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P151 Successful haploidentical hematopoietic stem cell transplantation of a patient with pre-existing donor specific anti-HLA antibodies
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P151
Abstracts / Human Immunology 78 (2017) 51–254
SUCCESSFUL HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION OF A PATIENT WITH PREEXISTING DONOR SPECIFIC ANTI-HLA ANTIBODIES Moheeb A. Al-Awwami a, Shahrukh Hashmi a, Riad El Fakih a, Mahmoud Aljurf a, Feras Alfraih a, Hana Al Khabbaz b, Fadi Alzayer a, Mariam Garcia a, Arlene Santos a, Marwan Shaheen a. aKing Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; bRiyadh Colleges for Dentistry and Pharmacy, Riyadh, Saudi Arabia. Aim: Pre-existing donor specific anti-HLA antibodies (DSA) are implicated in graft rejection in HLA mismatched and haploidentical HSCT. We report a case of severe aplastic anemia whounderwent allogeneic HSCT from HLA matched sibling but developed primary graft failure. Due to the lack of matched unrelated donor (MUD), the patient was offered haploidentical HSCT from a sibling with the lowest number and strength of DSA. Methods: Patient sera were tested using LABScreen PRA and LABScreen single antigen (SA) beads conventional IgG and C1q (One Lambda Thermo Fisher, Canoga Park CA). Flow cytometry crossmatch (FCXM) was performed with pronase treated T and B cell. FCXM was considered positive when the T cell and B cell were more than 38 and more than 50 MCS respectively. Desensitization was performed using 4 plasma exchange (1.5 volume) every other day followed by IVIG 1 g/kg on day 9 and Rituximab 375 mg/m2 on day-8 followed by ATG/ fludarabine/TBI conditioning and post-transplant cyclophosphamide. Patient sera were tested again to determine the successfulness of the desensitization process. Results: Initial anti-HLA antibody testing showed the patient was sensitized to HLA class I and II with three DSA. Anti-DRB1⁄ 04:02 (8265 MFI) DSA, anti-DQB1⁄ 03:02 (5419 MFI) DSA and anti-DR53 (566 MFI) DSA all of which were C1q negative. FCXM was positive for T- cell IgG (+75 MCS, most likely due to auto-antibodies) and positive B-cell IgG (+409 MCS). Post desensitization protocol, the DSA were as follows Anti-DRB1⁄ 04:02 (3154 MFI) DSA, anti-DQB1⁄ 03:02 (2141 MFI) DSA and anti-DR53 (1001 MFI) DSA. Patient had neutrophil and platelets engraftment on day 13 and 16 respectively. Currently, the patient is 60 days post transplant, alive with no graft versus host disease or other complications. Conclusions: Despite the partial reduction of the DSA strength, the patient engrafted successfully, the question remains, was it successful because the antibodies were non complement fixing antibodies? The clinical significance of non complement DSA in HSCT waits for further studies.
P151
Abstracts / Human Immunology 78 (2017) 51–254
SUCCESSFUL HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION OF A PATIENT WITH PREEXISTING DONOR SPECIFIC ANTI-HLA ANTIBODIES Moheeb A. Al-Awwami a, Shahrukh Hashmi a, Riad El Fakih a, Mahmoud Aljurf a, Feras Alfraih a, Hana Al Khabbaz b, Fadi Alzayer a, Mariam Garcia a, Arlene Santos a, Marwan Shaheen a. aKing Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; bRiyadh Colleges for Dentistry and Pharmacy, Riyadh, Saudi Arabia. Aim: Pre-existing donor specific anti-HLA antibodies (DSA) are implicated in graft rejection in HLA mismatched and haploidentical HSCT. We report a case of severe aplastic anemia whounderwent allogeneic HSCT from HLA matched sibling but developed primary graft failure. Due to the lack of matched unrelated donor (MUD), the patient was offered haploidentical HSCT from a sibling with the lowest number and strength of DSA. Methods: Patient sera were tested using LABScreen PRA and LABScreen single antigen (SA) beads conventional IgG and C1q (One Lambda Thermo Fisher, Canoga Park CA). Flow cytometry crossmatch (FCXM) was performed with pronase treated T and B cell. FCXM was considered positive when the T cell and B cell were more than 38 and more than 50 MCS respectively. Desensitization was performed using 4 plasma exchange (1.5 volume) every other day followed by IVIG 1 g/kg on day 9 and Rituximab 375 mg/m2 on day-8 followed by ATG/ fludarabine/TBI conditioning and post-transplant cyclophosphamide. Patient sera were tested again to determine the successfulness of the desensitization process. Results: Initial anti-HLA antibody testing showed the patient was sensitized to HLA class I and II with three DSA. Anti-DRB1⁄ 04:02 (8265 MFI) DSA, anti-DQB1⁄ 03:02 (5419 MFI) DSA and anti-DR53 (566 MFI) DSA all of which were C1q negative. FCXM was positive for T- cell IgG (+75 MCS, most likely due to auto-antibodies) and positive B-cell IgG (+409 MCS). Post desensitization protocol, the DSA were as follows Anti-DRB1⁄ 04:02 (3154 MFI) DSA, anti-DQB1⁄ 03:02 (2141 MFI) DSA and anti-DR53 (1001 MFI) DSA. Patient had neutrophil and platelets engraftment on day 13 and 16 respectively. Currently, the patient is 60 days post transplant, alive with no graft versus host disease or other complications. Conclusions: Despite the partial reduction of the DSA strength, the patient engrafted successfully, the question remains, was it successful because the antibodies were non complement fixing antibodies? The clinical significance of non complement DSA in HSCT waits for further studies.