Cryopreservation of rare pediatric red blood cells for support following bone marrow transplant.

BACKGROUND: A 2-year-old, 10.8 kg male pediatric patient with X-linked chronic granulomatous disease (CGD) with McLeod syndrome (MLS) was scheduled for a hematopoietic stem cell transplant (HSCT). Identification of allogenic red blood cells (RBC) for post-transplant support was unsuccessful prompting the development of a customized method to collect and freeze rare autologous pediatric cells. STUDY DESIGN AND METHODS: A protocol was developed for the collection of small volume pediatric whole blood (WB) via peripheral venipuncture with collection into 10 ml syringes containing anticoagulants. Additionally, a closed system RBC glycerolization and deglycerolization instrument was adapted to process small volume, non-leukoreduced WB. Both collection and WB processes were validated. In total 4 approximately 100 ml autologous units were collected and frozen. Two units were thawed, deglycerolized, and used for clinical transfusion support. To appreciate processing impacts on RBC rigidity, ektacytometry was performed on pre-processed and post-deglycerolization samples. RESULTS: Free hemoglobin (HGB) of validation units after thawing/deglycerolization was <150 mg/dL with an average red cell recovery of 85%. These units also showed little difference between pre-and post-processing Lorrca deformability curves or membrane rigidity. Two pediatric units were thawed and deglycerolized for transfusion. Free HGB was 70 mg/dL and 50 mg/dL post-thaw, and these RBCs had a slight decrease in deformability and increased membrane rigidity. DISCUSSION: Customized WB collection, glycerolization, freezing, and deglycerolization processes were developed to successfully support a pediatric patient with CGD and MLS after autologous HSCT. Both pediatric units showed increased membrane rigidity post-deglycerolization which may be a consequence of the CGD and MLS genetic background.

Chronic granulomatous disease and McLeod syndrome: Stem cell transplant and transfusion support in a 2-year-old patient-a case report.

Chronic granulomatous disease (CGD) with McLeod neuroacanthocytosis syndrome (MLS) is a contiguous gene deletion disorder characterized by defective phagocytic function and decreased Kell antigen expression. CGD cure is achieved through hematopoietic stem cell transplant (HSCT) usually in the peri-pubescent years. The presence of MLS makes peri-transfusion support complex, however. Herein, we present the youngest known case of HSCT for CGD in the setting of MLS. A 2-year-old male patient was diagnosed with CGD plus MLS. Due to the severity of the child's systemic fungal infection at diagnosis, HSCT was deemed the best treatment option despite his small size and age. A related, matched donor was available, and a unique red blood cell support plan had been implemented. Reduced-intensity conditioning was used to reduce the transplant-related mortality risk associated with myeloablative protocols. The transplant course was uneventful; autologous red blood cell (RBC) transfusion support was successful and allowed for the avoidance of possible antibody formation if allogeneic units had been used. The patient achieved 1-year relapse-free survival. The developed protocols provide a viable path to transplant in the very young, and early transplant to cure could reduce disease-related morbidity.