Pre-transplant CD69+ extracellular vesicles are negatively correlated with active ATLG serum levels and associate with the onset of GVHD in allogeneic HSCT patients

Graft versus host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). Rabbit anti-T lymphocyte globulin (ATLG) in addition to calcineurin inhibitors and antimetabolites is a suitable strategy to prevent GVHD in several transplant settings. Randomized studies already demonstrated its efficacy in terms of GVHD prevention, although the effect on relapse remains the major concern for a wider use. Tailoring of ATLG dose on host characteristics is expected to minimize its side effects (immunological reconstitution, relapse, and infections). Here, day -6 to day +15 pharmacokinetics of active ATLG serum level was first assayed in an explorative cohort of 23 patients by testing the ability of the polyclonal serum to bind antigens on human leukocytes. Significantly lower levels of serum active ATLG were found in the patients who developed GVHD (ATLG_AUC_CD45: 241.52 ± 152.16 vs. 766.63 +/- 283.52 (μg*day)/ml, p = 1.46e^-5). Consistent results were obtained when the ATLG binding capacity was assessed on CD3+ and CD3+/CD4+ T lymphocytes (ATLG_AUC_CD3: 335.83 ± 208.15 vs. 903.54 ± 378.78 (μg*day)/ml, p = 1.92e^-4; ATLG_AUC_CD4: 317.75 ± 170.70 vs. 910.54 ± 353.35 (μg*day)/ml, p = 3.78e^-5. Concomitantly, at pre-infusion time points, increased concentrations of CD69+ extracellular vesicles (EVs) were found in patients who developed GVHD (mean fold 9.01 ± 1.33; p = 2.12e^-5). Consistent results were obtained in a validation cohort of 12 additional ATLG-treated HSCT patients. Serum CD69+ EVs were mainly represented in the nano (i.e. 100 nm in diameter) EV compartment and expressed the leukocyte marker CD45, the EV markers CD9 and CD63, and CD103, a marker of tissue-resident memory T cells. The latter are expected to set up a host pro-inflammatory cell compartment that can survive in the recipient for years after conditioning regimen and contribute to GVHD pathogenesis. In summary, high levels of CD69+ EVs are significantly correlated with an increased risk of GVHD, and they may be proposed as a tool to tailor ATLG dose for personalized GVHD prevention.

Salvage Haploidentical Transplantation Using Low-dose ATG for Early Disease Relapse after First Allogeneic Transplantation: A Retrospective Single-center Review

Second allogeneic stem cell transplantation (allo-SCT) is a potentially curative therapy for patients who relapse after first allo-SCT. Human leukocyte antigen (HLA)-haploidentical related donors provide the broad opportunity to conduct second SCT at the appropriate time, but the efficacy of second SCT from haploidentical donors after relapse has not been established. We retrospectively analyzed the records of 33 patients who underwent second SCT. Twenty patients underwent haplo-SCT with low-dose antithymocyte globulin (ATG), and the other 13 patients underwent conventional- SCTs, including HLA-matched related peripheral blood, unrelated bone marrow or cord blood. Three years after the second SCT, the overall survival (OS) and progression-free survival (PFS) of all patients were 32.5% and 23.9%. Multivariate analyses indicated that non-complete response at second SCT, less than 1-year interval to relapse after first- SCT, and total score ≥ 3 on the hematopoietic cell transplantation-specific comorbidity index were significantly associated with a lower PFS rate. The haplo- and conventional- SCT groups showed equivalent results regarding OS, PFS, cumulative incidences of relapse, non-relapse mortality and graft-versus-host disease. The neutropenic period after transplantation was significantly shorter in haplo- SCT than conventional- SCT (10.5 days vs. 16 days, p=0.001). Our analysis revealed that haplo-SCT could be an alternative therapeutic option for relapsed patients after first SCT.

Not all anti-T lymphocyte globulin preparations are suitable for use in aplastic anemia: significantly inferior results with jurkat cell-reactive anti-T lymphocyte globulin in clinical practice

BACKGROUND

Immunosuppressive therapy (IST) with anti-T lymphocyte globulin (ATG) plus cyclosporine (CSA) is standard therapy in patients with non-severe aplastic anemia (AA) in need of treatment and severe aplastic anemia (SAA) who do not have an available HLA-matched donor. The aim of this study was to analyze patients submitted to different ATG preparations as first-line treatment.

PATIENTS AND METHODS

We retrospectively analyzed adult aplastic anemia (AA) patients who received ATG as first-line treatment between 1999 and 2013 to compare hematologic response and survival.

RESULTS

During the time period mentioned 4 different ATG preparations had been used in 38 AA patients (34 severe, 4 non-severe). Responses were better with Lymphoglobulin (6 complete response 1 partial response, 0 refractory disease and 2 death within 3 months after ATG, i.e. during induction), Thymoglobulin (3, 1, 4 and 1, respectively) or ATGAM (1, 2, 1 and 1) compared to the ATG-Fresenius (ATG-F) group (3, 0, 6 and 6) (P = .07). Statistically significant inferior results with ATG-Fresenius (3 complete or partial responses, 6 refractoriness and 6 induction deaths) were evident when other preparations are lumped together (14 complete or partial responses, 5 refractoriness and 4 induction mortalities) (P = .045). Estimated 1 year survival rates were 52.5% versus 76.9%, respectively (P = .13).

CONCLUSIONS

These data support the notion that not all ATG preparations are suitable for use in AA.

Comparison of efficacy and safety between rabbit anti-thymocyte globulin and anti-T lymphocyte globulin in kidney transplantation from donation after cardiac death: a retrospective cohort study

AIM

To compare the efficacy and safety between rabbit anti-thymocyte globulin (Thymoglobulin) and anti-T lymphocyte globulin (ATG-Fresenius, ATG-F) in donation after cardiac death (DCD) kidney transplantation.

METHODS

We retrospectively analyzed 255 cases of DCD kidney transplantation performed at our hospital from February 2007 to October 2013. The patients were divided into two groups based on their induction therapies with Thymoglobulin (n = 188) or ATG-F (n = 67). Clinical data were collected and compared between the two groups.

RESULTS

Delayed graft function (DGF) occurred in 36 (19.1%) patients in the Thymoglobulin group versus 17 (25.4%) patients in the ATG-F group (P = 0.281). However, if we subgroup the patients with increased risk factors for DGF, the DGF rate was 9/40 (22.5%) in the Thymoglobulin group versus 9/16 (56.3%) in the ATG-F group (P = 0.015). Duration of DGF was significantly shorter in the Thymoglobulin group (11.7 days vs. 16.1 days). The acute rejection rate was significantly lower in the Thymoglobulin group (9.6% vs. 19.4%, P = 0.035). One-year graft and patient survival were both comparable between the Thymoglobulin and ATG-F groups. The adjusted odds ratio of DGF was 4.283 (1.137-16.13) between the ATG-F and Thymoglobulin groups in patients with increased risk factors for DGF.

CONCLUSION

Compared with ATG-F, Thymoglobulin may reduce duration of DGF and acute rejection rate after DCD kidney transplantation. Moreover, Thymoglobulin significantly reduced DGF in patients with increased risk factors for DGF.