Determining the expected variability of immune cell populations is a foundational step in defining a "healthy" immune baseline and identifying clinically relevant anomalies. Research indicates that while an individual's immune profile is remarkably stable over time, there is massive —often spanning several orders of magnitude—among healthy people. Core Drivers of Immune Variability
Heritability plays a more pronounced role in T cell populations compared to B cells , which are more susceptible to environmental cues. Specific genetic variants (ccQTLs) have been identified that regulate leukocyte counts and contribute to disease susceptibility. Expected Variation in Healthy Adults
B cell subsets and certain antibodies like IgG1 show significant fluctuations based on the time of year.