Thymoglobuline

All patients initially received triple-drug maintenance immunosuppression based on tacrolimus (Advagraf, Astellas, 0.2 mg/kg/day, target trough levels within the first 14 days at 8–15 ng/ml), mycophenolate mofetil (Cellcept, Roche, 2 g/day or generics) or enteric-coated mycophenolic acid (Myfortic, Novartis, 1440 mg/day), and tapered prednisone (initial dose 20 mg tapered to 5 mg at 3 months). All but two patients received rabbit anti-thymocyte globulin (Thymoglobuline, Genzyme, first dose of 1.5 mg/kg initiated before reperfusion, a total cumulative dose aimed at 5–7 mg/kg) induction immunosuppression. Patients received desensitization protocol mostly with plasmapheresis and IVIg, patients at highest risk received rituximab in addition. Details on desensitization strategies are given in Figure 1, Table 3. Further analyses were adjusted for desensitization strategy to account for the heterogeneity of applied treatments.
Recipients diagnosed with ABMR were treated with high dose steroids, plasmapheresis (1 plasma volume; 5–10 sessions per patient), and IVIg administration (0.5 g/kg) after each session. In the cases of refractory ABMR, bortezomib (Velcade, Johnson & Johnson) was administered as previously described in detail (11 (link)).

The transplant days were numbered sequentially. The specific days preceding the transplant were indicated by a minus sign (−), such that the first day of the stem cell infusion was numbered “day 01,” the second day of infusion was “day 02”. The specific days after the last stem cell infusion were indicated by a plus sign (+). Patients in the Haplo-cord HSCT group were treated with a busulfan (BU)/cyclophosphamide (CY)-based regimen that included the following drugs. BU, 0.8 mg/kg intravenous (i.v.) was given four times daily on days −7 and −6. Cy, 50 mg/kg i.v., was given once daily from days −5 to −2, and ATG (rabbit, Thymoglobuline^®, Genzyme, Cambridge, MA, USA), 2.5 mg/kg i.v., was given once daily from days −5 to −2. In the MRD-HSCT group, patients were given fludarabine (Flu) + CY + ATG regimen, which included Flu 30 mg/m²/day i.v. given for six days (days −7 to −2), Cy 50 mg/kg/day i.v. for two days (days −4 and −3), and ATG 2.5 mg/kg/day i.v., given for five days (days −8 to −4).

The immunosuppressive treatment was not imposed by the study and was based on the assessment of immunological risk according to clinical practice in our department as detailed hereafter. Low immunological risk patients, defined as first time kidney transplant recipients and with PRA < 20%, received two injections of Basiliximab (Simulect; Novartis Pharma, Basel, Switzerland), while higher immunological risk recipients (previous transplantation, PRA > 20%) were more likely to receive antithymocyte globulines (ATG; Thymoglobuline; Genzyme, Lyon, France) during the first 3 to 7 days post-transplant. ATG was also used for induction in donors with cardiac arrest before brain death, in non-heart-beating donors, and when delayed graft function was anticipated by clinician. Moreover, between 2010 and 2013, no induction therapy was performed in patients aged >70 years old. All patients received a single methylprednisolone bolus of 500 mg followed by prednisone (1 mg/kg/day) with a progressive tapering and discontinuation at the end of month 5 post-transplant, unless there was an occurrence of AR. A maintenance immunosuppressive regimen relied mainly on mycophenolate mofetil or mycophenolic acid and tacrolimus.

The conditioning regimen was individualized based on the underlying disease, age, and clinical conditions of the patient. For GVHD prophylaxis, all patients received PTCy (50 mg/kg/day) on days +3 and +4 along with rabbit ATG (Thymoglobuline^®; Genzyme, Marcy-ľÉtoile, France) on days −3, −2, and −1. Intravenous mesna (Uromitexan^®; Baxter Oncology GmbH, Halle, Germany) was administered to prevent cyclophosphamide-related hemorrhagic cystitis. The total dose of ATG was adjusted, from 4.5 to 2.0 mg kg⁻¹. Methylprednisolone (3–4 mg kg⁻¹, maximum 250 mg; Solu-Medrol^®; Pfizer, Puurs, Belgium) was given before and 6 h after the start of ATG to alleviate ATG-related symptoms, such as high fever and chillness [20 (link)]. Patients also received CsA (3 mg kg⁻¹/day; Sandimmun^®; Novartis, Stein, Switzerland) and MMF (15 mg kg⁻¹ thrice a day; CellCept^®; Roche, Segrate, Italy), both starting on day +5. MMF was discontinued on day +35. The target trough levels of CsA were between 150 and 300 ng mL⁻¹. CsA tapering was started around day +60, and it was discontinued on day +90 if no acute GVHD.

Except for postoperative desensitization, the standard immunosuppressive regimen did not change during the study period (2004-2010). As previously described (12 (link)), in the postoperative period it included thymoglobulin induction therapy from day 0 to day 4 (rabbit ATG, Thymoglobuline, Genzyme, Lyon, France), methylprednisolone bolus infusion on day 1, ciclosporine after day 1, and mycophenolate mofetil (MMF) after day 4. Corticosteroids were converted to oral form starting on day 4, with a dosage of 1 mg/kg initially. They were progressively lowered to reach 20 mg/day at 2 months and 5 mg/day after the anniversary date of HTx. Ciclosporine was the only calcineurin-inhibitor used at the time, and trough targets depended on delay since transplantation.

The details of the immunosuppressive treatments have been detailed elsewhere [23 (link)]. Briefly, the induction regimen included one methylprednisolone bolus of 500 mg alone or in association with either two injections of basiliximab (Simulect; Novartis Pharma, Switzerland) (20 mg on day 0 and day 4 posttransplantation), or antithymocyte antibodies administration (Thymoglobuline; Genzyme, France) during the first 3 to 7 days posttransplantation. All patients received prednisone (1 mg/kg/day) with a progressive tapering and discontinuation at the end of month 5 post-transplant unless occurrence of more than one acute rejection episode. Maintenance immunosuppressive regimen relied on mycophenolate mofetil (Cellcept, Roche, France) and tacrolimus (Prograf, Fujisawa, Japan). In patients that did not experience AR, mycophenolate mofetil was withdrawn at month 4 posttransplant, and tacrolimus monotherapy was used as maintenance regimen after month 6 posttransplant.