Objectives:
The humoral immune response to SARS-CoV-2 vaccination in patients with chronic inflammatory disease (CID) declines more rapidly with TNFα inhibition. Furthermore, the efficacy of current vaccines against Omicron variants of concern (VOC) including BA.2 is limited. Alterations within immune cell populations, changes in IgG affinity and the ability to neutralise a pre-VOC strain and the BA.2 virus were investigated in these at-risk patients.
Methods:
Serum levels of anti-SARS-CoV-2 IgG, IgG avidity and neutralising antibodies (NA) were determined in anti-TNFα patients (n=10) and controls (n=24 healthy individuals; n=12 patients under other disease-modifying anti-rheumatic drugs, oDMARD) before and after the second and third vaccination by ELISA, immunoblot and live virus neutralisation assay. SARS-CoV-2-specific B- and T cell subsets were analysed by multicolour flow cytometry.
Results:
IgG avidity and anti-pre-VOC NA titres decreased faster in anti-TNFα recipients than in controls 6 months after the second vaccination (healthy individuals: avidity: p≤0.0001; NA: p=0.0347; oDMARDs: avidity: p=0.0012; NA: p=0.0293). Total plasma cell counts were increased in anti-TNFα patients (Healthy individuals: p=0.0344; oDMARDs: p=0.0254), whereas absolute numbers of SARS-CoV-2-specific cells were comparable 7 days after vaccination. These patients had lower BA.2 NA titres compared to both other groups, even after the third vaccination.
Conclusions:
We show a reduced SARS-CoV-2 neutralising capacity in patients under TNFα blockade. In this cohort, the plasma cell response appears to be less specific and show stronger bystander activation. While these effects were observable after the first two vaccinations and with older VOC, the differences in responses to BA.2 were magnified.