Prospective Descriptive Study of the Angiogenic T Cell Population in Subjects With Hereditary Hemorrhagic Telangiectasia (HHT)

Hereditary hemorrhagic telangiectasia (HHT) results from genetic deregulation of angiogenesis. It is characterized by mucocutaneous telangiectasia responsible for recurrent epistaxis affecting quality of life (anaemia, iron deficiency, social distress). More rarely, HHT is complicated by the appearance of pulmonary, hepatic or cerebral arteriovenous malformations that can lead to serious complications: cerebrovascular accidents, cerebral abscesses, high output heart failure, and massive hemoptysis (1). The intensity of symptoms increases with age but with significant individual variability, even for the same mutation in the same family. Thus, while the mutations responsible for the disease have been identified, the pathophysiology is not fully understood because these mutations do not explain the great diversity of clinical presentations. Other factors not yet identified probably play an important role. Angiogenic T cells (TANG) are a newly individualized T cell population, defined by a CD4+CXCR4+CD31+ phenotype, which plays a key role in differentiating endothelial progenitors (2).

In an earlier study, the investigators showed that patients with HHT had a decrease in CD4+ and CD8+ LT compared to a cohort of healthy subjects (3).

They hypothesize that the lymphopenia mainly involves TANG, whose quantification could make it possible to assess the individual level of angiogenesis during HHT. The evaluation of the TANG levels could thus make it possible to personalize HHT management.