Post-covid-19 immune signatures: Antibody and Th1 cytokine profiles among healthcare workers in Côte d’Ivoire

The post-SARS-CoV-2 immune response involves both neutralizing antibodies (NAbs) and T-cell cooperation. Healthcare workers, highly exposed in daily practice, represent a relevant population for study. This study aimed to describe the post-COVID-19 immune profiles of Ivorian healthcare workers by analyzing the association between antibodies (IgM, IgG, NAbs) and Th1 cytokines (IL-2, IFN-γ, TNF-α). This cross-sectional study, conducted during January 2022 to June 2023 in three university hospitals in Abidjan, included 36 participants with RT-PCR-confirmed infection. IgM and IgG were measured using an automated analyzer. NAbs were quantified on a multiparametric test system. IL-2, IFN-γ, and TNF-α were measured by a flow cytometer. A robust profile was defined by the combined presence of IgG ≥ 250 Binding Antibody Units (BAU)/ml, NAbs ≥ 800 BAU/ml, and at least one Th1 cytokine (IL-2 ≥ 2.3 pg/ml or IFN-γ ≥ 0.5 pg/ml). The study participants were 63.9% women with mean age of 40.7 years. All participants had detectable IgG; 69.4% displayed high NAbs, and 75.0% had IL-2 ≥ 2.3 pg/ml. IgG correlated positively with IL-2 (ρ = 0.667; p < 0.0001) but negatively correlated with IFN-γ (ρ = -0.535; p = 0.0008). NAbs were positively associated with IL-2 (ρ = 0.341; p = 0.0416) but negatively associated with IFN-γ (ρ = -0.740; p < 0.0001). Of the participants, 25 (69.4%) were classified as robust and 11 (30.6%) as non-robust. Robust profiles showed higher IgG, NAbs, and IL-2 levels, whereas non-robust profiles had higher IFN-γ. Vaccination status did not significantly differentiate groups. In conclusion, in Ivorian healthcare workers, robustness of the post-infection immune response is based on the synergy between NAbs and IL-2. Conversely, high IFN-γ levels were associated with weaker neutralization, probably influenced by post-infection kinetics. These results suggested that immune monitoring should integrate combined profiles, beyond IgG alone, to identify individuals requiring priority vaccination follow-up.