Experimental pulmonary schistosomiasis: lack of morphological evidence of modulation in schistosomal pulmonary granulomas

Numerous pulmonary schistosome egg granulomas were present in mice submitted to partial portal vein ligation (Warren's model). The granulomas were characterized by cellular aggregations formed within alveolar tissue. Main cellular types were macrophages (epithelioid cells), eosinophils, plasma cells and lymphocytes. These cells were supported by scanty fibrous stroma and exhibited close membrane contact points amongst themselves, but without forming specialized adhesion apparatus. When granulomas involved arterial structures, proliferation of cndothelial and smooth muscle cells occurred and fibrosis associated with angiogenesis became more evident. Granulomas formed around mature eggs in the pulmonary alveolar tissue presented approximately the same size and morphology regardless of the time of infection, the latter being 10, 18 and 25 weeks after cercarial exposure. This persistence of morphological appearance suggests that pulmonary granulomas do not undergo immunological modulation, as is the case with the granulomas in the liver and, to a lesser extent, in the intestines. Probably, besides general immunological factors, local (stromal) factors play an important role in schistosomal granuloma modulation.

Leflunomide and Polyomavirus-Associated Nephropathy in Renal Transplant

Polyomavirus nephropathy is a major complication in renal transplantation, associated with renal allograft loss in 14 to 80% of cases. There is no established treatment, although improvement has been reported with a variety of approaches. The authors report two cases of polyomavirus infection in renal allograft recipients. In the first case, a stable patient presented with deterioration of renal function, worsening hypertension and weight gain following removal of ureteral stent placed routinely at the time of surgery. Ultrasound examination and radiology studies revealed hydronephrosis due to ureteral stenosis. A new ureteral stent was placed, but renal function did not improve. Urinary cytology revealed the presence of decoy cells and polyomavirus was detected in blood and urine by qualitative polymerase chain reaction. Renal biopsy findings were consistent with polyomavirus -associated nephropathy. In the second case, leucopaenia was detected in an asymptomatic patient 6 months after transplantation. Mycophenolate mophetil dosage was reduced but renal allograft function deteriorated, and a kidney biopsy revealed polyomavirus -associated nephropathy, also with SV40 positive cells. In both patients immunosuppression with tacrolimus was reduced, mycophenolate mophetil stopped and intravenous immune globulin plus ciprofloxacin started. As renal function continued to deteriorate, therapy with leflunomide (40 mg/day) was associated and maintained during 5 and 3 months respectively. In the first patient, renal function stabilised within one month of starting leflunomide and polymerase chain reaction was negative for polyomavirus after 5 months. A repeated allograft biopsy 6 months later showed no evidence of polyomavirus nephropathy. In the second patient, polyomavirus was undetectable in blood and urine by polymerase chain reaction after 3 months of leflunomide treatment, with no evidence of polyomavirus infection in a repeated biopsy 6 months after beginning treatment.

Prognostic Factors in Adult Patients with Idiopathic IgA Nephropathy

Introduction. IgA nephropathy is the dominant primary glomerular disease found throughout the majority of the world’s developed countries. Accurately identifying patients who are at risk of progressive disease is challenging. We aimed to characterise clinical and histological features that predict poor prognosis in adults. Patients and Methods. We performed a single-centre retrospective observational study of biopsy-proven IgA nephropathy. The primary outcome was renal survival and death from any cause, and the secondary outcome was proteinuria remission. Results. Data from 49 cases were available for analysis with a median follow-up of 4 years. There were no deaths. Univariable analyses identified acute renal failure, low estimated glomerular filtration rate for ≥3 months (low eGFR), arterial hypertension, baseline proteinuria, glomerular sclerosis >50% and interstitial fibrosis >50% as poor prognostic markers. Low eGFR persisted significant by multivariable model that used only clinical parameters. Multivariable models with histopathologic parameters observed that tubular atrophy/interstitial fibrosis >50% was independently associated with the primary outcome. Proteinuria remission throughout follow-up had no prognostic value in our revision. Conclusions. Two independent predictors of poor renal survival at time of biopsy were found: low eGFR and tubular atrophy/interstitial fibrosis >50%.

LEPROSY NEPHROPATHY: A REVIEW OF CLINICAL AND HISTOPATHOLOGICAL FEATURES

Leprosy is a chronic disease caused by Mycobacterium leprae, highly incapacitating, and with systemic involvement in some cases. Renal involvement has been reported in all forms of the disease, and it is more frequent in multibacillary forms. The clinical presentation is variable and is determined by the host immunologic system reaction to the bacilli. During the course of the disease there are the so called reactional states, in which the immune system reacts against the bacilli, exacerbating the clinical manifestations. Different renal lesions have been described in leprosy, including acute and chronic glomerulonephritis, interstitial nephritis, secondary amyloidosis and pyelonephritis. The exact mechanism that leads to glomerulonephritis in leprosy is not completely understood. Leprosy treatment includes rifampicin, dapsone and clofazimine. Prednisone and non-steroidal anti-inflammatory drugs may be used to control acute immunological episodes.

Anti-Phospholipase A2 Receptor Antibodies in the Diagnosis of Idiopathic Membranous Nephropathy

Circulating anti-phospholipase A2 receptor antibodies (anti-PLA2R) have been described in 70% to 80% of the patients with idiopathic membranous nephropathy (iMN), but not in patients with secondary membranous nephropathy or other glomerular diseases. The goal of this study was to evaluate the sensitivity and specificity of the assay for anti-PLA2R in the diagnosis of iMN. Anti-PLA2R IgG, Elisa and immunofluorescence tests were used to detect circulating anti-PLA2R. These tests were applied in 53 patients who had a kidney biopsy. Of these, 38 had histological diagnosis of membranous nephropathy (MN) and the remaining had other glomerular diseases. The MN was classified as idiopathic in 33 patients after clinical exclusion of secondary causes. Anti-PLA2R were positive in 57.6% of the patients with iMN. All patients with secondary membranous nephropathy or other glomerular diseases did not show circulating anti-PLA2R. The sensitivity was 57.6% (CI 39.2-74.5) and specificity 100% (CI 47.8-100), AUC 0.788; p < 0.0001 for the detection of iMN. 71.4% of the iMN patients that tested negative for anti-PLA2R were in partial or complete remission. The detection of anti-PLA2R in the studied population had a specificity of 100% for the iMN diagnosis. Prior treatments seem to make the test negative and contribute to a lower sensitivity.

Family occurrence of schistosomal hepatosplenomegaly and maternal effect

In this paper we present a study of members of 265 nuclear families, aged six or more. This study is based of family heredograms, and takes into account the clinical form ofschistosomiasis observed before treatment with oxamniquine. The probability of occurrence of two or more cases ofhepatosplenomegaly is low, notwithstanding the fact that it was observed in 38 families. Even less frequent is the occurrence of three or more cases observed in 17 families (P=0.002). The concentration of the hepatosplenic form was higher among siblings than it was among mothers and children, or fathers and children. It was found to be not significant between husband (father) and wife (mother). These observations reinforce the evidence for the presence of a genetic component in susceptibility to the hepatosplenic form of the disease. In cases in which the mother was hepatosplenic there was a higher incidence of hepatosplenic children; the relative risk was a least five times higher than in those in which the father was the affected member (the maternal effect). In cases where both members were affected by the hepatointestinal form, the risk to the filial generation was similar to that of the population in general. Thus, in the process towards severe forms of Schistosomiasis mansoni, pre and post natal factors might be involved.

Guidelines for the diagnosis and treatment of schistosomal myeloradiculopathy

Schistosomal myeloradiculopathy is the most severe and disabling ectopic form of Schistosoma mansoni infection. The prevalence of SMR in centres in Brazil and Africa that specialise in attending patients with non traumatic myelopathy is around 5%. The initial signs and symptoms of the disease include lumbar and/or lower limb pain, paraparesis, urinary and intestinal dysfunctions, and impotence in men. The cerebrospinal fluid of SMR patients shows an increase in protein concentration and in the number of mononuclear cells in 90% of cases; eosinophils have been reported in 40%. The use of magnetic resonance imaging is particularly valuable in the diagnosis of Schistosomal myeloradiculopathy. The exclusion of other myelopathies and systemic diseases remains mandatory. Early diagnosis and treatment with steroids and schistosomicides provide a cure for most patients, whilst delayed treatment can result in irreversible physical disabilities or death. To improve awareness concerning Schistosomal myeloradiculopathy amongst public health professionals, and to facilitate the control of the disease, the Brazilian Ministry of Health has launched a program of education and control of this ectopic form of schistosomiasis. The present paper reviews current methods for the diagnosis of SMR and outlines protocols for treatment of the disease.

Cell-matrix interactions in Schistosomal portal fibrosis: a dynamic event

In recent years, one of the most significant progress in the understanding of liver diseases was the demonstration that liver fibrosis is a dynamic process resulting from a balance between synthesis and degradation of several matrix components, collagen in particular. Thus, fibrosis has been found to be a very early event during liver diseases, be it of toxic, viral or parasitic origin, and to be spontaneously reversible, either partially or totally. In liver fibrosis cell matrix interactions are dependent on the existence of the many factors (sometimes acting in combination) which produce the same events at the cellular and molecular levels. These events are: (i) the recruitment of fiber-producing cells, (ii) their proliferation, (iii) the secretion of matrix constituents of the extracellular matrix, and (iv) the remodeling and degradation of the newly formed matrix. All these events represent, at least in principle, a target for a therapeutic intervention aimed at influencing the experimentally induced hepatic fibrosis. In this context, hepatosplenic schistosomiasis is of particular interest, being an immune cell-mediated granulomatous disease and a model of liver fibrosis allowing extensive studies in human and animals as well as providing original in vitro models.

Anti-schistosomal drugs: observations on the mechanism of drug resistance to hycanthone, and on the involvement of host antibodies in the mode of action of praziquantel

This paper reports recent observations from our laboratory dealing with the anti-schistosome drugs hycanthone (HC) and praziquantel (PZQ). In particular, we discuss a laboratory model of drug resistance to HC in Schistosoma mansoni and show that drug sensitive and resistant lines of the parasite can be differentiated on the basis of restriction fragment length polymorphisms using homologous ribosomal gene probes. In addition, we summarize data demonstrating that effective chemotherapy of S. mansoni infection with PZQ in mice requires the presence of host anti-parasite antibodies. These antibodies bind to PZQ treated worms and may be involved in an antibody-dependent cellular cytotoxicity reactions which result in the clearance of worms from the vasculature.

Action of colchicine on hepatic schistosomal granuloma

Amorphous material and altered collagen fragments within dilated secretory vesicles and cisternae of fibroblast cytoplasm were the main ultrastructural changes seen in hepatic periovular granulomas formed in mice infected with Schistosoma mansoni and treated with colchicine. Despite promoting ultrastructural changes in the fibroblasts found in hepatic periovular granulomas, colchicine administration to infected mice did not significantly change the light microscopic appearance of the hepatic schistosomal lesions, did not diminish the amount of total hepatic collagen, and did not change the collagen isotypes in the granulomas, as observed after a comparative study with non-colchicine treated infected control mice. When administered to mice two weeks after curative treatment of schistosomiasis with praziquantel, colchicine did not seem to increase extracellular collagen degradation or to induce a more rapid resorption of hepatic periovular granulomas, although still promoting ultrastructura alterations in fibroblasts.

Hyperplasia of elastic tissue in hepatic schistosomal fibrosis

Elastic tissue hyperplasia, revealed by means of histological, immunocytochemical and ultrastructural methods, appeared as a prominent change in surgical liver biopsies taken from 61 patients with schistosomal periportal and septal fibrosis. Such hyperplasia was absent in ecperimental murine schistosomiasis, including mice with "pipe-stem" fibrosis. Displaced connective tissue cells in periportal areas, such as smooth muscle cells, more frequently observed in human material, could be the site of excessive elastin synthesis, and could explain the differences observed in human and experimental materials. Elastic tissue, sometimes represented by its microfibrillar components, also appeared to be more condensed in areas of matrix (collagen) degradation, suggesting a participation of this tissue in the remodelling of the extracellular matrix. By its rectratile properties elastic tissue hyperplasia in hepatic schistosomiasis can cause vascular narrowing and thus play a role in the pathogenesis of portal hypeertension.