[The origins of the Renal Immunopathology Group of the Italian Society of Nephrology].

This article describes the birth and development of the Renal Immunopathology Group of the Italian Society of Nephrology. It collects the stories of nephrologists and pathologists who, since the early Seventies up to the first decade of this century, devoted their professional lives to the study of renal pathology with a strong personal involvement, characterized by enthusiasm, commitment, ability, strong spirit of cooperation, and friendship. All this enabled the Group to: propose the criteria for a standardized histological and immuno-histological examination of renal biopsies and reporting; produce several multicenter studies, whose results were also published in important international journals; to set up a national registry of renal biopsies; to organize a number of courses, some of which were associated with the publication of monographs, on various renal diseases. This article also traces the history of renal pathology in Italy from the second half of the Sixties - when young Italian nephrologists and pathologists from different institutions moved to French laboratories to learn new techniques to apply to renal biopsies - up to the present days. It also shows us how Italian renal pathology has been an essential tool for the development of the nephrological clinical practice and the advancement of scientific research.

Reproducibility of the Oxford classification of immunoglobulin A nephropathy, impact of biopsy scoring on treatment allocation and clinical relevance of disagreements: evidence from the VALidation of IGA study cohort.

BACKGROUND: The VALidation of IGA (VALIGA) study investigated the utility of the Oxford Classification of immunoglobulin A nephropathy (IgAN) in 1147 patients from 13 European countries. Methods. Biopsies were scored by local pathologists followed by central review in Oxford. We had two distinct objectives: to assess how closely pathology findings were associated with the decision to give corticosteroid/immunosuppressive (CS/IS) treatments, and to determine the impact of differences in MEST-C scoring between central and local pathologists on the clinical value of the Oxford Classification. We tested for each lesion the associations between the type of agreement (local and central pathologists scoring absent, local present and central absent, local absent and central present, both scoring present) with the initial clinical assessment, as well as long-term outcomes in those patients who did not receive CS/IS. RESULTS: All glomerular lesions (M, E, C and S) assessed by local pathologists were independently associated with the decision to administer CS/IS therapy, while the severity of tubulointerstitial lesions was not. Reproducibility between local and central pathologists was moderate for S (segmental sclerosis) and T (tubular atrophy/interstitial fibrosis), and poor for M (mesangial hypercellularity), E (endocapillary hypercellularity) and C (crescents). Local pathologists found statistically more of each lesion, except for the S lesion, which was more frequent with central review. Disagreements were more likely to occur when the proportion of glomeruli affected was low. The M lesion, assessed by central pathologists, correlated better with the severity of the disease at presentation and discriminated better with outcomes. In contrast, the E lesion, evaluated by local pathologists, correlated better with the clinical presentation and outcomes when compared with central review. Both C and S lesions, when discordant between local and central pathologists, had a clinical phenotype intermediate to double absent lesions (milder disease) and double present (more severe). CONCLUSION: We conclude that differences in the scoring of MEST-C criteria between local pathologists and a central reviewer have a significant impact on the prognostic value of the Oxford Classification. Since the decision to offer immunosuppressive therapy in this cohort was intimately associated with the MEST-C score, this study indicates a need for a more detailed guidance for pathologists in the scoring of IgAN biopsies.

Risk factors for progression in children and young adults with IgA nephropathy: an analysis of 261 cases from the VALIGA European cohort.

BACKGROUND: There is a need for early identification of children with immunoglobulin A nephropathy (IgAN) at risk of progression of kidney disease. METHODS: Data on 261 young patients [age <23 years; mean follow-up of 4.9 (range 2.5-8.1) years] enrolled in VALIGA, a study designed to validate the Oxford Classification of IgAN, were assessed. Renal biopsies were scored for the presence of mesangial hypercellularity (M1), endocapillary hypercellularity (E1), segmental glomerulosclerosis (S1), tubular atrophy/interstitial fibrosis (T1-2) (MEST score) and crescents (C1). Progression was assessed as end stage renal disease and/or a 50 % loss of estimated glomerular filtration rate (eGFR) (combined endpoint) as well as the rate of renal function decline (slope of eGFR). Cox regression and tree classification binary models were used and compared. RESULTS: In this cohort of 261 subjects aged <23 years, Cox analysis validated the MEST M, S and T scores for predicting survival to the combined endpoint but failed to prove that these scores had predictive value in the sub-group of 174 children aged <18 years. The regression tree classification indicated that patients with M1 were at risk of developing higher time-averaged proteinuria (p < 0.0001) and the combined endpoint (p < 0.001). An initial proteinuria of ≥0.4 g/day/1.73 m2 and an eGFR of <90 ml/min/1.73 m2 were determined to be risk factors in subjects with M0. Children aged <16 years with M0 and well-preserved eGFR (>90 ml/min/1.73 m2) at presentation had a significantly high probability of proteinuria remission during follow-up and a higher remission rate following treatment with corticosteroid and/or immunosuppressive therapy. CONCLUSION: This new statistical approach has identified clinical and histological risk factors associated with outcome in children and young adults with IgAN.

Does asymptomatic recurrent diffuse capillary C4d complement deposition impair cardiac allograft function?

BACKGROUND: The aim of this study was to evaluate whether asymptomatic recurrent (≥2) antibody-mediated rejection (pAMR 1+), defined as diffuse capillary C4d immunostaining (rAMR) on endomyocardial biopsies (EMBs), during the first year after heart transplantation impairs left ventricular (LV) function. METHODS: Fifty-four consecutive heart transplant patients who survived well (New York Heart Association ≤2 and EF≥55%) the first month after transplantation were enrolled and prospectively underwent 490 echocardiographies and EMB. Asymptomatic rAMR without histopathologic findings was evaluated as a risk factor for deterioration of graft function. Primary endpoint, assessed 1 year after transplantation, was development of LV dysfunction and/or adverse remodeling according to pre-specified echo parameters. RESULTS: During the first year from transplantation, rAMR occurred in five patients. Recurrent AMR was associated with a significant higher risk to develop LV concentric hypertrophy (OR 3.6, 95% CI: 1.8-7.0, P=.02) or reduced lateral S' peak velocity (OR 2.3, 95% CI: 1.5-3.6, P=.03). Patients with rAMR showed significative adverse graft remodeling (ΔLV end-diastolic volume: +16±12.3 vs -0.2±14.4 mL; P=.02) and deterioration of graft function (Δlateral S' peak velocity: -3.3±3 vs -0.4±2.9 cm/s; P=.03). CONCLUSIONS: Recurrent asymptomatic diffuse capillary C4d immunostaining may play a role in the early development of cardiac allograft adverse remodeling and dysfunction.

Potential role of effector memory T cells in chronic T cell-mediated kidney graft rejection.

BACKGROUND: Chronic T cell-mediated rejection (TCMR) in kidney graft is characterized by reduction of the vessel lumen with marked intimal thickening, fibrous hyperplasia of the small renal arteries and leukocyte infiltrates. The aim of this study was to find specific gene expression profiles in chronic TCMR kidney biopsies. METHODS: RNA extracted from archival formalin-fixed, paraffin-embedded renal biopsies was used for gene expression profiling. Our study included 14 patients with chronic TCMR and 10 with acute TCMR. Fifty-two cadaveric donors were used as controls. The results were validated in an independent set of kidney biopsies. RESULTS: We identified 616 and 243 differentially expressed genes with a fold change ≥1.5 and a false discovery rate <0.05 in chronic and acute TCMR, respectively. Pathway analysis revealed upregulation of OX40 signalling. This pathway is involved in the generation of CD8+ effector memory T cells and the upregulation of killer cell lectin-like receptor G1 (KLRG-1), B lymphocyte-induced maturation protein 1 (BLIMP-1) and CD25, which characterize CD8+ effector memory T cells. However, the enhanced OX40 signalling pathway was specific to chronic TCMR; a significant increase of KLRG-1+/CD8+ and BLIMP-1+/CD8+ was only detected in these specimens. CONCLUSIONS: These results suggest the involvement of memory-committed CD8+ effector T cells in chronic TCMR. The generation of effector memory T cells is mediated by the OX40 gene pathway, and could be considered a future target for the specific treatment of chronic TCMR.

Treatment protocol with pulse and oral steroids for IgA Nephropathy after kidney transplantation.

BACKGROUND: No specific treatment for IgA nephropathy (IgAN) after kidney transplantation is currently available. METHODS: We conducted a retrospective single-center study on 29 patients with biopsy-proven de novo and recurrent IgAN after kidney transplantation, divided into two groups. Group 1 (n = 16) received intravenous methylprednisolone 500 mg per day for three consecutive days at the beginning of months 1, 3 and 5, plus oral prednisone 0.5 mg/kg every other day for 6 months. The control group (n = 13, Group 2) received supportive therapies. RESULTS: The two groups were comparable for serum creatinine (sCr) and proteinuria at the time of renal biopsy, but differed significantly at the end of follow-up. sCr was 1.8 ± 0.4 mg/dl in Group 1 vs. 2.7 ± 0.9 in Group 2 (p = 0.002), and proteinuria was 0.9 g/day in Group 1 vs. 1.9 in Group 2 (p = 0.04). The composite outcome of death-censored graft loss or doubling of sCr displayed 2 events in Group 1 (12.5 % of the entire group) and 5 events in Group 2 (38.5 % of the entire group), p = 0.19, odds ratio (OR) 4.4 [95 % confidence interval (CI) 0.7-27.8]. CONCLUSIONS: In the absence of therapeutic guidelines for de novo or recurrent IgAN after kidney transplantation, our study reports that therapy with pulse and oral steroids for 6 months is associated with an improved renal function. Nevertheless, further randomized controlled studies in larger patient cohorts are necessary to establish the gold standard treatment.

Relationship among C1q-fixing de novo donor specific antibodies, C4d deposition and renal outcome in transplant glomerulopathy.

BACKGROUND: The C1q-binding properties of donor specific antibodies (DSA) may be related to antibody-mediated rejection and poor outcome. METHODS: We retrospectively studied 35 kidney transplant recipients with transplant glomerulopathy (TG) and de novo DSA (dnDSA). C1q dnDSA were measured in the serum stored at renal biopsy and the association among C1q-fixing dnDSA, C4d deposition and graft loss was examined. RESULTS: Of the 35 patients with dnDSA and TG, 15 (42.9%) had C1q-positive dnDSA and 20 (57.1%) had C1q-negative dnDSA. Ten out of 15 patients with C1q-positive dnDSA (66.6%) and 5 with C1q-negative dnDSA (25%) had C4d positive staining renal biopsies (P=0.02), being the C1q-negative dnDSA/C4d-negative TG 42.9% of the total. The C1q-positive dnDSA group has significantly higher IgG DSA Class II MFI than the C1q-negative dnDSA group (P=0.004). Patients with C4d deposits have significantly higher IgG DSA MFI for both Class I and Class II than those without C4d deposits (P=0.02). We found a trend toward higher graft loss in the C1q-positive dnDSA group (60%) versus the C1q-negative dnDSA group (40%) without a statistical significance (P=0.31). CONCLUSION: Our study provides further characterization of TG associated with dnDSA. The major part of dnDSA-associated TG was C1q-negative and the presence of C1q-fixing dnDSA did not significantly correlate with graft outcome.

Can tonsillectomy modify the innate and adaptive immunity pathways involved in IgA nephropathy?

The benefits of tonsillectomy in IgA nephropathy (IgAN) are still debated. Tonsillectomy may remove pathogen sources and reduce the mucosal associated lymphoid tissue (MALT), limiting degalactosylated IgA1 (deGal-IgA1) production, which is considered to be the initiating pathogenetic event leading to IgA glomerular deposition. In the European network VALIGA, 62/1147 IgAN patients underwent tonsillectomy (TxIgAN). In a cross-sectional study 15 of these patients were tested and compared to 45 non-tonsillectomized IgAN (no-TxIgAN) and healthy controls (HC) regarding levels of deGal-IgA1, and markers of innate immunity and oxidative stress, including toll-like receptors (TLR)2, 3, 4 and 9 mRNAs, proteasome (PS) and immunoproteasome (iPS) mRNAs in peripheral blood mononuclear cells (PBMC), and advanced oxidation protein products (AOPP). Levels of deGal-IgA1 were lower in TxIgAN than in no-TxIgAN (p = 0.015), but higher than in HC (p = 0.003). TLR mRNAs were more expressed in TxIgAN than in HC (TLR4, p = 0.021; TLR9, p = 0.027), and higher in TxIgAN than in no-TxIgAN (p ≤ 0.001 for TLR2, 4, 9). A switch from PS to iPS was detected in PBMC of TxIgAN in comparison to HC and it was higher than in no-TxIgAN [large multifunctional peptidase (LMP)2/ß1, p = 0.039; LPM7/ß5, p < 0.0001]. The levels of AOPP were significantly higher in TxIgAN than HC (p < 0.001) and no-TxIgAN (p = 0.033). In conclusion, the activation of innate immunity via TLRs and ubiquitin-proteasome pathways and the pro-oxidative milieu were not affected by tonsillectomy, even though the levels of aberrantly galactosylated IgA1 were lower in patients with IgAN who had tonsillectomy. The residual hyperactivation of innate immunity in tonsillectomized patients may result from extra-tonsillar MALT.

Validation of the Oxford classification of IgA nephropathy in cohorts with different presentations and treatments.

The Oxford Classification of IgA Nephropathy (IgAN) identified mesangial hypercellularity (M), endocapillary proliferation (E), segmental glomerulosclerosis (S), and tubular atrophy/interstitial fibrosis (T) as independent predictors of outcome. Whether it applies to individuals excluded from the original study and how therapy influences the predictive value of pathology remain uncertain. The VALIGA study examined 1147 patients from 13 European countries that encompassed the whole spectrum of IgAN. Over a median follow-up of 4.7 years, 86% received renin-angiotensin system blockade and 42% glucocorticoid/immunosuppressive drugs. M, S, and T lesions independently predicted the loss of estimated glomerular filtration rate (eGFR) and a lower renal survival. Their value was also assessed in patients not represented in the Oxford cohort. In individuals with eGFR less than 30 ml/min per 1.73 m(2), the M and T lesions independently predicted a poor survival. In those with proteinuria under 0.5 g/day, both M and E lesions were associated with a rise in proteinuria to 1 or 2 g/day or more. The addition of M, S, and T lesions to clinical variables significantly enhanced the ability to predict progression only in those who did not receive immunosuppression (net reclassification index 11.5%). The VALIGA study provides a validation of the Oxford classification in a large European cohort of IgAN patients across the whole spectrum of the disease. The independent predictive value of pathology MEST score is reduced by glucocorticoid/immunosuppressive therapy.

New trends of an old disease: the acute post infectious glomerulonephritis at the beginning of the new millenium.

The association between acute renal disease and infection has been known since the mid '800s: acute post-infectious glomerulonephritis (PIGN) is a reactive immunological process against the kidney secondary to an infection, classically caused by a Streptococcus. The typical clinical presentation of PIGN is an acute nephritic syndrome with macro- or microscopic hematuria, proteinuria, hypertension, edema and renal function impairment of variable degree. The histology is characterized by an intracapillary glomerular proliferation, but may rarely be associated with an extracapillary proliferation. The classical childhood form is still present nowadays, even with severe cases, in developing countries, while in the last decades it almost disappeared in industrialized countries, where post-infectious GN are often found in elderly patients with multiple comorbidities. These clinical variants are usually related to other infective agents, like Staphylococcus aureus, both methicillin resistant (MRSA) and susceptible, and may be characterized by an IgA-dominant deposition. Kidney biopsy is rarely needed, especially in the child, while in the adult or old patient a biopsy is warranted if there is an atypical presentation or evolution, like rapidly progressive renal failure, absent or delayed function recovery, persisting low C3, nephrotic range proteinuria and persisting high proteinuria. Current therapy strategies rely on culture-guided systemic antibiotics, especially in the old patient, in which MRSA are relatively frequent, support therapy and only in very selected cases on steroids. These latter cases include the rare PIGN with crescents and those with a severe interstitial inflammation.

Systemic AA amyloidosis as a unique manifestation of a combined mutation of TNFRSF1A and MEFV genes.

We report the case of a 22-year-old Caucasian woman presenting with a new-onset nephrotic syndrome with normal renal function during the 35th week of pregnancy. AA (secondary) amyloidosis was further diagnosed at the renal biopsy. Extensive genetic testing revealed that the patient was heterozygous for both TNFRSF1A p.R92Q and MEFV p.M694I mutations leading to an autoinflammatory syndrome characterized by amyloid deposition as the sole manifestation.

A case of recurrent proliferative glomerulonephritis with monoclonal IgG deposits after kidney transplant treated with plasmapheresis.

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is a rare and recently identified disease with a poor prognosis irrespective of the treatment. Recently, the possibility of recurrent or de novo PGNMID after kidney transplantation has been reported, which is associated with a better prognosis compared to PGNMID on native kidneys. Nevertheless, at present, due to the very few cases of recurrent PGNMID diagnosed, there is no proven effective treatment. Here, we report a case of recurrent PGNMID successfully treated with plasmapheresis, steroids and mycophenolate mofetil. Our report suggests that plasmapheresis might be a valid therapeutic option to treat recurrent PGNMID.

FAN1 mutations cause karyomegalic interstitial nephritis, linking chronic kidney failure to defective DNA damage repair.

Chronic kidney disease (CKD) represents a major health burden. Its central feature of renal fibrosis is not well understood. By exome sequencing, we identified mutations in FAN1 as a cause of karyomegalic interstitial nephritis (KIN), a disorder that serves as a model for renal fibrosis. Renal histology in KIN is indistinguishable from that of nephronophthisis, except for the presence of karyomegaly. The FAN1 protein has nuclease activity and acts in DNA interstrand cross-link (ICL) repair within the Fanconi anemia DNA damage response (DDR) pathway. We show that cells from individuals with FAN1 mutations have sensitivity to the ICL-inducing agent mitomycin C but do not exhibit chromosome breakage or cell cycle arrest after diepoxybutane treatment, unlike cells from individuals with Fanconi anemia. We complemented ICL sensitivity with wild-type FAN1 but not with cDNA having mutations found in individuals with KIN. Depletion of fan1 in zebrafish caused increased DDR, apoptosis and kidney cysts. Our findings implicate susceptibility to environmental genotoxins and inadequate DNA repair as novel mechanisms contributing to renal fibrosis and CKD.

Physicochemical determinants in the cellular responses to nanostructured amorphous silicas.

Amorphous silicas, opposite to crystalline polymorphs, have been regarded so far as nonpathogenic, but few studies have addressed the toxicity of the wide array of amorphous silica forms. With the advent of nanotoxicology, there has been a rising concern about the safety of silica nanoparticles to be used in nanomedicine. Here, we report a study on the toxicity of amorphous nanostructured silicas obtained with two different preparation procedures (pyrolysis vs. precipitation), the pyrogenic in two very different particle sizes, in order to assess the role of size and origin on surface properties and on the cell damage, oxidative stress, and inflammatory response elicited in murine alveolar macrophages. A quartz dust was employed as positive control and monodispersed silica spheres as negative control. Pyrogenic silicas were remarkably more active than the precipitated one as to cytotoxicity, reactive oxygen species production, lipid peroxidation, nitric oxide synthesis, and production of tumor necrosis factor-α, when compared both per mass and per unit surface. Between the two pyrogenic silicas, the larger one was the more active. Silanols density is the major difference in surface composition among the three silicas, being much larger than the precipitated one as indicated by joint calorimetric and infrared spectroscopy analysis. We assume here that full hydroxylation of a silica surface, with consequent stable coverage by water molecules, reduces/inhibits toxic behavior. The preparation route appears thus determinant in yielding potentially toxic materials, although the smallest size does not always correspond to an increased toxicity.

Thickness of multiwalled carbon nanotubes affects their lung toxicity.

Two samples of highly pure multiwalled carbon nanotubes (MWCNTs) similar in hydrophobicity and surface reactivity were prepared with similar length, <5 µm, but markedly different diameter (9.4 vs 70 nm). The samples were compared for their cytotoxic activity, uptake, and ability to induce oxidative stress (ROS production and intracellular GSH depletion) in vitro in murine alveolar macrophages (MH-S). The in vivo toxicity was evaluated by measuring biochemical (LDH activity and total proteins) and cellular responses in bronchoalveolar lavage (BAL) after intratracheal instillation in rats. Both samples were internalized in MH-S cells. However, thin MWCNTs appeared significantly more toxic than the thicker ones, both in vitro and in vivo, when compared on a mass-dose basis. The data reported herein suggest that the nanotube diameter is an important parameter to be considered in the toxicological assessment of CNTs.

Oxidative stress and galactose-deficient IgA1 as markers of progression in IgA nephropathy.

BACKGROUND AND OBJECTIVES: We assessed the activation of the oxidative stress pathway in patients with IgA nephropathy (IgAN), while evaluating the classic marker of the disease (galactose-deficient serum IgA1). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Sera from 292 patients and 69 healthy controls from Italy and the United States were assayed for advanced oxidation protein products (AOPPs), free sulfhydryl groups on albumin (SH-Alb), and IgA1 with galactose-deficient hinge-region O-glycans (Gd-IgA1). Gd-IgA1 was detected by binding to Helix aspersa agglutinin (HAA) and expressed as total Gd-IgA1 or as degree of galactose deficiency relative to a standard Gd-IgA1 myeloma protein (%HAA). RESULTS: Sera from IgAN patients showed higher levels of Gd-IgA1, %HAA, and AOPPs, but lower levels of SH-Alb in comparison to that from healthy controls. Serum levels of AOPPs significantly correlated with serum Gd-IgA1 and %HAA. The relationship between these biomarkers and clinical features at sampling and during follow-up was assessed in 62 patients with long-term follow-up. AOPPs and %HAA correlated with proteinuria at sampling and independently associated with subsequent proteinuria. Levels of AOPPs correlated with rate of decline in renal function after sampling. The combination of a high level of AOPPs and a high level of %HAA associated with decline in estimated GFR. CONCLUSIONS: Serum levels of aberrantly glycosylated IgA1 are elevated and oxidative stress pathways are activated in patients with IgAN; the intensity of the stress correlated with expression and progression of the disease. We speculate that oxidative stress may modulate the nephrotoxicity of aberrantly glycosylated IgA1 in IgAN.

Kidney involvement in a patient affected by placental site trophoblastic tumor.

We report a 42-year-old woman who presents a few days after a spontaneous incomplete abortion at the ninth week of pregnancy with hypertension and nephrotic syndrome. Curettage findings and increased values for the ß subunit of human chorionic gonadotrophin were suspicious for a trophoblastic disease. A uterine placental site trophoblastic tumor was diagnosed 2 months later after hysterectomy and treated successfully using chemotherapy. Kidney biopsy showed features consistent with an unusual form of thrombotic microangiopathy characterized by the presence of large thrombus-like structures occluding the capillary lumina and smaller aggregates in the mesangium and along glomerular basement membranes. These deposits were positive for immunoglobulin M, C4, C1q, κ and λ light chains, and fibrinogen. Electron microscopy showed fibrin deposits located primarily in the subendothelial space. The differential diagnosis of this presentation included pre-eclamptic nephropathy, Waldenström disease, lupus anticoagulant glomerulonephritis, systemic lupus erythematosus, and cryoglobulinemic glomerulonephritis. We review the pathogenic mechanisms involved in this case.

The reliability of pre-transplant donor renal biopsies (PTDB) in predicting the kidney state. A comparative single-centre study on 154 untransplanted kidneys.

BACKGROUND: Pre-transplant donor biopsy (PTDB) is a common practice in marginal donors, taking for granted that it represents the whole kidney state, but its reliability has not yet been thoroughly investigated. This prompted us to carry out a comparative study on a needle biopsy group (NBG) and a wedge biopsy group (WBG) and their corresponding untransplanted kidneys. METHODS: One hundred and fifty-four biopsies and matched kidneys were scored for four morphologic indexes, i.e. tubular atrophy, interstitial fibrosis, vascular damage and global glomerulosclerosis. Categorical indexes were statistically evaluated for concordance with the k index, and the percentage of sclerotic glomeruli with correlation and linear regression analysis. RESULTS: Agreement between biopsies and kidneys was similar in both NBG and WBG with high scores for vascular damage (k 0.74 and 0.75) and intermediate ones for tubular atrophy (k 0.54 and 0.50). Agreement as to fibrosis and glomerular sclerosis was intermediate in the WBG (k 0.56 and 0.55) and poor in the NBG (k 0. 34 and 0.18). Vascular damage was underscored and glomerulosclerosis overscored in both groups, whereas interstitial fibrosis was underscored in the NBG and overscored in WBG. The agreement for the total score, i.e. the sum of the single indexes, was high in the NBG (k 0.73) and intermediate in WBG (k 0.57). Agreement for glomerulosclerosis and total score rose consistently in both groups along with the increasing number of biopsy glomeruli. There was an agreement as to biopsy and kidney evaluation for fitness for transplantation in 85% of NBG and 81% of WBG. CONCLUSIONS: PTDB supplies reliable data on the actual kidney state, with better results for needle biopsy. Although the biopsy size plays a role, samples with over 10 glomeruli suffice for clinical purposes. Vascular damage is the most faithful single parameter, whereas global glomerulosclerosis estimation requires some caution.