Retreatment by antithymocyte globulin for second kidney transplantation: efficacy, tolerance and safety.

BACKGROUND: It is unknown whether kidney transplant patients who receive rabbit antithymocyte globulin (rATG) become immunized against rabbit antibodies, leading to reduced efficacy, or are at higher risk of cytomegalovirus infection or post-transplant lymphoproliferative disorder (PTLD) on retreatment. The efficacy and tolerance of rATG when used as induction for the second time in patients undergoing retransplantation have not been evaluated. METHODS: In a retrospective case-control study, 54 retransplanted patients who received rATG (Thymoglobulin) induction for the second time during 2004-2010 were compared to a matched cohort of 108 patients receiving rATG induction for a first kidney transplantation during the same period. Maintenance treatment was similar in both groups. RESULTS: Median follow-up was 45.8 months and 47.3 months in the second and first treatment groups, respectively. No differences were observed between the two groups in terms of leukocyte, lymphocyte or platelet depletion. Dose and duration of rATG treatment were similar in both groups, suggesting a similar tolerance profile. Cytomegalovirus infection (including primoinfection and reactivation) occurred in 4/54 retreated patients versus 22/108 controls (p=0.108). Use of cytomegalovirus prophylaxis was similar between groups. PTLD occurred in one control patient and no retreated patients. CONCLUSION: A second course of rATG induction results in similar lymphocyte depletion and is as well tolerated as a first course. The incidence of cytomegalovirus infection and post-transplant lymphoproliferative disease was not increased during retreatment. Further studies are required to evaluate specific T cell subpopulation depletion and compare long-term outcome in patients receiving a second induction with rATG.

Profiling sirolimus-induced inflammatory syndrome: a prospective tricentric observational study.

BACKGROUND: The use of the immunosuppressant sirolimus in kidney transplantation has been made problematic by the frequent occurrence of various side effects, including paradoxical inflammatory manifestations, the pathophysiology of which has remained elusive. METHODS: 30 kidney transplant recipients that required a switch from calcineurin inhibitor to sirolimus-based immunosuppression, were prospectively followed for 3 months. Inflammatory symptoms were quantified by the patients using visual analogue scales and serum samples were collected before, 15, 30, and 90 days after the switch. RESULTS: 66% of patients reported at least 1 inflammatory symptom, cutaneo-mucosal manifestations being the most frequent. Inflammatory symptoms were characterized by their lability and stochastic nature, each patient exhibiting a unique clinical presentation. The biochemical profile was more uniform with a drop of hemoglobin and a concomitant rise of inflammatory acute phase proteins, which peaked in the serum 1 month after the switch. Analyzing the impact of sirolimus introduction on cytokine microenvironment, we observed an increase of IL6 and TNFα without compensation of the negative feedback loops dependent on IL10 and soluble TNF receptors. IL6 and TNFα changes correlated with the intensity of biochemical and clinical inflammatory manifestations in a linear regression model. CONCLUSIONS: Sirolimus triggers a destabilization of the inflammatory cytokine balance in transplanted patients that promotes a paradoxical inflammatory response with mild stochastic clinical symptoms in the weeks following drug introduction. This pathophysiologic mechanism unifies the various individual inflammatory side effects recurrently reported with sirolimus suggesting that they should be considered as a single syndromic entity.

Effect of two injections of non-adjuvanted influenza A H1N1pdm2009 vaccine in renal transplant recipients: INSERM C09-32 TRANSFLUVAC trial.

BACKGROUND: Enhancing vaccine immunogenicity in kidney transplant recipients, particularly against influenza, is required since the immunosuppression used to prevent graft rejection limits vaccine immunogenicity. We therefore investigated the immunogenicity and safety of a double dose non-adjuvanted vaccination regimen against influenza H1N1pdm2009 in kidney transplant adult recipients. METHODS: A prospective single-arm study was conducted including 121 renal transplant recipients under triple immunosuppressive regimen. Patients received 2 injections (day 0, day 21) of an inactivated, non-adjuvanted H1N1pdm2009 vaccine. Immunogenicity (hemagglutination-inhibition [HI] antibodies and anti-hemagglutin [HA] specific T cells) was evaluated after one and two injections (day 21, day 42) and at 6 months (day 182). RESULTS: The seroprotection rate (HI antibody titer≥1/40) was 19% at day 0 (n=119), 53% at day 21 (n=118), 60% at day 42 (n=116) (p=0.013; day 42 vs. day 21) and 56% at day 182 (n=113). The seroconversion rate was 24% and 32%, the geometric mean fold rise was 3.7 and 4.6 after the first and second injections, respectively. T-cell immunity to the H1N1pdm2009 vaccine showed a two-fold increase from baseline, though not statistically significant, in H1N1pdm2009-HA-specific CD4+ and CD8+ T cells in 34% and 48% of cases, respectively. No rejection episodes related to vaccination were observed while the donor-specific antibodies and creatinine clearance remained unchanged throughout the study. CONCLUSION: Administration of two doses of the non-adjuvanted influenza H1N1pdm2009 vaccine in renal transplant patients is safe and induces a significant seroprotection, not strong enough yet to meet European or US requirements for adults below 60 years, but comparable to seroprotection levels usually observed in the non immunosuppressed elderly population or conferred by a single dose of adjuvanted vaccine in solid organ transplant recipients. These results provide useful indications for future strategies required to improve immunogenicity of vaccines against influenza in transplanted patients.

Immunogenicity and safety of intradermal influenza vaccination in renal transplant patients who were non-responders to conventional influenza vaccination.

Seasonal influenza epidemics are associated with high morbidity and mortality particularly in high-risk patients. Conventionally administered influenza vaccines show reduced efficacy in populations with weakened immune systems such as solid-organ transplant patients. This study assesses the safety and immunogenicity of an intradermally administered influenza vaccine in renal transplant patients previously identified as non-responders to a licensed trivalent inactivated influenza vaccine (TIV). Renal transplant patients with low or no hemagglutination inhibiting (HI) antibody response to an A influenza (H3N2) vaccine strain were enrolled in a descriptive phase II, open-label, randomized, multicentre trial: 31 received an investigational intradermal TIV, and 31 received a conventionally administered TIV. Both vaccines contained 15 µg hemagglutinin (HA) per strain. The 62 study subjects were selected from 201 renal transplant patients aged 18-60 years who had been vaccinated in the previous year with a conventionally administered TIV. Vaccination was safe and well tolerated by each administration route. The immunogenicity results of this descriptive study showed ID TIV vaccination to induce HI antibody responses that trended higher in renal transplant patients than conventionally administered TIV. Our results suggest that ID influenza vaccination may offer enhanced immunogenicity and protection in persons who do not respond well to conventional TIV. Further studies should be conducted in immunocompromised populations to validate the trends for higher efficacy of ID vs. conventional route of immunization against influenza.