Antibody Production after COVID-19 Vaccination in Patients with Inborn Errors of Immunity.

Background: Few studies have evaluated COVID-19 vaccine efficacy in patients with inborn errors of immunity (IEI).

Objective: To evaluate the levels of antibody (Ab) production and function after COVID-19 vaccination in IEI patients with phagocytic, complement, and Ab deficiencies and their comparison with healthy controls.

Methods: Serum samples were collected from 41 patients and 32 healthy controls at least one month after the second dose of vaccination, while clinical evaluations continued until the end of the third dose. Levels of specific anti-receptor-binding domain (RBD) IgG and anti-RBD neutralizing antibodies were measured using EUROIMMUN and ChemoBind kits, respectively. Conventional SARS-CoV-2 neutralization test (cVNT) was also performed. Cutoff values of ≤20, 20-80, and ≥80 (for cVNT and Chemobined) and 0.8-4.2, 4.2-8.5, and ≥8.5 (for EUROIMMUN) were defined as negative/weak, positive/moderate, and positive/significant, respectively.

Results: A considerable distinction was observed between the Ab-deficient patients and the controls for Ab concentration (EUROIMMUN, p<0.01) and neutralization (ChemoBind, p<0.001). However, there was no significant difference compared with the other patient groups. A near-zero cVNT in Ab-deficient patients was found compared to the controls (p<0.01). A significant correlation between the two kits was found using the whole data (R2=0.82, p<0.0001).

Conclusion: Despite varying degrees of Ab production, all Ab deficient patients, as well as almost half of those with complement and phagocytic defects, did not effectively neutralize the virus (cVNT). In light of the decreased production and efficiency of the vaccine, a revised immunization plan may be needed in IEI.