Figure 1.

Plasmablast clonal lineages persist and evolve over time in anti-CCP+ RA. A, Representative phylogenetic tree captures the relationships among HC and LC sequences from blood plasmablasts obtained at two timepoints from an anti-CCP+ RA individual. Each leaf (colored by isotype and timepoint (T)) represents the concatenated, error-corrected, IMGT-aligned, consensus HC and LC sequence for a single CD19+CD3−IgD−CD14−CD20−CD27+CD38++ plasmablast, and the tree is anchored by HC V gene assignment. Branch colors indicate clonally expanded sequences (cyan) and sequences derived from plasmablasts that bound citrullinated-peptide tetramers (pink), including singletons and those belonging to clonal expansions. Sequences selected for recombinant expression are indicated (red arrows/lines). The inset images highlight representative clonal families/lineages encoding antibodies comprised of ≥1 isotypes or present at ≥1 timepoints. B, Representative chord diagrams depict plasmablast clonal families and persistent lineages observed at serial timepoints (T) taken months (mo) after the initial timepoint (T1). Persistent lineages include singleton observations at any one timepoint. Sector width and color indicate size and average number of mutations, respectively, for the given family/lineage at each timepoint. Connections between related lineages at different timepoints are colored by isotype. Lineages shared by ≥3 timepoints for Subject 3 are shaded darker to highlight these persistent lineages.