A reevaluation of the role of IgM Non-HLA antibodies in cardiac transplantation.

BACKGROUND: Preexisting IgG antibodies to donor human leukocyte antigens (HLA) are a risk factor for rapid allograft rejection. However, non-HLA antibodies, of the IgM class, also called autoreactive antibodies, are not believed to affect graft survival. The aim of this study was to determine the incidence and clinical relevance of pretransplant lymphocytotoxic non-HLA IgM antibodies on long-term cardiac allograft survival. METHODS: A retrospective study of 616 adult recipients of cardiac allografts, transplanted at this center between 1991 and 2003, has been performed. Antibodies in pretransplant sera were initially defined using complement-dependent cytotoxicity assays, and subsequently analyzed for HLA specificities using solid phase assays. RESULTS: HLA antibodies were present in 69 of 616 heart recipients (58 IgG, 11 IgM); in 22 of these, the antibodies were donor-specific. Non-HLA IgM antibodies were detected in 59 of 616 recipients who did not have HLA-specific antibodies; these patients had a 1, 2, 5, and 10 year survival of 55.9%, 54.2%, 49.9%, and 43.3% compared with 75.8%, 73.7%, 66.6%, and 52.8% for those without antibodies (P=0.0085 log-rank test). Multivariate analysis demonstrated pretransplant non-HLA IgM antibodies to be an independent risk factor for mortality (P=0.0001). Myocardial histology of postmortem heart and cardiac biopsies suggested an association with ischemic damage and "primary" allograft failure. CONCLUSIONS: We propose the hypothesis that the presence of cytotoxic IgM antibodies to non-HLAs before heart transplantation maybe a risk factor for early allograft failure.

Chronic kidney disease after heart transplantation.

BACKGROUND: Chronic kidney disease (CKD) is a complication of heart transplantation related to calcineurin inhibitor nephrotoxicity. However, it is unclear whether early ciclosporin (CsA) exposure influences CKD in the long term. METHODS: We analysed risk factors for CKD in 352 patients who underwent orthotopic heart transplantation (1995-2005). In 2000, we reduced our target CsA levels in the first year after transplantation. RESULTS: Actuarial patient survival was 79% at 1 year and 62% at 10 years. Estimated median glomerular filtration rate (eGFR) by the four-variable Modification of Diet in Renal Disease formula was 64 ml/min/1.73 m2 before transplantation, inter-quartile range (IQR) 54-78. After transplantation, the eGFR was 48 (IQR 37-61) at Year 1, and 41(35-57) at Year 10. The cumulative probability of eGFR <45 ml/min/1.73 m2 was 45% at Year 1, 71% at Year 5 and 83% at Year 10. A multivariable logistic regression model was constructed for the development of eGFR <45 ml/min/1.73 m2 by 3 years. The risk factors were post-operative renal replacement therapy for acute renal failure (ARF), P < 0.001; pretransplant diabetes, P = 0.005; increasing recipient age, P < 0.001; female recipient, P = 0.029; female donor, P = 0.04, but not CsA regimen. The cumulative probability of developing stage 5 CKD (eGFR <15) was 3% at Year 5 and 12% at Year 10. Although lower ciclosporin initial levels were associated with less renal dysfunction at Year 1 (P = 0.008), there was no significant effect by Year 3 (P = 0.7). CONCLUSION: The incidence of CKD increased with time and was not influenced by the CsA regimen. Some risk factors are not modifiable but measures to reduce the incidence of post-operative ARF may help to reduce CKD.

Limited utility of endomyocardial biopsy in the first year after heart transplantation.

BACKGROUND: Surveillance endomyocardial biopsies (EMBs) are used for the early diagnosis of acute cardiac allograft rejection. Protocols became standardized in an earlier era and their utility with contemporary immunosuppression has not been investigated. METHODS: We studied 258 patients after orthotopic heart transplantation comparing 135 patients immunosuppressed by mycophenolate mofetil (MMF) with 123 patients treated by azathioprine (AZA); both with cyclosporine and corticosteroids after induction therapy with rabbit antithymocyte globulin. Fifteen EMBs were scheduled in the first year. Additional EMBs were performed for suspected rejection, after treatment, or for inadequate samples. The MMF group had 1875 EMBs vs. 1854 in the AZA group. RESULTS: The yield of International Society for Heart and Lung Transplantation (ISHLT) grade> or =3A biopsy-proven acute rejection (BPAR) was 1.87% per biopsy (35 of 1875) with MMF vs. 3.13% (58 of 1854) with AZA P=0.024. The number of clinically silent BPAR ISHLT grade > or =3A (the true yield of surveillance EMBs) was 1.39% (26 of 1875) of biopsies MMF vs. 2.1% (39 of 1854) AZA, P=0.48. There were five serious complications requiring intervention or causing long-term sequelae; 0.13% (5 of 3729) per biopsy and 1.94% (5 of 258) per patient. The incidence of all definite and potential complications was 1.42% (53 of 3729) per biopsy and 20.5% (53 of 258) per patient. There was no biopsy-related mortality. CONCLUSION: The yield of BPAR was low in the AZA group and very low in the MMF group. The incidence of complications was also low, but repeated biopsies led to a higher rate per patient. Routine surveillance EMBs and the frequency of such biopsies should be reevaluated in the light of their low yield with current immunosuppression.

Mycophenolate mofetil may allow cyclosporine and steroid sparing in de novo heart transplant patients.

BACKGROUND: Mycophenolate mofetil (MMF) provides superior prophylaxis against acute rejection when compared with azathioprine (AZA) in heart and renal transplantation. However, it remains unclear whether this results in improved survival or reduced morbidity after heart transplantation. METHOD: In a sequential study, 240 cardiac transplant patients were treated with either MMF (n=119) or AZA (n=121) both in combination with cyclosporine and corticosteroids after rabbit antithymocyte globulin induction. RESULTS: By protocol lower cyclosporine levels were targeted in the MMF group during the first year (e.g. 203+/-52 ng/mL MMF vs. 236+/-59 ng/mL AZA, P=0.0006 at 6 months). Patient survival at 1 year (82% MMF vs. 79% AZA, P=0.55) and at 3 years was similar in both groups. The cumulative probability of receiving antirejection treatment within 1 year was lower in the MMF group, as was biopsy-proven acute rejection with International Society of Heart and Lung Transplantation grade > or =3A (24% vs. 35%, P=0.03). The MMF group also had fewer episodes requiring cytolytic therapy (6% vs. 13%, P=0.04) and more patients had steroids withdrawn by 1 year (66% vs. 32%, P<0.001). Renal function was better in the MMF group with lower creatinine levels at 1 year (133+/-45 vs. 155+/-46 micromol/L, P=0.0004). Calculated creatinine clearance (Cockcroft and Gault formula) at 1 year was also better (MMF 74+/-32 mL/min vs. AZA 62+/-24 mL/min, P=0.004). CONCLUSION: Our results suggest that immunosuppression with MMF rather than AZA may allow lower cyclosporine levels, better renal function, and increased steroid weaning at 1 year while also achieving better control of acute rejection.

Reversible sirolimus-associated pneumonitis after heart transplantation.

Sirolimus (rapamycin) and everolimus are immunosuppressive agents that inhibit cardiac allograft vasculopathy. Sirolimus has been widely used in renal transplantation, and its use in heart transplantation is increasing. Sirolimus-associated pneumonitis has been described in renal transplant patients. Two cases of sirolimus-associated pneumonitis have been reported after cardiac transplantation. Only 1 case has been described in detail, and this had a fatal outcome. Here, we present a case of sirolimus-associated interstitial pneumonitis in a cardiac transplant recipient that resolved completely with withdrawal of the drug and treatment with corticosteroids.