Renal involvement in POEMS syndrome.

We describe a patient with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) who was found to have renal involvement with particular renal pathological findings. So far, 17 other cases, most of them from Japan, of POEMS syndrome with renal involvement, have been published. Clinical features are variable: acute renal failure with anasarca or moderate chronic renal insufficiency with mild proteinuria. This latter presentation often passes unnoticed. There is no severe hypertension, no microangiopathic hemolytic anemia. Renal biopsy shows prominent glomerular changes which are unusual and distinct from membranoproliferative glomerulonephritis (MPGN) and from glomerular thrombotic microangiopathy (TMA). Mesangial proliferation and thickening of the capillary wall with double contour on light microscopy suggest an MPGN. By immunofluorescent microscopy, no immunoglobulins or complement deposits were found. The occurrence of mesangiolytic lesions has led to the term of "mesangiolytic glomerulonephritis". The presence, on electron microscopy, of lucent subendothelial spaces could indicate TMA. But there are neither thrombi nor arteriolar changes. We are inclined to consider that the microangiopathic lesions are due to chronic injury of glomerular endothelial cells, exacerbated at outbreaks of the disease. Increased production of IL 6 could support the efficacy of corticosteroid therapy, particularly in acute clinical situations.

Renal biopsy in the elderly.

314 patients, aged 65 years or older, were biopsied because of a history of renal disease. In 203 patients, glomerular disease was diagnosed with one fourth having systemic disease and the remaining primary glomerulonephritis. 90 patients had tubulointerstitial disease, and 21 patients showed prominent vascular pathology. In a comparison with patients of younger age groups, it appeared that amyloidosis, membranous nephropathy, vasculitis and diabetes had a significantly higher incidence in the elderly. Main glomerular syndromes such as nephrotic syndrome and rapidly progressive glomerulonephritis imply to be managed appropriately. Glomerulosclerosis was found in high frequency, either as an isolated feature or associated with other lesions. Glomerulosclerosis seemed to be ischemic in origin and seems to represent a distinct entity as a cause of pathology in the elderly.

[Study of CD45 isoforms on T CD8 lymphocytes, in the peripheral blood and the graft in patients after kidney transplantation]. / Etude chez le transplanté rénal des isoformes du CD45 sur les lymphocytes T CD8, dans le sang circulant et dans le greffon.

We report characterization of CD45 isoforms expressed by CD8+ lymphocytes in peripheral blood and in the graft of 40 kidney transplanted patients who underwent kidney biopsy on the basis of clinical signs suggesting rejection. Standard histological examination of the biopsy fragments and three-color cytofluorimetric analysis of lymphocytes extracted from the same fragments by mechanical and enzymatic treatment were performed simultaneously and compared to the peripheral blood lymphocytes. In 14/40 biopsies where lymphocyte extraction succeeded, the predominant subset was CD8 (CD4/CD8 mean ratio was 0.53). Almost all CD8+ cells were activated: among these CD8+ cells, 55 percent were HLA-DR+, and 68 percent CD45RO+, i.e. of a memory cell type with cytotoxic activity. This situation resembles the in vitro observation made during mitogenic stimulation of lymphocytes by phytohemagglutinin, OKT3 or CML ("culture mixte lymphocytaire"). Beside their evident interest for the diagnosis, these data could be useful for our understanding of the physiopathology of the rejection crisis.

[Crescent: structure, evolution, pathogenesis]. / Le croissant: structure, évolution, pathogénie.

Extracapillary crescent is an elementary lesion which can be superimposed to any type of glomerulonephritis, or constitute the main lesion as in vasculitis, or appear to be idiopathic. One must oppose cellular crescent which is partially reversible, to irreversible fibrous crescent. Cellular composition of crescents has been much controversial: initially considered as having an epithelial-cell origin, then an exclusive macrophagic origin, crescents are in fact composed of epithelial cells, monocytes-macrophages and lymphocytes all together. The former are prevailing when Bowman's capsule (BC) is intact, whereas macrophages predominate when there is extensive damage of GBM and of BC. The initial event in crescent formation appear to be breaches in glomerular capillary wall, leading the deposition of fibrin within Bowman's space. The consequence is the proliferation of parietal epithelial cells and of activated macrophages followed by a production, in series, of cytokines and growth factors.