic Pediatric Inflammatory Bowel Disease Patients.

ABSTRACT: Understanding coronavirus disease 2019 (COVID-19) in pediatric inflammatory bowel disease (PIBD) is important. We describe a single-center cohort of COVID-19 PIBD patients where seroconversion against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was examined.Immunosuppressed PIBD patients at Texas Children's Hospital who tested positive for SARS-CoV-2 by nasopharyngeal reverse transcriptase polymerase chain reaction were included in the study. The clinical course of IBD, concurrent medications, COVID-19 related symptoms, SARS-CoV-2 testing date, and SARS-CoV-2 immunoglobulin G (IgG) antibody testing date and result were examined. Of 14 SARS-CoV-2 positive PIBD patients, 12 were tested for qualitative anti-SARS-CoV-2 IgG (seven with transient COVID-19 symptoms, five asymptomatic). All symptomatic (7/7) and 60% of asymptomatic (3/5) patients seroconverted. No patients required hospitalization attributed to COVID-19.High rates of COVID-19 seroconversion occurred in immunosuppressed and symptomatic PIBD patients. More research to evaluate the significance of COVID-19 seroconversion is needed.

SERPINB12 Is a Slow-Binding Inhibitor of Granzyme A and Hepsin.

The clade B/intracellular serpins protect cells from peptidase-mediated injury by forming covalent complexes with their targets. SERPINB12 is expressed in most tissues, especially at cellular interfaces with the external environment. This wide tissue distribution pattern is similar to that of granzyme A (GZMA). Because SERPINB12 inhibits trypsin-like serine peptidases, we determined whether it might also neutralize GZMA. SERPINB12 formed a covalent complex with GZMA and inhibited the enzyme with typical serpin slow-binding kinetics. SERPINB12 also inhibited Hepsin. SERPINB12 may function as an endogenous inhibitor of these peptidases.

PCR Based Fecal Pathogen Panel Testing Should Be Interpreted with Caution at Diagnosis of Pediatric Inflammatory Bowel Diseases.

Pediatric inflammatory bowel disease (IBD) is in the differential diagnosis for children presenting with chronic diarrhea. During evaluation, stool studies are typically obtained to evaluate for an infectious source, and stool culture has been the conventional testing modality for bacterial pathogens. Recently, there has been increased utilization of molecular testing for enteric pathogens, including multiplex PCR. While these tests are highly sensitive for the detection of diverse pathogens, the clinical significance of positive results may not always be clear. We report two pediatric cases presenting with diarrhea and positive enteric pathogen (Biofire FilmArray GI Panel) PCR panels, but ultimately diagnosed with IBD. In one case, the PCR test results delayed diagnosis; in the other, they were ignored without any clinical consequence. In children with symptoms concerning for IBD, endoscopic evaluation should not be delayed based on positive molecular testing alone, especially when parallel culture for the same organism is negative.