Saknite, Inga; Patrinely, James R.; Weiss, Rachel; Chen, Heidi; Byrne, Michael; Tkaczyk, Eric R. (2026). Microvascular Research, 167, 104988.
Hematopoietic cell transplantation (HCT), a procedure used to replace a patient鈥檚 blood-forming cells, can cause major changes to the immune system. In this study, researchers used reflectance confocal videomicroscopy, a noninvasive imaging technique that allows real-time visualization of very small blood vessels near the surface of the skin, to examine the upper skin microvasculature of 31 patients after HCT. The diameter of these small blood vessels, as well as the number and size of leukocytes (white blood cells) that were either attached to vessel walls or rolling along them, were similar to previously published measurements from healthy individuals. Researchers also observed 鈥減aused鈥� leukocytes鈥攚hite blood cells that temporarily stopped moving when the surrounding blood flow also stopped. The number and size of these paused leukocytes and the length of time they remained paused were also similar to previously reported values in healthy individuals. However, patients who had undergone HCT had more blood vessels within each 500 脳 500 渭m虏 imaging area than healthy individuals, with a median of three vessels compared with two. The number of blood vessels was not related to the number of attached or rolling leukocytes. Larger blood vessels were associated with the size of paused leukocytes, but not with their number, while the size of paused leukocytes was not related to how long they remained paused. Overall, these findings show that reflectance confocal videomicroscopy can be used to examine small blood vessels and white blood cell behavior in the intact skin of patients after HCT, even when their immune systems have been substantially altered.
Fig. 1.聽Measurements of blood vessel diameter. Interconnective tissue space is the upper boundary of the true vessel diameter and flow width is the lower boundary of the true vessel diameter. Exclusion zone is the space between the flow and the visible surrounding connective tissue.