Pulmonary hypertension, a dangerous increase in the pressure of blood vessels in the lung, is one nasty disease, as I wrote in a Stanford Medicine article a few years ago. As many as three times as many women – many of them quite young – as men are diagnosed with the spontaneous form of PH (which can also arise from scleroderma or bad pharmaceuticals). While an increasing number of pharmaceutical treatments and advocacy groups have made the diagnosis more palatable, there is still no outright cure. Largely, this is because the molecular mechanisms of pulmonary hypertension have remained mysterious.

But recent work has strongly implicated inflammation in pushing predisposed tissues over the edge into the diseased state. And this week, a Journal of Experimental Medicine study led by PH specialist Marlene Rabinovitch, MD, and her colleagues at Stanford’s PH-focused Vera Moulton Wall Center plunks a potentially pivotal piece of the puzzle into place. Rabinovitch and her associates showed that levels of a pro-inflammatory growth factor usually designated by the acronym GM-CSF (if you really must know, it’s “granulocyte-macrophage colony stimulating factor”) rise substantially when a cell-surface receptor with a heavyweight acronym of its own,BMPR2 (for “bone morphogenic protein receptor”) isn’t functioning properly. That can be due to mutations in the gene that codes for the receptor (as occurs in familial versions of PH), to various environmental causes, or the interaction of the two.

Elevated GM-CSF levels in pulmonary tissue work like a siren to call various hot-tempered inflammatory cells to the vasculature of the lung, resulting in thickened vessel walls and commensurately narrowed blood vessels. Conversely, by finding ways to compensate for BMPR2 under-performance, perhaps researchers will be able to develop therapeutics that keep GM-CSF levels within safe limits, modifying the course of incipient PH or even arresting it.

Several million actual and potential sufferers await that Big If with bated breath.