Rapidly progressive glomerulonephritis in IgA/IgG cryoglobulinemia

Three Diseases Mediated by Different Immunopathologic Mechanisms-ANCA-Associated Vasculitis, Anti-Glomerular Basement Membrane Disease, and Immune Complex-Mediated Glomerulonephritis-A Common Clinical and Histopathologic Picture: Rapidly Progressive Crescentic Glomerulonephritis

Immune mechanisms play an important role in the pathogenesis of glomerulonephritis (GN), with autoimmunity being the main underlying pathogenetic process of both primary and secondary GN. We present three autoimmune diseases mediated by different autoimmune mechanisms: glomerulonephritis in vasculitis mediated by anti-neutrophil cytoplasmic antibodies (ANCAs), glomerulonephritis mediated by anti-glomerular basement membrane antibodies (anti-GBM antibodies), and immune complex-mediated glomerulonephritis. Some of these diseases represent a common clinical and histopathologic scenario, namely rapidly progressive crescentic glomerulonephritis. This is a severe illness requiring complex therapy, with the main role being played by therapy aimed at targeting immune mechanisms. In the absence of immune therapy, the crescents, the characteristic histopathologic lesions of this common presentation, progress toward fibrosis, which is accompanied by end-stage renal disease (ESRD). The fact that three diseases mediated by different immunopathologic mechanisms have a common clinical and histopathologic picture reveals the complexity of the relationship between immunopathologic mechanisms and their clinical expression. Whereas most glomerular diseases progress by a slow process of sclerosis and fibrosis, the glomerular diseases accompanied by glomerular crescent formation can progress, if untreated, in a couple of months into whole-nephron glomerulosclerosis and fibrosis. The outcome of different immune processes in a common clinical and histopathologic phenotype reveals the complexity of the relationship of the kidney with the immune system. The aim of this review is to present different immune processes that lead to a common clinical and histopathologic phenotype, such as rapidly progressive crescentic glomerulonephritis.

Immunoadsorption apheresis and immunosuppressive drug therapy in the treatment of complicated HCV-related cryoglobulinemia

The immunosuppressive drug therapy (IDT) is not always effective to avoid the development of complications in hepatitis C virus-related cryoglobulinemia (HCV-Cr). Removal of cryoglobulins by therapeutic plasmapheresis is currently accepted. In this randomized, parallel group study, 17 male and female patients aged 43-79 years, with complicated HCV-Cr, were submitted for 12 weeks (initial immunosuppressive therapy) to IDT (alpha-interferon, pegylated-interferon alpha-2a, cyclophosphamide, methylprednisolone, prednisone, cyclosporine, ribavirin, and melphalan). Then, they were randomly assigned to two parallel groups: A # 9 patients treated by immunoadsorption apheresis (Selesorb((R))) (IA) plus IDT, and B # 8 patients submitted to IDT only, for further 12 weeks. # 187 IA aphereses were performed. No adverse reactions or complications were observed. A Clinical Score (CS) was adapted from a pre-existing scoring model to evaluate signs and symptoms inherent to the underlying immunologic disorder. The CS was calculated at baseline (CS0), after the initial immunosuppressive therapy (CS1 = 12 weeks) when patients were treated only with IDT, and at the end of the study (24 weeks) in the group A (CSA; IA plus IDT) and B (CSB; IDT only). The score did not change significantly from CS0 to CS1. However, statistically significant differences were observed between CS1 and CSA (P < 0.001), and CSA versus CSB (P = 0.03), respectively. The changes observed were favorable to the patients assigned to the IA plus IDT group (A): in most case relief of symptoms and complications have been obtained.

Glomérulonéphrites extracapillaires

Crescentic glomerulonephritis are characterised by a crescent shaped cellular proliferation that may lead to glomerular destruction. Over 50% of at least 10 analysed glomeruli should be affected. The search for immune deposits by immunofluorescence is an important diagnostic step. Patients present with rapidly progressive glomerulonephritis (RPGN): renal failure, proteinuria and haematuria. Extra-renal symptoms may help diagnosis. Diseases are classified in three groups according to immunofluorescence studies. Group I is characterised by linear deposits along the glomerular basement membrane (GBM) with anti-GBM auto-antibodies responsible for Goodpasture's disease. Group II put together various diseases with immune complex deposits. In group III, no significant immune deposits are found. Those "pauci-immune" glomerulonephritis are secondary to anti-neutrophil cytoplasmic antibodies (ANCA) positive systemic vasculitis, mainly Wegener's granulomatosis and microscopic polyangiitis. Primary glomerulonephritis may also be associated with crescent formation. Treatment is urgently required. Diagnosis is suspected in the context of extra-renal symptoms or immunological abnormalities, and confirmed by a kidney biopsy, that also helps to define prognosis. Apart from some group II glomerulonephritis, the induction treatment is often an association of steroids and cyclophosphamide, with plasma exchange in case of Goodpasture's disease. After remission, a maintenance treatment is required for ANCA-positive vasculitis to prevent relapses. The high rate of opportunistic infections and cancer give the rational for searching less aggressive therapeutic options.

Immunoadsorption apheresis (Selesorb) in the treatment of chronic hepatitis C virus-related type 2 mixed cryoglobulinemia

In this short-term open label clinical pilot study, conducted at one center, the immune complex dextran sulphate adsorber (Selesorb) was used to treat four female patients aged 59-69 with HCV-related cryoglobulinaemia, vasculitis and/or neuropathy. The primary trial objective was to assess the clinical efficacy of the immunoadsorber. The secondary objective of the trial was to determine the safety of the adsorber and to investigate the adsorption capacity, measured as the adsorption of cryoglobulin-related immune complexes and the resulting influence on plasma components of the immune system. The patients have been submitted to treatment with the immunoadsorber, at approximately 1-3 days intervals, completing six sessions. The follow-up was one month. In the patients treated with Selesorb, we observed a statistically significant decrease in plasma of all classes of immunoglobulins (IgA: 5-28%; IgG: 14-44%; IgM: 8-38%). In two patients with peripheral neuropathy secondary to cryoglobulinemia, the symptomatology was improved. In a third patient the neurological involvement was substantially unchanged, and the same unsuccessful outcome was observed for Sjögren syndrome is concerned. Nevertheless, the two patients with lower extremity vasculitis showed an appreciable improvement. We failed to observe significant side effects directly related to the use of this immunoadsorbent.

Immunoperoxidase autopsy study of crescentic glomerulonephritis with extracapillary proliferation

Twenty-five cases of extracapillary crescentic glomerulonephritis were examined immunohistologically. The peroxidase-antiperoxidase (PAP) method was used, the presence of immunoglobulin, complement factors and fibrin was analysed and glomerular positivity was found in all but two cases. Two types of reaction could be discerned: linear and granular, which can be considered as evidence of the pathomechanism. Surprisingly, IgG and IgM positivity was seen most frequently. The author emphasizes the importance of immunoperoxidase examination in the renal histology. This method can be easily applied in paraffin-embedded samples and gives many useful information.

Pathology of dysproteinemia: light chain amyloidosis, non-amyloid immunoglobulin deposition disease, cryoglobulinemia syndromes, and macroglobulinemia of Waldenström

This review has dealt with four syndromes associated with dysproteinemia, and has emphasized studies of the tissue deposits and forms of tissue injury which occur in such patients. However, similar tissue deposits and tissue damage occasionally occur in the absence of a serum or urine paraprotein, in which case other clinical data are necessary to suggest the need for examination of tissue for Ig heavy and light chain determinants in order to provide a correct diagnosis of dysproteinemia. In such cases, one may speculate that there is a low rate of paraprotein production and secretion, in addition to tissue tropism. Some paraproteins are antibodies, in which case they may circulate and/or deposit as immune complexes, or bind to tissue antigens with immune complex formation in situ. Some paraproteins are also cryoproteins, and clues to this property can also be found in the tissue, particularly at the ultrastructural level. Thus, a wide spectrum of clinical manifestations of a B cell proliferative disorder may be associated with any of a variety of circulating paraproteins and a variety of forms of tissue deposit and injury. Consequently, the best understanding of an individual patient requires correlation of the clinical features of the disorder, the immunochemical characterization of the circulating and excreted paraproteins, and an immunohistochemical analysis of the tissue deposits and associated morphologic abnormalities. This should be correlated with histologic and immunohistologic assessment of bone marrow, looking for overt B cell neoplasia, the more difficult to define "lymphoproliferative disorders," or alterations in kappa to lambda plasma cell ratios which may correlate with the deposited material. Studies of the Ig synthesized by cultured bone marrow plasma cells, and biochemical analyses of the deposited material, have demonstrated structural abnormalities of paraproteins which may be responsible for their tissue deposition.