Panel (A) Correlation matrix of relevant continuous variables including MGUS, SMM, MM, and CG participants. Spearman coefficients are indicated in the lower part of the panel, whereas P-values in the upper part. Only significant correlations are plotted (P < 0.05). Positive correlations are shown in blue, whereas negative in red. (B, C) Detail of the correlation between the levels of SARS-CoV-2–specific IgG (Panel B) and IgA (Panel C) antibodies and neutralization capacity. Each symbol represents a participant, and are color-coding according to their disease group (MGUS, purple square; SMM, upper triangle turquoise; MM, lower triangle orange, and CG, blue diamond). Correlation coefficient and P-values were obtained from Spearman correlation.