Quite differently, in post-COVID-19 condition, three out of the four immunoglobulins studied appeared strongly correlated (Figure 3B): positive correlations were found between IgG and IgA or IgE levels, which were close to 1 (r=0.9537, p<0.0001; and r=0.8985, p<0.0001, respectively; Figure 3B, left and middle plots). Here, IGHE is linked to COVID-19.