Nailfold capillary abnormalities in sclerodermatous chronic GVHD.

Chronic GVHD (cGVHD) complicating allo-SCT commonly presents as sclerotic skin changes resembling systemic sclerosis (SSc), suggesting a common pathophysiological pathway. Damage to capillaries is considered an early event in the pathogenesis of SSc, and is associated with characteristic nailfold capillary abnormalities. Whether such nailfold capillary abnormalities occur in sclerodermatous cGVHD is unknown. Nailfold videocapillaroscopy (NVC) was used to evaluate capillary morphology, density and loop dimensions in 14 patients with sclerodermatous cGVHD, 14 sex- and age-matched SSc patients, and 14 healthy controls. It was shown that none of the cGVHD patients and controls, whereas all SSc patients showed severe capillary abnormalities. cGVHD patients and controls showed no differences in capillary density (9.05 vs 9.16 loops/mm, respectively, P=0.84), and capillary loop dimensions (total loop width 44.36 vs 45.56 μm, respectively, P=0.84). Compared with cGVHD patients, SSc patients had a reduced capillary density (9.05 vs 5.25 loops/mm, respectively, P<0.001), and an increase in capillary loop dimensions (total loop width 44.36 vs 99.97 μm, respectively, P=<0.001). In conclusion sclerodermatous cGVHD patients do not show the characteristic microvascular abnormalities seen in SSc, suggesting that capillary damage does not contribute to the pathophysiology of sclerodermatous cGVHD, and making NVC unsuitable for early identification.