The amount of a specific type of immune cells that line the lung blood vessels may be a biomarker for nonspecific interstitial pneumonia (NSIP) prognosis, researchers have found. Understanding the mechanism through which it occurs, may lead to the development of new therapeutic approaches.
The study, conducted by researchers at the Chinese Academy of Medical Sciences & Peking Union Medical College is titled “Prognosis of nonspecific interstitial pneumonia correlates with perivascular CD4+ T lymphocyte infiltration of the lung” and was published in BMC Pulmonary Medicine . It reveals that perivascular CD4-positive T lymphocyte infiltration close to the lung blood vessels significantly correlates with survival time.
Although interstitial lung diseases (ILD), such as NSIP, are often characterized by the accumulation of inflammatory cells, followed by matrix deposition and subsequent destruction of the alveoli, the precise role of inflammatory cell in the development of these diseases is not fully understood.
To address whether the type of infiltrating T lymphocytes in NSIP patients who responded to corticosteroid therapy was distinct from those found in patients who did not respond, the researchers evaluated the distribution of T lymphocyte subsets in the lung tissues of NSIP patients.
The study enrolled 55 patients, average age 48.9 years, who were diagnosed with NSIP. Patients were evaluated through pulmonary function tests and computed tomography, and the investigators studied their biopsies to identify T lymphocytes in distinct lung regions, including lymphoid follicles that are usually associated with infection or inflammation in the lung, and perivascular, interstitial, and peribronchial regions. All patients received oral prednisone for up to 18 months.
After a mean follow-up at 46 months, 23.6% of patients had died. The investigators showed that infiltration of perivascular CD4+ T-cells, but not CD8+ T-cells, was a risk factor for survival and correlated with survival time, meaning that patients with higher levels of perivascular CD4+ T cells survived for longer periods.
But the amount of CD4+ and CD8+ T cells that infiltrated the other anatomical regions did not correlate with survival time, and interestingly, patients with higher perivascular CD4+ T lymphocytes also showed improved lung capacity.
The researchers believe that CD4+ T cells are involved in the development of the disease, but since immunosuppressive agents suppress the inflammation of perivascular T lymphocytes, drugs work better in patients with higher levels of the cells.