Outcomes after Donor Lymphocyte Infusion for Insufficient Donor Chimerism Following Hematopoietic Cell Transplantation for Non-Malignant Disorders
Authors: Biewen Carter , Smith Angela R , Tolar Jakub , Miller Weston P 
Published: October 2019

Abstract

Background:
Little is reported of the utility of donor lymphocyte infusion (DLI) following HCT for non-malignant disorders (NMD). We describe outcomes after DLI for insufficient donor chimerism after HCT in a large NMD cohort.
Patients/Methods:
We queried the Institutional BMT Database for patients with NMD receiving DLI for insufficient post-HCT donor chimerism. HLA typing, graft selection and conditioning were per institutional guidelines. The use, timing and dosing of DLI was at the discretion of the treating physician. Donor chimerism values on the myeloid fraction of peripheral blood at pre-DLI and most-recent time-points were reviewed. Patients were considered best DLI responders if donor chimerism improved (pre-DLI to most-recent) and most recent chimerism was ³ 80%.
Results:
Twenty-three patients (43% female) were identified. Table 1 shows patient, disease, transplant and DLI characteristics. The median zenith chimerism post-HCT (but pre-DLI) was 84% (IQR, 39 - 99%), observed at a median 28 days post-HCT. The median chimerism just prior to first DLI was 40%. The median time to first DLI was 90 days. Patients underwent a median 2 cycles (IQR, 2 - 3; maximum, 5) of DLI; the median cumulative per-patient CD3+ dose was 11.5 x 106/kg. Post DLI, two patients developed aGvHD and 2 patients developed cGvHD.
Five patients (22%) were best DLI responders. At a mean 3.6 years post-HCT, they retained mean chimerism of 94% (mean increase from pre-DLI of 37%). Of the 18 non-best responders (78%), median chimerism at last follow-up was 10% (IQR, 2 - 25%). Seven patients underwent repeat HCT. Best response to DLI did not depend on HCT total nucleated cell dose, donor relatedness, serotherapy agent of HCT regimen, chimerism prior to DLI, or total DLI CD3+ dose. Best responders tended to have undergone myeloablative conditioning, be HLA-matched to the donor and receive first DLI later post-HCT (median 102 days, versus 83 days).
Conclusions:
In a large NMD cohort undergoing DLI after HCT, sustained high donor chimerism response was observed in 22%. Ongoing analyses aim to assess those with intermediate response (many of whom also enjoy improved or stable NMD), as well as the impact of peri-DLI immune suppression on outcomes.
Table 1. Patient, Disease and Transplant Characteristics. ID Dx Age (y) at HCT Conditioning/ Serotherapy Donor / Graft HCT TNC(x 108 /kg) Days# to DLI DLI@ CD3+ (x106 /kg) % Chimerism Pre/MRFU aGvHD (grade) / cGvHD Re-HCT? Survival (y#) Notes / Cause of Death 1 ALD 8.1 MA / ATG R / BM 2.16 508 6 92 / 100 n/n n A (10) SD 2 ALD 8.3 NMA / C R / BM 3.17 73 9 59 / 27 n/n n A (6) SD 3 ALD 8.4 NMA / C R / BM 3.97 51 45 44 / 23 n/n n A (4.6) SD 4 ALD 9.9 NMA / C R / BM 2.13 44 17 43 / 17 n/n n A (7.2) SD 5 HLH 18 NMA/ Unk U / BM 1.94 102 1 75 / 100 Y(4)/n n D (0.6) Viral; Resp Failure 6 HLH 1 NMA / C U / BM 9.39 181 3 3 / 4 n/n Y D (1.9) Sepsis 7 Hurler 2.5 MA / ATG R / BM 5.05 193 16 67 / 58 n/n n A (8.3) SD 8 Hurler 1 MA / C R / BM 4.25 305 1 64 / 80 n/n n A (6.7) SD 9 IPEX 1.3 NMA / Unk U / BM 4.99 160 13 44 / 56 n/n n A( 6.4) SD 10 JEB 0.5 NMA / ATG U / BM 5.22 81 6 25 / 13 n/n n D (0.4) Sepsis 11 RDEB 2.8 NMA / ATG R / BM 6.21 274 11 17 / 25 n/n n A (2.1) SD 12 RDEB 6.3 NMA / ATG R / BM 7.28 167 Unk 17 / 6 n/n n A (3.1) SD 13 RDEB 0.9 NMA / ATG U / BM 9.91 98 16 12 / 87 n/n n A (2.7) SD 14 RDEB 3.3 NMA / ATG R / BM 3.53 48 16 10 / 0 n/n Y A (1.6) SD 15 RDEB 0.9 NMA / ATG R / BM 3.35 90 65 40 / 100 n/Y n A (1) SD 16 RDEB 4.9 NMA / ATG R / BM 4.27 133 65 41 / 25 n/n n A (0.8) SD 17 RDEB 0.5 NMA / ATG R / BM 5.5 85 30 71 / 45 n/n n A (0.7) SD 18 SCD 9.1 NMA / ATG U / BM 3.19 34 0.5 0 / 0 n/n n D (13.7) Progressive SCD 19 SCD 10.2 NMA / ATG U / PBSC 0.13 57 12 69 / 4 n/n Y A (10) Rejected re-HCT 20 Thal 2.3 NMA / ATG R / BM 3 84 Unk 15 / 0 n/n Y A (7.3) E, SD 21 Thal 2.8 NMA / ATG U / PBSC 0.22 48 1 40 / 0 Y(2)/Y Y D (2.2) cGvHD 22 Thal 1.7 NMA / C U / PBSC 0.17 69 5 11 / 2 n/n Y A (7.6) E, SD 23 Thal 2.6 MA / ATG R / BM 6.23 159 Unk 17 / 4 n/n Y A (5.3) E, SD # = time referenced to HCT; @ = cumulative CD3+ cell dose; ALD = adrenoleukodystrophy; HLH = hemophagocytic lymphohistiocytosis; IPEX = immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome; JEB = junctional epidermolysis bullosa; RDEB = recessive dystrophic epidermolysis bullosa; SCD = sickle cell disease; Thal = thalassemia; y = years; MA = myeloablative; NMA - non-myeloablative; ATG = anti-thymocyte globulin; C = alemtuzumab; Unk = unknown; R = related; U = unrelated; BM = marrow; PBSC = peripheral blood stem cell; TNC = total nucleated cell dose; Pre = just prior to DLI; MRFU = most recent follow-up; n = no; Y = yes; A = alive; D = dead; SD = stable disease; E = engrafted.

Disclosures
No relevant conflicts of interest to declare.