Acute cellular and antibody-mediated rejection of the pancreas allograft: incidence, risk factors and outcomes.

Antibody-mediated rejection (AMR) after pancreas transplantation is a recently identified entity. We describe the incidence of, risk factors for, and outcomes after AMR, and the correlation of C4d immunostaining and donor-specific antibody (DSA) in the diagnosis of AMR. We retrospectively analyzed 162 pancreas transplants in 159 patients who underwent 94 pancreas allograft biopsies between 2006 and 2009. Univariate and multivariate analyses were performed to evaluate risk factors for pancreas graft AMR. One-year rejection rates and survival after rejection were calculated by Kaplan-Meier methods. AMR occurred in 10% of patients by 1-year posttransplant. Multivariate risk factors identified for AMR include nonprimary simultaneous pancreas-kidney (SPK) transplant, primary solitary pancreas (PAN) transplant and race mismatch. After pancreas rejection, patient survival was 100% but 20% (8 of 41) of pancreas grafts failed within 1 year. Graft survival after acute cellular rejection (ACR), AMR and mixed rejection was similar. Of biopsies that stained >5% C4d, 80% were associated with increased Class I DSA. In summary, AMR occurs at a measurable rate after pancreas transplantation, and the diagnosis should be actively sought using C4d staining and DSA levels in patients with graft dysfunction, especially after nonprimary SPK and primary PAN transplantation.

The significance of donor-specific HLA antibodies in rejection and ductopenia development in ABO compatible liver transplantation.

The role of humoral alloreactivity in ABO-compatible liver transplantation remains unclear. To understand the significance of donor-specific HLA alloantibodies (DSA) in liver rejection, we applied the currently used strategy for detection of antibody-mediated rejection of other solid allografts. For this purpose we reviewed the data on 43 recipients of ABO identical/compatible donor livers who had indication liver biopsy stained for complement element C4d and contemporaneous circulating DSA determination. Seventeen (40%) patients had significant circulating DSA in association with diffuse portal C4d deposition (DSA+/diffuse C4d+). These DSA+/diffuse C4d+ subjects had higher frequency of acute cellular rejection (ACR) 15/17 versus 13/26 (88% vs. 50%), p = 0.02, and steroid resistant rejection 7/17 versus 5/26 (41% vs. 19%), p = 0.03. Based on detection of the combination DSA+/diffuse C4d+, 53.6% of cases of ACR had evidence of concurrent humoral alloreactivity. Six of the 10 patients with ductopenic rejection had circulating DSA and diffuse portal C4d, three of whom (2 early and 1 late posttransplantation) developed unrelenting cholestasis, necessitating specific antibody-depleting therapy to salvage the allografts. Thus, in ABO-compatible liver transplantation humoral alloreactivity mediated by antibodies against donor HLA molecules appears to be frequently intertwined with cellular mechanisms of rejection, and to play a role in ductopenia development.

A comparative study of major histocompatibility complex and red blood cell antigen phenotypes as risk factors for recurrent urinary tract infections in women.

Recurrent urinary tract infections (RUTI) are a significant health problem for many women, and host characteristics that increase susceptibility are not completely defined. This study evaluated data from 99 patients to examine further the question of a possible association between major histocompatibility complex (MHC) or red blood cell (RBC) antigen phenotype and predisposition to RUTIs. MHC class I and II, ABO, and Lewis RBC phenotypes were determined serologically. The MHC class II phenotypes of 55 subjects were also determined by DNA polymerase chain reaction techniques. There were no significant differences in the proportions of HLA-A or -B antigen types between patients and controls, nor in the frequencies of serologically or DNA-defined HLA-DR or -DQ phenotypes. Patient ABO and Lewis RBC phenotypes were not statistically different than those for controls. Thus, the overall risk for women to develop RUTIs does not appear to be associated with any single HLA, ABO, or Lewis phenotype.

Identification of a new HLA-B*08 variant, HLA-B*0804.

The HLA-B locus is the most polymorphic locus known with currently over 100 different alleles described. Many of these alleles encode variants of the serologically-defined tissue transplantation antigens. This high level of diversity makes accurate tissue typing difficult. Here we present the sequence of a new HLA-B*08 variant, HLA-B*0804, found in Caucasian siblings JH and PF serologically typed as HLA-B51/B59 and HLA-B59/B60, respectively. Additionally, DNA-based typing by the polymerase chain reaction using sequence-specific primers (PCR-SSP) identified HLA-B*51 in JH and HLA-B*4001 in PF. However, PCR-SSP failed to identify a second allele in either of these individuals. The unusual finding of a B59 antigen in a Caucasian and the discrepant molecular typing results suggested that these individuals might express novel HLA molecules. Using denaturing gradient gel electrophoresis (DGGE) followed by direct sequencing, we characterized a novel HLA-B*08 variant, HLA-B*0804. The presence of this allele was confirmed by cloning and sequencing. HLA-B*0804 differed from HLA-B*0801 by only one nucleotide substitution resulting in an amino acid replacement of phenylalanine by serine at position 67. Incidentally, this single nucleotide difference was sufficient to prevent amplification by PCR-SSP. This striking difference between both the serologically typed antigen and the PCR-SSP-identified allele compared to the sequenced allele supports the use of sequence-based typing for the analysis of HLA class I locus alleles.

A 25% error rate in serologic typing of HLA-B homozygotes.

The microlymphocytotoxicity technique has been the accepted method for HLA class I typing since the early 1960s. However, it is often difficult to distinguish two related alleles expressed in an individual due to the cross-reactive nature of the alloantibodies used in this technique. This is especially evident at the HLA-B locus, whose more than 180 alleles fall into only 4 major interrelated cross-reactive antigen groups. To estimate the error rate in serologic typing due to the cross-reactive nature of sera, we used polymerase chain reaction with sequence-specific primers (PCR-SSP) amplification to retype 40 individuals who were previously typed as serologic HLA-B locus homozygotes. PCR-SSP revealed that 10 of these 40 individuals (25%) were actually heterozygous at their HLA-B loci. The HLA-B locus alleles of 9 of these 10 discrepant individuals were further analyzed by denaturing gradient gel electrophoresis followed by direct sequencing. The sequence analysis confirmed that all nine individuals were indeed HLA-B locus heterozygotes. This surprisingly high error rate in serologic definition of HLA-B molecules argues for the use of rapid DNA-based techniques in HLA class I typing, even in the setting of solid organ transplantation.

Cadaveric renal transplantation with quadruple immunosuppression in patients with a positive antiglobulin crossmatch.

The significance of the antiglobulin crossmatch in the cyclosporine era remains controversial. Over an 11-month period, 124 recipients of cadaveric renal allografts (109 primary, 15 nonprimary) were retrospectively crossmatched via the antiglobulin technique. Criteria for recipient selection for transplantation included a negative T lymphocytotoxic (CDC) crossmatch for current and historical sera. Fourteen patients (11.3%) underwent transplantation in the setting of a negative T and positive antiglobulin crossmatch. The patient group included 10 female and 4 male patients with a mean age of 43.8 years. All but one patient received a primary transplant, and current sera were positive in the antiglobulin crossmatch in all cases. The mean HLA-ABDR match was 1.4 (range 0-4). Preoperative PRA titers ranged from 0 to 80% (mean 18.3%). All patients underwent successful renal transplantation with quadruple immunosuppression consisting of prednisone, azathioprine, and the sequential use of MALG/cyclosporine. There were no episodes of hyperacute rejection. However, 10 patients (71.4%) experienced acute rejection, including 7 episodes within 4 days of transplant. Early rejection was significantly more common in patients with a positive antiglobulin test (50% vs. 20.9%, P less than 0.05). The mean one-month serum creatinine was 1.7 mg/dl. Actual patient and allograft survival are 92.9% and 85.7%, respectively. Risk factors for a positive antiglobulin crossmatch included female sex and prior sensitization as measured by PRA. Although these patients represent a high-risk group for early rejection, no adverse effect on patient or graft survival was noted with quadruple immunotherapy. In conclusion, a positive antiglobulin crossmatch is no longer a contraindication to renal transplantation with current immunosuppressive strategies.

Cadaveric renal transplantation in the cyclosporine and OKT3 eras: an update of the University of Wisconsin-Madison experience.

1. Quadruple immunosuppression yields excellent early renal allograft survival in primary renal transplant recipients when compared with non-primary renal transplant recipients. Although significant, the difference between primary and nonprimary recipients at 5 years has narrowed considerably (8%). 2. No beneficial effect of HLA or DR matching was noted in this study in primary transplant recipients. However, a trend toward improved graft survival was noted when patients with greater than or equal to 3 antigens matched or less than 3 antigens mismatched were compared to their counterparts. Further analysis of variables related to graft loss is required before statements regarding this trend can be made. 3. Significantly better results in nonprimary renal transplantation continues to be seen in DR matched recipients. Additionally, the use of OKT3 rather than ALG in DR matched recipients has resulted in a 92.3% 3-year allograft survival despite over half of these patients being highly sensitized. 4. Further follow-up of 2 high-risk groups of patients (diabetics and elderly patients) revealed significant decreases in patient survival at 5 years. This difference was not apparent in our earlier results (3-year follow-up) published in Clinical Transplants 1987. Despite this difference, we believe renal transplantation should continue to be offered to diabetic and elderly patients without other contraindications to transplantation. 5. The availability of the monoclonal antibody OKT3 during the CsA era has resulted in a trend toward improved patient and graft survival when compared with patients in the CsA pre-OKT3 era. This trend toward improved survival is also seen in the high-risk diabetic recipients.

Cadaveric renal transplantation in the cyclosporine and OKT3 eras.

With advances in clinical immunosuppression, results in organ transplantation continue to improve. During a 52-month period, 507 cadaver renal transplants were performed, including 435 primary and 72 nonprimary transplants. All patients were managed with quadruple immunosuppression (prednisone, azathioprine, sequential MALG and cyclosporine). Our experience is divided into pre-OKT3 (n = 228) and OKT3 (n = 279) eras. All kidneys were harvested locally and preserved with pulsatile machine perfusion. The mean duration of preservation was 30.1 hours, with an organ utilization rate of 98.1%. The preservation-related dialysis rate was 13.6%, and primary nonfunction occurred in 8 kidneys (1.6%). Actuarial patient survival in primary and secondary transplant recipients was 90% at 3 years. Overall primary graft survival was 81.6% and nonprimary graft survival, 61.1%. However, the current OKT3 era is characterized by improved patient survival (98% vs 90%, p = 0.001) and primary graft survival (91% vs 80%, p = 0.002) at 1 year when compared with the previous era. Forty-nine patients have received OKT3 therapy, with 31 grafts (63.3%) successfully rescued. Cadaveric renal transplantation with machine preservation, quadruple therapy, and OKT3 rescue is associated with excellent early graft function, reduced acute rejection, and improved patient and allograft survival, even in high-risk recipients.