Young IBD patients fail to develop neutralizing antibodies for SARS-CoV-2
Among young patients with inflammatory bowel disease, most whom were positive for SARS-CoV-2, had a non-neutralizing antibody, according to data presented at Digestive Disease Week.
“Rapid decline in antibody levels following SARS-CoV-2 infection in our IBD patients treated with biologics suggests greater risk for reinfection, especially for variants that can escape the antibodies,” Joelynn Dailey, DO, from Connecticut Children's Medical Center, Hartford, said during her presentation.
Dailey and colleagues collected serum from 426 young patients with IBD at the time of infusion with infliximab or vedolizumab. The researchers also collected possible SARS-CoV-2 exposure history data. They used a fluorescent bead-based immunoassay to measure antibodies to SARS-CoV-2. To detect specific immunoglobulin G (IgG) antibodies to the virus in patient serum, investigators immobilized biotinylated SARS-CoV-2 spike protein receptor binding domain (S-RBD) or nucleocapsid protein of SARS-CoV-2.
Dailey reported 305 patients had Crohn’s disease, 105 had ulcerative colitis/IBD-U, 341 were on infliximab, 69 on vedolizumab, 27 were positive for S-RBD and nucleocapsid specific IgG.
According to Dailey, titration curves from COVID-19 convalescent and healthy control participants were used to normalize area under the curve values to quantitate antibody levels. Anti-Ig (IgG, IgA, IgM, IgG1-4) specific secondary antibodies conjugated to a fluorescent tag were used to measure antibody isotypes. Specific inhibition of viral entry was evaluated with a sensitive and high throughput SARS-CoV-2 neutralization assay using a lentivirus that expresses spike protein.
AUC values ranged from 3,150 to 285,724, according to Dailey. Investigators found S-RBD specific IgA+ (15%) and IgG1+ (74%). However, other isotypes were undetectable. In 37%, patients’ serum efficiently neutralized the virus at up to 10,000-fold serum dilution. There were no differences observed in age, sex, diagnosis or specific therapies for positive vs. negative anti-SARS-CoV-2 antibody status. Thirteen patients were asymptomatic, according to Dailey.
According to Dailey, among the non-exclusive symptoms were rhinorrhea (33%), headache (30%), sore throat (15%), cough (15%), diarrhea (15%), chills 3 (11%), loss of smell/taste (7%), fever (4%). None of the patients were hospitalized. Four patients had a family member with PCR+ COVID-19.
“There were significantly more IBD patients who failed to develop neutralizing antibodies compared to non-IBD adults,” Dailey said.