HMGB1 and pemphigus foliaceus: Beyond that, further research has reported that HMGB1 is increased in the lungs of PF patients after acute exacerbation and that the alveolar capillary augmented lesions with reduced level of thrombomodulin, an intrinsic inhibitor of HMGB1, may exacerbate alveolar damage and fibrogenesis [74].