LIGHT AND ELECTRON MICROSCOPIC STUDY OF BIOPSIES FROM THIRTY-THREE HUMAN RENAL ALLOGRAFTS AND AN ISOGRAFT 134-212 YEARS AFTER TRANSPLANTATION

Chronic rejection of liver transplants revisited

We examined 27 hepatectomy specimens to assess the frequency of foam cell endovasculitis and bile duct loss in chronic rejection. Arterial lesions, defined as total occlusion by subintimal foam cells and/or fibromuscular proliferation, were found mainly in hilar and septal arteries, whereas bile duct loss, defined as the absence of bile ducts in more than 50% of portal tracts, affected mainly small tracts. Both were found in 20 livers (74%). In two livers (7%) there was significant bile duct loss but no arterial lesions, whilst in five cases (19%) there were occlusive arterial lesions but no bile duct loss. Small arteries were involved in only 10% of the cases. These results indicate that in one-third of the cases arterial and bile duct lesions develop independently of each other, suggesting different pathogenetic pathways. In addition, liver biopsy may not be pathognomonic since small arteries are involved in only 10% of cases and bile duct loss may not be extensive. In such cases the diagnosis of chronic rejection should only be made in the presence of progressive clinical deterioration.

Histopathologic findings associated with a chronic, progressive decline in renal allograft function

The relationship between specific histopathologic findings of chronic rejection (CR) and the clinical course of renal transplant recipients with a chronic progressive decline in allograft function (CPDAF) is unknown. We used one or two hinged regression lines, fitted by least-squares to serial creatinine clearances, to define the onset and clinical course of CPDAF. Biopsies (N = 100) from patients transplanted from 1978 to 1982 were studied retrospectively. Interstitial fibrosis, tubular atrophy, and fibrointimal arterial narrowing were more pronounced in biopsies obtained after, but not before the onset of CPDAF. Interstitial hemorrhage, an infrequent finding in acute vascular rejection, preceded the onset of CPDAF, but the more common histologic findings of acute cellular rejection did not. The severity of histologic features of CR (as reflected by a score combining fibrointimal arterial narrowing, interstitial fibrosis, tubular atrophy, glomerular sclerosis, glomerular mesangial expansion, and glomerular basement membrane reduplication) correlated with the duration of subsequent allograft survival (r = -0.65, P less than 0.001). Glomerular size increased after transplantation, but was not different in patients with or without CPDAF, suggesting that mechanisms related to compensatory hypertrophy did not play a major role in the pathogenesis of CR. In summary, the histologic findings of CR did not predict the onset of CPDAF, did not distinguish whether the pathogenesis was mediated by immune or nonimmune events, but did correlate with the duration of subsequent allograft survival.

Kidney graft rejection studies with labeled platelets and lymphocytes

The usefulness of In-111-labelled platelets and lymphocyte scintigraphy in acute kidney graft rejection is evaluated. One hundred fifty-five patients (36 treated with cyclosporine A) were studied with labelled platelets and 27 with labelled lymphocytes. Blood cels were labelled with 100-150 microCi of In-111-oxine and reinjected. Subsequently patients were scanned once daily from 2 hours post-reinjection up to a week. The graft/contralateral area activity ratio was calculated in all scans (index I). Four groups of patients were established: Functioning grafts (FG); post-operative acute renal failure (p-ARF); acute rejection (AR) and nephrotoxicity (NTX), the last one only in patients under cyclosporine therapy. Results with labelled platelets showed similar index I mean values in FG, p-ARF and NTX patients I = 1.1 +/- 0.1 and a significant increase (p less than 0.001), in acutely rejecting grafts I = 1.9 +/- 0.4. Evolving controls showed a decrease a decrease of graft activity parallel to rejection resolution while the activity maintains or increases in patients with less or no response to treatment. Overall sensitivity was 97.2%, specificity 90.2% and accuracy 92.8%. Results with labelled lymphocytes were similar to those with platelets. They showed a significant (p 0.001) difference of activity index between rejecting (I = 1.86 +/- 0.3) and non rejecting grafts (I = 1.05 +/- 0.1). Decrease of graft activity was only seen in patients with good response to treatment. It is concluded that In-111-labelled platelets scintigraphy is nowadays the method of choice for acute kidney graft rejection diagnosis, especially in patients under cyclosporine immunosuppression.

Interstitial fibrosis in renal allografts after 12 to 46 months of cyclosporin treatment: beneficial effect of low doses in early post-transplantation period

To investigate whether cyclosporin (CsA) causes chronic renal damage 38 renal allograft biopsies were performed 1 to 4 years after transplantation in 28 CsA-treated patients, in the absence of rejection or acute CsA nephrotoxicity. Blind, semi-quantitative light microscopic examination showed that interstitial fibrosis plus tubular atrophy occurred more often in CsA-treated patients than in patients treated with azathioprine. The degree of interstitial fibrosis correlated with high cumulative CsA dose during the first 6 months of treatment, as well as with the number of acute CsA nephrotoxic episodes, which suggests that the findings are an effect of chronic CsA nephrotoxicity. Maintenance doses of CsA (2.3-10.7 mg/kg/day) seemed to contribute little to the renal damage. The pathogenesis of the observed lesions is not known. A high trough CsA level at the time of biopsy correlated with the degree of interstitial mononuclear cell infiltrate in the renal tissue. The results thus demonstrate chronic morphological changes in renal allografts from CsA-treated patients. Avoiding high CsA doses may be a way of preventing this side-effect. Until this has been confirmed, the risk of chronic renal damage must be taken into consideration when new clinical trials of CsA are being planned.

The improving utility of renal transplantation in the management of end-stage renal disease

The results achieved by treating patients with end-stage renal failure with allotransplantation have improved dramatically since the 1950s when immunosuppression was induced by total body irradiation and there was a lack of HLA typing. Although long-term hemodialysis offers prolonged survival and partial rehabilitation for many individuals with end-stage renal disease, the technique is inconvenient and time consuming. Patients are restricted by necessary proximity to the machine, dietary limitations, potential failure of access sites, and complications of various organ systems. Despite the availability of dialysis and the federal funds to partially pay for treatment, long-term dialysis still remains a costly process for the individual in need of care. During the same period when dialysis techniques improved and became widely available, transplantation of the human kidney became an established and justified treatment for some patients with end-stage renal disease. Those with successful kidney allografts may achieve remarkable recovery and are often able to return to normal lives. One of the more striking improvements in the results of renal transplantation in recent years had been the decline in morbidity and mortality. Mortality by the end of the first year after transplantation during which time most deaths occur, is currently less than 5 percent in a number of major medical units. In part, this decline represents a change in philosophy by transplant teams, who now tend to decrease immunosuppression and sacrifice the kidney rather than the patient in instances of inexorable rejection. In addition, declining mortality is directly attributable to improved methods of preventing, discovering, and treating patients with potential or real infections. More recently, in some centers, the rate of successful engraftment has shown gratifying improvement due to refinements in tissue typing, improved cross matching, new immunosuppressive therapies, and pretransplant conditioning with blood products. These recent improvements are the primary focus of this review. Unfortunately, until very recently, rates of functional survival of allografts have not been satisfactory.

Immunofluorescent examination of biopsies from long-term renal allografts

Immunofluorescent examination of open renal biopsies revealed clear-cut glomerular localization of immunoglobulins not related clearly to the quality of donor-recipient histocompatibility in 19 of 34 renal allografts. The biopsies were obtained 18 to 31 months after transplantations primarily from related donors with a variable quality of histocompatibility match. IgG was the predominant immunoglobulin class fixed in 13 biopsies, and IgM in six. The pattern of immunoglobulin deposition was linear, connoting anti-GBM antibody in four of the 19; it was granular and discontinuous, connoting antigen-antibody-complex deposits, in 13. An immune process may affect glomeruli of renal allografts by mechanisms comparable to those that cause glomerulonephritis in native kidneys. The transplant glomerulonephritis may represent a persistence of the same disease that originally destroyed the host kidneys or the consequence of a new humoral antibody response to allograft antigens.

Chronic renal homograft function: correlation with histology and lymphocyte antigen matching

Renal function was studied in twenty-nine of thirty-four surviving renal allograft recipients from an initial group of sixty-four patients two years after transplantation. Mean clearances of inulin and PAH were, respectively, greater than and equal to half the donors’ initial predicted clearances. Minimum urine osmolality during water diuresis was greater, and maximum urine osmolality during hydropenia was less than normal, an effect attributable partly to enhanced solute load in a single transplanted kidney.

Patients with compatible donor-recipient lymphocyte antigens demonstrated statistically better function than those with one or more incompatibilities, although there was a definite degree of overlap between the two groups. In contrast, little correlation could be demonstrated between the cumulative histopathology and renal clearances.

Renal function in patients with compatible donors was statistically greater than half the donors’ initial predicted function. Serial increase in renal clearances was documented in one patient with a compatible donor. Serial decreases were demonstrated in two patients with incompatible donors. These findings suggest that hypertrophy of the denervated, transplanted kidney occurs when immune reaction is minimal.

Renal transplantation at the University of Colorado

From March 1962 to April 1966, 118 patients were treated with renal transplantation, 3 with kidneys from identical twins, 9 with cadaveric homografts, and 106 with homografts from volunteer donors. Sixty-two of the patients are still alive after nine months to almost five years. The only completely satisfactory group was that of the identical twin recipients.

The results after homotransplantation have not materially improved during this time despite the acquisition of increased experience, adjustments of timing and dosage of azathioprine and prednisone, and attempts to identify biologically suitable donors in advance of operation by tissue typing. It is suggested that an impasse has been reached, beyond which further reduction in mortality and morbidity will depend primarily upon the effective application of new immunosuppressive techniques.

Serotyping for homotransplantation. V. Evaluation of a matching scheme

An attempt was made to determine whether 36 long-term kidney homograft recipients and their donors were compatible for 7 major leukocyte groups. It was found that 21 of these recipients were surviving 2 to 3 years in spite of incompatibility for 1 or 2 major leukocyte antigens. Survival of mismatched grafts does not itself indicate that the antigens being measured are not transplantation antigens, for it was shown that the 15 recipients with no groups of mismatch were clinically superior to those with group incompatibilities. Moreover, histopathologic scores given to biopsy specimens taken 2 to 3 years after transplantation were significantly correlated with the number of group mismatches. Because the leukocyte groups were determined by cytotoxicity reactions of peripheral blood lymphocytes, the results may have been influenced considerably by chimerism in chronically dialyzed uremic patients or change in lymphocyte antigenicity or susceptibility to lysis upon prolonged immunosuppressive treatment. Although the possibility of these complications could not be ruled out in all instances, it was shown that 52 dialyzed uremic patients and 49 patients who had been treated with immunosuppression for over 1 year did not possess more or less antigens than a random population of normal individuals. It is concluded that: (1) the major leukocyte antigens are histocompatibility antigens and (2) since survival can be attained at times despite mismatches for these groups, the antigens are of intermediate strength and kidney homograft rejection may occur if excessive numbers of antigens are incompatible or if particular combinations of antigens are mismatched.