Susan Martin

Posttransplantation production of donor HLA-specific antibodies as a predictor of renal transplant outcome

Background. This study aimed to determine whether the production, in renal transplant recipients, of antibodies directed against donor HLA mismatches is predictive of transplant failure. Methods. The failure study group comprised 112 adult recipients of primary renal transplants who had re-entered the transplant waiting list after failure of the first graft. A control group of 123 recipients with functioning transplants was selected from transplantations performed during the same time period, in which patients had equivalent HLA matching and immunosuppression and a minimum of 5 years of follow-up. Sera taken before transplantation and at 1, 3, and 6 months and annually after transplantation were tested by enzyme-linked immunoabsorbent assay (ELISA) for the presence of HLA class I- and class II-specific antibodies. Antibody specificity was defined by a combination of cytotoxicity, ELISA, and flow cytometry techniques to determine whether the antibodies were directed against donor mismatches. Results. All recipients were negative for donor HLA-specific antibodies before transplantation. After transplantation, 57 (50.9%) of the 112 patients in the failure group produced donor HLA-specific antibodies compared with 2 (1.6%) of the 123 controls (P <0.0001; odds ratio [OR]=64.98; confidence interval [CI], 14.78–399.51). For 60% of the donor-specific antibody-positive patients, antibodies were detected before transplant failure. In 17 cases, these were class I specific; in 14 cases, class II specific; and in 3 cases, specific for both class I and II. Conclusions. This study has demonstrated that the production of posttransplantation antibodies directed against donor HLA-A, -B, -Cw, -DR, and -DQ mismatches are all strongly predictive of transplant failure.

Importance of minimizing HLA-DR mismatch and cold preservation time in cadaveric renal transplantation.

Univariate and multivariate analyses have been performed on donor an d recipient variables to determine possible effects on the outcome of 516 primary cadaveric renal transplants performed in our single center from 1989 until 1993. The overall actuarial patient survival at 1 year and 5 years was 94.4% and 87.4%, respectively; the 1 year and 5 year graft survival rates were 88.3% and 77.8%, respectively. A total of 95 grafts were lost; death with function (35%) and chronic rejection (22%) were the major causes. Three variables (HLA-DR mismatch, delayed graft function, and prolonged cold ischemia time) had a significant detrimental effect on both short- and long-term graft survival. Zero HLA-DR mismatched grafts showed significantly enhanced survival over those with 1 HLA-DR mismatch both at 1 year (92.8% vs. 84.5%) and at 5 years (88.3% vs. 73.9%) only if cold ischemia time was less than 26 hours (P=0.0009). Occurrence of delayed graft function significantly lowered graft survival at both 1 year and 5 years (P=0.002), and the incidence was significantly associated with prolonged cold ischemia time (P<0.0001). HLA-A or HLA-B matching, percentage panel reactive antibodies (PRA), and anastomosis time showed no independent effect on long-term survival. The small number of 2 HLA-DR mismatched grafts (n=6) precluded separate analysis of this group. Acute rejection accounted for 12% of losses but had no statistically significant effect on graft survival, even though an increased frequency of rejection episodes was significantly associated with HLA-DR mismatch (P<0.0001). These results would suggest that significant survival benefits may be achieved by prospective HLA matching if cold ischemia times are limited. The efficiency of organ sharing must he improved to make optimal use of a limited resource.

Tools for human leukocyte antigen antibody detection and their application to transplanting sensitized patients.

In recent years there have been major advances in the technology for the detection and definition of human leukocyte antigen antibodies. In this overview we describe the evolution in laboratory technology, the techniques currently available and consider their application in antibody specificity definition and in understanding a patients sensitization profile. We discuss the importance of antibody specificity definition in facilitating efficient national organ allocation and informing clinical discussion regarding the appropriate pathway for sensitized patients awaiting renal transplantation.

Association between C4d staining in renal transplant biopsies, production of donor-specific HLA antibodies, and graft outcome.

Background. We carried out a retrospective study of C4d staining in paraffin sections from renal transplant biopsies to determine the association between C4d staining, donor-specific antibodies (DSA), histological features, and graft outcome. Methods. We studied 92 patients who had been biopsied for graft dysfunction. Biopsies were classified using Banff 97 criteria and features suggestive of antibody-mediated rejection were noted. Paraffin sections were stained with a polyclonal antibody using an immunoperoxidase technique. The presence of DSA in concurrent sera was determined by enzyme-linked immunosorbent assay and clinical data were reviewed. Results. Of the 92 cases, 15% showed diffuse and 24% showed focal C4d positivity. The grafts failed in 36% of the diffuse (P<0.025), 23% of the focal, and 7% of the negative group at between one month and 15 years posttransplantation. Only patients in the group with diffuse C4d positivity had concurrent DSA (five cases, P<0.001). Of the five DSA-positive patients, three had type II acute rejection and two of these transplants subsequently failed. The remaining two had chronic allograft nephropathy with features of alloimmune injury. Only two of the nine DSA-negative/C4d-positive transplants had failed at the time of writing, in one case due to recurrent disease. Conclusion. We demonstrated a significant association between diffuse C4d staining, production of DSA, and graft failure. Although the concurrent detection of DSA and C4d positivity is uncommon in our patients, these results indicate that outcome in this group is poor and they may benefit from therapies directed at the humoral response.

A comparison of enzyme-linked immunoabsorbent assays and flow cytometry techniques for the detection of HLA specific antibodies.

LATM, Quikscreen (QS), and B-Screen (QSB) are ELISA-based tests for the detection of HLA specific antibodies. FlowPRA beads are microparticles coated with HLA antigens for the detection of HLA specific antibodies by flow cytometry. The aim of this study was to evaluate the sensitivity and specificity of the LATM, QS, QSB, and FlowPRA screening tests. One hundred sixty-three sera from renal transplant patients were tested using LATM, FlowPRA, QS, and QSB. Discrepant results were further investigated using complement dependent cytotoxicity, QuikID, and PRA-STAT. When QS was compared with LATMI and FlowPRAI for the detection of HLA class I specific antibodies the overall concordance was 82.8% with no particular specificity missed by any one test. Comparing QSB with LATMII and FlowPRAII, for the detection of HLA class II specific antibodies, there was 90.7% concordance. Although the overall concordance was better for class II specific antibodies, QSB failed to detect antibodies to HLA-DQ in a number of samples from different patients. Of the methods tested, flow cytometry using FlowPRA beads appeared to be the most sensitive and specific, missing the least number of specificities. However, the ELISA methods offer the advantage of being more suitable for testing large numbers of samples in a more time- and cost-effective manner.

DETECTION OF HLA-SPECIFIC ANTIBODIES BY PRA-STAT AND THEIR ASSOCIATION WITH TRANSPLANT OUTCOME

OBJECTIVEnThe aim was to investigate the correlation between renal transplant outcome and the presence of HLA-specific antibodies detected using the ELISA kit PRA-STAT as compared with complement-dependent cytotoxicity (CDC).nnnMETHODn295 sera from 95 renal transplant recipients (99 transplants) were investigated for the presence of HLA-specific antibodies using both PRA-STAT and CDC. The patients were divided into group I (49 transplants failed within 1 month) and group II (50 successful transplants).nnnRESULTSnThe concordance between PRA-STAT and CDC for the detection of HLA class I-specific antibodies was 87.8% (259 of 295). For 19 sera, antibodies were detected only by PRA-STAT; for 17 sera, antibodies were detected only by CDC. No donor-specific antibodies were detected by either technique for patients in group II. For four group I patients (six sera), donor-specific IgG antibodies were detected only by PRA-STAT (one before, three after transplant) and all four transplants failed. For five other group I patients (six sera), donor HLA-specific antibodies were detected only by CDC (one before, four after transplant) and all five transplants failed. The antibodies detected before transplant by CDC were shown to be IgM alloantibodies.nnnCONCLUSIONnThis study showed that PRA-STAT could detect HLA-specific IgG antibodies relevant to transplant outcome that were not detected by CDC. However, it could not detect IgM alloantibodies that were also shown to be important. PRA-STAT is therefore a useful addition to a histocompatibility laboratorys screening repertoire only when used in conjunction with other techniques.

The outcome of pediatric cadaveric renal transplantation in the UK and Eire

Abstract: An analysis of all pediatric cadaveric renal transplant recipients in the UK and Eire was undertaken to review the outcomes of pediatric cadaveric renal transplantation and to consider the implications for organ allocation procedures for pediatric recipients. Factors influencing the outcome of 1,252 pediatric cadaveric renal transplants in the UK and Eire in the 10‐yr period from 1 January 1986 to 31 December 1995 were analyzed by Cox proportional hazards regression, including analysis of four distinct post‐transplant epochs (0–3u2003months, 3–12u2003months, 12–36u2003months, and beyond 36u2003months). At the time of analysis (December 2000), 113 (11%) recipients had died and 47% of grafts had failed. In the multi‐factorial modelling, the factors significantly affecting transplant outcome were cold ischaemia time, donor and recipient age and human leucocyte antigen (HLA) matching. Epoch analysis demonstrated that these factors operated at different times post‐transplant. Cold ischaemia time had a strong influence on outcome at 3u2003months. A highly significant increased risk of graft failure was associated with donors under 5u2003yr of age. Young recipients had an increased risk of failure in the short term, but beyond 1u2003yr post‐transplant there were few failures in young recipients while a steady rate of graft loss persisted in the older children. In terms of HLA matching, the worst outcome was observed for two HLA‐DR mismatched grafts, while 000 and favorably matched kidneys (100, 010, 110 HLA‐A, ‐B, ‐DR mismatches) survived longest. Hence, a policy of exchanging organs on the basis of HLA matching is justified for 000 mismatched and favorably matched kidneys. The poor outcome associated with very young donors should discourage pediatric units from transplanting kidneys from such young donors. The reasons for late losses in older recipients need investigation.

The detection and definition of IgM alloantibodies in the presence of IgM autoantibodies using flowPRA beads

We have developed a flow cytometry-based screening method using FlowPRA (One Lambda) human leukocyte antigen (HLA) class I panel beads and FlowPRA (One Lambda) HLA class I specificity beads for the detection and definition of immunoglobulin (Ig)M HLA-specific antibodies in the presence of IgM autoantibodies. Forty-six autoantibody-positive patients who were on the waiting list for a renal transplant (56 sera) were tested in parallel with FlowPRA (One Lambda) HLA class I beads and FlowPRA (One Lambda) control beads. Sera that were positive for IgM HLA class I antibodies were subsequently tested with FlowPRA HLA class I specificity beads to determine the HLA specificities. Thirteen of the 46 patients were positive for IgM HLA class I-specific antibodies. Eleven of the 13 had previous failed transplants and 2 were awaiting a primary transplant. For 9 of the 13 positive patients, IgM HLA class I specificities were defined. We have demonstrated the presence of IgM HLA-specific antibodies in patients with IgM autoantibodies. This study demonstrates the value of FlowPRA HLA class I panel and specificity beads for the detection and definition of IgM HLA class I-specific antibodies.

Manualised Individual Cognitive Behavioural Therapy for mood disorders in people with mild to moderate intellectual disability: A feasibility randomised controlled trial

BACKGROUNDnEvaluation of complex interventions, including standardisation of the intervention, types of outcomes selected and measures of change, is a fairly novel concept in the field of intellectual disabilities. Our aim was to explore these issues in a feasibility study of Manualised Individual Cognitive Behaviour Treatment (M-iCBT) compared to the treatment as usual alone (TAU).nnnMETHODSnService users with mild to moderate intellectual disability experiencing a mood disorder or symptoms of depression and/or anxiety (mini PAS-ADD total score >10 or 7 respectively) were randomly assigned to either.nnnRESULTSnIn total, 32 participants were randomly assigned to 16 sessions of M-iCBT (n=16) in addition to TAU or TAU alone (n=16). We explored recruitment and accrual rates, willingness to participate, acceptability of the intervention and suitability of assessment tools. Mean change (95% CI) in the Beck Depression Inventory-Youth (BDI-Y) score from baseline to the 16 week endpoint (primary variable) was 0.10 (95% CI: -8.56, 8.76) and in the Beck Anxiety Inventory-Youth (BAI-Y) 2.42 (95% CI: -5.27, 10.12) in favour of TAU. However, there was a clear trend in favour of CBT in depressed participants with or without anxiety.nnnLIMITATIONSnThe intervention targeted both depression and anxiety following a transdiagnostic model. This may have impacted the anticipated size of change in the primary outcome. The precise impact of cognitive limitations on ability to use therapy effectively is not fully understood.nnnCONCLUSIONSnThis study demonstrates that it is feasible to carry out a pragmatic randomised controlled trial of M-iCBT for people with mild to moderate intellectual disability. However, uncertainties about its clinical and cost effectiveness can only be fully answered by further examination of its superiority against other treatments.

Cognitive behaviour therapy (CBT) for anxiety and depression in adults with mild intellectual disabilities (ID): a pilot randomised controlled trial

BackgroundSeveral studies have showed that people with intellectual disabilities (ID) have suitable skills to undergo cognitive behavioural therapy (CBT). Case studies have reported successful use of cognitive behavioural therapy techniques (with adaptations) in people with ID. Modified cognitive behavioural therapy may be a feasible and effective approach for the treatment of depression, anxiety, and other mood disorders in ID. To date, two studies have reported group-based manaulised cognitive behavioural treatment programs for depression in people with mild ID. However, there is no individual manualised programme for anxiety or depression in people with intellectual disabilities. The aims of the study are to determine the feasibility of conducting a randomised controlled trial for CBT in people with ID. The data will inform the power calculation and other aspects of carrying out a definitive randomised controlled trial.MethodsThirty participants with mild ID will be allocated randomly to either CBT or treatment as usual (TAU). The CBT group will receive up to 20 hourly individual CBT over a period of 4 months. TAU is the standard treatment which is available to any adult with an intellectual disability who is referred to the intellectual disability service (including care management, community support, medical, nursing or social support). Beck Youth Inventories (Beck Anxiety Inventory & Beck Depression Inventory) will be administered at baseline; end of treatment (4 months) and at six months to evaluate the changes in depression and anxiety. Client satisfaction, quality of life and the health economics will be secondary outcomes.DiscussionThe broad outcome of the study will be to produce clear guidance for therapists to apply an established psychological intervention and identify how and whether it works with people with intellectual disabilities.Trial registrationISRCTN: ISRCTN38099525