SAT0158 Type of Vasculitis in Blood Vessels of Different Sizes-A Comparative Postmortem Study Of 36 Rheumatoid Arthritis and 11 Progessive Systemic Sclerosis Patients
Authors: M. Bély, Á. Apáthy
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Objectives</h3> <i>Systemic vasculitis</i> (<b>SV</b>) followed by chronic degenerative (ischemic) and progressive (fibrotic) changes is a basic complication of <i>rheumatoid arthritis</i> (<b>RA</b>) and of <i>progressive systemic sclerosis</i> (<b>SSc</b>). The <b>aim</b> of this study was to compare the <b>SV</b>, according to the type of vasculitis and involved blood vessels of different sizes, in <b>RA</b> and <b>SSc</b>. <h3>Methods</h3> Twelve organs (heart, lung, liver, spleen, kidneys, pancreas, gastrointestinal tract, adrenal glands, skeletal muscle, peripheral nerve, skin and brain) of <b>36 RA</b> and and <b>11 SSc</b> in-patients with <b>SV</b> were studied. <b>RA</b> and <b>SSc</b> were confirmed clinically according to the criteria of the <b>ACR</b>. The type of vasculitis and the size of involved vessels were determined histologically. <h3>Results: SV</h3> was present in the investigated organs with different incidence. In <b>RA</b> three types of vasculitis were observed: <b>non-specific (Ns)</b>, <b>fibrinoid necrotic (Fn)</b> and <b>granulomatous (Gr)</b>, which existed in different (acute-subacute-subchronic-chronic) stages. In <b>SSc</b> only two types of vasculitis or vascular changes were present, <b>non-specific (Ns)</b> and <b>fibrinoid necrotic</b><b>(Fn)</b> vasculitis, each with or without <b><i>progressive fibromuscular</i></b><i>and/or</i><b><i>intimal proliferation</i></b> and successive adventitial fibrosis (<b>FIP</b>). Vessels of all sizes, arterioles (<b>a</b>), small arteries (<b>A</b>), medium size arteries (<b>AA</b>), venules (<b>v</b>), small veins (<b>V</b>), and medium size veins (<b>VV</b>) were involved, with varying incidence in both diseases (capillaries were not evaluated). Average values of <b>incidence</b> in <b>RA</b> and <b>SSc</b> patients with vasculitis (based on the absolute number of involved vessels in all investigated organs) <h3>Conclusions</h3> The presence (existence) of <b>SV</b> was more prominent in <b>SSc</b> than in <b>RA</b> (total sum of incidence in 11 <b>SSc</b> patients: 38.64 versus 36 <b>RA</b> patients: 9.56). In both diseases <b><i>non- specific vasculitis</i></b> was dominant; in <b>RA</b> (<b>67.1%</b> of the total sum) existing in different (acute-subacute-subchronic-chronic) stages and in <b>SSc</b> (<b>71.8%</b>) with or without accompanying <b><i>fibromuscular</i></b><i>and/or</i><b><i>intimal proliferation</i></b> and successive adventitial fibrosis. <b><i>Fibrinoid necrotic</i></b> type of vasculitis was relatively frequent in <b>SSc</b> (<b>28.2%</b> of the total) in comparison with <b>RA</b> (<b>19.8%</b>). <b><i>Granulomatous</i></b> type of vasculitis was not found in <b>SSc</b>; granulomatous vasculitis is not characteristic of <b>SSc</b>. <b>Non-specific</b> or <b>fibrinoid necrotic vasculitis</b> combined with <b><i>fibromuscular</i></b><i>and/or</i><b><i>intimal proliferation</i></b> and successive adventitial fibrosis are supporting the diagnosis of <b>SSc</b>. <b>FIP</b> in its typical form was never present in <b>RA</b>, <b>FIP</b> is not characteristic of <b>RA</b>. Blood vessels of all sizes may be involved in both diseases: dominant involvement of arterioles and small arteries is characteristic of <b>RA</b> and the relative high prevalence in veins is characteristic of <b>SSc</b>. (Regarding <b>a</b>:51.5 and <b>A</b>:32.6% in <b>RA</b> versus <b>a</b>:35.5 and <b>A</b>:27.3% in <b>SSc</b>, regarding <b>v</b>:1.7, <b>V</b>:2.6 and <b>VV</b>:0.9% in <b>RA</b> versus <b>v</b>:7.5, <b>V</b>:9.7 and <b>VV</b>:8.0% in <b>SSc</b>) Histological difference in the types of vasculitis or vascular changes, and the size of the involved blood vessels, may help in the identification of certain autoimmune disorders. <h3>Disclosure of Interest</h3> None Declared