A new hypothesis on the mechanism of digital clubbing secondary to pulmonary pathologies.

Our hypothesis concerns the chronic activation of macrophages, and the continual production of pro-fibrotic tissue repair factors, as a cause of digital clubbing in an array of pulmonary pathologies. The level of macrophage activation will differ between individuals, corresponding to the variable immune response to these pulmonary pathologies. Due to this variability, there is a corresponding inconsistency in the presentation of clubbing.