Risk factors for graft-versus-host-disease after donor lymphocyte infusion following T-cell depleted allogeneic stem cell transplantation

Abstract

Introduction: Unmodified donor lymphocyte infusions (DLI) after allogeneic stem cell transplantation (alloSCT) can boost the beneficial Graft-versus-Leukemia (GvL) effect but may also induce severe Graft-versus-Host-Disease (GvHD). To improve the balance between GvL and GvHD, it is crucial to identify factors that influence the alloreactivity of DLI.

Methods: We investigated the effects of the presence of patient-derived antigen-presenting cells at time of DLI as estimated by the bone marrow (BM) chimerism status, lymphopenia as measured by the absolute lymphocyte count (ALC) at time of DLI, and the presence of a viral infection (de novo or reactivation) close to DLI on the risk of GvHD after DLI. The cohort consisted of patients with acute leukemia or myelodysplastic syndrome who prophylactically or pre-emptively received DLI as standard care after alemtuzumab-based alloSCT. In patients at high risk for relapse, DLI was administered at 3 months after alloSCT (n=88) with a dose of 0.3x10⁶ or 0.15x10⁶ T cells/kg in case of a related or unrelated donor, respectively. All other patients (n=76) received 3x10⁶ or 1.5x10⁶ T cells/kg, respectively, at 6 months after alloSCT.

Results: For both DLIs, patients with reduced-intensity conditioning and an unrelated donor had the highest risk of GvHD. For DLI given at three months, viral infection within 1 week before and 2 weeks after DLI was an additional significant risk factor (hazard ratio (HR) 3.66 compared to no viral infection) for GvHD. At six months after alloSCT, viral infections were rare and not associated with GvHD. In contrast, mixed BM chimerism (HR 3.63 for ≥5% mixed chimerism compared to full donor) was an important risk factor for GvHD after DLI given at six months after alloSCT. ALC of <1000x10⁶/l showed a trend for association with GvHD after this DLI (HR 2.05 compared to ≥1000x106/l, 95% confidence interval 0.94-4.45). Furthermore, the data suggested that the presence of a viral infection close to the DLI at three months or ≥5% mixed chimerism at time of the DLI at six months correlated with the severity of GvHD, thereby increasing their negative impact on the current GvHD-relapse-free survival.

Conclusion: These data demonstrate that the risk factors for GvHD after DLI depend on the setting of the DLI.

Keywords: acute lymphoblastic leukemia; acute myeloid leukemia; allogeneic stem cell transplantation; donor lymphocyte infusion; graft-versus-host-disease; multi-state modelling; myelodysplastic syndrome.

Figure 1

Multi-state model to evaluate the development and outcome of GvHD and other clinical events after DLI. Boxes represent states, arrows represent transitions. Starting state and time was DLI1. From here, patients could move to the state ‘relapse after DLI1’ at time of relapse, ‘death after DLI1’ at time of death, ‘tIS after DLI1’ at time of the start of tIS for GvHD and ‘DLI2’ at time of the administration of a second DLI, whichever occurred first. From the state ‘relapse after DLI1’ patients could only enter the state ‘death after relapse after DLI1’. From the state ‘tIS after DLI1’ patients could move to ‘stop tIS after DLI1’ at time of stop of all tIS, ‘relapse after DLI1’ at time of relapse, 'death after tIS after DLI1’ at time of death or ‘DLI2’ at time of the administration of a second DLI, whichever occurred first. From the state ‘stop tIS after DLI1’ patients could return to ‘tIS after DLI1’ when patients had to restart tIS for recurrent GvHD, ‘relapse after DLI1’ at time of relapse, ‘death after tIS after DLI1’ at time of death or ‘DLI2’ at time of the administration of a second DLI, whichever occurred first. After DLI2, similar states were constructed, except that any further DLIs were ignored. The cGRFS is the sum of the probabilities of all green (thick border) states, the probability of being alive with GvHD the sum of all yellow (dashed border) states, the probability of death after start of tIS for GvHD the sum of all red (dotted border) states, the RFS the sum of all green (thick border) and yellow (dashed border) states, and the OS the sum of all non-death states. For these summarizing measures, no distinction was made between states after the first DLI or after multiple DLIs.

Figure 2

Outcomes after low-dose 3-month DLI: stacked transition probabilities from state DLI1 (low-dose 3-month DLI) estimated in the non-parametric model in Supplementary Figure 1 . The difference between two adjacent curves represents the probability of being in the corresponding state. 39 patients reached the second DLI as planned. Bold lines show the overall survival (OS), relapse-free survival (RFS) and current GvHD-relapse-free survival (cGRFS), of which the 5-year probabilities with 95%-CI are stated next to the figure.

Figure 3

Outcomes after 6-month DLI: stacked transition probabilities from state DLI1 (6-month DLI) estimated in the non-parametric model in Supplementary Figure 2 . The difference between two adjacent curves represents the probability of being in the corresponding state. Nine patients required a second DLI because of MC. The legend only shows the states which were occupied within 5 years after the 6-month DLI. Bold lines show the overall survival (OS), relapse-free survival (RFS) and current GvHD-relapse-free survival (cGRFS), of which the 5-year probabilities with 95%-CI are stated next to the figure.

Figure 4

Cox proportional hazards models for the transition from first DLI to requiring tIS for GvHD (see Figure 1 ). Based on complete case analysis (A: n=84, B: n=87, C: n=88, D, E: n=74). Viral infection was treated as a time-varying covariate. DLI, donor lymphocyte infusion; BM, bone marrow; MAC, myeloablative conditioning; RIC, reduced-intensity conditioning; UD, unrelated donor; RD, related donor; low MC, 1-4% mixed chimerism; high MC, ≥5% mixed chimerism; FDC, full donor chimerism (no patient material detectable); ALC, absolute lymphocyte count (x10⁶/l).

Figure 5

Estimated probabilities of cGRFS, being alive with clinically relevant GvHD, and of death after start of tIS for GvHD after the low-dose 3-month DLI based on the viral status at time of DLI (viral infection during the last week before DLI (n=25) or no viral infection until DLI (n=63)). The estimates are based on the non-parametric multi-state model in Supplementary Figure 3 which has two starting states (‘DLI1 without early viral infection’ and ‘DLI1 with early viral infection’). See Supplementary Figure 13 for the probabilities of all states separately.

Figure 6

Prediction of cGRFS, being alive with clinically relevant GvHD, and of death after start of tIS for GvHD after the 6-month DLI for reference patients with different characteristics. The prediction is based on the multi-state model in Supplementary Figure 2 with semi-parametric transition-specific proportional hazards models with BM chimerism and conditioning/donor combination as covariates for the transition from ‘DLI1’ to ‘tIS for GvHD after DLI1’ and BM chimerism (high MC vs other) for the transition from ‘tIS for GvHD after DLI1’ to ‘death after tIS after DLI1’. No covariates were assessed for the other transitions of the model.