Electron microscopy and capillaroscopically guided nailfold biopsy in connective tissue diseases: Detection of ultrastructural changes of the microcirculatory vessels

The aims of the study were to describe and compare the frequency and nature of histologically detectable microvascular lesions in patients with variou s connective tissue diseases (CTD). An electron microscopic examination of specimens obtained by the technique of capillaroscopically guided nailfold biopsy was performed in 52 patients with CTD [nine systemic lupus erythemat osus (SLE), eight mixed CTD, 18 scleroderma, 17 undifferentiated CTD] and 2 7 controls. The microvascular changes most frequently observed by electron microscopy were multilayering of the basal lamina (similar to 70% of the CT D patients), an increased amount of perivascular connective tissue, perivas cular oedema formation, and an increased number of perivascular fibroblasts and mast cells (each in 30-37% of the CTD patients). In contrast, no parti cular histopathological feature was found in >25% of the controls, multilay ering (22.6%) being the most frequently observed. Comparing the different c onditions studied, there were distinct differences in the frequency and nat ure of the histologically observed microvascular changes. In particular, SL E seems to be based on a separable type of vasculopathy consisting of signi ficantly less frequent microvascular abnormalities. In conclusion, ultrastr uctural abnormalities of the microvascular system are a frequent finding in CTD. Electron microscopic examination of specimens obtained by capillarosc opically guided nailfold biopsy is able to disclose histopathological diffe rences between defined entities. Therefore, this approach may be a useful t ool to gain further insights into potentially separable aetiopathological m echanisms of the various types of CTD.