Adaptive bandwidth of immunity: a systems-level framework for understanding immune regulation across time.

Immune-mediated diseases display substantial variability in clinical expression, treatment durability, relapse timing, and long-term trajectories that are not always fully explained by genetic predisposition, molecular pathways, or pharmacological exposure alone. Increasing observations from systems immunology suggest that immune behavior emerges through interactions across molecular, environmental, and temporal dimensions. This article introduces Adaptive Bandwidth of Immunity (ABI) as a conceptual systems-level framework describing the functional range within which immune regulatory networks preserve adaptive responsiveness, proportionality, reversibility, and coordinated recovery across biological perturbations. ABI is not proposed as a discrete biological pathway or a directly measurable variable. Instead, it is introduced as an emergent property inferred through longitudinal clinical trajectories, temporal response dynamics, and integrated biological observations. The framework draws upon concepts from immune homeostasis, trained immunity, immune tolerance, systems immunology, and environmental modulation while emphasizing preservation of adaptive flexibility across time. Within this interpretation, immune-mediated disease may be viewed not only through dysregulated activation but also through progressive restriction of adaptive regulatory capacity. The framework generates empirically approachable predictions and outlines potential directions for future operationalization through longitudinal cohorts, trajectory-based analyses, and integration of multi-omics with temporal clinical data. ABI is presented as a hypothesis-generating framework intended to support future investigation into adaptive regulation and dynamic immune behavior.