L. C. Paul

Vascular endothelial alloantigens in renal transplantation.

Revue detudes faites chez lhomme et chez lanimal: la composition alloantigenique de lendothelium dans le rein; les reactions produites lors de transplantations; les antigenes endotheliaux definis par anticorps monoclonaux. Importance dune meilleure recherche sur ces phenomenes pour la comprehension de la pathogenese du rejet

FK778, a powerful new immunosuppressant, effectively reduces functional and histologic changes of chronic rejection in rat renal allografts.

Background. FK778 is a new derivative of the active leflunomide metabolite A77 1726. It effectively prevented acute allograft rejection in several experimental transplant models, and it is currently in phase II trials in human transplant recipients. In this study, we examined the effects of FK778 in a well-established model of chronic renal allograft rejection in the rat. Methods. Kidneys of Lewis (LEW) and F344 rats were orthotopically transplanted into bilaterally nephrectomized LEW recipients as the isograft and allograft control, respectively. Allograft recipients were orally administered FK778 at doses of 3 mg/kg per day, 10 mg/kg per day, and 20 mg/kg per day for 10 days. Blood and 24-hr urine samples were collected once a week after grafting for plasma creatinine, allo-specific antibodies, and proteinuria determination. Kidney grafts were harvested on the 90th day after transplantation and subjected to histologic, immunohistologic, and reverse transcriptase-polymerase chain reaction analysis. Histologic sections were semiquantitatively scored using criteria adapted from the Banff’ classification for transplant pathologic conditions. Results. Recipients treated with FK778 for 10 days exhibited a dose-dependent decrease in proteinuria and plasma creatinine for the entire 90-day period after transplantation when compared with the allograft control. FK778, at doses of 10 mg/kg per day and 20 mg/kg per day, remarkably reduced chronic histologic changes, including tubular atrophy, glomerulosclerosis, fibrointimal hyperplasia, and transplant glomerulopathy. In addition, FK778 treatment was associated with decreased intragraft mononuclear cell infiltration, serum allo-specific immunoglobulin (Ig)M and IgG antibody production, and intragraft transforming growth factor &bgr; messenger RNA expression in those recipients surviving 90 days after transplantation when compared with the allograft control. Conclusion. FK778 effectively reduces functional and histologic chronic kidney allograft rejection in the rat.

Association of rheumatoid factors in renal transplant recipients with cytomegalovirus infection and not with rejection

Because rheumatoid factors (RF) were detected in the circulation of the majority of early renal transplant recipients and could he eluted from rejected transplants, RF were hypothesized to he related to antibody responses to the histoincompatible graft, The possibility that EF production might have been related to infection and not rejection has not been considered previously. Therefore, we investigated serial serum samples from 147 adult renal transplant recipients for RF with latex agglutination and radioimmune assays. RF were detected hi the sera of 32 patients, 30 of whom had coincident active cytomegalovirus (CMV) infections. Another 45 patients with active CMV infections did not have detectable circulating RF. In contrast, of 74 patients who experienced a total of 103 treated reversible or irreversible rejection episodes in the absence of evidence of active CMV infections, only 2 patients produced RF during their rejection episodes. Nine of the patients who did not produce RF during a rejection episode subsequently produced RF during a later CMV infection. These data indicate that EF production in renal transplant recipiento is associated with CMV infection and not rejection. Moreover, EF production was found to be more frequently associated with primary and severe CMV infections than with secondary or milder CMV infections. SF production was not more frequent in patients who were HLA-DR-4-positive., older, or female, characteristics that have been associated with RF production in other populations. Ail of the sera, with detectable RF contained IgM antibodies that were directed to the Fc portion of human IgG, and about half contained additional IgM antibodies directed to Fab. Thus CMV infections may be the stimuli for the IgM anti-Fab antibodies that have been reported in pretransplant serum samples. Eleven patients produced IgG or IgA RF in addition to IgM RF during CMV infections.

Genes Expressed by the Kidney, but Not by Bone Marrow-Derived Cells, Underlie the Genetic Predisposition to Progressive Glomerulosclerosis after Mesangial Injury

Progressive renal failure is accompanied by uncontrolled accumulation of extracellular matrix in glomeruli and tubulointerstitium, eventually resulting in glomerulosclerosis. Although glomerulosclerosis occurs secondary to various renal diseases, the fact that not all patients develop progressive glomerulosclerosis suggests that genetic factors may underlie the tendency to progress, or not to progress. Identified were two Lewis rat substrains with small genetic differences but with considerable difference in resolution of glomerulonephritis after anti-Thy-1 administration. In the Lewis/Møllegard rat strain, anti-Thy-1 glomerulonephritis spontaneously resolves within 4 wk. In contrast, Lewis/Maastricht rats develop progressive glomerulosclerosis after induction of this disease. The involvement of bone marrow-derived cells and kidney cells in the development of glomerulosclerosis was determined. In the first study, exchange of bone marrow between these substrains did not affect the course of anti-Thy-1 nephritis. Lewis/Møllegard rats recovered rapidly, but Lewis/Maastricht rats showed progressive disease regardless of the genotype of the bone marrow they received. In the second study, kidneys were exchanged between the substrains. After transplantation, anti-Thy-1 nephritis was induced and glomerular damage assessed at day 21. Severe damage was observed in Lewis/Maastricht glomeruli independent of whether the kidney had been transplanted or not. Similarly, Lewis/Møllegard glomeruli, whether transplanted or not, revealed no residual histopathologic abnormalities. The inherited differences between the two substrains with regard to their insusceptibility to develop progressive glomerulosclerosis after mesangial injury are governed by genes expressed by the kidney, but not by bone marrow-derived cells.

Convergence of health ratings across nephrologists, nurses, and patients with end-stage renal disease.

We evaluated a health rating for renal failure patients that was completed by patients, nurses, and nephrologists. The study was a prospective inception-cohort follow-up design. Measurements were taken before initiating dialysis (n=206) or at the initiation of dialysis (n=200) and at 18 (n=225), 30 (n=181), 42 (n=162), 54 (n=137), and 66 (n=112) months after initiating dialysis. Patients, nurses, and nephrologists independently rated patients health at each measurement occasion. Objective measures of health status, abstracted from the medical record, included emergency and non-emergency admissions, smoking, diabetes mellitus, pulmonary edema, history and number of myocardial infarctions (MI), basal rales, comorbid illnesses, and uremic symptoms. Simultaneous multiple regression analyses examined the correspondence between objective measures of health status and subjective health ratings separately for each rater and measurement occasion. Health ratings were averaged and submitted to the same analyses. Raters showed good agreement (average Pearson r=.43 overall), although agreement was higher between nephrologists and nurses (average r=.64) than between health professional and patients (average r=.34 and .31, respectively). All three ratings and the combined rating corresponded significantly to objective measures of health status. Uremic symptoms, emergency hospital admissions, diabetes mellitus, and recent MI correlated uniquely and most consistently with subjective health ratings. Despite overall convergence, objective measures of health status related to the groups ratings in a complementary fashion. The health rating is reliable and relates to the current status of the patient. Performance was superior for the combined score that incorporated ratings by patients, nurses, and nephrologists.

Comparison of monoclonal antibodies used for immunological monitoring of renal transplant recipients

To investigate the comparability of the OKT and Leu monoclonal antibodies (mAbs) used for immunological monitoring, T cell subpopulations in 360 blood samples from 35 renal allograft recipients were studied by flow cytometry using both series of mAbs. To identify the activated cells in the different subpopulations, those labeled with the Leu mAbs were double-labeled with an anti-HLA-DR mAb. The percentages of T cells that stained with the Leu3a and Leu2a mAb using a direct immunofluorescence technique were significantly lower than the percentages of cells that stained with the OKT4 and OKT8 mAb using an indirect immunofluorescence technique (47.6 +/- 12.8% and 14.5 +/- 9.1% [mean +/- SD] versus 50.5 +/- 11.2% and 18.3 +/- 8.0%, respectively; P less than 0.0001). Since the difference between the Leu2a+ and OKT8+ cells was relatively greater (21%) than that between the Leu3a+ and OKT4+ cells (6%), the mean Leu3a/2a ratio was significantly higher than the mean OKT4/8 ratio (6.64 +/- 9.7 versus 3.60 +/- 2.82; P less than 0.0001). The difference between the Leu2a+ and OKT8+ cells were not attributable to a difference in the sensitivity of the direct and indirect immunofluorescence technique. A large difference between the Leu2a+ and OKT8+ cells correlated with a high percentage of DR+ cells within the Leu2a population (P less than 0.001). No correlation was found for the difference between the OKT4+ and Leu3a+ cells and the DR expression in the Leu3a+ cell population. These observations suggest that activation of some T cells of the cytotoxic-suppressor phenotype leads to antigen modulation in which the OKT8 epitope is not affected but the Leu2a epitope disappears or cannot be detected with the present method.

Anti-tubular basement membrane antibodies and giant cell formation in a model of chronic renal allograft rejection

Background. In the Fisher (F344)-to-Lewis (LEW) kidney transplantation (Tx) model of chronic rejection, antibodies reactive with tubular basement membranes have been found. We investigated whether giant cells, typical for a granulomatous inflammatory reaction, can be found during allograft rejection. Methods. F344-to-LEW renal Txs were performed, and kidneys were removed at various time points. Kidneys were analyzed by histology and immunohistochemistry. Interferon-γ levels were measured by reverse-transcriptase polymerase chain reaction. Results. Multinucleated Langhans’-type giant cells were found in F344 allografts at days 21 and 30 and disappeared thereafter. Giant cells were not observed in LEW allografts. The giant cells were ED1, OX-43, and major histocompatibility complex class II positive. All grafts showed transient expression of interferon-γ, peaking at days 7 to 14 post-Tx. Conclusion. Granulomatous inflammation with giant cell formation occurs in the F344-to-LEW model and may represent an alloimmune response against tissue-specific antigens.

Perivascular deposits of IgM in the skin of transplant recipients during active cytomegalovirus infections. Correlation with IgM rheumatoid factors and IgM immune complexes.

Skin biopsies from 30 renal transplant patients were investigated for cellular infiltrates and deposits of IgM, IgA, IgG, C3, and C5–9 neoantigen. Granular perivascular deposits of IgM were detected in biopsies of 8 of 14 patients during active cytomegalovirus (CMV) infections and in none of 16 controls. In 5 biopsies, the IgM deposits were accompanied by little or no IgG, IgA, or C, while in 3 biopsies definite C3 deposits were present. One of the biopsies with C3 deposits also had C5–9 deposits and another had C5–9 and IgA deposits. Three monoclonal antibodies failed to detect early or late nuclear antigens of CMV in the deposits. These deposits were not associated with clinically evident manifestations of vasculitis. A strong correlation was found between IgM deposits in the skin and IgM circulating immune complexes (CIC) and also IgM rheumatoid factor (RF). The deposition of IgM was not more frequent in primary than in secondary CMV infections, and it did not correlate with the production of IgM antibodies that were specific for CMV antigens.

Bladder content and residual urine in renal transplant patients: measurement using ultrasonography and relevance to urinary tract infection

SummarySince the incidence of urinary tract infection after renal transplantation is high, and residual urine after voiding may be associated with urinary tract infection, the reliability of ultrasonographic determination of bladder content and residual urine in renal transplant recipients was investigated. Both bladder content and residual urine, calculated by the formula 0.6 × length × width × depth of the bladder (in cm), correlated closely (r>0.9, P<0.001) to the measured volumes of urine obtained by voiding and catheterization. We conclude that ultrasonography is a reliable method for determining bladder content and residual urine in renal transplant recipients. Out of 44 patients, 4 exhibited residual urine of more than 10 cm3; 25 of the 44 patients (57%) had one or more urinary tract infections within the first year of transplantation. One of the patients with residual urine had recurrent pyelonephritis and another had recurrent cystitis; the other two patients did not have any urinary tract infection at all. Since residual urine does not appear to be a frequently occurring phenomenon, it probably does not contribute to the high incidence of urinary tract infections in renal transplant recipients.