Effect of corticosteroids on long-term humoral and memory T cell responses in follow-up visit of hospitalized COVID-19 patients

Background Corticosteroids have demonstrated their beneficial effects in improving outcomes in hospitalized patients with severe COVID-19 by suppressing excessive immune responses. However, the effect of corticosteroids on the humoral and T cell responses of COVID-19 survivors one year after infection remains uncertain, as it relates to the extent of immediate, antigen-specific defense provided by protective memory. Research Question What’s the effect of corticosteroids on long-term humoral and T cell immune responses? Study Design and Methods In this retrospective cohort study conducted at a single center, we analyzed data from a post-COVID cohort to compare the one-year seropositivity and titers change of neutralizing antibodies (NAbs) and SARS-CoV-2 specific antibodies. Additionally, we evaluated the magnitude and rate of SARS-CoV-2 specific T cell response in individuals who had received corticosteroids during hospitalization and those who did not. Results Our findings indicate that corticosteroids do not statistically influence the kinetics or seropositive rate of NAbs against the Wuhan strain from half year to one year. However, subgroup analysis reveals a numerical increase of absolute NAbs titres, from 20.0 to 28.2, in categories where long-term (>15 days) and high dosage (>560 mg) corticosteroids are administered. Similarly, corticosteroids show no significant effect on N and RBD-IgG at one year, except for S-IgG (β 0.08, 95% CI 0.04-0.12), which demonstrate a delayed decline of titres. Regarding T cell immunity, corticosteroids do not significantly affect the rate and magnitude of T cell responses either. However, functional assessment of memory T cells reveals higher interferon-γ (IFNγ) responses in CD4 (β 0.61, 95% CI 0.10-1.12) and CD8 (β 0.63, 95% CI 0.11-1.15) memory T cells in the corticosteroids group at one year. Interpretation Based on our findings, short-term and low-dose corticosteroid therapy during hospitalization does not have a significant effect on long-term humoral kinetics, as well as the magnitude and rate of memory T cell responses to SARS-CoV-2 antigens. However, the potential harmful effects of long-term and high-dose corticosteroid usage on memory immune responses require further investigation.