Killer cell immunoglobulin-like receptor polymorphisms in HLA-identical kidney transplant recipients: lack of 2DL2 and 2DS2 may be associated with poor graft function.

Killer cell immunoglobulin-like receptors (KIR) on natural killer cells mediate killing by recognizing class I presentation of peptides by infected or oncogenic cells. KIR differences in stem cell transplants have been implicated in increased graft vs host disease. Human leukocyte antigen (HLA)-matched-related kidney recipients have the best graft survival as compared to one haplotype-matched recipients. These HLA-identical transplant pairs may be ideal for studying minor HLA antigens and KIR polymorphic differences and their relation to graft function. We have studied KIR polymorphism in recipients and donor pairs of HLA-matched sibling kidney transplants to demonstrate differences in genotype as related to long-term graft function and/or chronic rejection. We employed a KIR genotyping kit (Dynal, Brown Deer, WI), that uses sequence-specific priming by PCR to identify 19 alleles for genotypes in 12 donor/recipient (D/R) pairs at least 1 year posttransplant. There were two pairs that had different alleles in the recipient that were not found in the donor. One pair had different alleles found in the donor that were not present in the recipient. Two pairs had difference in alleles in both the donor and recipient. Seven of the 12 pairs had the same KIR genotype. Eight of the 12 pairs (both donor and recipient) exhibited a haplotype with 2DL2+ and 2DS2+. Four of the 12 exhibited a haplotype 2DL2- and 2DS2-. Three out of four of these recipients had increased creatinine levels and at least one graded rejection episode. One of these three has lost their graft. In conclusion, the genotyping of HLA-matched sibling kidney transplant D/R pairs demonstrates that there may be an association of higher risk for poor graft function when both genotypes lack 2DL2 and 2DS2.

The importance of anti-HLA-specific antibody strength in monitoring kidney transplant patients.

Approximately 25% of patients who undergo kidney transplantation develop HLA-specific antibodies, the strength of which has not been previously correlated with graft failure. The strength of these de novo antibodies is investigated in this study. Serial dilution of strong HLA-specific allo-antibodies (up to 1:25,600) and testing with HLA-antigen-coated beads showed that the titer of the reaction to different HLA antigens is directly correlated to maximum fluorescence values and the molecules of equivalent soluble fluorochrome (MESF) values obtained by Luminex machines. Thus, the strength of antibodies can be measured utilizing maximum fluorescence and MESF. The strength of antibodies in the sera from 39 patients who subsequently had graft failure were markedly higher than those in the sera of 26 patients who continued to have good graft function (p = 0.0084). A clear increase in the strength of antibodies was identified in nine patients with a subsequent increase in serum creatinine levels. If analyzed for donor specificity, a strong association was noted for donor-specific MESF and failure (p = 0.00000027). Our results suggest that it is important to monitor the strength of antibodies when evaluating patient sera posttransplant.

An association of lower serum citrulline levels within 30 days of acute rejection in patients following small intestine transplantation.

INTRODUCTION: In a prospective protocol we studied whether serum citrulline level within 30 days of an acute rejection was predictive of the episode. METHODS: An acute rejection episode was defined as the date of occurrence of any biopsy-proven rejection in which treatment was initiated until two successive biopsies showed no further rejection. We compared the mean citrulline level based on values determined within 30 days of the start of an acute rejection episode with the mean citrulline level measured on the same patient during a rejection-free period. Serum citrulline measurements were available immediately prior to the occurrence of rejection for 22 patients who experienced 37 episodes. RESULTS: For the 12 episodes of mild rejection, the mean serum citrulline level +/- SE (standard error) was 15.0 + 2.3 micromol/L prior to rejection and 18.8 +/- 2.4 micromol/L during the rejection-free periods. A paired t test of the mean differences was not significant (P = 17). For the 25 episodes of moderate or severe rejection, the mean serum citrulline level was 12.4 +/- 1.1 micromol/L before rejection and 18.8 +/- 2.0 micromol/L during the rejection-free periods. A paired t test of the mean difference was statistically significant (P = .002). CONCLUSIONS: Although further study of citrulline as a marker for the early detection of acute rejection episodes is needed, our hope is that its use will help to prevent some of these early episodes from evolving into full-blown moderate or severe grades of rejection.

Abrogation of the alloreactive responses of cadaveric donor intestinal lymphocytes by intraoperative Campath-1H exposure.

A number of recent reports in clinical and experimental intestinal transplantation have suggested that the donor lymphocytes present in and around the gastrointestinal system are potent mediators of graft-versus-host (GvH) reactivity and that GvH responses may contribute to posttransplant morbidity. Therefore, we have tested the proliferative and cytotoxic capabilities of gut-associated lymphocytes from cadaveric donors obtained prerevascularization (pre-r) and about 6 hours postrevascularization (post-r) in recipients pretreated with Campath-1H antibody (alemtuzumab). Mixed lymphocyte reactions (MLR) were performed with lymphoid cells isolated from intestinal epithelial mucosa, lamina propria, and lymph nodes. The pre-r lymphocytes responded strongly to both the recipient and third-party alloantigenic stimulating cells. However, similar preparations from the post-r samples responded in MLR at significantly lower levels (P < .01). This post-r decrease in responsiveness was not observed in similar lymphocyte samples obtained from donors of recipients not treated with Campath-1H. Both the pre-r and post-r samples had similar flow cytometric profiles, suggesting that there was no receptor loss in these lymphoid tissues by the short-term 6-hour exposure to Campath-1H given to the recipient. Conversely, in preliminary experiments where the donor were treated with Campath-1H, it was observed that very few lymphocytes could be obtained from intestinal tissues (n = 3). These results suggested that Campath-1H treatment of the recipient could bring about a drastic reduction in an otherwise strong GvH reactivity by the donor intestinal immune cells.

Transplantation for the treatment of intra-abdominal fibromatosis.

MATERIALS AND METHODS: During the last 9 years we treated 14 patients with a diagnosis of intra-abdominal fibromatosis. The 11 patients who received an intestinal allograft included isolated intestine (n = 6), liver-intestine (n = 1), intestine-kidney (n = 1), multivisceral (n = 1), multivisceral-kidney (n = 1), multivisceral-no liver (n = 1). Three patients received an intestinal autograft after partial abdominal evisceration and ex vivo tumor resection. Three patients additionally underwent an abdominal wall allograft. RESULTS: At follow-up until August 2004, all autotransplant patients are alive. Four intestinal transplant patients died within the first postoperative month. There were three graft losses. A patient who lost his graft early postoperatively was retransplanted but died of sepsis shortly there after. Two more patients lost their graft due to severe rejection and were retransplanted successfully. Two patients developed desmoid tumor recurrence in their abdominal or thoracic wall. Ten patients are alive 1 to 9 years posttransplantation. Nine have fully functioning grafts and one patient requires TPN supplementation at night due to dysmotility of her autograft. CONCLUSION: Intestinal allo-, or autotransplantation combined with transplantation of the abdominal wall can be lifesaving for patients suffering from extensive intra-abdominal fibromatosis.

The impact of Campath 1H induction in adult liver allotransplantation.

BACKGROUND: We report our experience with Campath 1H in adult liver allotransplantation. METHODS: Between December 2001 and February 2004, 77 patients underwent liver transplantation using Campath 1H induction and low-dose maintenance tacrolimus immunosuppression. The control group consisted of 50 patients with similar baseline characteristics and the same eligibility criteria, transplanted under our standard Tacrolimus/steroids regimen. Hepatitis C patients were excluded from the study. RESULTS: Patient and graft survival were similar for both groups. The incidence of rejection was significantly lower in the Campath vs the control group (51% vs 65% at 12 months, P = .009). Tacrolimus trough levels and conversion from Tacrolimus or the addition of other immunosuppressive drugs due to nephrotoxicity were also significantly lower in the Campath 1H group. CONCLUSION: Campath 1H induction with low-dose Tacrolimus maintenance immunosuppression is an effective regimen in reducing acute rejection in adult liver transplantation, while maintaining lower tacrolimus levels and less nephrotoxicity than our conventional immunosuppressive regimen.

Six-year clinical effect of donor bone marrow infusions in renal transplant patients.

BACKGROUND: To date, several single- and multicenter clinical trials have attempted to induce specific immunological unresponsiveness using donor bone marrow cell infusions to augment solid organ transplantation, but the outcomes have not been definitive. METHODS: Between September 1994 and May 1998, 63 cadaver (CAD) renal transplant recipients of either one or two postoperative donor bone marrow cell (DBMC) infusions were prospectively compared with 219 non-infused controls given equivalent immunosuppression. There was at least a 1 HLA DR antigen match present between donors and recipients. The immunosuppressive regimen included a 10-day course of OKT3 induction, and tacrolimus, mycophenolate mofetil, and methylprednisolone maintenance. A total 7.01x10(8)+/-1.9x10(8) (SD) DBMC/kg was infused into the CAD recipients on either days 4 and 11 (n=42) or one half of that dose on day 4 (n=21) postoperatively. Clinical follow-up has ranged from 2.9 to 6.3 years (mean, 4.7 years). Studies were also performed of humoral immunity and quantitative cellular chimerism. RESULTS: There is clear-cut equivalence in immunosuppressive dosaging and in the other major demographic variables in both groups. However, only 2/63 DBMC recipients had biopsy-proven chronic rejection, whereas 41/219 showed chronic rejection in the controls (P = <0.01). In both groups, mortality was not associated with rejection. The actuarial graft survival at 6.3 years in the CAD DBMC group was 84.3% compared with 72.2% in the control group (not statistically significant). However, if death with a functioning graft was excluded, graft survival was 94.1% in the DBMC group and 79.8% in the controls (P=0.039). Forty patients in the control group continue to have deteriorating renal function (increasing serum creatinine concentrations to 2 mg/dl and higher), compared with 2 patients in the DBMC group (P=0.04). In the DBMC group, chimerism in iliac crest marrow aspirates has increased 3-fold in yearly sequential measurements between 1 and 4 years postoperatively averaging 1.3+/-0.36% (SE) most recently. This has not occurred in the controls. CONCLUSIONS: There now appears to be more solid long-term evidence, in kidney transplant recipients prospectively receiving DBMC infusions, of an improvement in long-term graft survival, and of the degree of chimerism positively correlating with the absence of graft loss.