Longitudinal COVID-19 immune trajectories in patients with neurological autoimmunity on anti-CD20 therapy

Abstract

Background and objectives: During the COVID-19 pandemic, B cell depleting therapies pose a clinical concern for patients with neuroimmune conditions, as patients may not mount a sufficient immune response to SARS-CoV-2 infection and vaccinations. Studies to-date have reported conflicting results on the degree of antibody production post-SARS-CoV-2 infection and vaccinations in B cell depleted patients, focusing primarily on short-term immune profiling. Our objective was to follow longitudinal immune responses in COVID-19 B cell depleted patients with neuroimmune disorders post-COVID-19 and SARS-CoV-2-vaccination.

Methods: CD20 B cell depleted autoimmune patients and age/sex-matched controls positive for SARS-CoV-2 were recruited at Dell Medical School, UT Austin between 2020 and 2021, followed prospectively for 12 months and evaluated at multiple time points for spike S1 receptor binding domain (RBD) antibody titers, B and T cell composition, and frequency of T cells specific for SARS-CoV-2 antigens.

Results: Immune responses post-SARS-CoV-2 infection and vaccination were evaluated in a cohort of COVID-19 B cell depleted neuroimmune patients (n = 5), COVID-19 non-B cell depleted autoimmune patients (n = 15), COVID-19 immunocompetent patients (n = 117), and healthy controls (n = 6) for a total of 259 samples in 137 participants. 4/5 B cell-depleted patients developed detectable anti-spike RBD antibodies, which were boosted by vaccination in 2 patients. While spike RBD antibodies were associated with presence of CD20⁺ B cells, very few B cells were required. In contrast, patients whose B cell compartment primarily consisted of CD19⁺CD20^- Bcells during acute COVID-19 disease or vaccination did not seroconvert. Interestingly, circulating Bcells in B cell depleted patients were significantly CD38^high with co-expression of CD24 and CD27, indicating that B cell depletion may impact B cell activation patterns. Additionally, all B cell depleted patients mounted a sustained T cell response to SARS-CoV-2 antigens, regardless of seroconversion. Specifically, all patients developed naïve, central memory, effector memory, and effector memory RA+ T cells, suggesting intact T cell memory conversion in B cell depleted patients compared to controls.

Discussion: We present the longest COVID-19 immune profiling analysis to date in B cell depleted patients, demonstrating that both humoral and cellular immune responses can be generated and sustained up to 12 months post SARS-CoV-2 infection and vaccination. Notably, failure to establish humoral immunity did not result in severe disease. We also highlight specific T and B cell signatures that could be used as clinical biomarkers to advise patients on timing of SARS-CoV-2 vaccinations.

Keywords: COVID-19 CD20 B cell depletion therapy Multiple Sclerosis Autoimmune.

Graphical abstract

Fig. 1

Longitudinal SARS-CoV-2 spike RBD antibody titers in COVID-19 B cell depleted patients. Spike RBD antibody titers over (A) 12 months and (B) first 40 days post symptom onset for COVID-19. (C) Comparison of peak spike RBD antibody titer detected per patient in samples from the first 30 days. The cut-off for a positive antibody response is 1 a.u. (dotted line). For pairwise comparisons the Wilcoxon rank-sum test with Benjamini-Hochberg corrections was used. For asymptomatic patients, days from their first SARS-CoV-2 PCR positive test result were used instead of days from symptom onset.

Fig. 2

Longitudinal characterization of circulating B cells in COVID-19 B cell depleted patients, COVID-19 and healthy controls. Timepoints were grouped into early (days 8-13), mid (days 16-34), and late (days 52-225) in days from symptom onset, or for asymptomatic patient, days from first SARS-CoV-2 PCR positive test. (A) Frequency of B cells in live PBMCs. (B) Frequency of CD19+ CD20- cells in B cells and (C) live PBMCs. (D) Average Isotype frequency of B cells per group. Frequency of (E) CD38+, (F) CD27+CD38+, (G) CD24+CD38+, and (H) spike responsive B cells (CD19+ and/or CD20+). Frequency of (I) CD38+ in CD20- B cells, (J) CD38+ in CD20+ B cells, (K) CD38+CD27+ in CD20- B cells, and (L) CD38+CD27+ in CD20+ B cells.

Fig. 3

Longitudinal characterization of circulating T cells in COVID-19 B cell depleted patients, COVID-19 and healthy controls. Timepoints were grouped into early (days 8-13), mid (days 16-34), and late (days 52-225) in days from symptom onset, or for asymptomatic patients, days from first SARS-CoV-2 PCR positive test. Trajectory plots of CD4+ and CD8+ T cell subset frequencies. (A) Frequency of CD4+ T cells and CD4+ subtypes including (B) OX40+ CD4+ T cells, (C) Tfh CD4+ T cells, (D) Naïve CD4+ T cells, (E) TCM, (F) TEM, (G) TEMRA. (H) Frequency of CD8+ T cells and frequency of subtypes in CD8+ cells including (I) CD69+ CD8+ T cells, (J) CD25+ CD8+ T cells, and (K) CXCR5+ CD8+ T cells.

Fig. 4

COVID-19 T cell stimulation in B cell depleted patients. Stimulation Index to cytomegalovirus (CMV), spike (S), nucleocapsid (N), membrane (M), and envelope (E) megapools for (A) OX40+ CD69+ CD4+ T cells, (B) CD40L+ CD69+ CD4+ T cells, (C) 41BB+CD69+ CD8+ T cells. Average percentages of Naïve, TCM, TEM, and TEMRA for CMV, PMA, S, N, and M megapool stimulation in (D) OX40+ CD69+ CD4+ T cells and (E) CD40L+ CD69+ CD4+ T cells. Timepoints were grouped into early (days 8-13) and late (days 52-225) in days from symptom onset, or for asymptomatic patients, days from first SARS-CoV-2 PCR positive test.

Fig. 5

B cell depleted COVID-19 immune trajectories over one year. Humoral and cellular response trajectories and clinical event timeline over a course of 12 months in B cell depleted patients. (A, E, I, M, Q) B cell frequency of all PBMCs via flow cytometry (dashed lines, right axis), and spike RBD IgG antibody titer (solid lines, left axis). The black dotted line is at 1 a.u. indicating the positivity threshold for the spike RBD IgG antibody assay. (B, F, J, N, R) Percent of B cells positive for CD20 at each patient visit. (C, G, K, O, S) T cell dynamics across visits with stimulation indices of CD4+ and CD8+ T cells (solid lines, left axis) and frequency of CD4+, CD8+, and Tfh T cells in unstimulated PBMCs (dashed lines, right axis). (D, H, L, P, T) Patient timeline of clinical events including B cell depleting therapy administration, symptom onset, seroconversion, vaccination, and hospitalization. In asymptomatic patient B2, days from their first SARS-CoV-2 PCR positive test result was used instead of days from symptom onset.