IgA antibodies against oxidation-specific epitopes are generated by double negative B cells and are associated with impaired lung function in fibrotic interstitial lung diseases.

Otoupalova, E.; Hannan, R. T.; Raichura, P.; Batrash, N.; Dell, P.; Rodrigues-Jesus, M. J.; Zunder, E. R.; Wilson, J. M.; Woodfolk, J. A.; Taylor, J. J.; Ma, S.-F.; Barros, A. J.; Shim, Y. . M.; Noth, I.; Bonham, C.; Kim, J. S.; Sturek, J. M.

doi:10.64898/2025.11.28.691061

bioRxiv · 10.64898/2025.11.28.691061

IgA antibodies against oxidation-specific epitopes are generated by double negative B cells and are associated with impaired lung function in fibrotic interstitial lung diseases.

Otoupalova, E.·Hannan, R. T.·Raichura, P.·Batrash, N.·Dell, P.·Rodrigues-Jesus, M. J.·Zunder, E. R.·Wilson, J. M.·Woodfolk, J. A.·Taylor, J. J.·Ma, S.-F.·Barros, A. J.·Shim, Y. . M.·Noth, I.·Bonham, C.·Kim, J. S.·Sturek, J. M.

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Abstract

BackgroundFibrotic interstitial lung diseases (fILD) are characterized by progressive scarring of the lung and high mortality. Oxidation-specific epitopes (OSEs) form on oxidized lipids and proteins, are abundant in lungs of patients with fILD and perpetuate lung injury and fibrosis in animal models. OSE-targeting antibodies bind to OSEs and modulate their downstream effects. The objective of this study was to determine the association of OSE-targeting antibodies with lung function and other clinical outcomes, and to characterize OSE-specific B cell phenotypes in fILD. MethodsTo determine the association of OSE-targeting antibodies and clinical outcomes in fILD, we measured plasma levels of OSE-specific antibodies against the malondialdehyde modified LDL mimotope P1 and anti-ApoB100 immune complex (anti-ApoB100 IC) in patients with fILD and age-matched controls. We then performed B cell phenotyping of patients with idiopathic pulmonary fibrosis (IPF) and healthy controls utilizing mass cytometry time of flight (CyTOF). To investigate effects of pro-fibrotic mediators on anti-OSE IgA antibody production, we measured B cell responses to OSEs in vitro. ResultsCohort of 109 patients with fILD (Hypersensitivity Pneumonitis, Idiopathic Pulmonary Fibrosis, Nonspecific Interstitial Pneumonia, Connective Tissue Disease-Associated Interstitial Lung Disease) and 55 healthy donors, and a second cohort of 20 patients with IPF and 9 healthy donors were included in the study. OSE-specific antibody levels anti-P1 and anti-ApoB100 IC IgA and IgG were significantly elevated in participants with fILD compared to healthy donors (p<0.0001). Higher anti-OSE IgA was associated with worse baseline lung function, including forced vital capacity (FVC) (p<0.001) and diffusing capacity for carbon monoxide (DLCO) (p<0.01). IgA+CD27-CD21-CD11c+ double negative type 2 (DN2) B cells correlated with anti-OSE IgA levels (p<0.05) and were enriched in OSE-specific cells. DN2 B cell precursors, CXCR5-CD11c+ naive B cells and IgA+CD27-CD21-CD11c- DN3 B cells, were significantly expanded in IPF compared to healthy donors. Both DN2 and DN3 B cells correlated with plasmablast pools in IPF patients and showed high baseline levels of IL-21 receptor, which was reduced in more differentiated cells. TGF-{beta} combined with OSEs, but not OSEs alone, induced OSE-specific IgA production in vitro. ConclusionsCirculating anti-OSE IgA antibodies are elevated in patients with fibrotic ILDs regardless of underlying pathology and negatively correlate with lung function. These antibodies correlated with the DN2 B cell subset which was enriched in OSE-specific cells. Phenotypic analysis of B cell subsets showed expression of markers consistent with DN to plasmablast differentiation. Finally, TGF-{beta} promoted OSE-IgA production in vitro. These findings show a novel link between oxidative tissue damage, anti-OSE antibodies and DN2 B cells in fILD which may provide opportunities for new targeted therapies.

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Otoupalova, E., Hannan, R. T., Raichura, P., Batrash, N., Dell, P., Rodrigues-Jesus, M. J., Zunder, E. R., Wilson, J. M., Woodfolk, J. A., Taylor, J. J., Ma, S.-F., Barros, A. J., Shim, Y. . M., Noth, I., Bonham, C., Kim, J. S., Sturek, J. M.. 2025-12-02. IgA antibodies against oxidation-specific epitopes are generated by double negative B cells and are associated with impaired lung function in fibrotic interstitial lung diseases.. https://doi.org/10.64898/2025.11.28.691061

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