Toward precision host-directed immunomodulation in community-acquired pneumonia: a proposed endotype-target-natural-product framework and a roadmap for validation in human lung organoids.

Community-acquired pneumonia (CAP) still causes high mortality despite effective antibiotics. Much of this death is driven by a dysregulated host immune response rather than by the pathogen itself, and antimicrobial resistance deepens the problem. Host-directed therapy has accordingly shifted toward precision immunomodulation, yet its benefit appears conditional on the inflammatory state. Stratification by a single inflammatory axis such as C-reactive protein (CRP) separates broad prognostic subgroups, but it does not indicate which effector pathway to target or which agent to use; we designate this limitation, as a conceptual shorthand rather than a validated threshold, the "CRP ceiling." Existing reviews treat natural-product host-directed therapy, CAP inflammatory endotyping, and human lung organoid modeling separately; the gap we address is the absence of a framework that connects them. Integrating these three fields, we propose, as a hypothesis-generating rather than a validated scheme, an endotype-target-natural-product framework for bacterial CAP. We first outline the interventable core of CAP immunopathology across the inflammasome, neutrophil extracellular trap (NET), and resolution axes, together with the pathogen-specific virulence that biases them; we then propose that the multi-target pharmacology of natural products may suit candidate endotypes driven by several co-activated nodes, where single-target agents have often failed, while noting that their comparatively favorable toxicity is itself a hypothesis rather than an established class property; and we position human lung organoids as a promising human-relevant platform, alongside complementary systems, that could test endotype-, compound-, and pathogen-specific hypotheses and provide a roadmap for validation before clinical translation. The framework is intended to complement, not replace, pathogen-directed treatment, and to reframe host-directed therapy from uniform anti-inflammation toward modulation matched to mechanism, pathogen, and patient. The principal challenges concern immune-competent organoids, validated pathway-level endotype biomarkers, and standardized characterization of multi-component natural products.