Scientists have discovered differences in the physical expression of the lymphatic cells involved in a rare lung disease called lymphangioleiomyomatosis (LAM), which affects mostly women of childbearing age, according to new research.

LAM is a lung disease that affects about 1 in 200,000 Americans, according to the study. Physicians utilize bronchoscopy to diagnose rare lung diseases such as LAM.

When LAM cells accumulate in lungs, cysts can form and impede airflow, making it hard to breathe. Researchers have been studying the physical characteristics of those cells in order to help people afflicted with the disease.

LAM cells in the lung are found in nodules. Lymphatic endothelial cells line those nodules and are helping researchers better understand LAM.

The idea is that additional study may facilitate personalized therapies for people living with LAM and other rare lung diseases. Researchers also are examining the role that the lymphatic cells may play in the disease’s progression.

The CHEST Foundation says that LAM affects women in their 30s and 40s. Although female hormones and pregnancy can aggravate LAM, they are not considered a cause or risk factor for it.

LAM is the result of an abnormal growth of smooth muscle cells. When it is associated with tuberous sclerosis complex (TSC), it is an inherited disorder. This means that at least one parent passes on the gene for it to his or her daughter, according to CHEST. In cases where the disease occurs alone, it is related to changes in certain genes that are an important part of cell growth.

The disorder also sometimes affects kidneys and the lymphatic system in addition to the lungs, according to NORD’s rare disease data base.

The same mixture of characteristics in cells was also seen in a small percentage of lung cells studied in people living with another rare lung disease called idiopathic pulmonary fibrosis (IPF).

That’s according to a National Institutes of Health media advisory citing the study published in the American Journal of Respiratory Cell and Molecular Biology, entitled “A Mixed Blood-Lymphatic Endothelial Cell Phenotype in LAM and IPF But Not in Kaposi’s Sarcoma or TSC,” by Dr. Gustavo Pacheco-Rodriguez and others.

The researchers noted they did not see the that same kind of crossover, in which cells had characteristics of both lymphatic and blood endothelial cells, in cells of healthy volunteers or in people with the blood-related cancer Kaposi’s sarcoma.