Long-term survival of kidneys transplanted from live A2 donors to O and B recipients.

The long-term outcome of kidneys transplanted from blood group A(2) live donors into blood group O or B candidates is not known. From 1986 through 2006, we transplanted eight blood group O patients and one blood group B patient with kidneys from blood group A(2) live donors. Immunosuppression was no different for these patients than for ABO-compatible recipients. All patients received methylprednisolone, cyclosporine or tacrolimus and azathioprine or mycophenolate mofetil with or without antibody induction (monoclonal or polyclonal). Of the nine live-donor A(2) to O and B transplants performed, seven grafts remain functioning. One of those seven was lost to follow-up at 9.2 years with a functioning kidney. Of the remaining six patients, length of follow-up is 10.4, 6.5, 5.3, 4, 2.1 and 1 years. Of the two patients who lost their grafts, one died with a functioning graft (DWFG) at 8.8 years and one lost his graft at 13.2 years due to noncompliance with immunosuppression. These data show that good long-term graft survival can be expected in live-donor A(2) to O and B transplantation despite some of those patients experiencing the type of clinical problems seen with ABO-compatible transplants.

Point-of-care testing in an organ procurement organization donor management setting.

PURPOSE: Our organ procurement organization (OPO) evaluated the clinical and financial efficacy of point-of-care testing (POCT) in management of our deceased organ donors. METHODS: Before we implemented point-of care testing with the i-STAT into routine clinical donor management, we compared the i-STAT result with the result from the respective donor hospital lab (DHL) for certain analytes on 15 consecutive donors in our OPO from 26 March to 14 May 2001. The financial impact was studied by reviewing 77 donors from July 2001 to March 2002. RESULTS: There was a strong correlation for each analyte between the POC and DHL test results with r-values as follows: pH 0.86; PCO2 = 0.96; PO2 = 0.98; sodium = 0.98; potassium = 0.95; chloride = 0.94; BUN = 0.98; glucose = 0.92; haematocrit = 0.87 and creatinine = 0.95. Since our OPO coordinators began using i-STAT in their routine clinical management of organ donors, they can now more quickly maximize oxygenation and fluid management of the donor and make extra-renal placement calls sooner. Finally, since we are no longer being billed for the testing performed on the i-STAT, average financial savings to our OPO are US dollars 733 per case. CONCLUSIONS: Point-of-care testing in management of our OPO donors provides a result that is equivalent to that of the donor hospital lab, has quicker turn-around time than the donor hospital laboratory, allowing more immediate clinical management decisions to be made so that extra-renal offers may begin sooner.

Cold ischemia time: an independent predictor of increased HLA class I antibody production after rejection of a primary cadaveric renal allograft.

BACKGROUND: Cadaveric kidneys experiencing longer cold ischemia time (CIT) are associated with higher levels of delayed graft function, acute rejection, and early graft loss. One mechanism to explain these results is that ischemia/reperfusion (I/R) injury makes the allograft more immunogenic by upregulating molecules involved in the immune response (e.g., HLA Class I/II). METHODS: We evaluated the influence of CIT on the production of HLA Class I antibody level, measured by an antihuman globulin panel reactive antibody (AHG PRA) level, in 90 unsensitized recipients of primary cadaveric renal transplants (from a total of 1442 between 1985 and 1997) who rejected their kidneys. RESULTS: By multivariate analysis, a CIT of 15 hr or more (vs. < 15 hr) independently increased the risk of the AHG Class I PRA level being > or = 20% after unsensitized patients rejected their first kidneys (relative risk=3.57; 95% confidence interval=1.26 to 10.14; P=0.01), despite the same degree of Class I/II mismatch between the two CIT groups. The overall mean peak PRA level after primary kidney rejection was significantly lower for the CIT < 15 hr group (25.9%+/-33.9; n=24) compared with the CIT > or = 15 hr group (46.3%+/-36.5; n=66) (P<0.001). CONCLUSION: Longer CIT induces a humorally more immunogenic kidney.

The influence of age, gender and ethnicity on cadaveric organ recovery rate.

In view of the influence of donor factors such as age on graft outcome and the performance standards that measure OPO productivity by the number of organs recovered and transplanted, it is important to understand the relationship of certain donor factors on organ recovery for transplantation from cadaveric donors. We examined the influence of donor age, gender and ethnicity on the number and type of transplanted organs recovered from 598 consecutive cadaveric donors in our OPO between 1994 and July 1999. The highest number of organs/donor ocurs in the 11-20 donor age range and declines significantly with each age range. The type of organ recovered is also influenced by age, but the least effect is on liver recovery. No difference was seen in the number of organs recovered/donor by race. When the data were re-analyzed with regard to renal and extra-renal organs transplanted/million donor population, 78% of the kidneys (n=781/1006) were from the 11-50 age range and 81% of the extra-renal organs (n=822/1,192) were from that age range. Stepwise regression yielded a model where donor age significantly influenced (P=0.001) the number of organs recovered. Finally, the incidence of recovered and transplanted organs was significantly higher in males compared with females for hearts [51% (187/360) vs. 40% (86/214); P<0.006] and pancreata [18% (66/360) vs. 11% (24/214); P<0.02]. The number of organs recovered and transplanted from cadaveric organ donors is influenced predominantly by the age of the donor, with the exception being liver donors. Increasing organ recovery and transplantation of organs from donors from the two age extremes results in less gain in the number of organs/million population than recovery from the 11-50 age range.

IgM antibodies identified by a DTT-ameliorated positive crossmatch do not influence renal graft outcome but the strength of the IgM lymphocytotoxicity is associated with DR phenotype.

A positive crossmatch that is rendered negative by treating the serum with the IgM-reducing agent dithiothreitol (DTT) is generally reported not to influence short-term renal graft outcome. Its effect on long-term (> or = 3 years) cadaveric and live-donor transplant function, however, is less clear. We evaluated the effect of IgM antibodies in a DTT-ameliorated positive crossmatch (DTT-APXM) on long-term renal graft outcome in 1,290 consecutive cadaveric renal transplants (8-year survival) and 384 live-donor renal transplants (7-year survival) from patients transplanted between 1990 and 1999. The data show that 1- and 8-year graft survival for cadaveric renal transplants in patients with IgM antibodies (n=72) (DWFG censored = 91% and 65%; DWFG not censored = 90% and 60%) was not significantly different from the group without IgM antibodies (n = 1,218) (DWFG censored = 92% and 71%; DWFG not censored = 87% and 55%) (log-rank = 0.25 for DWFG censored, log-rank = 0.92 for DWFG not censored). The one- and seven-year graft survival for live-donor renal transplants in patients with IgM antibodies seen in a DTT-APXM (n = 22) (DWFG censored = 95% and 83%; DWFG not censored = 95% and 66%) was not significantly different from the group without IgM antibodies (n = 362) (DWFG censored = 94% and 81%; DWFG not censored = 92% and 73%) (log-rank = 0.61 for DWFG censored, log-rank = 0.89 for DWFG not censored). DR phenotype was found to be associated with the strong (>40% cell death) IgM reactivity in both black and white patients. In white patients, DR2 was more frequently seen with a strong IgM crossmatch (48.2%) than in molecularly typed controls (28.5%) (P < 0.03) and concomitant with that DR increase, DR4 was decreased in white patients (6.8%) compared with controls (25.5%) (P < 0.02). In black patients with strong IgM reactivity, DR6 was increased in patients (46.1%) compared with controls (20.5%) (P = 0.07) and concomitant with that DR6 increase, DR5 was decreased in frequency in black patients (7.6%) compared with controls (41%) (P < 0.03). These data show that long-term graft survival in renal transplantation is not negatively influenced by the presence of donor-reactive lymphocytotoxic antibodies in the crossmatch ameliorated by serum DTT treatment. They also suggest that the strength of the IgM antibody response is regulated in part by certain gene (s) of the DR region.

Identification of alpha3, alpha4, and alpha5 chains of type IV collagen as alloantigens for Alport posttransplant anti-glomerular basement membrane antibodies.

BACKGROUND: Alport syndrome is a hereditary disorder of basement membranes especially affecting the kidneys, ears, and eyes. Some patients who undergo renal transplantation lose their kidneys as a result of posttransplant anti-glomerular basement membrane (anti-GBM) disease. METHODS: In the present study, we analyzed serum from 21 unselected Alport patients who underwent renal transplantation. Eleven samples were from patients without posttransplant anti-GBM nephritis, and 10 were from patients with this disease. RESULTS: Thirteen serum samples [10 alport posttransplant nephritis serum (APTN) and three Alport posttransplant serum (APT)] revealed linear binding to the GBM by indirect immunofluorescence. By using direct ELISA and immunoblotting with GBM constituents and type IV collagen NC1 domains from bovine, human, and recombinant sources, we detected anti-GBM antibodies in all Alport patients in varying titers. Five samples showed specific reactivity to the alpha3 chain, four to the alpha5 chain, six to both alpha3 and alpha5 chains, one to the alpha3 and alpha4 chains, and two to the alpha3, alpha4, and alpha5 chains of type IV collagen. The varied spectrum of reactivities was present equally in nephritic and non-nephritic sera. Ten control samples from non-Alport transplant patients did not exhibit specific binding to the GBM. CONCLUSIONS: These results suggest that the absence of alpha3, alpha4, and alpha5 chains of type IV collagen in the Alport kidney leads to alloantibodies in all Alport patients who receive transplants, irrespective of whether they develop nephritis or not. Although all Alport transplant patients develop this humoral response, only a select few develop anti-GBM disease. We suggest that this difference could be attributable to a genotypic effect on the ability of some individuals to launch a cell-mediated immune response.

Successful cadaveric renal transplantation of patients highly sensitized to HLA Class I antigens.

The purpose of our investigation was to evaluate long-term graft survival and the role of histocompatibility in patients who were highly sensitized to human leukocyte antigen (HLA) Class I antigens and received a cadaveric renal transplant. Our multi-institutional study evaluated 7-yr graft outcomes and the histocompatibility requirements of 61 (6.1%) highly sensitized (anti-human globulin panel reactive antibody [AHG PRA], > or = 80%) cadaveric renal transplantation patients, transplanted between 1988 and 1997, among 999 consecutive cadaveric renal transplants. One- and 7-yr graft survival in the high PRA group (n = 61) was 76 and 59%, and was not significantly different from that in the low PRA group (n = 938), 86 and 59% (Wilcoxon = 0.11; log-rank = 0.45) (died with a functioning graft [DWFG] not censored). When those data were divided into primary and regrafts, 1- and 7-yr graft outcomes for high and low PRA groups were not significantly different [(primary, 1- and 7-yr survival: high PRA = 83 and 74%, n = 30, and low PRA = 87 and 61%, n = 825; log-rank = 0.37 for DWFG not censored) (regrafts, 1- and 7-yr survival: high PRA = 70 and 42%, n = 31, and low PRA = 80 and 43%, n = 113; log-rank = 0.36 for DWFG not censored)]. We did observe a subgroup of the high PRA patient group that had inferior graft outcomes. Graft outcome at 1 and 6 yr in the high PRA group for patients who had one to two DR mismatches (65 and 50%, n = 41) was significantly worse than for high PRA patients who had zero DR mismatches with their donors (100 and 78%, n = 20) (log-rank = 0.01 for DWFG not censored). Furthermore, the mean number of HLA-A and -B mismatches was significantly greater in the high PRA/DR-mismatched group (1.7 +/- 1.2, n = 41) compared with the high PRA/zero DR-mismatched group (0.5 +/- 1.1, n = 19) (p < 0.001). Overall, these data suggest that the patient who is highly sensitized to HLA Class I antigens has a long-term graft outcome that is equivalent to less sensitized patients, but that HLA-DR mismatching and a higher degree of Class I mismatching may be poor prognostic indicators in such patients.

Role for transforming growth factor-beta1 in alport renal disease progression.

BACKGROUND: Alport syndrome results from mutations in either the alpha3(IV), alpha4(IV), or alpha5(IV) collagen genes. The disease is characterized by a progressive glomerulonephritis usually associated with a high-frequency sensorineural hearing loss. A mouse model for an autosomal form of Alport syndrome [collagen alpha3(IV) knockout] was produced and characterized. In this study, the model was exploited to demonstrate a potential role for transforming growth factor-beta1 (TGF-beta1) in Alport renal disease pathogenesis. METHODS: Kidneys from normal and Alport mice, taken at different stages during the course of renal disease progression, were analyzed by Northern blot, in situ hybridization, and immunohistology for expression of TGF-beta1 and components of the extracellular matrix. Normal and Alport human kidney was examined for TGF-beta1 expression using RNase protection. RESULTS: The mRNAs encoding TGF-beta1 (in both mouse and human), entactin, fibronectin, and the collagen alpha1(IV) and alpha2(IV) chains were significantly induced in total kidney as a function of Alport renal disease progression. The induction of these specific mRNAs was observed in the glomerular podocytes of animals with advanced disease. Type IV collagen, laminin-1, and fibronectin were markedly elevated in the tubulointerstitium at 10 weeks, but not at 6 weeks, suggesting that elevated expression of specific mRNAs on Northern blots reflects events associated with tubulointerstitial fibrosis. CONCLUSIONS: The concomitant accumulation of mRNAs encoding TGF-beta1 and extracellular matrix components in the podocytes of diseased kidneys may reflect key events in Alport renal disease progression. These data suggest a role for TGF-beta1 in both glomerular and tubulointerstitial damage associated with Alport syndrome.

Determinants of waiting time for heart transplants in the United States.

BACKGROUND: Reports have been published on factors affecting the variations in waiting times for kidney and liver transplant candidates who have been registered on the United Network for Organ Sharing's waiting list. This study reports on determinants of waiting time differences that occur in the eleven UNOS regions for heart transplant candidates. METHODS: Retrospective analysis of 11,345 primary heart waiting-list registrations and 15,868 cadaveric donors, from whom 7,043 hearts were recovered and transplanted for the years 1994-96. Because estimated populations in the eleven UNOS regions vary from 10.8 to 43.2 million, analyses utilized Registrations/million population and Transplants/million population to obtain an R/T ratio. The relationship of the R/T ratio to the median waiting time was then examined for different demographic variables. RESULTS: The numbers of new heart candidate registrations, heart transplants performed, and waiting list deaths have undergone little change from 1991 through 1996. National median waiting times varied by basic demographic variables such as ABO blood type, race, age group, and UNOS medical urgency status. In the eleven UNOS regions, registrations per million ranged from 11.5 to 33.0 and transplants per million from 5.3 to 10.7. Registration/Transplant ratios correlated with median waiting times for urgency Status 1 and 2 as well as for blood group O recipients. Correlation with blood type AB recipients was less consistent, in part, due to the small number of AB recipients. CONCLUSIONS: There are wide variations in the number of heart transplant candidate registrations and in the number of heart transplants performed in the eleven UNOS regions. The registration to transplantation ratio correlated with median waiting times in these regions. Factors possibly contributing to the observed variations were examined.

Center-specific graft and patient survival rates: 1997 United Network for Organ Sharing (UNOS) report.

CONTEXT: Multiple comprehensive, risk-adjusted studies evaluating short-term surgical mortality have been reported previously. This report analyzes short-term and long-term outcomes, both nationally and at each individual transplant program, for all solid organ transplantations performed in the United States. OBJECTIVES: To report graft and patient survival rates for all solid organ transplantations, both nationally and at each specific transplant program in the United States, and to compare the expected survival rate with the actual survival rate of each individual program. DESIGN AND SETTING: Multivariate regression analysis of donor and recipient factors affecting graft and patient survival of all kidney, liver, pancreas, heart, lung, and heart-lung transplants reported to the United Network for Organ Sharing from 742 separate transplant programs. PATIENTS: A cohort of 97587 solid organ transplantations performed on 92966 recipients in the United States from January 1988 through April 1994. MAIN OUTCOME MEASURES: Short-term and conditional 3-year national and individual transplant program graft and patient survival rates overall and from 2 separate eras (era 1, January 1988-April 1992; era 2, May 1992-April 1994); comparison of actual center-specific performance with risk-adjusted expected performance and identification of centers with better-than-expected or worse-than-expected survival rates. RESULTS: One-year graft follow-up exceeded 98% and conditional 3-year follow-up exceeded 91% for all organs. Graft and patient survival improved significantly in era 2 compared with era 1 for all cadaver organs except heart, which remained the same. One-year cadaveric graft survival ranged from 81.5% for heart to 61.9% for heart-lung and 3-year conditional graft survival ranged from 91.3% for pancreas to 74.7% for lung. The percentage of programs whose actual 1-year graft survival was not different from or was better than their risk-adjusted expected survival ranged from 98.3% for heart-lung to 75.7% for liver. Most kidney, liver, and heart programs whose actual survival was significantly less than expected performed small numbers (less than the national average) of transplantations per year. CONCLUSIONS: Graft and patient survival for solid organ transplantations showed improvement over time. Conditional 3-year graft and patient survival rates were approximately 90% for all organs except for lung and heart-lung. The conditional 3-year survival rates were better than 1-year survival rates, indicating the major risk after transplantation occurs in the first year. The majority of transplant programs achieved actual survival rates not significantly different from their expected survival rates. Center effects were most significant within the first year after transplantation and had much less influence on long-term survival outcomes.

Influence of the Rh (D) blood group system on graft survival in renal transplantation.

BACKGROUND: The Rh (D) blood group system has not traditionally been considered to be a clinically relevant histocompatibility barrier in transplantation since conflicting results of its clinical importance have been reported. METHODS: We analyzed 786 consecutive primary cadaveric renal transplants performed by transplant centers in our Organ Procurement Organization (OPO) between 1990 and 1997. We also analyzed United Network for Organ Sharing (UNOS) data on 26,469 kidney transplants done from April 1994 to June 1996. RESULTS: Multivariate analysis revealed that Rh identity between the recipient and donor was significantly related to better graft outcome (risk ratio, 0.43; 95% confidence interval, 0.30 to 0.61; P=0.0001). Multivariate analysis of the UNOS data revealed that the Rh -/- group may have a positive influence on graft survival with a risk ratio of 0.43 (P=0.14). CONCLUSION: Multivariate analysis of primary cadaveric renal allografts performed within the Midwest Organ Bank OPO indicates that Rh (D) is a clinically relevant histocompatibility barrier that influences 7-year graft survival.

Ten-year experience in transplantation of A2 kidneys into B and O recipients.

BACKGROUND: This article summarizes our 10-year multicenter experience with transplantation of 50 blood group A2 and A2B kidneys into B and O patients. METHODS: Since 1986, we have transplanted kidneys from 46 cadaver donors and 4 living donors who were blood group A2 (47 donors) or A2B (3 donors) into 19 B and 31 O patients. In 1991, we began allocating these kidneys preferentially to B and O recipients who were selected based on a history of low (< or =4) anti-A IgG isoagglutinin titers. Immunosuppression was no different from that used in ABO-compatible grafts. RESULTS: The 1-month function rate before thus selecting the patients was 68% (19/28), but is now 94% (17/18). Two-year cadaver-donor graft survival with this selection method is 94%, compared with 88% for 640 concurrent and consecutive ABO-compatible transplants (log-rank, 0.15). All four living-related transplants are still functioning, with a mean follow-up of 71 months. Since we began allocating A2 kidneys preferentially to B and O recipients, the percentage of the B patients who received A2 or A2B kidneys has increased from 29% (8/28) to 55% (10/18). CONCLUSIONS: Transplantation of A2 or A2B kidneys into B and O patients is clinically equivalent to that of ABO-compatible transplantation when recipients are selected by low pretransplant anti-A titer histories. This approach increases access of blood group B recipients to kidneys.

ABO-mismatched renal transplantation in children: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) and the Midwest Organ Bank (MOB).

Successful ABO-mismatched renal transplantation (RT) (blood group A2 donor to blood group B or O recipient) has occurred in adults in the setting of a low titer (< or =4) natural isoagglutinin (anti-A) level in the recipient of the mismatched organ. Similar experiences have rarely occurred in children. Between 1986-1996, 11 pediatric patients (6 male and 5 female) received 11 ABO-mismatched kidneys [7 cadaveric (CAD) and 4 living related donor (LRD)]. There were 8 O recipients/A2 donor pairs, 2 B recipients/A2 donor pairs and 1 B recipient/A2B donor pair. Recipient age at the time of RT was 14.7+/-3.0 yr (mean +/- SD). Prior to RT, 2 recipients underwent splenectomy and none received donor-specific transfusions. Induction and early maintenance immunosuppression consisted of corticosteroids (11 pts), ALG/ATG (6 pts), OKT3 (3 pts), azathioprine (11 pts) and cyclosporine (8 pts). The mean 30-d cyclosporine dosage was 10.6+/-4.0 mg/kg/d. Eight patients suffered > or =1 acute rejection episodes, the initial episode occurring within the first 31 d post-transplant in 7 of them. Five grafts (45.4%) failed secondary to vascular thrombosis (1), acute rejection (2) and chronic rejection (2). The remaining grafts (54.5%) all functioned for >1000 d (range: 1023-3746 d). The pre-transplant anti-A titer was determined in 6 pts; in 4 it was low (2) and in 2 it was high (8). Graft survival in all but one of these patients (whose titer was 8 and who suffered a non-rejection-related vascular thrombosis) was > or =2 yr. In summary, ABO-mismatched RT in pediatric patients is an uncommon practice. However, the adult experience and our preliminary pediatric experience suggests that evaluation of recipient isoagglutinin levels in this setting may be helpful in the selection of donor/recipient pairs in whom mismatched transplantation can be successful.

Transplantation rate of the blood group B waiting list is increased by using A2 and A2B kidneys.

BACKGROUND: We have increased the transplantation rate for blood group B cadaveric waiting list candidates by transplanting them with A2 and A2B kidneys. METHODS: Since 1991, five of the seven renal transplant programs in our organ procurement organization service area have preferentially transplanted blood group A2 and A2B cadaveric kidneys to B blood group waiting list candidates with histories of low anti-A isoagglutinin titers. RESULTS: Between 1991 and 1997, these five centers performed transplantations on 71 patients from the B cadaveric waiting list. Of those 71 patients, 29% (21 of 71) underwent transplantation with either A2 (n=18) or A2B (n=3) cadaveric kidneys. In 1997 alone, 48% (11 of 23) of the B patient transplant recipients received A2 or A2B kidneys. CONCLUSIONS: Transplantation of A2 and A2B kidneys into B waiting list patients has successfully increased access of B patients to kidneys. Such an allocation algorithm implemented nationally may similarly increase the transplantation rate of B waiting list candidates.

Long-term graft survival is improved in cadaveric renal retransplantation by flow cytometric crossmatching.

BACKGROUND: Cadaveric renal retransplantation is associated with a higher risk of early graft failure than primary grafts. A large proportion of those graft losses is likely attributable to donor-directed HLA class I antibodies, detectable by flow cytometry cross-matching but not by conventional crossmatching techniques. METHODS: Long-term graft survival in a group of 106 recipients of consecutive cadaveric renal regrafts between 1990 and 1997, in whom a negative flow T-cell IgG crossmatch was required for transplantation, was compared with two other groups of cadaveric transplant recipients. The first group consisted of 174 cadaveric regrafts transplanted between 1985 and 1995 using only a negative anti-human globulin (AHG) T-cell IgG crossmatch. The second group was primary cadaveric transplants done concurrently with the flow group (1990 to 1997) using only the AHG T-cell IgG crossmatch. RESULTS: The long-term (7 year) graft survival rate of flow crossmatch-selected regraft recipients (68%; n= 106) was significantly improved over that of regraft recipients who were selected for transplantation by only the AHG crossmatch technique (45%; n=174; log-rank=0.001; censored for patients dying with a functioning graft). Graft outcome for the flow cross-matched regraft recipients was not significantly different from that of primary cadaveric patients (72%; n=889; log-rank=0.2; censored for patients dying with a functioning graft). Finally, a positive B-cell IgG flow cytometric crossmatch had no influence on long-term regraft outcome. CONCLUSIONS: The use of the flow T-cell IgG cross-match as the exclusion criterion for cadaveric renal retransplantation yields an improved long-term graft outcome over that obtained when only the AHG cross-match is used and has improved survival of regraft recipients to the level of our primary cadaveric renal transplant population.

Nonenzymatic glycation of type IV collagen and matrix metalloproteinase susceptibility.

The glomerular basement membrane (GBM) is damaged in diabetes through complex mechanisms that are not fully understood. Prominent among them is nonenzymatic protein glycation leading to the formation of so-called advanced glycation end products (AGEs). We examined the effects of in vitro glycation of intact collagen type IV in bovine lens capsule (LBM) and kidney glomerular (GBM) basement membranes on their susceptibility to matrix metalloproteinases, using stromelysin 1 (MMP-3) and gelatinase B (MMP-9). Sites of cleavage of unmodified LBM collagen were located in the triple helical region. In vitro glycation by glucose severely inhibited the release of soluble collagen cleavage peptides by MMP-3 and MMP-9. The distribution of AGEs within the three domains of collagen IV (7S, triple helical, and noncollagenous NC1) were compared for LBM glycation using AGE fluorescence, pentosidine quantitation, and immunoreactivity towards anti-AGE antibodies that recognize the AGE carboxymethyllysine (CML). Marked asymmetry was observed, with the flexible triple helical domain having the most pentosidine and fluorescent AGEs but the least CML. The in vivo relevance of these findings is supported by preliminary studies of AGE distribution in renal basement membrane (RBM) collagen IV domains from human kidneys of two insulin-dependent diabetics and one normal subject. Pentosidine and fluorescent AGE distributions of diabetic RBM were similar to LBM, but the CML AGE in diabetic kidney was less in the triple helical domain than in NC1. Our results support the hypothesis that nonenzymatic glycation of collagen IV contributes to the thickening of basement membranes, a hallmark of diabetic nephropathy.

Antilymphocyte induction therapy in cadaver renal transplantation: a retrospective, multicenter United Network for Organ Sharing Study.

Antilymphocyte induction therapy in cadaver renal transplantation is controversial. The effectiveness of antilymphocyte therapy in the current era of cyclosporine and tacrolimus use has been questioned. The United Network for Organ Sharing data set for the Center-Specific Outcomes Analysis, which has been verified by the transplant centers, was used for this study. At the time information in the database was confirmed, all transplant centers were queried on their use of an antilymphocyte preparation at the time of transplantation, and whether it was used within 24 hr of transplant surgery, the duration of the specific reagent. This allowed us to analyze 24,191 cadaver transplant procedures performed between the October 1, 1987, and the January 31, 1991. Using Cox regression analysis, as well as semiparametric logistic regression models, we demonstrated improved allograft outcomes in patients who received either Minnesota antilymphocyte globulin for 5 days or more or OKT3 for 7 days or more. The relative risk was 0.82 for Minnesota antilymphocyte globulin and 0.86 for OKT3 (for both, P<0.001). Semiparametric models were then used to compare the effectiveness of the antilymphocyte preparation in both a patient with at least a three-antigen mismatch and patients who had a zero-antigen mismatch. The improvement in graft survival was seen in both match grades. These data demonstrate the improved outcomes with the use of antilymphocyte preparations during the early posttransplant period in the modern cyclosporine era.

Isoform switching of type IV collagen is developmentally arrested in X-linked Alport syndrome leading to increased susceptibility of renal basement membranes to endoproteolysis.

Normal glomerular capillaries filter plasma through a basement membrane (GBM) rich in alpha3(IV), alpha4(IV), and alpha5(IV) chains of type IV collagen. We now show that these latter isoforms are absent biochemically from the glomeruli in patients with X-linked Alport syndrome (XAS). Their GBM instead retain a fetal distribution of alpha1(IV) and alpha2(IV) isoforms because they fail to developmentally switch their alpha-chain use. The anomalous persistence of these fetal isoforms of type IV collagen in the GBM in XAS also confers an unexpected increase in susceptibility to proteolytic attack by collagenases and cathepsins. The incorporation of cysteine-rich alpha3(IV), alpha4(IV), and alpha5(IV) chains into specialized basement membranes like the GBM may have normally evolved to protectively enhance their resistance to proteolytic degradation at the site of glomerular filtration. The relative absence of these potentially protective collagen IV isoforms in GBM from XAS may explain the progressive basement membrane splitting and increased damage as these kidneys deteriorate.