C Geffriaud | PubMed Health

PubMed1992

Decrease of tumor-like calcification in uremia despite aggravation of secondary hyperparathyroidism: a case report.

Extraskeletal pseudotumoral calcifications generally develop in uremic patients with a high calcium x phosphorus (Ca x P) product and severe secondary hyperparathyroidism. In the present case report we describe a chronic hemodialysis patient presenting with a massive calcification of the left shoulder region, severe aluminum (Al) intoxication and moderate hyperparathyroidism. Her initial serum Ca x P product was only slightly elevated: 5.01 mmol2/l2. Under deferoxamine treatment during the subsequent 4 months, Al overload decreased. On the other hand, parathyroid overfunction worsened, as reflected by an increase of the serum immunoreactive parathyroid hormone [1-84] level from initially 690 to 1052 pg/ml (normal, 15-60 pg/ml) and an increase of alkaline phosphatase activity, and plasma calcitriol increased from undetectable to a low-normal value. Predialysis serum total Ca levels decreased rapidly from 2.9 to 2.5 mM but serum P concentrations remained elevated: 1.6-2.5 mM. Unexpectedly, the extent of the periarticular calcification diminished considerably during the same time period. The present observation shows that in a subset of uremic patients with Al overload, pseudotumoral calcifications may regress during Al chelation therapy despite progression of hyperparathyroidism. Since Al may predispose collagen to develop dystrophic or metastatic calcification, it is suggested that this process is reversible by correcting Al intoxication.

Aluminum↗

PubMed1991

Antigen specificities and clinical distribution of ANCA in kidney diseases.

The antigenic specificity and clinical distribution of the antineutrophil cytoplasmic antibodies (ANCA) in kidney diseases have recently been extensively studied. In patients with systemic vasculitis, the great predominance of two major ANCA antigens, proteinase 3 (PR3) and myeloperoxidase (MPO), is now established. PR3 and MPO are colocalized in the azurophilic granules of neutrophils and translocated to the cell surface during activation, and thus are able to interact with autoantibodies after neutrophil preactivation. Furthermore, by comparison of amino acid and DNA sequences, it has been shown that PR3 is identical to myeloblastin, which has been described independently and is involved in the control of growth and differentiation of leukemic cells. Aside from the two major ANCA antigens, a number of neutrophil cytoplasmic antigens recognized by ANCA have been identified, including human leukocyte elastase, lactoferrin, CAP57, and cathepsin G. These rare ANCA specificities occur in a limited number of patients. The variety of ANCA antigen specificities contrasts, however, with the fact that the vast majority of ANCA-positive sera are monospecific for one single ANCA antigen. With regard to clinical distribution, ANCA have major diagnostic significance in the four conditions in which they are frequently detected: Wegener's granulomatosis (WG), Churg and Strauss Syndrome (CSS), microscopic periarteritis (MPA), and necrotic and crescentic glomerulonephritis (NCGN). However, the initial dichotomy between MPO-associated vasculitis (NCGN, MPA) and that associated with anti-PR3 antibodies (WG) appears far from absolute.

Autoantibodies↗