FIGURE 4.

Levels of plasmablasts in healthy controls and transplant recipients after SARS-CoV-2 vaccination and correlation with antibody and T cell responses. Numbers of plasmablasts were compared (A) between healthy controls (n = 56 after first and n = 68 after second vaccination) and solid organ transplant recipients (SOT, n = 36 and n = 33, respectively) and (B) between individuals after immunization with vector-based and/or mRNA vaccines. (C) Plasmablasts were correlated with levels of SARS-CoV-2 spike-specific IgG and CD4 and CD8 T cells. Correlation parameters for controls (white symbols) and transplant recipients (gray symbols) as individual groups are summarized in Table S1. Individuals who received the mRNA-1273 vaccine are indicated by triangles in (B) (1 control in the heterologous vector/mRNA group, 4 controls and 1 transplant recipient in the homologous mRNA/mRNA group). Bars in (A) and (B) represent medians with interquartile ranges. Differences between the groups were calculated using Mann-Whitney test or Kruskal-Wallis test for comparison of two or three groups, respectively. Correlations in (C) were analyzed according to Spearman. Dotted lines indicate detection limits for IgG, indicating negative, intermediate, and positive levels, respectively, as per the manufacturer’s instructions (left panel) or detection limit for SARS-CoV-2–specific CD4 and CD8 T cells (middle and right panels, respectively)