Autoimmunity may drive idiopathic pulmonary fibrosis (IPF), according to a study that found a link between certain autoantibodies —those that target the body’s own cells and tissues — and disease progression in these patients.
In their quest to examine autoimmune processes in IPF, researchers had earlier discovered that IPF patients had higher levels of autoantibodies against a protein called vimentin. They also found that immune cells extracted from patients and later grown in the lab were more reactive against vimentin when compared to immune cells from healthy people.
Vimentin is an intracellular protein commonly found in the so-called cytoskeleton — fibers inside cells that give them structure and sometimes mobility.
It turned out that vimentin levels were higher in patients’ blood and lung tissue when compared to these same tissues from healthy people. Vimentin concentrations were also linked to lung function: higher levels were typically found in patients with more severe disease.
“We found a significant inverse correlation between levels of anti-vimentin autoantibodies and measures of pulmonary function, and these were remarkably similar in both independent IPF cohorts,” researchers wrote.
Serious adverse events were most common among patients with the highest levels of antibodies against vimentin, they noted. In fact, patients with the highest levels were 2.5 to 2.7 times more likely to experience adverse outcomes than those with the lowest levels.
In an attempt to study the molecular processes connecting vimentin to IPF, they exposed lab-grown cells to the transforming growth factor (TGF)-beta, a well established player promoting inflammation. This factor — which is also commonly higher in IPF patients — made cells produce and release more vimentin.
Overall, the study concluded, these findings “raise the possibility that therapies specifically directed at these autoimmune processes could have therapeutic efficacy.”