Humoral and cellular SARS-CoV-2 specific immune responses in patients with MS (pwMS) and healthy controls (hospital employees, HE). (a) Sera of anti-CD20-treated pwMS (anti-CD20), pwMS before anti-CD20 therapy (no anti-CD20), and HE were tested for anti-SARS-CoV-2-S1 IgG antibodies. Anti-SARS-CoV-2-specific S1 IgG OD ratios among pwMS after two vaccinations, pwMS not vaccinated/infected and pwMS after SARS-CoV-2 infections are shown. The dotted horizontal line represents an OD ratio of 1.1, levels above which indicate the presence of anti-SARS-CoV-2-S1 IgG. (b) Functionality of SARS-CoV-2-specific antibodies after two vaccinations was analyzed in anti-CD20-treated pwMS, pwMS before anti-CD20 therapy and HE by determination of SARS-CoV-2 neutralizing capacity, using a plaque reduction neutralization test (PRNT). (c) SARS-CoV-2 IgG avidity maturation was studied using a modified SARS-CoV-2-S1 ELISA (see the Supplement for methodological details). Dotted horizontal lines indicate relative antibody indices > 40%, which were considered borderline, and relative antibody indices > 60%, which were considered high avidity. (d) SARS-CoV-2-specific T cell responses were measured in whole blood samples by IGRA in pwMS and HE vaccinated twice and in pwMS who were not vaccinated/infected. SARS-CoV-2-specific T cells were considered to be present if IFN-γ release was higher than the highest value in the not vaccinated/infected control group (111.41 mIU/ml, dotted horizontal line). (e) Heatmap summarizing the percentage of positive outcomes per test system in pwMS and HE (results for groups with n < 3 were not included). (a–d) Of the 14 pwMS before initiation of anti-CD20 therapy, 10 had not received any disease-modifying therapies (green circles), 1 was treated with glatiramer acetate (green triangle), and 3 were treated with dimethyl fumarate (green squares) at the time of vaccinations. Horizontal lines indicate the median; p values were calculated by the non-parametric Kruskal–Wallis test with Dunn’s multiple comparisons test.
HE: hospital employees; IFN-γ: interferon-γ; IFT: immunofluorescence test; IgA: immunoglobulin A; IgG: immunoglobulin G; IGRA: interferon-γ release assay; IU: international units; ns: not significant; OD: optical density; PRNT: plaque reduction neutralization test; RBD: receptor binding domain; S1: SARS-CoV-2 spike protein S1 domain; vac: vaccination.