Interior Decorative VOCs Elevate T Cell‐Mediated Obstructive Lung Disease Risks via Osteogenesis‐Driven Lymphoid‐Biased Hematopoiesis

Abstract Volatile organic compounds (VOCs) emitted from interior decorations are suggested to pose substantial respiratory hazards as they disturb the immune response in the lung. Despite this, the characteristics and mechanisms underlying immune cell responses to real‐world VOC mixtures, rather than previously individual or dominant VOC species, remain poorly understood. Employing a whole‐body inhalation exposure model, we reveal that interior decorative VOCs alter pulmonary immune cell profiles with a persistent increase in alveolar T cells. This sustained elevation results from intensified lymphoid‐biased hematopoiesis in the bone marrow (BM) rather than in situ lung, which is followed by thymic maturation and subsequent recruitment to lung tissues. The ex vivo biosensor and antibody neutralization assays clarify that VOCs‐induced lymphoid‐biased hematopoiesis is primarily driven by osteogenic differentiation within the BM niche, a process further regulated by interleukin‐6 (IL‐6) and interleukin‐17A (IL‐17A). Moreover, the cohort study associates VOCs‐expanded lymphocytes with increased risks of obstructive lung diseases, where exposed individuals show elevated IL‐6 and IL‐17A levels, correlating with VOC concentrations and lymphocyte proportions. These findings highlight compelling indicators (i.e., T cells) and potential interventions (i.e., IL‐6 and IL‐17A) for evaluating and mitigating VOC‐associated respiratory risks.