Haploidentical hematopoietic cell transplantation is even more advantageous during the COVID‐19 pandemic

Abstract

To the Editor The SARSCoV2 has overwhelmed healthcare systems worldwide. Hematopoietic cell transplantation (HCT) has been uniquely affected as this virus may not only severely impact the immunocompromised recipient but also the potential stem cell donor.1 A recent review of SARSCoV2 reported that 15% of allogeneic HCT recipients developed severe disease requiring mechanical ventilation.2 The coronavirus disease19 (COVID19) pandemic has also disrupted donor availability, as some prospective unrelated donors have been infected prior to donation or others are less likely to volunteer due to fear of contracting the virus. Moreover, COVID19 has exhausted hospital resources restricting in some cases access to bone marrow and peripheral stem cell collections. Consequently, HCT donor registries have recommended cryopreservation after stem cell collection to safeguard against these disruptions. Under these circumstances, use of haploidentical (haplo)related donors has become even more advantageous. We report a successful haploHCT after both the donor and the recipient had been infected and recovered from SARSCoV2. The recipient was a 17yearold Hispanic boy with highrisk preB acute lymphocytic leukemia. He was diagnosed with SARSCoV2 during interim maintenance as his nasopharyngeal (NP) swab was positive for SARSCoV2 viral RNA and remained positive for a month (Figure 1). He developed mild respiratory symptoms and lowgrade fever therefore required no specific therapy while his chemotherapy was delayed for two weeks. Serology performed 4 weeks after his infection demonstrated positive SARSCoV2 IgG. He developed a bone marrow relapse two months after acquiring SARSCoV2 infection. As his relapse occurred on therapy and within 10 months from his original diagnosis, he was considered for a HCT after achieving a second complete remission with no measurable residual disease following a twoweek chemotherapy induction and a fourweek blinatumomab infusion.3 The donor was his 26yearold sister, whom during screening was found to be positive for SARSCoV2 viral RNA by RTPCR of her NP swab and serology revealed SARSCoV2 IgG positivity (Figure 1). She remained asymptomatic with NP RTPCR converting to negative after 18 days. HaploHCT was therefore delayed for a month while the patient was bridged with a second course of blinatumomab. The donor uneventfully underwent a bone marrow harvest, and her brother received a noncryopreserved Treplete haploidentical bone marrow transplant (haploBMT) following conditioning with fractionated total body irradiation (200 cGy × 6) and fludarabine.4,5 Posttransplant cyclophosphamide was given on days +3 and +4. The patient is now 45 days following his haploBMT and remains in remission with no evidence of infection while interestingly his serology remained positive for SARSCoV2 IgG on day +32. As the COVID19 continues to spread globally, nonurgent transplants have been placed on hold or delayed. Guidelines on when to transplant are situational as delay for hematologic malignancies may be detrimental to the patient.1 The logistics of securing an unrelated donor have become even more complicated especially