Expression and function of fibronectin receptors on peripheral mononuclear cells in IgA nephropathy

The ß1 integrin family, major adhesive receptors forthe extracellular matrix (ECM), have been reported to be presentin normal and diseased kidneys. Attachment of glomerular cellsto ECM is mediated by ß1 integrins. Several membersof the ß1 integrins are referred to as VLA (very lateactivation) antigens. Peripheral mononuclear cells also expressVLA antigens in both resting and activated states. We examinedthe expression and function of VLA antigens on peripheral lymphocytesand monocytes in patients with IgA nephropathy using monoclonalantibodies (mAbs) specific for VLA -chains. Peripheral lymphocytesfrom patients with IgA nephropathy expressed VLA-4 and 5, butnot VLA-1 2 or 3. Peripheral monocytes from patients with IgAnephropathy expressed VLA-2 4 and 5, but not VLA-1 or 3. Theexpression of VLA adhesive receptors was observed in healthyindividuals. Adhesion assay to fibronectin revealed augmentedadhesion of mononuclear cells in IgA nephropathy (P<0.05),and this increased adhesion was inhibited by mAbs to VLA-4 and5. The expression of ß1 integrins in IgA nephropathywas similar to that of healthy individuals, but the functionof these molecules in terms of adhesion to fibronectin thoughVLA-4 and VLA-5 is increased in these patients. These findingssuggest that the activation of fibronectin receptors on peripheralmononuclear cells plays an important role in the pathogenicprocess of IgA nephropathy.     

Effect of age on protein catabolic rate, morbidity, and mortality in uraemic patients with adequate dialysis

To test the validity of the assumption that the protein catabolicrate (PCRn g/kg/day) is dependent on the normalized dose ofdialysis (Kt/V urea), and to try to define the charactensticsof the patients in the undefined domain A of the mechanisticmap of the National Cooperative Dialysis Study (NCDS), whichshould include patients with adequate amount of dialysis butinadequate PCRn, urea kinetic model ling was performed over12 months on 85 patients undergoing haemodialysis All the patientswere man aged to maintain a Kt/V urea 0.9. During the entireperiod of study the total number of hospitalizations and thenumber of days of hospitalization were recorded. Total serumproteins and serum albumin concentrations were measured at thestart and at the end of the study. The results of the studyshow that there was no correlation between Kt/V and PCRn norbetween Kt/V and patient's age, but there was a strong inversecorrelation between age and PCRn (r=0.578; P <0.0001). Furtherdivision of the patients into four groups according to age showedthat the lowest values of PCRn were for the group of patients75 years old. Twelve patients with PCRn0.8 and Kt/V0.9 wereincluded in domain A of the mechanistic map. Eleven (92%) ofthese 12 patients were years old. No correlations were foundbetween the total number of hospitalizations, the total daysof hospitalization, Kt/V, time on HD, body weight and PCRn bymultiple regression analysis, while the inverse correlationbetween PCRn and age was confirmed. Body weight, total serumproteins and serum albumin concentration remained stable throughoutthe study. However, the basal serum albumin was less in thegroup of patients 75 years old. We conclude that if an adequateamount of dialysis is delivered, the protein intake becomesindependent of the quantity of dialysis and dependent on otherfactors not yet known. In this situation, the age of the patientsexerts a great negative influence on PCRn, particularly in patients75 years old. In the 12 patients from the whole group with Kt/V0.9 and PCRn 0.8g/kg/day (domain A of the mechanistic map),we could find no differences in death, hospitalization rate,or duration of hospitaliza flon compared to the others. Thereduced PCRn in the oldest patients does not affect body weight,total serum protein, and serum albumin concentrations over time.This suggests that these patients might do well even with lessprotein intake.     

Predictive value of dialysis adequacy and nutritional indices for mortality and morbidity in CAPD and HD patients. A longitudinal study

BACKGROUND: The effects of dialysis inadequacy on patient survival and nutritionalstatus and that of malnutrition on survival have not been clearlyassessed. Studies comparing dose/mortality and morbidity curveson continuous ambulatory peritoneal dialysis (CAPD) and on haemodialysis(HD) are also needed, to assess adequate treatment on CAPD. METHODS: We have evaluated the effects of age, 13 pretreatment risk factors,serum albumin, transferrin, normalized protein catabolic rate,Kt/V, normalized weekly creatinine clearance, residual renalfunction and subjective global assessment of nutritional statuson survival and morbidity, in a 3-year prospective study of68 CAPD and 34 HD patients. RESULTS: Survivals did not differ for CAPD and HD patients. In the Coxhazard regression model, age, peripheral vasculopathy, serumalbumin <3.5 g/dl and Kt/V < 1.0/treatment on HD and <1.7/weekon CAPD were independent factors negatively affecting survival.On the contrary, adjusted survivals were not affected by gender,modality, other comorbid factors, normalized protein catabolicrate, or subjective global assessment of nutritional status.Persistence of residual renal function significantly improvedsurvival. Observed and adjusted survival did not significantlydiffer for CAPD and HD patients with either low (HD, <1.0/treatment;CAPD, < 1.7/week) or high ( 1.0 and 1.7) Kt/V. On HD, adjustedsurvivals were similar for 1.0 Kt/V < 1.2 or 1.2. On CAPD,Kt/V 1.96/week was associated with definitely better survival,with only one death/23 patients versus 19/45, with Kt/V 1.96.Survival was not different for 1.96 Kt/V < 2.03 and 2.03.Normalized weekly creatinine clearance and wKt/V were positivelyrelated on CAPD (r 0.39, P<0.01) and wKt/V=1.96 correspondedto 58 litres of normalized weekly creatinine clearance. CONCLUSION: Indices of adequacy were predictors of mortality and morbidity,both on CAPD and HD, whereas normalized protein catabolic rateand subjective global assessment of nutritional status werenot. Serum albumin did not decrease during dialysis; hence itspredictive effect for survival is due to the predialysis conditionand not to dialysis-induced malnutrition.     

Relationship between elevated creatine phosphokinase and the clinical spectrum of rhabdomyolysis

The incidence, causes and complications of severe rhabdomyolysis(creatine phosphokinase (CK) 5000 U/l) were studied during a7-year study period in a large university hospital population.This condition was present in 0.074% of all admitted patients.The mortality in the study group (n=93) was 32% and the incidenceof acute renal failure (ARF) 51%. Ischaemia was the most frequentcause, and drugs, alcohol and/or coma were the second most commoncause of severe rhabdomyolysis. Patients with rhabdomyolysisdue to ischaemia were older, had ARF more often, and also hadthe highest mortality. Hyperkalaemia (potassium 5.5 mmol/1)occurred in 13% of the patients, and all of them had or developedan impaired renal function. Hypocalcaemia (calcium 2.00 mmol/1)was found in 41%. The incidence of ARF and electrolyte disturbanceswas higher in patients with CK levels exceeding 15 000 U/l.Mortality was significantly higher in patients with ARF. Plasmaconcentrations of potassium and calcium correlated better withthe severity of renal failure than with the maximal height ofplasma CK.     

Lipoprotein (a) in patients on maintenance haemodialysis and continuous ambulatory peritoneal dialysis

Lipoprotein (a) concentrations and apoprotein (a) isoforms weremeasured in 99 haemodialysis and 79 peritoneal dialysis patientsand compared with a normal population. Peritoneal dialysis patientsdemonstrated a threefold and haemodialysis a twofold increasein median Lp(a) values compared to controls (P0.001). The peritonealdialysis group had significantly more patients with Lp(a) valuesgreater than 30 mg/dl compared to controls, (53% versus 22%P0.001). In addition both patient groups demonstrated significanthypertriglyceridaemia (P0.001), reduction in HDL (P0.001) andelevation of the cholesterol/HDL ratio (P0.001) compared withcontrols. Peritoneal dialysis patients also demonstrated significanthypercholesterolaemia (P0.003). Lipoprotein (a) concentrations are considerably elevated inpatients on maintenance dialysis and this occurs in additionto the typical lipoprotein disturbances. This elevation mayincrease vascular risk, particularly in the peritoneal dialysisgroup who also have hypercholesterolaemia and reduced HDL.     

Circulating 1,25-Dihydroxycholecalciferol After Intravenous Injections of l{alpha}-Hydroxycholecalciferol in Patients on Regular Haemodialysis

The formation of 1.25-dihydroxycholecalciferol (1.25-(OH)₂D₃after single intravenous injections of 1-hydroxycholecalciferol(1-OHD₃) was examined in four patients with chronic renal failureon regular haemodialysis. Following 1–3µg 1-OHD₃administered at weekly intervals, 1.25-(OH)₂D₃ appeared in thecirculation within 1 h, and peak concentrations were reachedbetween 2 h and 5 h. By 8 h serum 1.25-(OH)₂D₃ concentrationshad started declining and by 44 h they had returned to baselineafter 1µg 1-OHD₃ but they were still above basal after2 and 3 µg by an average of 30 pmol/l. One week afterinjections, concentrations were back to basal in all patientsstudied. The serum 1,25-(OH)₂D₃ dose response to injected la-OHDwas linear, indicating ample capacity of the liver 25-hydroxylaseto further hydroxylate 1-OHD. However, examination of the individualresponses revealed lower increments in serum 1.25-(OH)₃ concentrationsin the patients with the highest basal serum 25-hydroxyvitaminD concen trations. Intravenous 1-OHD₃ may be useful in the furtherstudy of the interactions between 1.25-(OH)₂₃ calcium and PTHin chronic renal failure, as well as of the hepatic metabolismof vitamin D.     

Progression rate to end-stage renal failure in non-diabetic kidney diseases: a multivariate analysis of determinant factors

BACKGROUND.: The respective contribution of the type of nephropathy, gender,and proteinuria, and of the potentially alterable factors bloodpressure level and daily protein intake on the rate of progressionin non-diabetic renal diseases is debated. METHODS.: We retrospectively analysed the influence of primary renal disease,gender, urinary protein excretion, mean arterial pressure (MAP),and dietary protein intake on the rate of decline in creatinineclearance (Ccr) in 159 adult patients with well-defined nondiabetickidney diseases. All patients had been followed from a baselineCcr of 40–50 ml/min/1.73 m² until endstage renal diseaseand need for dialysis. RESULTS.: Mean (±SD) Ccr (ml/min/1.73 m²/year) was 9.9±6.5in 51 patients (45 males) with chronic glomerulonephritis, 6±2.5in 50 patients (26 males) with polycystic kidney disease, 5.5±2.4in 17 patients (16 males) with hypertensive angionephrosclerosis,and 3.9±2 in 41 patients (21 males) with chronic tubulointerstitialnephritis. Ccr was higher in males than in females (7.5±5.2versus 4.8±2.5; P <0.001). Linear regression analysisof the whole population disclosed a strong relationship betweenCcr and proteinuria (r² = 0.23; P < 0.001), and a weak relationshipbetween Ccr and protein intake (r² = 0.03; P = 0.02), but norelationship between Ccr and MAP (r² = 0.01; P = 0.23). Stepwisemultiple regression analysis identified the type of nephropathy,gender, and proteinuria as independent predictive factors ofprogression; however, these factors together accounted for only36% of the variation in Ccr, suggesting the contribution ofother yet unidentified factors. CONCLUSIONS.: Primary kidney disease and urinary protein excretion (reflectingthe severity of renal disease in individual cases) appear asthe major determinants of the rate of progression, with fasterprogression in males in all types of nephropathy, whereas potentiallyalterable factors such as blood pressure and protein intakehad only a modest influence in the range of values observedin our patients.     

The renal histopathology in systemic vasculitis: an international survey study of inter- and intra-observer agreement

In order to relate histopathological findings of the kidneyin systemic vasculitis to renal outcome, scoring of variousmorphological parameters is necessary. Therefore, we conducteda standardization study for evaluating renal biopsies from patientswith systemic vasculitis. Four experienced renal pathologistsfrom four European centres joined in the study. A scoring protocolwas devised that required the observers to score an extensivenumber of histopathological lesions either quantitatively (asa percentage of the total number of glomeruli) or dichotomously(on a present/absent scale). Twenty renal biopsies were scoredindividually by all the observers, from which the inter-observervariability was analysed. Ten randomly chosen biopsies werescored again, in order to obtain the intra-observer variability.For inter-observer agreement, the evaluation of the quantitativevariables was satisfactory for both rounds (0.55Kendall's W0.95and 0.59W0.96, respectively, with all P<0.05). However, theinter-observer agreement for the dichotomous data was poor (K0.30in more than half of the parameters in both rounds). Also thedata on intra-observer agreement showed more favourable resultsfor the analysis of the quantitative data (Pearson's r>0.45in more than 85% of the variables in both rounds) than for thedichotomous scoring system (K0.30 in more than half of the variables).It is concluded that even between experienced renal pathologistsdiscrepancies occur in scoring kidney biopsies. Inter- and intra-observeragreement is greater if a quantitative method for reviewingthe biopsies is applied that requires the observers to scorethe tissue specimens systematically.     

Once-weekly erythropoietic therapy: is there a difference between the available preparations?

Sir, Iain Macdougall provided, in general, a comprehensive reviewof once-weekly administrations of epoetin , epoetin ßand darbepoetin [1]. However, additional mention could havebeen made of the differences between epoetin and epoetin ß,as well as further analysis of the data from studies of subcutaneous(s.c.) administration. With regard to the differences between epoetin and epoetin     

Plasma Concentrations of Atrial Natriuretic Peptide in Relation to Body Fluid Status in Chronic Uraemia

Basal plasma -human natriuretic peptide (-hANP) values werefound to be significantly higher in 7 fluid-overloaded chronicdialysis patients than in 13 non-dialysed renal patients withoutextracellular fluid (ECF) expansion. Iso-osmotic reduction ofthe body weight by a single 3-h ultrafiltration caused -hANPto decrease significantly in all anuric patients to values comparableto those of non-dialysed subjects. In this latter group, however,there was a significant inverse relationship between -hANP andglomerular filtration rate but not between -hANP and total bloodvolume. These findings suggest that both ECF expansion and impairedrenal removal of -hANP might be responsible for the high -hANPin chronic uraemia.     

Interleukin 6 production by human proximal tubular epithelial cells in vitro: analysis of the effects of interleukin-1{alpha} (IL-1{alpha}) and other cytokines

Proximal tubular epithelial cells (PTEC) from human renal tissueobtained from biopsy or nephrectomy were grown in monocultureand evaluated in vitro at passage 2–4 for interleukin6 (IL-6) production in response to medium alone or to interleukin1 alpha (IL-1), tumour necrosis factor alpha (TNF), interleukin2 (IL-2), interferon gamma (INF) or lipopolysaccharide (LPS).IL-6 bioactivity was quantitated using the IL-6-dependent murinehybridoma cell line (B9) and expressed as IL-6 units/ml/10⁵PTEC. PTEC cell lines exposed to medium alone produced intermediateamounts of IL-6 with substantial variability between cell lines.Introduction of IL-1 resulted in a dose- and time-dependentincrease in IL-6 production by PTEC that was maximal at 1 ng/mlIL-1 at 24 h. All PTEC cell lines showed an increased IL-6 productionon exposure to IL-1 varying from 1.3- to 24-fold increase overbaseline production. This response was completely blocked byanti-rIL-1. No significant IL-6 production by PTEC could beinduced by TNF, IL-2, IFN, or LPS over a broad dosage range.Cycloheximide inhibited IL-6 production without irreversiblecell toxicity, indicating de-novo synthesis. IL-6 produced byPTEC had a molecular weight of 26-29 kDa as demonstrated byWestern blot analysis. Using PCR analysis we could demonstrateupregulation by IL-1 of IL-6 mRNA in a dose-response fashion,indicating that IL-1 regulates IL-6 production at a pretranslationalvalue of protein synthesis. These results show that human culturedPTEC produce IL-6 under both normal and IL-1-stimulated conditions,and suggest that they may have a regulatory function in responseto cytokines in the setting of inflammation in the renal cortex.     

Peripheral blood mononuclear cells from patients with chronic renal failure release factors which suppress erythropoietin secretion in vitro

Decreased production of erythropoietin (Epo) as a result ofreduced renal mass is considered the main factor underlyingthe anaemia that is invariably associated with chronic renalfailure (CRF). Other mechanisms such as accumulation of inhibitorsof Epo also contribute. In this study we show that supernatantfrom peripheral blood mononuclear cells (PBMC) cultured frompatients with CRF inhibits Epo release by Hep G2 cells in vitro.Ten patients (5 male) with CRF (mean age 42 years, range 25–60)were studied. Five were approaching end-stage renal failureand five were maintained on haemodialysis (HD). Ten apparentlyhealthy volunteers were used as controls. Full blood countsand serum Epo (RIA) levels were determined and adherent PBMCwere cultured for 48 h with and without LPS. There was a significantrise in TNF- and IL1-ß levels measured in monocytesupernatant (MS) from patients and controls after LPS stimulation(P<0.05) and in IL-l levels in patients (P<0.05). IL-1ßlevels were higher in patients compared to controls both beforeand after stimulation with LPS (P<0.05). Hep G2 cells werecultured in 5% CO₂ and 20% O₂ and incubated with MS from patientsand controls for 24 h. Hep G2 harvest fluids were then analysedfor Epo levels, which were expressed as a function of totalcell protein (mU/mg). Epo production was inhibited by MS frompatients compared to controlsboth before and after stimulationwith LPS (P<0.0001). There was, however, no direct correlationbetween the degree of Epo suppression and concentrations ofMS TNF-, IL-l, and IL-ß. Inhibition byspecific polyclonalanti-TNF- antibodies and anti-IL-ß antibodies didnot abrogate the inhibition ofEpo release by Hep G2 cells. Theseresults demonstrate that although PBMC from patients with CRFproduce factors that inhibit Hep G2 cell secretion of Epo invitro, this effect does not appear to be directly related tothe proinflammatory cytokines TNF-, IL-l, and IL-ß.     

Sera from patients with anti-GBM nephritis including Goodpasture syndrome show heterogenous reactivity to recombinant NC1 domain of type IV collagen {alpha} chains

BACKGROUND.: Goodpasture (GP) syndrome is defined by the clinical associationof pulmonary haemorrhage with rapidly progressive glomerulonephritis.The disease is caused by pathogenic autoantibodies directedagainst type IV collagen, which is a major structural componentof glomerular basement membranes (GBM). METHODS.: The non-collagenous domains (NC1) of all six human type IV collagenchains was produced in E. coli as recombinant fusion proteinswith glutathione-S transferase. Sera from 10 patients with differenttypes of anti-GBM nephritis, including GP syndrome, were testedfor reactivity with the six proteins using immunoblotting ofdenatured and reduced proteins and ELISA without reduction. RESULTS.: All 10 sera reacted with the 3(IV) collagen chain by immunoblottingand ELISA. One serum also recognized the 2(IV) 4(IV), 5(IV)and 6(IV) chains by immunoblotting. ELISA measurements revealedreactivity of several other sera with 2(IV), 4(IV) or 6(IV)but not with 5(IV) collagen chains. No reactivity was observedwith the 1(IV) chain. CONCLUSION.: Autoantibodies in anti-GBM nephritis may not be directed onlyagainst the 3(IV) collagen chain and they frequently recognizeconformational epitopes.     

Effect of calcium-channel blocker on tumour necrosis factor alpha (TNF{alpha}) production in cyclosporin-treated renal transplant recipients

PURPOSE OF THE STUDY.: The influence of calcium-channel blocker treatment on in-vitroTNF production by peripheral blood mononuclear cells (PBMC)from renal transplant recipients treated with cyclosporin wasstudied. DESIGN.: We compared spontaneous and OKT3-induced TNF production of 12renal transplant recipients treated with calcium-channel blockertherapy with that of 18 renal transplant recipients who werenever treated with a calcium antagonist. RESULTS.: The two groups were similar with regards to age, time aftertransplantation, dosage of immunosuppressive drugs, and bloodcyclosporin levels. Spontaneous (481±161 versus 319±74pg/ml, n.s.) and OKT3-induced (745±182 versus 632±112pg/ml, n.s.) TNF production were similar in both groups. CONCLUSIONS.: The results indicate that in cyclosporintreated renal transplantrecipients calcium-channel blockers do not affect TNF production.     

Animal models of Alport syndrome.

Introduction The last decade of the twentieth century was a very productiveperiod for the study of Alport syndrome. Alport syndrome wasshown to result from mutations in certain members of the typeIV collagen family of proteins, the 3(IV), 4(IV), and 5(IV)chains. Several hundred different mutations in the COL4A5 gene,which encodes the 5(IV) chain, were described in patients withX-linked Alport syndrome [1]. A few dozen mutations were foundin the COL4A3 and COL4A4 genes, which respectively encode the3(IV) and 4(IV) chains, in patients with autosomal recessiveAlport syndrome [2,3]. Autosomal dominant Alport syndrome, dueto heterozygous mutations in COL4A3 or COL4A4, was establishedas an entity, and distinguished from Fechtner and Epstein syndromes,which arise from mutations in a non-collagen locus, MYH9 [4–7].Investigators established that mutations in the 3(IV), 4(IV),or      

Serum {alpha}2-macroglobulin in haemodialysis patients: baseline and kinetic studies

The pathogenesis of dialysis related amyloidosis remains unresolveddespite the identification of ß₂-microglobulin (ß₂M)as the major protein constituent, as well as other proteinsbeing present in the deposits. Among the latter we have assessedthe serum concentrations of ₂-macroglobulin (₂M) both in thebaseline stage and during the haemodialysis (HD) procedure.We have also assessed the influence of the membrane on ₂M kinetics. Fifteen HD patients with histologically proven dialysis-relatedamyloidosis (DRA group) and 15 HD patients clinically and radiologicallyconsidered dialysis-related amyloidosis free (control group)were included in the baseline study. Blood was sampled the daybefore the second dialysis of the week and ₂M, ß₂Mand ₁, antitrypsin were determined along with the routine biologicalanalysis of these patients. Serum ₂M was greater in dialysis-relatedamyloidosis than in control patients (t = 2.35; P<0.026).Serum ß₂M was similar in both groups. The serum ₂Mand ß₂M correlated in patients with dialysis-relatedamyloidosis (r = 0.64; P<0.01), while no correlation wasfound in controls (r = 0.17; NS). Stepwise analysis taking thepresence of dialysis-related amyloidosis as the dependent variableretained the serum ₂M concentration as the first variable inthe model (F = 4.4; partial r = 0.38; P<0.046). The sameproteins were determined in another group of seven patients,before and hourly during HD as well as 2 and 8 h after the endof HD during nine consecutive dialyses (3 cycles of 3 HD eachusing AN69 and cuprophane membranes in a crossover design).Serum ₂M significantly increased from hour 3 and continued toincrease 2 hours post-HD (+11% and +9% with AN69 and cuprophanerespectively; P<0.001). Total proteins peaked at hour 4 (+4% and +3% P<0.01) and decreased after HD. Serum ß₂Msignificantly decreased with AN69 HD ( – 29% P<0.001)and remained unchanged during cuprophane HD. In conclusion, significant increases in serum ₂M are observedimmediately after and during the early post-dialysis periods,regardless of the membrane used. Further, serum ₂M correlateswith ß₂M only in patients with dialysis-related amyloidosis,and this variable was retained in the multivariate regressionanalysis to predict dialysis-related amyloidosis. Although thebaseline results require confirmation with larger studies, wepostulate that the present results are of relevance for dialysis-relatedamyloidosis pathogenesis since ₂M, previously identified indialysis related amyloid deposits, is closely related to acute-phasereactant proteins, and interacts with the main infiltratingcells of the deposits (macrophages). ₂M modifications couldrepresent a new manifestation of the inflammatory response tothe haemodialysis procedure.     

Tissue-specific distribution of the Goodpasture antigen demonstrated by 2-D electrophoresis and Western blotting

The target of autoantibodies in Goodpasture's disease, the Goodpastureantigen has recently been characterized as the NC1 domain ofthe 3 chain of type IV collagen. In order to study the Goodpastureantigen in different organs, NC1 domains were isolated frombasement membranes (BM) of human glomeruli (GBM), tubules (TBM),alveoli (ABM), placenta (PBM) and aorta (VBM). NC1 preparationswere separated by 2-D electrophoresis, and silver stained orimmunoblotted to determine the subunit structure and antigenicityof different basement membranes. All basement membranes containedmonomeric components of MW 26 kDa and 24 kDa, and associateddimers, corresponding to the 2-D location of 1(IV) and cc2(IV)chains respectively. However, GBM, ABM, and to a lesser extentTBM possessed an extra set of monomeric components of MW 28kDa and associated dimers corresponding to the proposed locationof 3(IV) and 4(IV) chains. 2-D-separated polypeptides were Westernblotted with autoantibodies from patients with Goodpasture'sdisease, a monoclonal antibody to the Goodpasture antigen (P1)and a monoclonal antibody to the bovine 3(IV) chain. The predominantbinding of all these reagents was to cationic 28 kDa monomersof GBM, ABM and TBM, corresponding to the 3(IV) chain, althoughautoantibodies and P1 also bound to neutral 28 kDa monomers,corresponding to the 4(IV) chain. Autoantibodies bound weaklyto more neutral components of PBM and VBM, but neither monoclonalantibody bound to these basement membranes. This study suggeststhat there are two separate type IV collagen networks: one containingthe l(IV) and 2(IV) chains appears to be present in all basementmembranes, and the other containing the 3(IV) and 4(IV) chainshas a tissue specific distribution. The latter network bearingthe Goodpasture antigen is expressed in the basement membranesof both kidney and lung, the organs involved in Goodpasture'sdisease.     

Risk factors of the progression of abdominal aortic calcification in patients on chronic haemodialysis

Background. Vascular calcification is an independent determinantof cardiovascular events in maintenance haemodialysis (HD) patients.It is not known whether acute changes of the serum calcium concentrationbefore and after HD (Ca) are associated with the developmentof aortic calcification. Methods. We enrolled 71 patients dialysed with a dialysate with3.0 mEq/l calcium and determined their aortic calcificationindex (ACI) by abdominal computed tomography twice at an intervalof 3 years. To identify the factors contributing to the rateof progression of aortic calcification, we analysed the averagevalues for clinical and laboratory data obtained between thefirst and second evaluations of ACI. Results. The second ACI (mean ± SD: 80.2 ± 63.9)was significantly greater than the first ACI (61.0 ±61.0) after an interval of 35.8 ± 4.2 months. The annualizedchange of ACI (ACI/year) was significantly and directly associatedwith the Ca and C-reactive protein (CRP) (both P < 0.001,P for trend). Stepwise multivariate regression analysis revealedthat ACI/year was positively and independently associated withCRP, presence of diabetes mellitus and Ca, but negatively associatedwith a premenopausal status in women. Similarly, Ca was positivelyand independently associated with ACI/year and the ultrafiltrationrate, but was negatively associated with pre-HD Ca. Conclusion. The increase of serum calcium after HD was relatedto the rate of progression of aortic calcification. Excess calciumis transferred into patients on HD when using a dialysate of3.0 mEq/l calcium. This may be a risk factor for the developmentof vascular calcification.     

Evaluation by histology, immunohistology and PCR of protocollized renal biopsies 1 week post-transplant in relation to subsequent rejection episodes

Renal biopsies were performed 1 week following renal transplantationat a time without clinical evidence of rejection in 43 patients(13 females, mean age 48 years range 18–60 and 30 males,mean age 43 years range 17–59 years). Thirty-six biopsieswere available for histological or immunohistochemical analysis.Immunohistochemical analyses were performed with monoclonalantibodies against leukocytes (CD45), monocytes (WT14), complementfactor 3 (C3), T-cells (Leu4), T-cell receptor ß and, tumour necrosis factor (TNF) IL-2 receptor (IL2-R, TAC), intercellularadhesion molecule-l (ICAMI) and HLA-DR. The slides were scoredsemiquantitatively with the observers having no knowledge ofclinical or patient data. TNF and IL-2R were also measured byquantative PCR. None of the studied parameters correlated todelayed graft function or graft loss. Histological analysisshowed that both focal interstitial infiltrate (18/35) and tubularbasement membrane disruption (11/35) were followed by a higherincidence of subsequent rejection (P = 0.03 and 0.02 respectively).Also positivity for WT14 around tubuli (P = 0.02) was associatedwith subsequent occurrence of rejection. The intensity of stainingof ICAM-I on PTC as well as TAC on proximal tubular cells wasassociated with the number of subsequent rejection episodes.The association between the IL-2 receptor and subsequent rejectionwas also found applying PCR to the tissue specimens. We conclude that the presence of focal interstitial infiltratesand tubulitis in 1-week biopsies from well-functioning graftscarries an increased risk of subsequent rejection. The observedinfiltrate outside the tubuli may consist of either monocytesor lymphocytes. Further studies, both in vitro and in vivo,applying immunohistochemical and molecular biological techniqueswill be necessary to further elucidate the role of adhesionmolecules and interleukins in early and ongoing rejection.