Persistent expression of clonotypic IgM is significantly correlated with decreased survival.

Kaplan-Meier survival curves comparing patients with detectable clonotypic IgM transcripts in less than 50% of blood samples (low IgM detection rate, or IgM-DR) versus patients with clonotypic IgM transcripts in 50% or more of blood samples (high IgM-DR). The group with low IgM-DR exhibits significantly better survival than the group with high IgM-DR (median survival not yet reached in low IgM-DR group; 395 days in high IgM-DR group; P < .0001 by the log-rank test).