De novo donor HLA-specific antibodies after heart transplantation are an independent predictor of poor patient survival.

Preformed donor HLA-specific antibodies are a known indicator for poor patient survival after cardiac transplantation. The role of de novo donor-specific antibodies (DSA) formed after cardiac transplantation is less clear. Here we have retrospectively analyzed 243 cardiac transplant recipients, measuring HLA antibody production every year after transplantation up to 13 years post-transplant. Production of de novo DSA was analyzed in patients who had been negative for DSA prior to their transplant. DSA including transient antibodies were associated with poor patient survival (p = 0.0018, HR = 3.198). However, de novo and persistent DSA was strongly associated with poor patient survival (p = 0.0001 HR = 4.351). Although complement fixing persistent DSA correlated with poor patient survival, this was not increased compared to noncomplement fixing persistent DSA. Multivariable analysis indicated de novo persistent DSA to be an independent predictor of poor patient survival along with HLA-DR mismatch and donor age. Only increasing donor age was found to be an independent risk factor for earlier development of CAV. In conclusion, patients who are transplanted in the absence of pre-existing DSA make de novo DSA after transplantation which are associated with poor survival. Early and regular monitoring of post-transplant DSA is required to identify patients at risk of allograft failure.

Lack of effect of MICA antibodies on graft survival following heart transplantation.

Little is known about the effect of MICA antibodies (Abs) on cardiac allograft function and survival. Pretransplant and posttransplant serum from 491 and 196 adult cardiac allograft recipients, respectively, has been investigated for MICA Abs, donor specificity and the effect of MICA Abs on graft survival, acute rejection episodes (AR) and cardiac allograft vasculopathy (CAV). Patients with HLA Abs (11.6%) were excluded from the analysis. A total of 11.8% of patients had MICA Abs, without HLA Abs, before their transplant. Actuarial graft survival demonstrated slightly better survival of patients with donor-specific MICA Abs at 1 and 5 years (88.9% and 83.3%) than patients negative for MICA Abs (72% and 63.7%, p = 0.051). After transplantation, 15.8% of patients produced MICA Abs, and in 17 patients these were produced de novo. There was no effect of pretransplant or posttransplant production of MICA Abs on numbers of AR episodes in year 1, or CAV assessed at years 3 and 5. Immunocytochemistry of cardiac biopsies from 11 patients did not demonstrate a presence of MICA. Sera from only 4/69 patients with MICA Abs fixed complement prior to transplantation and from 7/38 patients following transplantation. In conclusion, this study suggests that MICA Abs do not adversely affect the outcome of cardiac transplantation.

Heart transplantation for homozygous familial transthyretin (TTR) V122I cardiac amyloidosis.

Heart failure is the usual cause of death in patients with amyloid cardiomyopathy. The commonest form of hereditary cardiac amyloidosis is associated with the Val122Ile variant of transthyretin (TTR), which is carried by 3-4% of the African American population. Here, we report the outcome of the first cardiac transplantation in a patient with TTR V122I. A 59-year-old Caribbean man presented with biventricular failure. Other than previous bilateral carpel tunnel syndrome, he had been well and had no evidence of extracardiac amyloidosis. An endomyocardial biopsy demonstrated amyloid of TTR type. Sequencing of TTR gene indicated homozygosity for V122I. He underwent cardiac transplantation and 3 years later, remains well with no evidence of allograft or systemic amyloid deposition.

Current outcome of heart transplantation: a 10-year single centre perspective and review.

BACKGROUND: Heart transplantation (HTx), the gold standard therapy for advanced heart failure, is limited by donor availability; alternative therapies are now becoming available. AIM: We examined the outcome of HTx with current immunosuppressive and adjunctive therapy. DESIGN AND METHODS: We analysed the outcome of 399 consecutive patients who underwent transplantation at our centre (1995-2007). Prior to HTx 23% (98) required inotropic support, 8.5% (34) an intra-aortic balloon pump and 11% (43) a ventricular assist device. RESULTS: Actuarial patient survival was 86% at 30 days, 79% at 1 year and 62% at 10 years. Survival was similar regardless of the heart failure severity, P=0.22. The cumulative incidence of allograft vasculopathy, Costanzo grade≥2, was 7% at 5 years and 23% by 10 years with an 11% cumulative probability of requiring a percutaneous coronary intervention by 10 years. Allograft function was preserved with a mean±SD left ventricular ejection fraction of 73±7% at 1 year and 74±8% at 10 years. The cumulative incidence of malignancy by 10 years was 27% (skin malignancy 13% and post transplant lymphoproliferative diseases 10%). The cumulative incidence of developing chronic kidney disease (CKD) with an estimated glomerular filtration rate≤45 ml/min/1.73 m2 was 42% at 1 year, 62% at 5 years and 72% at 10 years and of requiring long-term renal replacement therapy was 10.6% at 10 years. CONCLUSION: HTx provided good medium-term survival for patients with advanced heart failure, independent of its severity. The incidence of allograft vasculopathy was lower than reported previously but malignancy and CKD remain cause for concern.

C4d fixing, luminex binding antibodies - a new tool for prediction of graft failure after heart transplantation.

The standard method to detect pretransplant antibodies has been the complement dependent cytotoxicity (CDC) test of donor leukocytes. Solid phase assays to detect HLA antibodies in pretransplant serum reveal a greater number of sensitized patients, but their clinical impact is less certain. Here we have developed a method of detecting C4d fixing HLA antibodies on Luminex beads. Pretransplant serum from 565 cardiac transplant patients was retrospectively tested for the presence of HLA antibodies using CDC, HLA coated Luminex beads and C4d deposition on Luminex beads, and the results correlated with graft survival. Whereas 5/565 patients had CDC positive donor specific antibodies (DSA) before their transplant, this number was increased by 19 using Luminex beads. The 1-year survival of CDC -ve/Luminex +ve patients with DSA (n = 19) was 42% compared with 77% for CDC -ve/Luminex +ve without DSA (n = 39, p = 0.0039). Fixation of C4d (22/67 Luminex positive sera) had a negative effect on graft outcome; 1-year graft survival was, C4d +ve/DSA +ve (n = 11) 20%, C4d +ve/DSA -ve (n = 11) 91%, C4d -ve DSA +ve (n = 13) 54%, C4d -ve DSA -ve (n = 32) 75%, compared with 75% for antibody-negative patients (p = 0.0002). In conclusion, detection of Luminex +ve DSA in pretransplant serum provides a powerful negative predictor of graft survival, especially if they bind C4d.