EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Key words : Alloantigens, Dimethyl sulfoxide, Hydroxyethyl starch, Pediatric bone marrow transplantation

Hematopoietic stem cell transplantation (HSCT) is a curative treatment for many malignant and non-malignant diseases in children and adults. Peripheral blood stem cells, bone marrow, and umbilical cord blood are preferred sources of hematopoietic stem cells.¹

During HSCT, adverse reactions (ARs) may occur, which may be infusion-related or may be as a result of the transplant product itself. The transplant product may contain mature and immature hema-topoietic stem cells and plasma, as well as agents used for cryopreservation if applied. Adverse reactions during HSCT are often associated with dimethyl sulfoxide (DMSO), which is used in cryopreservation.²

So far, other than cases with cord blood transplantation (CBT), no cases of anaphylaxis have been reported in children with HSCT products. This case report presents 2 children who developed anaphylaxis with an allogeneic bone marrow transplantation (BMT).

Case 1
A 10-year-old girl with a diagnosis of thalassemia major was consulted on the first day of the HLA-matched (10/10), ABO-mismatched (B Rh+ recipient, AB Rh+ donor) allogeneic HSCT from her sibling. Forty-five minutes after completion of an ap-proximately 40-minute stem cell infusion, the patient experienced flushing, urticaria, and itching, following a large amount of watery diarrhea. She did not have desaturation or hypotension. Premedication was administered to the patient 1 hour before the infusion with intravenous pheniramine, methylprednisolone, and paracetamol, but no other drugs were used before, during, or after the infusion. For cryopreservation of the graft product, 8% concentration of DMSO and 12% concentration of hydroxyethyl starch (HES) were used. In addition, erythrocyte depletion was performed as a result of ABO incompatibility between the recipient and the donor. The patient did not have any history of hypersensitivity to any other drugs, including premedication drugs or blood products. She was diagnosed with HSCT-induced anaphylaxis and was treated with intramuscular adrenaline, intravenous pheniramine, and methylprednisolone, which resulted in complete resolution of symptoms within 1 hour. The tryptase level during the reaction was 15.9 µg/L (normal, <11.4 <g/L).

Because stem cell infusion was planned to be given in 2 consecutive days due to the large volume, the patient’s premedication protocol was changed. On day 2, methylprednisolone was administered 13 and 7 hours before the infusion, and pheniramine, famotidine, and montelukast were administered together with methylprednisolone 1 hour before the infusion. The patient received the infusion without any problems. After day 30, the patient’s chimerism analysis was found to be 94%. However, at month 4 after HSCT, thalassemia recurred and she is being prepared for a second transplant.

Case 2
A 9-year-old girl diagnosed with aplastic anemia was consulted for flushing, dyspnea, abdominal pain, and vomiting that occurred during minute 15 of the planned 30-minute stem cell infusion. The patient received approximately 90 mL of transplant product from an HLA 10/10 and ABO-matched unrelated donor (A Rh+ patient and donor). At that time, the patient’s oxygen saturation was 90% (in room air), blood pressure was 60/40 mm Hg, respiratory rate was 30 breaths/minute, and heart rate was 120 beats/minute. Premedication was done with intravenous pheniramine, methylprednisolone, and paracetamol 1 hour before the infusion. Except for premedication, no other medication was used before, during, or after the infusion; DMSO at 8% concentration and HES at 12% concentration were used for cryopreservation. Because there was no ABO incompatibility between the patient and the donor, erythrocyte depletion was not applied. The patient did not have any history of hypersensitivity to any other drugs, including premedication drugs. On the other hand, she had a history of severe anaphylaxis with apheresis platelet suspension, which did not contain a cryoprotective agent.

The patient, who was evaluated as anaphylaxis with HSCT, was given intramuscular adrenaline twice at 5-minute intervals. Her clinical condition improved after the initiation of adrenaline and saline infusions due to unresponsive persistent hypo-tension to intramuscular adrenaline treatments. Her tryptase level could not be measured during the reaction. After 24 hours, before the administration of the second unit of the transplant product, DMSO removal was performed by centrifugation. In addition, the premedication protocol was changed, similar to the first case. However, the infusion had to be stopped after administration of 180 mL of the transplant product due to a seizure that occurred.

During follow-up, 35 days after the first transplant, haploidentical HSCT was performed using a fresh transplant product (not cryopreserved) from the patient's half-matched (5/10) and ABO-matched sibling. Only methylprednisolone, pheniramine, and paracetamol were applied 1 hour before the infusion for premedication. The chimerism analysis of the patient, who completed HSCT without any problems in this application, was evaluated to be 100% after day 26. She is currently 1 year posttransplant and doing well.

For the first time to our knowledge, we present 2 pediatric cases of allogeneic BMT-induced moderate-to-severe anaphylaxis. It was thought that DMSO could be the trigger in both anaphylactic reactions; however, it could not be excluded that it was related to stem cell components, plasma, or HES.

Cryopreservation must be applied to preserve the viability of hematopoietic stem cells in autologous HSCT and allogeneic CBT. Although fresh products are recommended for allogeneic HSCT, cryopre-servation is still used in cases where simultaneous transplantation is not possible.^3-5 Agents such as DMSO, dextran, HES, and trehalose are used for cryopreservation.³ In both of our cases, stem cell products were cryopreserved because of the pandemic. As a result, cryopreservation was performed using DMSO and HES.

Dimethyl sulfoxide is an effective agent that easily passes through the cell membrane, inhibits both intracellular and extracellular ice formation, and protects cells from dehydration. However, DMSO can affect central limbic-hypothalamic pathways, cause histamine release, and directly cause cell death, especially at high concentrations. Nausea or vomiting, hypotension or hypertension, arrhythmia, fever, encephalopathy, respiratory distress, and allergic reactions during HSCT are frequently explained by these effects of DMSO.² However, limited data are available regarding DMSO-associated anaphylaxis.^3,6,7 The most commonly observed AR in autologous HSCTs performed with cryopreserved transplant products in adult patients was reported to be flushing (39.4%).⁶ In the study, anaphylaxis related to HSCT was not reported; however, flushing was associated with DMSO.⁶ In a more recent study conducted in Turkey on adults, severe ARs, including allergic reactions, were shown to be more common in HSCTs with cryopreservation using DMSO than HSCTs with fresh product.⁷

In Ikeda and colleagues, only 1 patient, who was an allogeneic CBT recipient, was reported to have experienced HSCT-induced anaphylaxis out of 1125 HSCT applications. The cryoprotective agent used in this patient’s transplant product was DMSO, but no diagnostic test was performed to identify the trigger for anaphylaxis.³ In a study that evaluated allogeneic CBT-associated ARs, 13.3% of 128 reactions were anaphylaxis. Two of the cases that developed anaphylaxis were fatal, and 1 was reported to be a pediatric patient. In the study, DMSO and dextran were used together in all CBTs, but no interpretation was made for the anaphylaxis trigger.⁸ In another study, anaphylaxis was reported in 2 adult patients among 34 allogeneic HSCT applications. One patient underwent BMT with fresh transplant product, and the other had CBT with cryopreservation using DMSO and dextran. Passive-immune basophil activation test (pi-BAT) performed on both cases with HSCT products were positive, but pi-BAT performed for DMSO and dextran was negative. Therefore, anaphylaxis in both adult cases was attributed to HSCT products.⁹

Indeed, in a previous study from Ikeda and colleagues, all ARs were more common in allogeneic BMTs without cryopreservation products.³ Therefore, it was suggested that alloantigens could also be responsible for ARs. However, although ARs that occur during HSCT are often associated with DMSO in many publications, this has not yet been demonstrated in any test to our knowledge.² In our study, we associated anaphylaxis with DMSO in both cases. Because of the ongoing immunosuppression in our case 1 and the lack of consent from the family in case 2, neither in vivo nor in vitro allergy tests could be performed for DMSO.

To prevent ARs that may occur with DMSO, a different cryoprotective agent can be used, premedication can be applied, the concentration of DMSO in the product can be reduced, and DMSO removal can be performed from the transplant product before infusion.² We were able to perform the HSCT without removing DMSO by modifying the premedication protocol in our first case. However, in the second case, we were unable to complete the HSCT due to the patient having a seizure, despite modifying the premedication and removing DMSO. We believed that we could not remove DMSO sufficiently in our case due to this neurotoxicity.

Anaphylaxis has been reported during HSCT in 2 adult cases and 1 pediatric case, specifically as-sociated with bovine serum albumin, bovine DNase, and dextran, with the exception of DMSO.^10-12 In addition to these, there are case reports of anaphylaxis during the use of HES, another cryoprotective agent, as a volume expander, but no anaphylaxis report was encountered with its use in cryopreservation.¹³

Anaphylaxis can occur as a result of HSCT, and the diagnosis of anaphylaxis is primarily clinical, based on the patient's symptoms and/or findings. Demonstrating an elevation in tryptase level during anaphylaxis supports the diagnosis. Although HSCT-induced anaphylaxis is often associated with DMSO, so far, there are no standardized in vivo or in vitro tests to definitively determine the trigger. In addition, the efficacy of preventive methods (such as reducing DMSO concentration, DMSO removal, and using a different cryoprotective agent) is still a matter of debate, even in cases where anaphylaxis is associated with DMSO. Future studies are needed that focus on reducing allergenicity without compromising the quality of the transplant product in this field.

Volume: 22 Issue: 6 June 2024

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