Multicentric Castleman's disease associated with glomerular microangiopathy and MPGN-like lesion: does vascular endothelial cell-derived growth factor play causative or protective roles in renal injury?

TAFRO syndrome with renal biopsy successfully treated with steroids and cyclosporine: a case report

Background

TAFRO syndrome is an acute or subacute systemic inflammatory disease with no apparent cause, presenting with fever, generalized edema, thrombocytopenia, renal damage, anemia, and organ enlargement. Interleukin-6, vascular endothelial growth factor, and other cytokines are thought to be the etiologic agents that increase vascular permeability and cause the resulting organ damage. Only few reports of renal biopsy performed in patients with TAFRO syndrome exist.

Case presentation

A 61-year-old woman, with a history of Sjogren’s syndrome, was admitted to our hospital with anasarca and abdominal distension. Based on the clinical course and various laboratory findings, we diagnosed TAFRO syndrome. Renal biopsy revealed thrombotic microangiopathy, including endothelial cell swelling, subendothelial space expansion, and mesangiolysis. She was treated with oral prednisolone and cyclosporine, with consequent resolution of anasarca, pleural effusion, and ascites, and improvement in renal function and urinary findings. The patient’s platelet count also normalized after 2 months of treatment.

Conclusions

Given that only few reports of improvement in the systemic symptoms of TAFRO syndrome using steroids and cyclosporine exist, our study investigating the relationship between the pathogenesis of TAFRO syndrome and renal disorders, as well as treatment methods, provides valuable insights.

Fibronectin Glomerulopathy Confused with Glomerular Endothelial Injury in a Patient with Takotsubo Cardiomyopathy

A 46-year-old woman developed takotsubo cardiomyopathy and nephrotic syndrome. The first kidney biopsy suggested non-immune-complex-mediated membranoproliferative glomerulonephritis (MPGN), and she was diagnosed with glomerular endothelial injury associated with takotsubo cardiomyopathy. A second biopsy was performed two years later because of persistent proteinuria despite renin-angiotensin system inhibition. This biopsy indicated non-immune-complex-mediated MPGN, but a mesangial and subendothelial substance of a higher electron density than that in the first biopsy was detected, suggesting the possibility of glomerular disease with non-immune deposits rather than endothelial injury. Finally, she was diagnosed with fibronectin nephropathy. Although rare, fibronectin glomerulopathy should be considered in non-immune-complex-mediated MPGN.

Successful treatment with tocilizumab for refractory anemia and slowly progressive renal glomerulosclerosis in multicentric Castleman disease: A case report

RATIONALE

Multicentric Castleman disease (MCD) is a rare lymphoproliferative disorder accompanied by systemic symptoms characterized by polyclonal hypergammaglobulinemia and chronic inflammation due to overexpression of interleukin-6. Histological heterogeneity of renal involvement in MCD has been described, although the number of reports is limited. Tocilizumab, a humanized anti-interleukin-6 receptor antibody, has been reported to be effective for MCD.

PATENT CONCERNS

A 64-year-old man experienced refractory anemia and slowly progressive renal dysfunction with proteinuria, accompanied by persistent inflammation for 11 years.

DIAGNOSIS

Two renal biopsies were obtained. The first biopsy performed 7 years before admission revealed non-specific interstitial inflammation, whereas the second biopsy demonstrated global sclerosis in most glomeruli and interstitial fibrosis. The patient had multiple lymphadenopathies. Cervical lymph node biopsy histological findings were compatible with plasma cell type Castleman disease. The patient had no evidence of human hepatitis virus-8 infection.

INTERVENTION

The patient was treated with 60 mg/d prednisolone followed by 8 mg/kg intravenous tocilizumab every 2 weeks.

OUTCOME

His anemia significantly improved, as well as a marked reduction in proteinuria and stabilization of renal function. He did not experience renal function during the 2-years follow-up period.

LESSONS

The heterogeneity of the renal manifestations of MCD sometimes makes early diagnosis difficult. We need to interpret the histological findings of the renal biopsy carefully. For advanced-stage renal diseases, tocilizumab might be an effective treatment strategy for MCD.

HHV-8-negative multicentric Castleman disease presenting as a crescentic immune complexes membranoproliferative glomerulonephritis

Multicentric Castleman disease is a rare polyclonal lymphoproliferative disorder mainly associated with two renal manifestations: thrombotic microangiopathy and amyloidosis. Nevertheless, we report here a case of human herpes virus-8 negative multicentric Castleman disease with membranous proliferative glomerulonephritis and extracapillary proliferation. A patient was successfully treated with corticosteroids, anti-CD20 and cyclophosphamide therapy.

TAFRO syndrome as a cause of glomerular microangiopathy: a case report and literature review

Background

TAFRO syndrome is a systemic inflammatory disorder that manifests as thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (R), and organomegaly (O). Renal dysfunction is frequently complicated with TAFRO syndrome, however, it is challenging to perform kidney biopsy in patients with TAFRO syndrome in the presence of thrombocytopenia. Renal histology in TAFRO syndrome mainly shows membranoproliferative glomerulonephritis (MPGN)-like lesions or thrombotic microangiopathy (TMA)-like glomerulopathy. We review our case and previous reports of TAFRO syndrome with kidney biopsy findings and discuss the renal pathophysiology of TAFRO syndrome.

Case presentation

We describe a previously healthy 48- year-old woman with TAFRO syndrome. Kidney biopsy performed before the treatment showed diffuse global endocapillary proliferative changes with endothelial cell swelling, double contours of partial capillary walls, and mesangiolysis, consistent with TMA-like glomerulopathy. Glucocorticoid therapy including steroid pulse was ineffective and she developed anasarca, renal dysfunction and oliguria. Hemodialysis was required. However, the anti-Interleukin (IL)-6 receptor antibody (tocilizumab) therapy was very effective. An increase in urinary volume was achieved about 2 weeks after the tocilizumab therapy and hemodialysis was discontinued. To investigate the renal pathophysiology of TAFRO syndrome, we performed immunohistological staining of vascular endothelial growth factor (VEGF)-A, CD34, and D2–40, in our case and a normal control kidney. Glomerular VEGF-A was especially positive in podocytes both, in the control and in the case, with no significant difference and there was a significant increase of VEGF-A staining area in the cortical peritubular capillaries in the case. Both glomerular and renal cortical CD34 expression were significantly decreased in our case. D2–40 expression in cortex was not significantly different.

Conclusions

We reviewed our case and other 10 previous reports about renal biopsy findings in TAFRO syndrome and found that glomerular microangiopathy was a common finding. IL-6-VEGF-axis-induced glomerular microangiopathy may play a crucial role in developing acute kidney injury in TAFRO syndrome and the anti-IL-6 receptor antibody therapy may be useful for TAFRO syndrome refractory to glucocorticoids. About the pathophysiology of VEGF in TAFRO syndrome, VEGF balance in the glomerulus and perhaps in the peritubular capillary system as well may be critical. Further investigation is needed.

Association of vascular endothelial growth factor and renal thrombotic microangiopathy-like lesions in patients with Castleman's disease

AIM

Renal thrombotic microangiopathy (TMA) is a common pathological manifestation of Castleman's disease (CD)-associated renal lesions. Increased level of plasma vascular endothelial growth factor (VEGF) has been shown in single-case reports. We aimed to investigate the dysregulation of VEGF in the pathogenesis of CD-associated TMA-like lesions (CD-TMA) in a larger cohort.

METHODS

Nineteen patients with clinico-pathologically diagnosed CD with renal involvement were enrolled. Ten patients with pregnancy TMA or TMA of unknown reasons were enrolled as TMA control group. The plasma levels of VEGF, soluble Flt-1 and interleukin-6 (IL-6) were detected using enzyme-linked immunosorbent assay kits. The expression of VEGF in the kidney biopsied tissue sections and the lymph node specimens were detected by immunostaining.

RESULTS

The plasma levels of VEGF and IL-6 levels were the highest in CD-TMA group compared to TMA control group and healthy controls. The levels of plasma VEGF was positively correlated with that of IL-6, and increased expression of VEGF and IL-6 was also observed in the lymph nodes from CD-TMA patients. However, the expression of VEGF in the glomerular podocytes was significantly decreased in CD-TMA group as well as in the TMA control.

CONCLUSION

Our findings suggest that renal VEGF expression might be important in the pathogenetic mechanism of CD-associated TMA-like lesions.

Serial Manifestation of Acute Kidney Injury and Nephrotic Syndrome in a Patient with TAFRO Syndrome

A 76-year-old woman suddenly developed anasarca and a fever, and an examination revealed thrombocytopenia, reticulin fibrosis, and acute kidney injury, yielding the diagnosis of thrombocytopenia, anasarca, fever, reticulin fibrosis, organomegaly (TAFRO) syndrome. Renal replacement therapy and steroid treatment were soon started. Her proteinuria was minor at first; however, once the kidney function improved, nephrotic syndrome occurred. A kidney biopsy showed membranoproliferative glomerulonephritis-like glomerulopathy with massive macrophage infiltration. Although kidney dysfunction is often observed in TAFRO syndrome patients, its detailed mechanism is unclear. This case suggests that TAFRO syndrome involves both acute kidney injury with minor proteinuria and nephrotic syndrome, and these disorders can develop serially in the same patient.

A rare case of renal thrombotic microangiopathy associated with Castleman's disease

Background

Castleman’s disease (CD) is an uncommon, heterogeneous lympho-proliferative disorder leading to high circulating levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF). Renal involvement has been only described in a limited number of small studies. Herein, we report a rare case of renal thrombotic microangiopathy (TMA) associated with CD and investigate the podocyte expression of VEGF in the renal biopsy prior to initiation of treatment.

Case presentation

An 18-year-old male presented with fever, diarrhea, diffuse lymphadenopathy, ascites and acute kidney injury. Laboratory tests for hemolytic uremic syndrome and thrombotic thrombocytopenic purpura were negative. The kidney biopsy showed TMA. An excisional lymph node biopsy was consistent with CD, plasma cell variant. Immunofluorescence staining showed suppressed podocyte VEGF expression. Chemotherapy that inhibits production of inflammatory mediators including IL-6 and VEGF led to complete recovery of renal function.

Conclusions

Our case illustrates a rare renal histological feature of CD. IL-6 and VEGF are postulated to suppress glomerular VEGF expression, thereby causing renal TMA. Therapy directed against these inflammatory mediators may have important therapeutic implications.

Balkan endemic nephropathy: an update on its aetiology

Balkan endemic nephropathy (BEN) is a unique, chronic renal disease frequently associated with upper urothelial cancer (UUC). It only affects residents of specific farming villages located along tributaries of the Danube River in Bosnia-Herzegovina, Croatia, Macedonia, Serbia, Bulgaria, and Romania where it is estimated that ~100,000 individuals are at risk of BEN, while ~25,000 have the disease. This review summarises current findings on the aetiology of BEN. Over the last 50 years, several hypotheses on the cause of BEN have been formulated, including mycotoxins, heavy metals, viruses, and trace-element insufficiencies. However, recent molecular epidemiological studies provide a strong case that chronic dietary exposure to aristolochic acid (AA) a principal component of Aristolochia clematitis which grows as a weed in the wheat fields of the endemic regions is the cause of BEN and associated UUC. One of the still enigmatic features of BEN that need to be resolved is why the prevalence of BEN is only 3-7 %. This suggests that individual genetic susceptibilities to AA exist in humans. In fact dietary ingestion of AA along with individual genetic susceptibility provides a scenario that plausibly can explain all the peculiarities of BEN such as geographical distribution and high risk of urothelial cancer. For the countries harbouring BEN implementing public health measures to avoid AA exposure is of the utmost importance because this seems to be the best way to eradicate this once mysterious disease to which the residents of BEN villages have been completely and utterly at mercy for so long.

Diet-related DNA adduct formation in relation to carcinogenesis

The human diet contributes significantly to the initiation and promotion of carcinogenesis. It has become clear that the human diet contains several groups of natural foodborne chemicals that are at least in part responsible for the genotoxic, mutagenic, and carcinogenic potential of certain foodstuffs. Electrophilic chemicals are prone to attack nucleophilic sites in DNA, resulting in the formation of altered nucleobases, also known as DNA adducts. Since DNA adduct formation is believed to signal the onset of chemically induced carcinogenesis, the DNA adduct-inducing potential of certain foodstuffs has been investigated to gain more insight into diet-related pathways of carcinogenesis. Many studies have investigated diet-related DNA adduct formation. This review summarizes work on known or suspected dietary carcinogens and the role of DNA adduct formation in hypothesized carcinogenesis pathways.

The influence of ochratoxin A on DNA adduct formation by the carcinogen aristolochic acid in rats

Exposure to the plant nephrotoxin and carcinogen aristolochic acid (AA) leads to the development of AA nephropathy, Balkan endemic nephropathy (BEN) and upper urothelial carcinoma (UUC) in humans. Beside AA, exposure to ochratoxin A (OTA) was linked to BEN. Although OTA was rejected as a factor for BEN/UUC, there is still no information whether the development of AA-induced BEN/UUC is influenced by OTA exposure. Therefore, we studied the influence of OTA on the genotoxicity of AA (AA-DNA adduct formation) in vivo. AA-DNA adducts were formed in liver and kidney of rats treated with AA or AA combined with OTA, but no OTA-related DNA adducts were detectable in rats treated with OTA alone or OTA combined with AA. Compared to rats treated with AA alone, AA-DNA adduct levels were 5.4- and 1.6-fold higher in liver and kidney, respectively, of rats treated with AA combined with OTA. Although AA and OTA induced

NAD(P)H

quinone oxidoreductase (NQO1) activating AA to DNA adducts, their combined treatment did not lead to either higher NQO1 enzyme activity or higher AA-DNA adduct levels in ex vivo incubations. Oxidation of AA I (8-methoxy-6-nitrophenanthro[3,4-d]-1,3-dioxole-5-carboxylic acid) to its detoxification metabolite, 8-hydroxyaristolochic acid, was lower in microsomes from rats treated with AA and OTA, and this was paralleled by lower activities of cytochromes P450 1A1/2 and/or 2C11 in these microsomes. Our results indicate that a decrease in AA detoxification after combined exposure to AA and OTA leads to an increase in AA-DNA adduct formation in liver and kidney of rats.

Chinese herbs containing aristolochic acid associated with renal failure and urothelial carcinoma: a review from epidemiologic observations to causal inference

Herbal remedies containing aristolochic acid (AA) have been designated to be a strong carcinogen. This review summarizes major epidemiologic evidence to argue for the causal association between AA exposure and urothelial carcinoma as well as nephropathy. The exposure scenarios include the following: Belgian women taking slimming pills containing single material Guang Fang Ji, consumptions of mixtures of Chinese herbal products in the general population and patients with chronic renal failure in Taiwan, occupational exposure in Chinese herbalists, and food contamination in farming villages in valleys of the Danube River. Such an association is corroborated by detecting specific DNA adducts in the tumor tissue removed from affected patients. Preventive actions of banning such use and education to the healthcare professionals and public are necessary for the safety of herbal remedies.

Mechanisms of enzyme-catalyzed reduction of two carcinogenic nitro-aromatics, 3-nitrobenzanthrone and aristolochic acid I: Experimental and theoretical approaches

This review summarizes the results found in studies investigating the enzymatic activation of two genotoxic nitro-aromatics, an environmental pollutant and carcinogen 3-nitrobenzanthrone (3-NBA) and a natural plant nephrotoxin and carcinogen aristolochic acid I (AAI), to reactive species forming covalent DNA adducts. Experimental and theoretical approaches determined the reasons why human

NAD(P)H

quinone oxidoreductase (NQO1) and cytochromes P450 (CYP) 1A1 and 1A2 have the potential to reductively activate both nitro-aromatics. The results also contributed to the elucidation of the molecular mechanisms of these reactions. The contribution of conjugation enzymes such as N,O-acetyltransferases (NATs) and sulfotransferases (SULTs) to the activation of 3-NBA and AAI was also examined. The results indicated differences in the abilities of 3-NBA and AAI metabolites to be further activated by these conjugation enzymes. The formation of DNA adducts generated by both carcinogens during their reductive activation by the NOQ1 and CYP1A1/2 enzymes was investigated with pure enzymes, enzymes present in subcellular cytosolic and microsomal fractions, selective inhibitors, and animal models (including knock-out and humanized animals). For the theoretical approaches, flexible in silico docking methods as well as ab initio calculations were employed. The results summarized in this review demonstrate that a combination of experimental and theoretical approaches is a useful tool to study the enzyme-mediated reaction mechanisms of 3-NBA and AAI reduction.

Monoclonality and cytogenetic abnormalities in hyaline vascular Castleman disease

Hyaline vascular Castleman disease is traditionally regarded as a reactive hyperplastic process. Occasional cases, however, have been reported with cytogenetic anomalies bringing this concept into question. In this study, we used conventional and methylation-specific polymerase chain reaction methods to assess the human androgen receptor α (HUMARA) gene in 29 female patients with hyaline vascular Castleman disease and compared the results with three cases of plasma cell Castleman disease and 20 cases of age-matched lymphoid hyperplasia. We also assessed for immunoglobulin gene and T-cell receptor gene rearrangements, and conventional cytogenetic analysis was performed in three cases of hyaline vascular Castleman disease. In cases with informative results, conventional and methylation-specific human androgen receptor α gene analyses yielded a monoclonal pattern in 10 of 19 (53%) and 17 of 23 (74%) cases of hyaline vascular Castleman disease, respectively. A monoclonal pattern was also detected in three cases of plasma cell Castleman disease but not in cases of lymphoid hyperplasia. The frequency of monoclonality was higher for lesions >5 cm in size (100%) and for the stromal-rich variant (91%). Cytogenetic abnormalities in stromal cells were revealed in two cases of hyaline vascular Castleman disease and no cases showed monoclonal immunoglobulin or T-cell receptor gene rearrangements. Follow-up data showed persistent disease in 4 of 23 (17%) patients. We conclude that hyaline vascular Castleman disease is often a monoclonal proliferation, most likely of lymph node stromal cells.

Knockout and humanized mice as suitable tools to identify enzymes metabolizing the human carcinogen aristolochic acid

1. Aristolochic acid I (AAI) is the predominant component in plant extract of Aristolochia genus that is involved in development of aristolochic acid nephropathy, Balkan endemic nephropathy and urothelial cancer. The diseases do not develop in all individuals exposed to AAI and patients exhibit different clinical outcomes. Differences in the activities of enzymes catalyzing the metabolism of AAI might be one of the reasons for this individual susceptibility. 2. Understanding which human enzymes are involved in reductive activation of AAI generating AAI-DNA adducts, and/or its detoxication to the O-demethylated metabolite, aristolochic acid Ia (AAIa), is necessary in the assessment of the susceptibility to this compound. 3. This review summarizes the results of the latest studies utilizing genetically engineered mouse models to identify which human and rodent enzymes catalyze the reductive activation of AAI to AAI-DNA adducts and its oxidative detoxication to AAIa in vivo. 4. The use of hepatic cytochrome P450 (Cyp) reductase null (HRN) mice, in which NADPH:Cyp oxidoreductase (Por) is deleted in hepatocytes, Cyp1a1((-/-)), Cyp1a2((-/-)) single-knockout, Cyp1a1/1a2((-/-)) double-knockout and CYP1A-humanized mice revealed that mouse and human CYP1A1 and 1A2, besides mouse

NAD(P)H

quinone oxidoreductase, were involved in the activation of AAI but CYP1A1 and 1A2 also oxidatively detoxified AAI.

Multicentric Castleman's disease: a challenging diagnosis

Multicentric Castleman's disease (MCD) is a sytemic disorder with flares of non-specific symptoms suggestive of a chronic inflammatory syndrome. It is typically accompanied by generalized lymphadenopathy and multiorgan involvement. Histologically, two main variants of Castleman's disease exist, the hyalin vascular type and the plasma cell variant. Upon localization unicentric (localized), and multicentric (diffuse, systemic) subtypes can be distinguished with more different disease outcomes. Patients often exhibit acute phase reactions and several autoimmune phenomena, and are at high risk for developing malignancies. Both the idiopathic and the HHV-8-driven infectious forms of MCD represent distinct disease entities with a less favorable prognosis. The induction of human IL-6 excess via yet unknown upstream mechanisms, and overexpression of viral IL-6 by HHV-8 can pivotally influence MCD biology. Based on the role of IL-6 in pathogenesis, MCD is also designated as IL-6 lymphadenopathy. To date there are no direct therapeutic evidences, but having been translated to daily practice the main regulatory factors may serve as promising therapeutic targets.

Clinical features and outcome of patients with HIV-negative multicentric Castleman's disease treated with combination chemotherapy: a report on 10 patients

To investigate the clinical characteristics and outcome of patients with HIV-negative multicentric Castleman's disease (MCD) treated exclusively with combination chemotherapy, and review literature to improve the diagnosis and management of this disease. A retrospective study was performed on the medical records of 10 patients with HIV-negative MCD treated exclusively with combination chemotherapy at one medical institution from May 2004 to April 2012. And relevant clinical, pathological, radiographic, and laboratory data were examined in order to evaluate treatment responses, with symptom onsets and survival period serving as the endpoints of the assessment. All patients have multifocal lymphadenopathy, and the associated system symptoms are found in 80 % of the cases. All patients were treated with lymphoma-based chemotherapy alone. The duration of follow-up ranged from 5 to 77 months for nine patients. Four patients were treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) alone: One was alive with no evidence of disease, and three were alive with disease. Three patients received cyclophosphamide, vincristine, and prednisone (COP) alone: One remained alive with disease, and two experienced recurrences and passed away. Two had only minimal response to COP and were switched to CHOP, and they were still alive with disease. MCD is a more progressive clinical entity, and long-term follow-up is necessary. CHOP chemotherapy may be an effective treatment option for patients with MCD, whereas when to start chemotherapy, how many cycles of chemotherapy required, and the role of combined radiotherapy remain to be further studied.

Membranoproliferative glomerulonephritis complicating Propionibacterium acnes infection

Background

Propionibacterium acnes (P. acnes) is a common microbe of the skin and mucosal surfaces rarely considered a true pathogen. However, it has been reported to cause serious infections. Subsequent ongoing low-grade antigenaemia may, in turn, lead to an immune-mediated glomerulonephritis with various renal histologies including that of membranoproliferative glomerulonephritis (MPGN).

Methods

Here, we describe two cases of P. acnes infection-induced MPGN and their treatment.

Results

Both patients were successfully treated by the eradication of the infection. One patient also received immunosuppressive medication prior to the correct diagnosis.

Conclusions

A vigorous exclusion of infection is warranted in MPGN type I or immune-complex-mediated MPGN and may sometimes yield a diagnosis of secondary MPGN.

Efficacy of tocilizumab, a humanized neutralizing antibody against interleukin-6 receptor, in progressive renal injury associated with Castleman's disease

Castleman's disease is a benign lymphoproliferative disorder in which interleukin-6 (IL-6), a pleiotropic proinflammatory cytokine, is thought to play a pathogenetic role. Presented is the case of a 72-year-old man with Castleman's disease who exhibited progressive renal dysfunction with proteinuria. Renal biopsy revealed mesangial hypercellularity and matrix expansion in most glomeruli and peritubular inflammatory cell infiltration. Immunofluorescence studies showed intense deposition of IgG in a granular pattern along the glomerular basement membrane. Histological features were compatible with membranoproliferative glomerulonephritis accompanied by interstitial inflammatory cell infiltration. Immunohistological analysis showed that IL-6 was abundantly expressed by tubular cells and interstitial macrophages, suggesting involvement of IL-6 in the renal injury. As a result of administration of tocilizumab, a humanized anti-IL-6 receptor antibody, the patient experienced clinical and biochemical improvement of Castleman's disease, including marked reduction of proteinuria and stabilization of renal function. These findings suggest the efficacy of tocilizumab against Castleman's disease and its renal complications.

Membranoproliferative glomerulonephritis in Castleman's disease: a systematic review of the literature and 2 case reports

We report two cases of membranoproliferative glomerulonephritis, involved in Castleman's disease of hyaline vascular variant and mixed variant, respectively. The diagnoses were confirmed by cervical lymph node and renal biopsy. Both cases were sensitive to chemotherapy with cyclophosphamide, vindesine and prednisone (COP). With the experience from treating case 1, which was misdiagnosed 9 years previously, we followed a more vigilant approach toward case 2 and achieved a more timely diagnosis. Finally, we reviewed pertinent literature of diagnosis and therapy to facilitate an early diagnosis of rare cases in the future.

Successful use of tocilizumab in a patient with nephrotic syndrome due to a rapidly progressing AA amyloidosis secondary to latent tuberculosis

AA (secondary) amyloidosis is one of the most severe and uncommon complications of several rheumatic disorders and chronic infections such as tuberculosis (TB). Successful treatment depends on the control of the underlying inflammatory process, what can lead to an improvement or a regression in organ dysfunction. If the disorder persists, it has been reported in some cases of AA amyloidosis secondary to rheumatic diseases, that the use of biologic therapy is so far the only opportunity to reduce the development of AA amyloidosis and to reverse established deposits. We report herein a case of a latent TB infection complicated by a life-threatening AA amyloidosis presented as nephrotic syndrome. After an adequate antituberculostatic treatment, AA amyloidosis remained active and Tocilizumab (TCZ) was started with a dramatic resolution of the proteinuria, stabilization of the amyloid deposits and improvement in general condition.

Renal involvement in a large cohort of Chinese patients with Castleman disease

BACKGROUND

The association of kidney disease with Castleman disease (CD) is uncommon. To date, most studies have been based on single-case reports. Here, we describe renal involvement in CD in a large Chinese cohort.

METHODS

Seventy-six CD patients were identified in one clinical center. Clinical and pathological characteristics of patients with renal involvement were described, which were also compared with cases identified through a systematic literature review.

RESULTS

Nineteen patients (25%) exhibited renal involvement. Patients with multicentric clinical type (59 versus 0%) or plasma cell (PC)/mixed cellularity histological variant (61.5 versus 6%) were more likely to have renal involvement (P < 0.001). Proteinuria (with 7/19 reaching nephrotic range) and acute renal failure (12/19, 63%) were the main clinical presentations. Kidney biopsy revealed various glomerular diseases (10/11) and interstitial nephritis (1/11), while with 'thrombotic microangiopathy-like' lesions were the most common pathological characteristics (6/11, 55%). This contrasted significantly with the literature in which amyloidosis was the most reported. Renal outcomes responded well to chemotherapy. Nine (9/12, 75%) patients with acute renal failure recovered completely, one recovered partially. Overall, only three (3/19, 16%) patients progressed to end-stage kidney disease. Renal involvement did not influence survival rate (log-rank test, P = 0.73) in the follow-up.

CONCLUSIONS

CD with multicentric type and PC or mixed cellularity variant are often associated with renal complications. Thrombotic microangiopathy-like lesions are the most common pathological characteristics. Chemotherapy can reverse kidney damage in most cases.

Renal involvement in Castleman disease

BACKGROUND

Castleman disease (CD), or angiofollicular lymph-node hyperplasia, is an atypical lymphoproliferative disorder with heterogeneous clinical manifestations. Renal involvement in CD has been described in only single-case reports, which have included various types of renal diseases.

METHODS

Nineteen patients with histologically documented CD and renal biopsies available were included. Clinical features and renal histological findings were reviewed, and the available samples were immunolabelled with anti-vascular endothelial growth factor (VEGF) antibody.

RESULTS

Nineteen CD cases were identified: 89% were multicentric, and 84% were of the plasma-cell or mixed type. Four cases (21%) were associated with human immunodeficiency virus (HIV) infection. Among HIV-negative patients, two main patterns of renal involvement were found: (i) a small-vessel lesions group (SVL) (60%) with endotheliosis and glomerular double contours in all patients and with superimposed glomerular/arteriolar thrombi or mesangiolysis in most; and (ii) AA amyloidosis (20%). Renal histology was more heterogeneous among HIV-positive patients. Decreases in glomerular VEGF were observed only in some patients with SVL, whereas VEGF staining was normal in all other histological groups. Interestingly, glomerular VEGF loss associated with SVL was correlated with plasma C-reactive protein levels, a marker of CD activity.

CONCLUSIONS

Small-vessel lesions are the most frequent renal involvement in CD, whereas loss of glomerular VEGF is correlated with CD activity and could have a role in SVL pathophysiology.

Successful stabilisation of nephropathy in a patient with POEMS (polyneuropathy, organomegaly, endocrinopathy, M-band, skin changes) syndrome on treatment with mycophenolate and steroids: a case report

Introduction

Renal involvement in POEMS (polyneuropathy, organomegaly, endocrinopathy, M-band, skin changes) syndrome is considered to be an under-diagnosed phenomenon with no clear treatment path. The limited literature suggests steroids to be the drug of choice, although improvements are limited and usually reverse on withdrawal of the drug.

Case presentation

A 52-year-old Caucasian woman presenting with features consistent with POEMS syndrome developed progressive renal impairment with proteinuria. Renal biopsy revealed a membranoproliferative glomerulonephritis. She was treated with relatively low dose oral mycophenolate mofetil and prednisolone which stabilised her nephropathy and neuropathy.

Conclusion

We describe an alternative therapeutic option in patients with this serious but poorly understood condition.

Castleman's disease: a study of a rare lymphoproliferative disorder in a university hospital

Castleman's disease (CD) is a group of rare lymphoproliferative disorders sharing characteristic clinical and histological features, and usually accompanied by a marked systemic inflammatory response. Two histological patterns of lymph nodes were described: the hyaline-vascular and plasma-cell types. The former is more common (80-90%) and tends to be localized. The plasma cell type is more aggressive and usually multicentric. It is interesting that the inflammatory manifestations seem to be related to a lymph node lesion, because the systemic symptoms and inflammatory activity can return to normal after surgical excision or successful medical treatment of the disease. We report here our 15-year experience with this rare disease in King Fahd Hospital of the University, Al-Khobar, Saudi Arabia, focusing on the clinical features, therapy, and patients'outcome.

Cytochrome P450 1A2 detoxicates aristolochic acid in the mouse

Aristolochic acids (AAs) are plant-derived nephrotoxins and carcinogens responsible for chronic renal failure and associated urothelial cell cancers in several clinical syndromes known collectively as aristolochic acid nephropathy (AAN). Mice provide a useful model for study of AAN because the renal histopathology of AA-treated mice is strikingly similar to that of humans. AA is also a potent carcinogen in mice with a tissue spectrum somewhat different from that in humans. The toxic dose of AA in mice is higher than that in humans; this difference in susceptibility has been postulated to reflect differing rates of detoxication between the species. Recent studies in mice have shown that the hepatic cytochrome P450 system detoxicates AA, and inducers of the arylhydrocarbon response protect mice from the nephrotoxic effects of AA. The purpose of this study was to determine the role of specific cytochrome P450 (P450) enzymes in AA metabolism in vivo. Of 18 human P450 enzymes we surveyed only two, CYP1A1 and CYP1A2, which were effective in demethylating 8-methoxy-6-nitro-phenanthro-(3,4-d)-1,3-dioxolo-5-carboxylic acid (AAI) to the nontoxic derivative 8-hydroxy-6-nitro-phenanthro-(3,4-d)-1,3-dioxolo-5-carboxylic acid (AAIa). Kinetic analysis revealed similar efficiencies of formation of AAIa by human and rat CYP1A2. We also report here that CYP1A2-deficient mice display increased sensitivity to the nephrotoxic effects of AAI. Furthermore, Cyp1a2 knockout mice accumulate AAI-derived DNA adducts in the kidney at a higher rate than control mice. Differences in bioavailability or hepatic metabolism of AAI, expression of CYP1A2, or efficiency of a competing nitroreduction pathway in vivo may explain the apparent differences between human and rodent sensitivity to AAI.

Mutational spectra of human cancer

The purpose of this review is to summarize the evidence that can be used to reconstruct the etiology of human cancers from mutations found in tumors. Mutational spectra of the tumor suppressor gene p53 (TP53) are tumor specific. In several cases, these mutational spectra can be linked to exogenous carcinogens, most notably for sunlight-associated skin cancers, tobacco-associated lung cancers, and aristolochic acid-related urothelial tumors. In the TP53 gene, methylated CpG dinucleotides are sequences selectively targeted by endogenous and exogenous mutagenic processes. Recent high-throughput sequencing efforts analyzing a large number of genes in cancer genomes have so far, for the most part, produced mutational spectra similar to those in TP53 but have unveiled a previously unrecognized common G to C transversion mutation signature at GpA dinucleotides in breast cancers and several other cancers. Unraveling the origin of these G to C mutations will be of importance for understanding cancer etiology.

Interleukin-6 receptor inhibition with tocilizumab in various renal involvements associated with multicentric Castleman's disease: a report of three cases

Multicentric Castleman's disease (MCD) is an inflammatory lymphoproliferative disorder characterized by polyclonal hypergammopathy and dysregulated overproduction of interleukin-6 (IL-6). A variety of renal involvements infrequently arise in patients with MCD. However, there is no established treatment for MCD and its associated renal involvements. We present the effects of an anti-IL-6 receptor monoclonal antibody, tocilizumab, on three patients with MCD associated with various renal manifestations. In all three patients, tocilizumab treatment was very effective in reducing proteinuria and stabilizing renal function, as well as improving other clinical symptoms. These findings indicate the pathological significance of IL-6 in renal involvements associated with MCD, and the potential use of tocilizumab in its treatment.

A case of Castleman's disease complicated with nephrotic syndrome due to glomerulopathy mimicking membranoproliferative glomerulonephritis

Castleman's disease is a rare atypical lymphoproliferative disorder. Renal manifestations, such as proteinuria, hematuria, and renal dysfunction, are common in Castleman's disease; however, a nephrotic syndrome rarely occurs. We have encountered an unusual case of Castleman's disease of the plasma cell type characterized by nephrotic syndrome because of glomerulopathy mimicking membranoproliferative glomerulonephritis. Our patient showed higher levels of circulating cytokines (interleukin-6/vascular endothelial cell-derived growth factor), the glomerular lesions not associated with immunocomplex deposition, and the resolution of nephrotic syndrome after successful corticosteroids therapy resulting in a decline in cytokines levels, thereby implicating a cytokine-induced glomerular cell injury/activation as a possible cause of the glomerular pathological changes in this case.

Selective Toxicity of Aristolochic Acids I and II

Ingestion of herbal remedies containing aristolochic acids (AAs) is associated with the development of a syndrome, designated aristolochic acid nephropathy (AAN), which is characterized by chronic renal failure, tubulointerstitial fibrosis, and urothelial cancer. To distinguish the component(s) of AA responsible for these varied toxic effects, we administered 2.5 mg/kg/day of AA-I or AA-II for 9 days, either i.p. or p.o., to male C3H/He mice. Tissues were then collected and subjected to biochemical and histopathologic examination. Genotoxicity was assessed by determining quantitatively the level of aristolactam-DNA adducts in various tissues using (32)P-postlabeling/polyacrylamide gel electrophoresis and an internal standard. In the primary target tissues, represented by the renal cortex, medulla, and bladder, we found similar levels of DNA adducts derived from AA-I and AA-II. However, in nontarget tissues, the liver, stomach, intestine, and lung, the levels of aristolactam-DNA adducts derived from AA-I were significantly higher than those derived from AA-II. Histopathologic analysis revealed tubular cell necrosis and interstitial fibrosis in the renal cortex of AA-I-treated mice but only minimal changes in the renal cortex of mice treated with AA-II. We conclude that AA-I and AA-II have similar genotoxic and carcinogenic potential, and, although both compounds are cytotoxic, AA-I is solely responsible for the nephrotoxicity associated with AAN.

Blood pressure control in haemodialysis patients: an audit

OBJECTIVE

This audit was conducted to study the level of achievement of some criteria relevant to blood pressure control in haemodialysis patients and to evaluate if auditing process improves the quality of medical care given to these patients.

METHODS

The records of all 105 patients on maintenance haemodialysis were included in the study. Five criteria relevant to blood pressure control were selected for auditing. The criteria were: predialysis blood pressure control <140/80, dry weight, dialysis adequacy, salt and water intake restriction, and patient education. The auditing process was conducted at two different times 6 months apart.

RESULTS

The first data collected in the auditing process showed that there were only 40 patients (38%) with controlled predialysis blood pressure. In the second data collection the number of patients with controlled predialysis blood pressure had risen significantly to 78 (74.3%), P < 0.0001. The same improvement was achieved for dry weight 39 (37%) to 73 (69.5%) P < 0.0001, dialysis adequacy 38 (36.2%) to 75 (71.4%) P = 0.043, salt and water intake restriction 39 (37%) to 71 (67.6%) P = 0.045, and patient education 30 (28.6%) to 55 (52.4%) P < 0.0001.

CONCLUSION

Setting up audit cycles to evaluate achievement of required standard in relevant criteria contribute to better blood pressure control and leads to improvement in the care of patients on dialysis. Auditing can be an essential tool in identification of poorly controlled blood pressure, its cause and is useful in control of hypertension in the haemodialysis population.

Treatment of Castleman's disease

Castleman's disease (CD) was first described in 1954 and further defined in 1956 by Castleman. Since then much has been learned about the heterogeneity of this condition. Subsequently, three pathologic classifications have been developed (hyaline vascular variant, plasma cell variant, and mixed variant) and two clinical classifications (unicentric [unifocal or localized] and multicentric [multifocal or generalized]). The pathology found with the unicentric presentation is most commonly that of the HV variant. It responds well to surgical resection and is associated with a benign course. The multicentric presentation is rarely composed of lymph nodes with HV pathology, but rather with the plasma cell or mixed pathology. This presentation requires systemic therapy and prognosis is guarded. Associated systemic symptoms are common. There is an increased incidence of CD in patients with HIV. The human herpes virus-8 is associated with nearly all of the HIV-associated CD cases and nearly 50% of non-HIV cases. Interleukin (IL)-6 has also been shown to play a significant role in the pathogenesis of the disease. Paraneoplastic and autoimmune entities are not uncommon in the disorder. Variable benefit has been achieved with single agent chemotherapy, combination chemotherapy, interferon (IFN)-alpha, rituximab, anti-IL-6 receptor antibodies, and thalidomide. Patients with CD are at increased risk for developing frank malignant lymphoma.

Renal involvement in multicentric Castleman disease with glomeruloid hemangioma of skin and plasmacytoma

A 47-year-old man presented with fever of unknown origin, generalized weakness, edema, and renal failure. He had left-sided pleural effusion, generalized lymphadenopathy, multiple nontender cutaneous nodules, hepatomegaly, renal failure, and hypergammaglobulinemia. Axillary lymph node biopsy showed findings consistent with Castleman disease of the hyaline vascular type associated with interfollicular plasmacytosis. A renal biopsy performed in view of proteinuria and acute renal failure showed hypercellular glomeruli with capillary loop thickening and double contours consistent with membranoproliferative glomerulonephritis. Skin nodule biopsy showed a glomeruloid hemangioma characterized by dermal proliferation of capillary loops in a nodular manner resembling a glomerulus. He experienced clinical and biochemical remission with steroids. Discontinuation of steroid therapy was associated with recurrence of renal failure, reappearance of nodules, lymphadenopathy, and appearance of bony lytic lesions. Biopsy of bony lytic lesions showed plasmacytoma. The patient achieved complete remission on treatment with steroids and cyclophosphamide and is free of symptoms at the end of 40 months of follow-up. To our knowledge, this is the first case report of the occurrence of membranoproliferative glomerulonephritis, glomeruloid hemangioma of the skin, and plasmacytoma in a patient with multicentric Castleman disease without human immunodeficiency virus infection.

Quantitative determination of aristolochic acid-derived DNA adducts in rats using 32P-postlabeling/polyacrylamide gel electrophoresis analysis

Aristolochic acids (AA) are nephrotoxic and carcinogenic nitroaromatic compounds produced by the Aristolochiaceae family of plants. Ingestion of these phytotoxins by humans results in a syndrome known as AA nephropathy, characterized by renal tubulointerstitial fibrosis and upper urothelial cancer. After activation by cellular enzymes, AA I and II react with DNA to form covalent adducts and as such represent potential biomarkers for studies of AA toxicity. Using site-specifically modified oligodeoxynucleotides as standards, we have developed a method for quantifying 7-(deoxyadenosin-N(6)-yl) aristolactam-DNA or 7-(deoxyguanosin-N(2)-yl) aristolactam-DNA adducts in tissues of Wistar rats using an assay in which (32)P-postlabeling techniques are coupled with nondenaturing polyacrylamide gel electrophoresis. The limit of detection with this technique is five adducts in 10(9) nucleotides for a 5-microg DNA sample. In contrast to previous reports, we find that the levels of AA adducts in renal tissues of Wistar rats treated p.o. with AA for 1 week with 5 mg/kg/day of AA I or AA II were much higher than that in the forestomach. Highest adduct levels were observed in rats treated with AA II, suggesting that this compound may be more genotoxic than AA I. Treatment of rats with aristolactam I, an end-product of AA I metabolism, resulted in a much lower level of adduction. This study establishes the feasibility of using AA-DNA adducts as intermediate biomarkers of exposure in studies of AA nephropathy and its associated urothelial cancer.