Is there long-term value of pathology scoring in immunoglobulin A nephropathy? A validation study of the Oxford Classification for IgA Nephropathy (VALIGA) update

Background

It is unknown whether renal pathology lesions in immunoglobulin A nephropathy (IgAN) correlate with renal outcomes over decades of follow-up.

Methods

In 1130 patients of the original Validation Study of the Oxford Classification for IgA Nephropathy (VALIGA) cohort, we studied the relationship between the MEST score (mesangial hypercellularity, M; endocapillary hypercellularity, E; segmental glomerulosclerosis, S; tubular atrophy/interstitial fibrosis, T), crescents (C) and other histological lesions with both a combined renal endpoint [50% estimated glomerular filtration rate (eGFR) loss or kidney failure] and the rate of eGFR decline over a follow-up period extending to 35 years [median 7 years (interquartile range 4.1–10.8)].

Results

In this extended analysis, M1, S1 and T1–T2 lesions as well as the whole MEST score were independently related with the combined endpoint (P < 0.01), and there was no effect modification by age for these associations, suggesting that they may be valid in children and in adults as well. Only T lesions were associated with the rate of eGFR loss in the whole cohort, whereas C showed this association only in patients not treated with immunosuppression. In separate prognostic analyses, the whole set of pathology lesions provided a gain in discrimination power over the clinical variables alone, which was similar at 5 years (+2.0%) and for the whole follow-up (+1.8%). A similar benefit was observed for risk reclassification analyses (+2.7% and +2.4%).

Conclusion

Long-term follow-up analyses of the VALIGA cohort showed that the independent relationship between kidney biopsy findings and the risk of progression towards kidney failure in IgAN remains unchanged across all age groups and decades after the renal biopsy.

The role of iron impurities in the toxic effects exerted by short multiwalled carbon nanotubes (MWCNT) in murine alveolar macrophages

Lung toxicity mediated by multiwalled carbon nanotubes (MWCNT) has been widely demonstrated and recently associated with induction of carcinogenic asbestos-like effects, but the chemical features that drive this toxic effect have still not been well elucidated. The presence of metals as trace contaminants during MWCNT preparation, in particular iron (Fe) impurities, plays an important role in determining a different cellular response to MWCNT. Our goal was to clarify the mechanisms underlying MWCNT-induced toxicity with correlation to the presence of Fe impurities by exposing murine alveolar macrophages to two different MWCNT samples, which differed only in the presence or absence of Fe. Data showed that only Fe-rich MWCNT were significantly cytotoxic and genotoxic and induced a potent cellular oxidative stress, while Fe-free MWCNT did not exert any of these adverse effects. These results confirm that Fe content represents an important key constituent in promoting MWCNT-induced toxicity, and this needs to be taken into consideration when planning new, safer preparation routes.

Loss of nephrin expression in glomeruli of kidney-transplanted patients under m-TOR inhibitor therapy

The development of proteinuria has been observed in kidney-transplanted patients on m-TOR inhibitor (m-TORi) treatment. Recent studies suggest that m-TORi(s) may alter the behavior and integrity of glomerular podocytes. We analyzed renal biopsies from kidney-transplanted patients and evaluated the expression of nephrin, a critical component of the glomerular slit-diaphragm. In a group of patients on 'de novo' m-TORi-treatment, the expression of nephrin within glomeruli was significantly reduced in all cases compared to pretransplant donor biopsies. Biopsies from control transplant patients not treated with m-TORi(s) failed to present a loss of nephrin. In a group of patients subsequently converted to m-TORi-treatment, a protocol biopsy performed before introduction of m-TORi was also available. The expression of nephrin in the pre-m-TORi biopsies was similar to that observed in the pretransplant donor biopsies but was significantly reduced after introduction of m-TORi(s). Proteinuria increased after the m-TORi inititiation in this group. However, in some cases proteinuria remained normal despite reduction of nephrin. In vitro, sirolimus downregulated nephrin expression by human podocytes. Our results suggest that m-TORi(s) may affect nephrin expression in kidney-transplanted patients, consistently with the observation in vitro on cultured podocytes.

Life Expectancy of Women with Lupus Nephritis Now Approaches That of the General Population

Immunosuppressive treatment has changed the prognosis of Lupus nephritis over time, but improvement in prognosis is difficult to analyze in different historical periods, and should be better demonstrated in comparison with life expectancy of sex-and age-matched people. Long-term patient and renal survival of 90 patients diagnosed with Lupus nephritis at our center from 1968 to 2001 with a follow-up time of 14±8 years was retrospectively evaluated. Patient and kidney survival significantly increased over time. Multivariate analyses show that risks of patient and renal death decreased by 8% at each year of follow-up, and increased by more than 5 time in patients aged > 30 years at diagnosis. As only 14 patients were men, relative survival as compared to that of the sex- and age-matched general population of the Piedmont Region was calculated for the 76 women. Improvement in the survival of the cohort of women was seen at any time of follow-up: in particular, it was sharply lower in the first period (relative survival at 5,10 and 15 years = 0.784, 0.665, and 0.620, respectively) and increased in the second (relative survival at 5,10 and 15 years = 0.939, 0.921, and 0.850, respectively) nearly approaching that expected for the general population, i.e. 0.993, 0.983 and 0.967, respectively. Taken together, our data allow us to draw the conclusion that life expectancy in women with Lupus nephritis has improved over time, paralleling an improved awareness of the disease and a significant increase in steroid pulse therapy as induction/remission phase. Improvement in survival is for the first time demonstrated to cover the gap with life expectancy of the general population for women with Lupus nephritis.

Phenotype/Genotype Correlations in the Ultrastructure of Monogenetic Glomerular Diseases

Electron microscopy defined classic patterns of hereditary glomerular disease long before genetics revealed an underlying specific mutation. Genetic analysis is now easier to perform in clinical practice but an earlier optimism that genetics would predict disease severity and phenotype is challenged. The classic paradigm is Alport nephritis in which only a subset of mutations may predict glomerular abnormalities and disease severity. Interpretation of ultrastructural pathology of monogenetic diseases like Alport nephritis is complicated when the proband is the first family member to be diagnosed or there is discrepancy between clinical presentation and ultrastructural changes. In this review the authors have selected a dozen cases representative of common monogenetic glomerular diseases as a platform to discuss the utility of diagnostic electron microscopy in the era of molecular genetics. The emphasis is on genotype/glomerular phenotype correlations.

[The histological picture of CRF in kidney grafts]

The most common immunological causes of delayed renal function failure in kidney grafts are recurrent glomerular disease, de novo glomerulonephritis, and chronic cellular or antibody-mediated rejection. Glomerulonephritis can recur any time in the natural history of renal allografts, with the same morphological features of the disease occurring in the native kidney. It has a frequency varying from 100% to 1% and a generally favorable prognosis with the exception of FSGS, SHU and diabetic glomerulosclerosis. The most frequent glomerular diseases to occur de novo in the kidney graft are membranous glomerulopathy, antiglomerular basement membrane disease in patients with Alport's syndrome, and nephrotic syndrome of the Finnish type with antinephrin antibodies in patients with NPHS1 gene mutations. Chronic rejection, including chronic transplant arteriopathy and chronic transplant glomerulopathy, is the cause of renal failure in up to 20% of kidney grafts and may occur as early as a few months after transplant.

Improvement in Relative Survival of Patients with Vasculitis: Study of 101 Cases Compared to the General Population

Immunosuppressive treatment has changed the prognosis of renal vasculitis over time, but improvement in prognosis is difficult to analyze in different historical periods, and can be better demonstrated by comparison with life expectancy of sex- and age-matched people. Long-term survival of 101 patients diagnosed with systemic vasculitis at our center from 1975 to 2002 was retrospectively evaluated in comparison with that of the Region's age- and sex-matched population. Patient and kidney survival significantly increased over time. Multivariate analyses showed that risks of patient and renal death decreased by 10% and 7%, respectively, at each year of follow-up, and increased by 6.3% and 5.2% for each year of age. Relative survival significantly improved over time, approaching that of the general population for cases diagnosed after 1993, mainly in women <60 years (from 0.671 at 5-years in the first period to 0.916 in the last period), while 5-year-relative-survival was still 0.530 and 0.682 in men and women > 60 years, respectively. Poisson-based multinomial analyses confirmed the significant risk of the first periods of diagnosis and of dialysis in worsening of the relative survival of patients compared to that of the general population. Life expectancy in patients with renal vasculitis has improved over time, paralleling a significant increase in steroid pulse/cyclophosphamide association therapy and an earlier diagnosis due to the introduction of the ANCA test. Relative survival has considerably improved, and now approaches that expected in the general population for women, but not for men.

Risk management of renal biopsy: 1387 cases over 30 years in a single centre

BACKGROUND

Although renal biopsy is largely employed, even in old patients with systemic diseases, few clinical studies have addressed its risk management. We aimed to obtain a comprehensive assessment of safety/utility ratio of percutaneous renal biopsy.

PATIENTS AND METHODS

Retrospective review of all the 1387 patients who consecutively underwent renal biopsy in a single centre over three decades (1973-2002) was made, with calculation of complications, multivariate logistical analyses to evaluate risk factors of complications, and rate of alteration of clinical hypotheses by pathological diagnosis.

RESULTS

There were no deaths and five major complications, (0.36%). One nephrectomy (0.07%), two surgical revisions (0.1%) and two arterial-venous fistulae (0.1%). There were also 337 minor bleeding complications (24.2%) (16.4% gross haematuria and 7.8% clinically relevant haematomas needing at least prolonged bed rest). Multivariate analyses demonstrated that the risk for complications was significantly increased by systemic autoimmune diseases with odds ratio (OR) 2.06, 95% confidence interval (CI)=1.40-3.01, end-stage kidney/acute-tubular necrosis (OR 2.96, 95% CI=1.19-7.30), and prolonged bleeding time test (BTT) (OR 1.87, 95% CI=1.17-2.83). Among the 1288 cases in which a clinical hypothesis before renal biopsy was recorded, renal pathology changed previous diagnoses in 423/1,288 (32.8%) of cases.

CONCLUSIONS

Risk assessment demonstrates that renal biopsy is a useful procedure with a low incidence of serious complications. Platelet function is the only modifiable factor significantly related to bleeding complications, suggesting the need for a more standardized alternative to the BTT. Platelet function should be evaluated to select low-risk patients for renal biopsy as 'a day case procedure', in order to build adequate risk management strategies.

[Antiphospholipid syndrome and kidney]

The diagnosis of antiphospholipid syndrome (APS) relies on clinical and laboratory criteria, which have been recently outlined in specific consensus conferences. Renal involvement in APS is not infrequent and includes different clinical patterns. For clinical purposes a distinction can be made between large vessel and microvascular involvement. Renal artery stenosis is frequent in APS. In case of microvascular involvement with an acute clinical course a differential diagnosis with other thrombotic microangiopathic diseases has to be made, taking in account thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, malignant hypertension, drug nephrotoxicity (cyclosporin) and others. The disease is often chronic, with hypertension, different degrees of renal insufficiency and mild proteinuria. In patients with systemic lupus erythematosus and antiphospholipid antibodies the prognosis of kidney disease is generally poorer than in lupus alone. Finally, the kidney is almost invariably a target in catastrophic antiphospholipid syndrome. Anticoagulation is the therapy of choice, especially in arterial stenosis and acute disease, but is probably also indicated in chronic and subacute patterns. The role of immunomodulatory therapy has to be assessed.

Karyomegalic interstitial nephritis: report of 3 new cases and review of the literature

Karyomegalic interstitial nephritis is a rare, but perhaps an "underdiagnosed" condition. Peculiar nuclear changes characterize it, involving mainly tubular cells along with glomeruli and blood vessels. Herein, 3 bioptically proven new cases of patients with chronic renal failure are discussed. The first case had a recently diagnosed karyomegalic nephritis which, to date, still does not require dialysis. The other 2 (brother and sister) required dialysis 4 and 1 years after diagnosis. Karyomegalic changes were found not only in the skin and duodenal biopsies of the male, in skin and liver biopsies of the female and in the urine cells of both patients, but also in several organs (brain, thyroid, lung, esophagus, arteries) as shown at the autopsy of the female. There was a fatal outcome for both patients. The data reported in this study emphasize the usefulness of pathologic investigation of both tissue and urine samples in the identification of this disease. Moreover, as karyomegalic interstitial nephritis is strongly suspected to have a genetic background, its identification may well not only be of clinical relevance, due to its ominous outcome, but may also bear eugenetic value.

[Renal damage in type 2 diabetes]

Renal involvement in patients with type 2 diabetes will (probably) be one of the most important clinical problems for nephrologists to face during the next few years. Unlike type 1 diabetes, in type 2 diabetes the renal damage has not yet been well defined at both clinical and pathological levels. Pathological examination of renal biopsies has displayed different patterns of renal damage including diabetic glomerulosclerosis (Class 1), mostly chronic vascular changes (Class 2) and superimposed glomerular diseases (Class 3a) or unrelated to diabetic glomerulosclerosis (Class 3b). Despite the large number of papers published in this field, the actual prevalence and outcome of the different histological classes still remain to be established. Reported discrepancies are most likely caused by ethnic and geographic factors. However, as documented by a recent study carried out on a large number of patients, the prevalence of histological patterns is also greatly influenced by the policy for performing renal biopsies adopted at the various nephrological centers. Although the natural history of type 2 glomerulosclerosis (Class 1) still remains to be defined, those patients with clinical nephropathy and impairment of renal function have very poor outcome with a high rate of mortality and progression to uremia. Moreover, when diabetic glomerulosclerosis is complicated by superimposed glomerular diseases (Class 3a) the prognosis is much worse. On the contrary, when glomerular diseases are not associated with glomerulosclerosis lesions (Class 3b) the prognosis is markedly better. During the last ten years controlled studies have shown that the outcome in type 1 diabetic nephropathy has improved as a result of the use of drugs inhibiting the renin-angiotensin system. Although it is likely that this type of drug might also favourably influence the outcome of type 2 diabetic nephropathy, any conclusive evidence is presently still lacking.

[Polyomavirus BK nephropathy in renal transplant: 2 cases with different clinical expressions and review of the literature]

INTRODUCTION

Polyomavirus BK nephropathy is emerging as a significant cause of interstitial nephritis and allograft dysfunction (1-2).

CASE REPORT

Two patients with renal transplants from cadaveric kidneys were treated with Tacrolimus plus Mycophenolate Mofetil (MMF) and Cyclosporine plus MMF, respectively. Their renal function gradually deteriorated eight to twelve months after the transplant. The renal biopsy of the first patient showed signs of significant interstitial tubulite, which necessitated the anti-rejection therapy with intravenous steroid pulses. After the pulses there was an additional dramatic increase in plasmatic creatinine, which suggested a revaluation of the kidney biopsy because of suspected Polyomavirus BK (BKV) nephropathy. In fact, after a more careful review, the suspicion of BKV infection was confirmed by the presence of intranuclear inclusions of tubular epithelium cells and marked denudation of the tubular basal membrane. The subsequent screening in both cases confirmed the presence of decoy cells in the urine, while the immunohistochemical analysis of the renal biopsy was strongly positive for the SV40 antigen. Our diagnosis was that of interstitial nephritis due to Polyomavirus BK that, in the first patient, was expressed by more aggressive clinical progress, probably due to enhanced immunosuppression from incorrect diagnosis of the interstitial rejection. The pre-transplant clinical outcome of the first patient was characterised by proteinuric nephropathy without any histological confirmation. Furthermore, we observed abundant pre-transplant residual diuresis and glucose intolerance. All these elements led us to hypothesise that native kidneys could have a fundamental role as viral reservoirs.

CONCLUSION

Even though we reconfirm the decisive role of the immunosuppressive therapy and of the donor s kidney as the fundamental causes of Polyomavirus reactivation, we believe that it cannot be the result of a possible active role by the native kidney. In fact, as already noted, the SV40 genome is important in the pathogenesis of focal gomerulosclerosis. Furthermore, reports of polyoma nephropathy in not-yet-transplanted patients could accredit the role of the native kidneys as important viral reservoirs capable of inducing nephropathy in renal transplant patients.

Molecular characterization and sequence analysis of polyomavirus strains isolated from needle biopsy specimens of kidney allograft recipients

We retrospectively examined 29 renal allograft biopsy specimens from 42 kidney transplant recipients by means of molecular biologic techniques (nested polymerase chain reaction), immunohistochemical analysis (anti-SV40 antibody), and histologic examination to evaluate the presence of polyomaviruses (PVs), viral genotypes, genomic mutations, and their pathologic significance. PV genomes were found in six cases (21%); restriction fragment length polymorphism analysis characterized 4 as JC virus (JCV) and 2 as BK virus (BKV). The latter also were positively stained immunohistochemically and showed histologically typical intranuclear viral inclusions; JCV cases were negative. DNA sequence analysis revealed only minor changes in the 4 JCV cases (3 archetypes and 1 JCV type 3, not associated with a known pathogenic genotype) but identified 2 specific variants in the BKV isolates (AS and WW strains). Given the different histologic findings (mixed inflammatory infiltration in the AS and no inflammation in the WW strain), we speculate that different BKV strains may cause differential damage in transplanted kidneys. Finally, the negative histologic and immunohistochemical JCV results, as well as the absence of viral mutations, indicate that JCV renal infection is latent in transplant recipients.

Molecular characterization and sequence analysis of polyomavirus strains isolated from needle biopsy specimens of kidney allograft recipients

We retrospectively examined 29 renal allograft biopsy specimens from 42 kidney transplant recipients by means of molecular biologic techniques (nested polymerase chain reaction), immunohistochemical analysis (anti-SV40 antibody), and histologic examination to evaluate the presence of polyomaviruses (PVs), viral genotypes, genomic mutations, and their pathologic significance. PV genomes were found in six cases (21%); restriction fragment length polymorphism analysis characterized 4 as JC virus (JCV) and 2 as BK virus (BKV). The latter also were positively stained immunohistochemically and showed histologically typical intranuclear viral inclusions; JCV cases were negative. DNA sequence analysis revealed only minor changes in the 4 JCV cases (3 archetypes and 1 JCV type 3, not associated with a known pathogenic genotype) but identified 2 specific variants in the BKV isolates (AS and WW strains). Given the different histologic findings (mixed inflammatory infiltration in the AS and no inflammation in the WW strain), we speculate that different BKV strains may cause differential damage in transplanted kidneys. Finally, the negative histologic and immunohistochemical JCV results, as well as the absence of viral mutations, indicate that JCV renal infection is latent in transplant recipients.

Molecular characterization and sequence analysis of polyomavirus BKV-strain in a renal-allograft recipient

The significance of polyomavirus (PV) infection was investigated in a 53-year-old patient who underwent renal transplantation and was treated with triple immunosuppressive therapy (tacrolimus, prednisone, and azathioprine). A renal biopsy taken because of the suspicion of acute rejection showed focal inflammatory interstitial infiltration, tubulitis, and tubular cell nuclear changes consistent with the hypothesis of viral infection. Both the tubular and decoy cells identified by means of urinalysis positively stained for anti-SV40 antibody. Polymerase chain reaction performed on the DNA extracted from renal tissue and isolated from urine showed the presence of an antigenic variant (AS) of the BKV archetype after sequence analysis of the transcription control region (TCR). On the basis of the diagnosis of BKV infection, immunosuppressive therapy was reduced. The patient's renal function improved and was still stable 8 months later when urinalysis showed only a few decoy cells, which were found to be infected by JC but not BK virus. These data suggest that only the BKV, probably favoured by immunosuppressive therapy (tacrolimus), causes renal damage. It is worth underlining that even small and sporadic viral genome mutations may lead to pathologic effects.

[Biopsy experience at the G. Bosco Hospital from 1996 to 1999]

BACKGROUND

Aim of this study was a retrospective analysis of the renal biopsies performed in our Division.

METHODS

Since January 1, 1996 to September 30, 1999 289 biopsies were performed on native kidneys, 90 patients were older than 65.

RESULTS

The most frequent nephropathy was IgA glomerulonephritis (IgAGN) (28%), followed by membranous glomerulonephritis (MGN) (11%). In patients older than 65, the most frequent was MGN (20%), followed by IgAGN (12.2%). The total complications were 84 (29.1%) (hematomas >3 cm 1%; blood transfusion: 1.4%). Complications were not related to age, blood pressure, renal function, clinical presentation, number of shots. In 217 patients, the results obtained with two different modalities were compared: manual system (needle size=15 gauge) and automatic system (18 gauge). No statistically significant differences were found as regards the number of shots for single biopsy, number of glomeruli and major complications (1.6% vs 1.3%), while minor complications were more frequent in the second group.

CONCLUSIONS

In conclusion, the number of renal biopsies performed in our Division has been increasing year after year. This trend can be partially explained by our wider indications to renal biopsy in elderly population (the data related to resident population showed the greatest prevalence of biopsies in patients 70 to 79 years old). Renal biopsy actually represents a safe examination even in elderly patients. From a technical point of view, on the basis of personal experience, 18 gauge acecut automatic needles seem to be preferred to other kind of devices.

Distribution of alpha-chains of type IV collagen in glomerular basement membranes with ultrastructural alterations suggestive of Alport syndrome

BACKGROUND

In Alport syndrome (AS) impaired production and/or assembly of col IV alpha-chain isoforms results in abnormal structure of glomerular basement membrane (GBM), haematuria and, frequently, progressive renal disease. We investigated the relationship between col IV alpha-chains expression and morphology of GBM, as a possible key to the better understanding of the pathogenesis of renal disease in AS.

METHODS

GBM distribution of col IV alpha1-, alpha3-, and alpha5-chain was investigated by immunohistochemistry in 32 patients (21 males and 11 females, mean age at biopsy of 11.5 years) with ultrastructural findings suggestive of AS. Ten patients had a proven COL4A5 mutation. Based on the severity of ultrastructural findings, the biopsies were grouped in three (I-III) electron microscopy (EM) classes. Significant EM changes of GBM (thinning, thickening, splitting, basket weaving of the lamina densa) were singularly evaluated using a semiquantitative scale (0-3).

RESULTS

Col IV alpha1-chain was demonstrated in GBM of all patients. Three patterns of staining for col IValpha3- and alpha5-chains were observed: positive, negative, and alpha3(IV)-positive/alpha5(IV)-negative. By chi(2)-test, EM class III lesions and complete loss of alpha3(IV)- and alpha5(IV)-antigen were significantly more frequent (P<0.05 and P<0.01) in male patients, but no significant relation was observed between EM classes and immunohistochemical patterns. GBM alterations did not correlate with staining for alpha5(IV)-chain. Intensity of alpha3(IV)-chain staining, however, had a negative correlation (P<0.05) with the severity of GBM basket weaving.

CONCLUSIONS

Our results suggest that the alpha3(IV)-chain-containing col IV-network plays a fundamental role in structural and, possibly, functional organization of GBM. Absence of alpha3(IV)-chain in GBM could indicate a more severe renal disease in AS.

The concept of 'glomerulonephritis'. the fascinating history of evolution and emergence of a specialist's nosology focus on Italy and Torino

Though the term 'nephritis' first appeared in the 19th century, this word did not bear the same meaning as it does today; indeed, for many years it was used to indicate 'renal diseases' (in the sense of Bright's disease) in a larger sense. This review summarizes the long gestation of the concept of 'glomerulonephritis' from the prehistory of medicine up to the beginning of the second half of the 20th century with emphasis on Italy and, in particular, on Torino, which was the capital of the Kingdom of Italy from 1861 to 1865. To the best of our kowledge, this is the first study reporting an epidemiology survey of Bright's disease in Italy from 1880 up to 1960. Towards the end of the 19th century, Bright's disease accounted for 26 deaths/year/10(5) population (in comparison with more than 200 from tuberculosis) in Italy, roughly paralleling that reported in the USA. At the beginning of the 20th century, Bright's disease was the seventh cause of death (almost 1% of total deaths) in Italy. Furthermore, in Italy, as elsewhere, autopsy studies showed a higher percentage of deaths attributed to Bright's disease (5-7%) in comparison with those obtained from vital statistics. In 1960, just before the beginning of renal replacement therapy, Bright's disease accounted for 15.7 deaths/year/10(5) population (= 1.46% of all deaths), roughly paralleling that reported in the United Kingdom (13.8/10(5) population = 1.25% of deaths). Probably, it was difficult to recognize the real incidence of chronic renal diseases leading to death in the 1960s, and vital statistics were able to furnish only approximate estimates. However, noteworthy is the fact that these values were very close to those estimated as being the annual need for renal replacement therapy (10-20 cases/year/10(5) population).

Renal Encephalitozoon (Septata) intestinalis infection in a patient with AIDS. Post-mortem identification by means of transmission electron microscopy and PCR

We describe the occurrence of renal Encephalitozoon (Septata) intestinalis infection in a 35-year-old AIDS patient who died with disseminated tuberculosis. The patient did not complain of specific symptoms involving the kidney or lower urinary tract during life, but at autopsy, light microscopic examination of the kidney revealed numerous small round or oval bodies in the tubules and tubular cell cytoplasm that were interpreted as intracellular protozoa. Transmission electron microscopy of tissue retrieved from paraffin-embedded samples identified these organisms as microsporidia belonging to the Encephalitozoonidae family, but did not allow definitive identification of the species of infecting parasite. This was made possible only by means of Southern blot hybridization after the polymerase chain reaction, which recognized the micro-organism as E. intestinalis.

Ultrastructural and immunohistochemical findings in Alport's syndrome: a study of 108 patients from 97 Italian families with particular emphasis on COL4A5 gene mutation correlations

A total of 108 patients affected by Alport's syndrome, taken from 97 families, were enrolled in a genetic and ultrastructural study. Sixty-four families (75 patients) were X-linked, seven autosomal recessive, two autosomal dominant, five uninterpretable, and 19 sporadic. The ultrastructural features were consistent with Alport's syndrome in 66, doubtful in 20, and not significant for Alport's syndrome in 22 patients in the X-linked, sporadic, and genetically uninterpretable groups (without significant differences), as well as in the autosomal group. Mutations of the COL4A5 gene were present in 36 patients in the first three groups, without significant differences. More severe mutations were more frequently present in patients with an ultrastructural pattern consistent with Alport's syndrome. Nevertheless, there seems to be no strict correlation between mutation and ultrastructure, because a major rearrangement was found in a patient with no significant lesions, and different morphologic patterns were detected in patients Belonging to the same family. Immunohistochemical investigation into 24 patients for alpha (IV) chains showed that both alpha 3(IV) and alpha 5(IV) were lacking in the glomerular basement membrane of 13 patients (five with mutations) and were expressed in another six (three with mutations and one in the autosomal group). On the contrary, in this study the retained expression of alpha 3(IV) chain was found, despite the lack of alpha 5(IV) in the glomerular basement membrane of five patients (two with mutation). These different patterns could be related to both the type and severity of the COL4A5 mutations. All of the ultrastructural patterns were identified in all three immunohistochemical groups. Ultrastructural features and alpha 5(IV) chain production, even if an expression of a genetic mutation, do not strictly correlate. The combined use of analysis of collagen expression and electron microscopy made it possible to diagnose Alport's syndrome in 92% of the cohort, and therefore this approach is advisable. A multidisciplinary approach is recommended in the study of Alport's syndrome in an attempt to achieve a better diagnostic definition of and insight into the pathogenetic mechanisms.

Long-term prognosis of Henoch-Schönlein nephritis in adults and children. Italian Group of Renal Immunopathology Collaborative Study on Henoch-Schönlein purpura

BACKGROUND

The aim of this multicentre collaborative study was to compare the progression of renal disease in children and adults with Henoch-Schönlein purpura (HPS) nephritis selected on the basis of IgA-dominant renal deposits and biopsy material available for review.

METHODS

The analysis was performed in 152 patients (95 adults and 57 children < 16 years old at diagnosis) with a follow-up (> or = 1 year up to 20 years (4.9 +/- 3.4 years in adults and 4.8 +/- 3.9 years in children).

RESULTS

Renal histology and clinical presentation were similar in both age groups: crescents were found in 36% of adults and 34.6% of children (in only 2.7% of adults and 1.9% of children involving > 50% of glomeruli), nephrotic-range proteinuria in 29.5% of adults and 28.1% of children and functional impairment in 24.1% of adults and 36.9% of children. The outcome was similar for both age groups (remission, 32.5% of adults and 31.6% of children; renal function impairment, 31.6% of adults and 24.5% of children). Endstage renal disease was observed in 15.8% of adults and in 7% of children. Renal function survival at 5 years was not significantly different in the two groups (85% in adults and 95% in children) and at 10 years it was approximately 75% in both groups. None of the children died and adult survival was 97% at 5 years. In adults at presentation, renal function impairment (P < 0.02) as well as proteinuria higher than 1.5 g/day (P < 0.02) and hypertension (P < 0.001) were negative prognostic factors. Multivariate analysis stressed the main statistical relevance of proteinuria (relative risk 2.37, P < 0.02). Conversely, in children no definite level of proteinuria, hypertension or other data were found to be associated with poor prognosis.

CONCLUSIONS

Among patients with a clinical presentation which warrants renal biopsy, HSP nephritis has a similar prognosis in children and adults. The evolution is more predictable in adults than in children.

Processing of IgA aggregates in a rat model of chronic liver disease

Heavy alcohol intake and/or lipotrope-deficient diet induced hepatocellular injury and mesangial deposition of IgA and often IgG in Lewis rats. The experimental animals showing more severe urinary abnormalities and histologic damage in the glomeruli had increased levels of IgA antibodies to dietary antigens and altered intestinal permeability. Based on human studies, the prolonged circulation of IgA-containing complexes associated with the liver disease could be envisaged as important for the development of mesangial IgA deposits. In order to verify this hypothesis, four groups (G) of Lewis rats were studied: G1 received thrice a weak an intragastric infusion of 1.5 ml/100 g body wt of whiskey; G2 rats were nourished with lipotrope-deficient diet; G3 rats were given both whiskey and LD diet; G4 rats were nourished with regular chow. After 12 weeks, heat-aggregated rat monomeric IgA was labeled with 133I and intravenously injected. Three control subgroups of rats, one given whiskey, one nourished with LD diet, and one with regular chow, were injected with radiolabeled heat-aggregated rat IgG. A large field-of-view digital gamma camera, equipped with an ultra-high-resolution collimator and interfaced to a dedicated computer, was used to analyze tracer kinetics and fate. The liver was the main organ involved in clearance of both test probes. The hepatic mean transit (MTT) was 11.4 +/- 11 min in G1 (proteinuria of 6.9 +/- 1.41 mg/day and hematuria +/+2), 221 +/- 19 min in G2 (proteinuria 9.1 +/- 0.64 mg/day and hematuria +2/+3), and 230 +/- 15 min in G3 (proteinuria 9.5 +/- 0.58 mg/day and hematuria +2/+3). In each case MTT value was found to be significantly prolonged compared to G4 (85 +/- 4 min). The multiple regression analysis showed that MTT values, proteinuria, and hematuria were significantly correlated (P < 0.01). Controls had trace amount proteinuria (0.82 +/- 0.17 mg/day, significantly lower than for each study group, P < 0.08) and undetectable hematuria. Similar results were obtained in control rats injected with aggregated IgG; i.e., MTT values were more prolonged in rats given whiskey or LD diet than normally nourished rats (P < 0.01). The lipotrope-deficient diet and the chronic alcohol abuse per se seem to lead to critical changes in hepatic uptake and catabolism of both an IgA and an IgG aggregate, which could account in turn for the reported appearance of renal immunoglobulin deposits in this experimental model. Due to the comparable delay in removal of IgA and IgG probes in equally nourished animals, additional factors are likely to be involved in the prominent deposition of IgA.

Renal changes in patients with acquired immunodeficiency syndrome: a post-mortem study on an unselected population in northwestern Italy

The renal pathologic features of 120 consecutively autopsied patients affected by acquired immunodeficiency syndrome was investigated by light microscopic analysis. Variously associated renal changes were found in 82 patients (68.3%). Glomerular changes were present in 25. The following diagnoses were made: mesangial glomerulonephritis (16 patients), defined by the presence of deposits in the mesangium and/or mesangial cell proliferation; membranous glomerulonephritis (4 patients), cirrhotic glomerulosclerosis (2 patients); and lupuslike glomerulonephritis (3 patients). Glomerular diseases seemed to be significantly associated with chronic hepatitis or liver cirrhosis. Interstitial inflammation was present in 19 cases: chronic pyelonephritis (2 patients), focal nephritis (5 patients), multiple cortical abscesses (7 patients), granulomatous nephritis (5 patients). Cryptococci were found in one and undetermined microorganisms in two cases of multiple cortical abscesses. Atypical mycobacteria were found in two cases of granulomatous nephritis. Mycotic infections were identified in another 6 patients, in whom they did not elicit any inflammatory response. It is worth stressing that, although various generalized infections are common in patients with acquired immunodeficiency syndrome, only cryptococci and atypical mycobacteria also frequently involve the kidney. Focal tubular necrosis was observed in 15 patients. Benign nephrosclerosis was the most common vascular change (27 patients). Changes recalling hemolyticuremic and localized intravascular coagulation were found in three and six patients, respectively. Our data, dealing with a European Caucasian population, considerably differ from those reported in North American literature, in as much as we found no cases of human immunodeficiency virus nephropathy. Conversely, immune-mediated glomerular diseases were frequent, in agreement with recent studies on renal biopsy specimens from AIDS patients with acquired immunodeficiency syndrome. This type of infections, supplies multiple sources of antigens that may stimulate immune complex formation and, therefore, glomerular diseases.

Scleroderma renal crisis is still a life-threatening syndrome

Scleroderma renal crisis (SRC) was known as a rare and catastrophic syndrome responsible for acute renal failure (ARF) in a context of widespread microvascular disease occurring in progressive systemic sclerosis (PSS). Following pathogenetic hypoteses, angiotensin converting enzyme (ACE) inhibitors, plasma infusions (PI), and plasma-exchange (PE) have been employed in SRC with favorable results. Our purpose was to verify whether these therapies have consistently changed the fatal prognosis of SRC, even in our experience. In the last 10 years, SRC was diagnosed in eight patients (all eight with histologic data). The first five cases were treated with steroids, antihypertensive-cocktail, and PI: all five died, two within 48 hours, three after 10, 15, and 300 days, respectively. Three other patients were treated with ACE inhibitors, PI, and PE: all three died after 1, 9, and 12 months of HD. Clinical-histological correlations showed a strong relationship between the extent of glomerular involvement and the degree of renal failure, while arterial lesions seem to be more related to the past history of PSS, independently from the previous existence of hypertension. We conclude that "true" SRC diagnosed by restrictive criteria is still a rare life-threatening syndrome, and, unfortunately, no clear predictive biochemical or clinical signs could be identified; vascular renal involvement correlates to the duration of PSS independently of previous clinical evidence of renal failure or hypertension; a glomerular pattern similar to that reported for hemolytic-uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) syndrome is directly related to the degree of acute renal involvement; SRC may occur even in the absence of hypertension, mainly if cardiomyopathy is present: in our experience. ACE inhibitors and plasma therapies have changed the short-time prognosis of SRC, but they may be unable to provide recovery from dialysis and do not avoid further evolution of extrarenal PSS exiting in late death.

Adriamycin-induced proteinuria in nude mice: an immune-system-mediated toxic effect

BACKGROUND

The renal minimal lesion disease induced in rats by adriamycin (ADR) is generally thought to be consequent to a direct cytotoxic effect of this drug on glomerular epithelial cells. Only recently an altered synthesis of mediators, including reactive oxygen species and monocyte-macrophage cytokines, has been hypothesized.

METHODS

A mouse strain (nude) bearing a congenital thymic aplasia is a suitable experimental animal to evaluate the role of immune reactions in the development of the ADR nephropathy, provided mouse susceptibility to its toxic effect. Therefore, experimental mice were divided into three groups (G) each receiving adriamycin 7.5 mg/kg b.w.: GA (15 heterozygous nu/O mice with normal immune system); GB (15 homozygous nu/nu athymic mice); GC (15 homozygous nu/nu mice which were also splenectomized, irradiated, and treated with anti-asialo Gm1 antibody to abolish NK and decrease macrophage activity). All animals were maintained under pathogen-free conditions. Urinary proteins, albumin and TNF-alpha excretion were measured.

RESULTS

After 14 days the proteinuria was 43.8+/-1.7 microg/min in GA, 30.2+/-2.9 microg/min in GB (P<0.05) and 12.2+/-2.8 microg/min in GC (GA vs GC, P<0.0001; GB vs GC, P<0.05). Albuminuria gave a similar profile. TNG-alpha urinary excretion was significantly higher in GA (17.3+/-3.2 mU/min) than in GB (5+/-0.6 mU/min, P<0.001) and GC (3.2+/-0.9 mU/min, P<0.001). A significant correlation was found in GA between urinary TNF-alpha and protein losses (r2=0.63 P<0.0001). Kidney tissue homogenates failed to show in each experimental group any evidence of mRNA encoding for TNF-alpha, which was detectable in peripheral mononuclear cells from GA and GB, but undetectable in GC mice. Segmental effacements of glomerular epithelial cell foot process were observed by electron-microscopy in GA only, while they were minimal in GB and absent in GC. Iron colloidal staining for anionic sites on frozen sections always showed a normal pattern.

CONCLUSIONS

Nude mice bearing cellular immunity deficiency are protected from proteinuria following ADR toxicity. An impaired synthesis and release of lymphomonocyte mediators including TNF-alpha could be envisaged.

Incidence of biopsy-proven primary glomerulonephritis in an Italian province

Between January 1, 1970, and December 31, 1994, 1,926 cases of biopsy-proven primary glomerulonephritis (PGN) were diagnosed in an adult population (> 15 years of age) in a northwestern region of Italy with approximately 3.5 million inhabitants. The principal long-term changes were an increase in the absolute number of biopsies per year, an increase in the mean age of patients undergoing biopsy (from 29.3 +/- 12.2 years to 47.0 +/- 17.8 years), an increase in the percentage of patients older than 65 years (from 1.7% to 20.4%), and an increase in the percentage of isolated urinary abnormalities as an indication for biopsy (from 3.5% to 29.6%). In the total biopsy material, immunoglobulin A glomerulonephritis (IgA-GN) is the most frequent type (26%), followed by membranous glomerulonephritis (MGN; 20%). An incidence study was begun in 1990; this survey was restricted to the population of the province of Torino (approximately 2 million inhabitants) as only this area completely refers to the nephrologic centers that entered patients into this study. The overall incidence of PGN is 4.68 new cases/yr/10(5) population with a predominance of males (> 2:1); IgA-GN is the most common type (1.47/yr/10(5) population [34.5%]) in the overall population. In the elderly, cases of PGN are twice as high as in adults (8.19/yr/10(5) population v 4.02/yr/10(5) population in the 65 to 74 year and 45 to 54 year age groups, respectively); MGN mainly accounts for this high incidence (3.4/yr/10(5) population), while the nephrotic syndrome is the most common indication for biopsy (53.8%). A comparison with the incidence in the same area in the early 1970s is evaluable only for PGN, which was mainly registered in the age groups for which an unrestricted biopsy policy was already in place (15 to 35 years). In contrast with a misleading increase of all types of PGN, which is in reality due to the extension of the biopsy policy to older and asymptomatic patients, membranoproliferative glomerulonephritis type I shows a countercurrent decrease from 0.43 to 0.13/yr/10(5) population. Evidence of a simultaneous decrease in severe cardiac valvulopathy, due to rheumatic fever, is also provided. We feel that before epidemiologic conclusions can be reached, a clear understanding of one's own biopsy policy is essential. An apparent change in the PGN rate in our region over the last 25 years mainly depends on modifications in our biopsy policy, most probably coupled with a change in the threshold of detection of symptoms in the general population. At present, according to our experience, IgA-GN is the most common type of PGN in the total bioptic material, as demonstrated in other European countries, while the elderly show a peculiar pattern with a higher PGN incidence, mainly represented by MGN and heralded by the nephrotic syndrome. We also confirm that membranoproliferative glomerulonephritis type I is indeed decreasing in parallel with changes in the microbiologic environment.

Intracellular protozoan infection in small intestinal biopsies of patients with AIDS. Light and electron microscopic evaluation

Small intestinal biopsies of 21 patients with acquired immunodeficiency syndrome (AIDS) with light microscopic findings diagnostic or suspicious for parasite infection were investigated by transmission electron microscopy (TEM). TEM allowed us to identify and specify the genus and species of involved parasites in 16 out of the 21 cases: 7 Cryptosporidium parvum, 5 Enterocytozoon bieneusi and 4 Isospora belli. Cryptosporidium was easily identified on light microscopy (LM), and only slightly influenced by parasite burden in all the 7 cases; TEM confirmed LM diagnosis and made it possible to characterize the parasites as C. parvum. The identification of Microsporidium on LM in our cases was related to the burden of parasite; its presence was certainty identified in 2 cases and suspected in 3. TEM allowed to identify these parasites as E. bieneusi. Intracytoplasmic coccidia could be detected with certainly in semithin sections in all 4 cases, but TEM was always needed to specify the infectious agent as I. belli. In 5 cases the suspicious of protozoan infection on LM (3 microsporidia, 1 intracytoplasmic coccidia and 1 Cryptosporidium) was not confirmed by TEM. Our data suggest that TEM is an appropriate diagnostic tool in this field of pathology and necessary in most of the cases.

Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.

Clinical and Diagnostic Aspects of Travelers' Diarrhea due to Cyclospora Organisms

Cyclospora sp, a recently described protozoan, is associated with prolonged self-limiting and relapsing diarrhea. The species has a worldwide distribution and a high prevalence in tropical countries. Some reports suggest that the agent is a common cause of travelers' diarrhea.

Clinical and microscopical features of small-intestinal microsporidiosis in patients with AIDS

Intestinal microsporidiosis by Enterocytozoon bieneusi is an increasingly recognized infection in AIDS patients. We report eight cases of microsporidiosis. All patients were severely immunodepressed. Clinical features were highly variable. Patients were followed up for a mean period of 7.8 months. All patients had persistent infection during the follow-up and spore excretion remained constant. Two patients became asymptomatic during the follow-up. None of the patients presented clinical and echographic signs of biliary involvement. Treatment with albendazole, metronidazole or paromomycin failed to produce a durable clinical response or to eradicate the organism. Cases were identified by stool examination and additionally investigated with light and electron microscopy. It was found that light microscopy was a sensitive method, while electron microscopy was less sensitive but allowed the definition of the infecting species. The modified trichrome stain was a satisfactory method for diagnosis on fecal smears. The calcofluor stain and the combination of DAPI with calcofluor was a rapid and simple staining method for screening.

Pattern of glomerular involvement in human immunodeficiency virus-infected patients: an Italian study

Renal biopsy specimens from 26 adult human immunodeficiency virus (HIV)-infected patients with glomerular involvement were reviewed from the files of three hospital pathology services in Northern Italy. All the patients were Italian and most (19 of 26 patients) were intravenous drug addicts. The types of glomerular lesions were as follows: minimal-change glomerulopathy (two cases), mesangial proliferative glomerulonephritis (GN) with scanty immunoglobulin deposits (four cases), and various patterns of immune complex-mediated glomerulonephritis, including postinfectious GN (six cases), membranoproliferative GN (one case), membranous GN (three cases), immunoglobulin (Ig) A nephropathy (four cases), a mixed membranous and proliferative (three cases) and diffuse proliferative lupus-like pattern with subendothelial deposits, and intraluminal thrombi (two cases) or subepithelial and subendothelial deposits (one case). None of the patients had evidence of HIV-associated nephropathy. Our study confirms previous observations on the low incidence of HIV-associated nephropathy among white HIV-infected patients in Europe, where immune complex-mediated GN seems to predominate. Apart from the frequent electron microscopic observation of endothelial tubuloreticular structures, none of the reported lesions could be distinguished on morphologic grounds from those occurring in uninfected patients. The high variability of the glomerular lesions upholds the need for accurate diagnosis for the clinician confronted with an HIV-positive patient with suspected glomerular involvement.

Glomerulopathy associated with predominant fibronectin deposits: a newly recognized hereditary disease

A newly recognized type of familial glomerulopathy observed in patients of both sexes in six families is reported. Proteinuria, often within the nephrotic range, microscopic hematuria, hypertension and a slowly decreasing renal function over several years were common. No underlying systemic diseases were identified. Generally, light microscopy showed enlarged glomeruli with minimal hypercellularity and with extensive deposits in the mesangium and subendothelial space. By electron microscopy, granular deposits with some admixture of fibrils were most common. In one family, the deposits were predominantly fibrillary. Immunoglobulins and complement factors were inconstant or lacking. A main finding was a strong immune reactivity to fibronectin, corresponding to the distribution of the deposits. In one patient, the deposits recurred in a renal transplant. There was no indication of systemic deposition. Abnormalities in the metabolism of circulating fibronectin may play a pathogenetic role in this disease of probably autosomal dominant inheritance.

A possible role for nitric oxide in modulating the functional cyclosporine toxicity by arginine

The renal damage consequent to cyclosporine A (CsA) administration ranges from hemodynamic alterations to irreversible chronic lesions. The initial vasoconstriction depends upon the imbalance between the various modulators of the renal vascular tone, among which the most powerful are endothelins and nitric oxide (NO). CsA could play a crucial role by inhibiting the Ca++/calmodulin-mediated activation of the constitutive NO synthase (NOS) isoform, which converts L-arginine (L-Arg) into NO and citrulline, with a 1:1 stoichiometry. To investigate the possibility of modulating CsA nephrotoxicity with L-Arg we studied six groups (G) of Lewis rats treated with daily gavage up to eight weeks: G1, CsA 40 mg/kg; G2, G1 plus L-Arg 300 mg/kg; G3, G2 plus the competitive inhibitor of NOS, NG-nitro-L-Arg (L-NNA); G4, L-Arg alone; G5, L-NNA alone; and G6, controls receiving vehicle alone. After eight weeks L-Arg treated rats were protected against the toxic effects of CsA [creatinine (Cr) values, G2, 0.62 +/- 0.05 mg/dl vs. G1, 0.99 +/- 0.16 mg/dl, P < 0.001; proteinuria (P), G2, 7.2 +/- 1.02 mg/day vs. G1, 15.1 +/- 1.9 mg/day, P < 0.01]. The administration of L-NNA abolished the protective effect of L-Arg (G3, Cr 1.23 +/- 0.16 mg/dl; P 16.9 = 2.3; P < 0.02 and P < 0.005, respectively vs. G2). The levels of Cr in G2 rats were superimposable to control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Intertubular capillary changes in the cortex and medulla of transplanted kidneys and their relationship with transplant glomerulopathy: an ultrastructural study of 12 transplantectomies

Twelve kidney allografts removed 3 to 98 months (mean, 44.8 months) after transplantation were investigated. The presence and severity of intertubular capillary changes, which were characterized by splitting and multilayering of the basement membrane, were carefully noted. These changes were graded as mild, moderate, and severe according to the number of basement membrane layers. They were found in both cortical and medullary capillaries in all but one kidney and were always associated with transplant glomerulopathy. Ultrastructural changes observed in the glomeruli and capillaries were similar, suggesting that they share the same pathogenetic mechanisms, probably connected to immune-mediated endothelial cell damage. Although glomeruli can be absent in small biopsy specimens, intertubular capillaries are easily detectable. Because capillary changes can be considered a marker of transplant glomerulopathy, which is known to have ominous prognostic significance, the identification of such changes acquires clinical relevance. Electron microscopic investigation is therefore strongly advisable whenever a renal biopsy is performed to identify transplant glomerulopathy.