Background The basic pathological process in progressive systemic sclerosis (SSc) is non-specific or fibrinoid necrotic systemic vasculitis (SV) with or without fibromuscular and/or intimal proliferation and successive adventitial fibrosis (FIP) (1). The vascular changes are accompanied by focal, multifocal (more or less confluent), or diffuse interstitial fibrosis depending on the stage of the disease.
Objectives The aim of this study was to determine: the severity of SV in SSc patients at death and the role of SV in the mortality of SSc patients.
Methods Twelve organs (heart, lung, liver, spleen, kidneys, pancreas, gastrointestinal tract, adrenal glands, skeletal muscle, peripheral nerve, skin and brain) of 11 SSc in-patients with SV were studied.
SSc was confirmed clinically according to the criteria of the ACR. SV was determined histologically. The “severity” of vasculitis was evaluated by semi-quantitative, visual estimation on a 0 to 3 plus scale.
Results Blood vessels with SV or FIP were observed with variable frequency and severity in all examined organs of 11 SSc patients.
Two patients (18.2 rel. %) had marked (average value of severity/SSc patient with SV >1.75); and 9 (81.8 rel. %) had a mild, or moderate degree of SV (average value of severity/SSc patient with SV <1.2). The “severity” of vasculitis showed a step-wise growth curve according to increasing average values of vasculitis/patient. There was no gradual transition between “marked” and “mild or moderate degree” of SV.
SV with or without FIP and consecutive interstitial fibrosis led to death in all patients. Six of 11 SSc patients died of uremia (due to complex nephropathy) and 5 of 11 patients died of circulatory failure (due to endo-myocardial fibrosis or myocardiocytolysis - with or without honeycomb lung) (2). There was no direct relationship between severity of SV/patient and mode of death (e.g. uremia or circulatory failure) (Figure).
Conclusions SV with or without FIP and consecutive interstitial fibrosis is a progressive cumulative process. The severity of vasculitis in SSc patients – arranged according to the increasing value of “average severity” of vasculitis - showed a step-wise profile of intensity. This step-wise change – without gradual transition - may indicate that different genetic, immunologic etc. factors may play a role in determining the severity of vasculitis. Conceivably, the pathogenesis of mild and extremely severe vasculitis may be different.
The course of the disease (mortality due to SV) depends on the location of the affected vessels (and involved organs), but not on the severity of SV. Mild or moderate SV located to the kidneys, heart or lung may be lethal in its complexity, even in an early stage of the disease. Based on these mortality data the kidneys, heart and lung are the most critical targets in SSc, while SV in other organs seems to be less life-threatening (2).
Bély M, Apáthy Άgnes: Characteristics of Systemic Vasculitis in Progressive Systemic Sclerosis. Annals Rheum Dis 2007 (Suppl II), 66:201. Available from: http://www.abstracts2view.com/eular/
Apáthy Άgnes, Bély M: Mortality and Histological Characteristics of SSc. Annals Rheum Dis 2007 (Suppl II), 66:198-199. Available from: http://www.abstracts2view.com/eular/
Disclosure of Interest None Declared