The distribution of the log probability log10Ppostσ for the inferred progenitors of clonal lineages observed in individuals from different cohorts is shown in Figure 3A. We find an overabundance of BCR lineages with progenitors that have a low probability of entering the periphery (i.e., a lower Ppostσ) in individuals with COVID-19 compared with healthy individuals (Figure 3A). The gene discussed is BCR; the disease is COVID-19.