Autologous peripheral blood stem cell mobilization and apheresis in pediatric patients with cancer: A single-center report of 64 procedures

BACKGROUND

The published experience concerning autologous peripheral blood stem cell collection in children is very limited.

METHODS

The data of pediatric patients who underwent autologous stem cell mobilization and apheresis between January 2011 and April 2020 were analyzed retrospectively.

RESULTS

We studied retrospectively 64 mobilization and apheresis procedures in 48 pediatric patients (34 males, 14 females), mean age of 7.31 ± 5.38 (range, 1.5-19.7) years, the underlying disease was mostly neuroblastoma (NBL). The body weight of 21 patients (43.75%) was 15 kg or less. The targeted autologous peripheral stem cell apheresis (APSCA) was successfully achieved in 98% of patients. Neuroblastoma patients were younger than the rest of the patients and underwent apheresis after receiving fewer chemotherapy cycles than others and all of them mobilized within the first session successfully. Plerixafor was added to mobilization in nine heavily pretreated patients (18.7%), median two doses (range, 1-4 doses). 11 patients (22.9%) underwent radiotherapy (RT) before mobilization with doses of median 24 Gy (range, 10.8-54.0 Gy). Patients with RT were older at the time of apheresis and had received more chemotherapy courses than patients without RT. As a result, patients with a history of RT had significantly lower peripheral CD34+ cells and CD34+ yields than those without RT. In 17 patients (35.4%), 22 different complications were noted. The most common complications were catheter-related infections (n:10, 20.8%), followed by catheter-related thrombosis in eight patients (16.7%).

CONCLUSIONS

Patients who had far less therapy before apheresis were more likely to mobilize successfully. Our study provides a detailed practice approach including complications during APSCA aiming to increase the success rates of apheresis in transplantation centers.

Effective peripheral blood stem cell collection in a 4.6-kg child

BACKGROUND

Due to unique technical challenges, effective peripheral blood stem cell collections (PBSCs) have not been consistently reported in patients weighing less than 5 kg. We describe three PBSCs performed in a 4.6-kg child undergoing myeloablative chemotherapy for high-grade glioma.

STUDY DESIGN AND METHODS

A multidisciplinary group representing the clinical and apheresis teams adapted a PBSC protocol to accommodate the patient's size and collection targets. Special considerations included timing of the collection relative to chemotherapy, vascular access, strategies for monitoring adverse events during collection, and contingencies.

RESULTS AND DISCUSSION

The patient underwent three PBSC procedures over 2 days due to suboptimal collection after the first two procedures. For procedure 1, a conservative inlet: anticoagulant (AC) ratio and AC infusion rate of 15 and 0.6 mL/min/L total blood volume (TBV) resulted in premature discontinuation due to clotting. A ratio of 8 and AC infusion rate of 1.5-1.7 mL/min/L TBV with subsequent titration to higher levels were adopted for the second and third procedures. These changes resulted in greater acid-citrate-dextrose exposure, that was managed by continuous calcium chloride infusion. There was no hypocalcemia, hypotension, or distress during any procedure. A total of 15 × 106 CD34+ cells/kg were collected. This retrospective review illustrates that PBSC can be safely undertaken in children weighing less than 5 kg.

Peripheral blood stem cells collection by apheresis in very low-weight children with malignant diseases-A single center experience

BACKGROUND

Hematopoietic stem cell transplantation is used in the treatment of children with malignant and non-malignant diseases. However, apheresis of peripheral blood stem cells (PBSC) represents a challenge in children below 10 kg.

METHODS

A retrospective trial was conducted in the Cellular Therapy Department of Portuguese Oncology Institute of Porto.

INCLUSION CRITERIA

children with body weight inferior to 10 kg who underwent autologous PBSC apheresis until 2021. Demographic and clinical data were collected and our institutional protocol was described. COBE Spectra apheresis system (TerumoBCT, Lakewood, Colorado) until 2012 and then Spectra Optia (TerumoBCT) were used.

RESULTS

Sixteen leukocytaphereses were performed in 13 patients-nine females (69%). Mean age and weight were 13.31 months (±5.26) and 8.31 kg (±1.17), respectively. The initial CD34+ cells/μL in peripheral blood was 70.8 (±61.9). A central venous catheter (CVC) was exclusively used in all but one patient, in whom a peripheral vein was also required. In 10 procedures, both heparin and anticoagulant citrate dextrose solution-formula A (ACD-A) were used; in the remaining ones, only ACD-A was employed. The median duration of each procedure was 168 minutes (±45) and 2.96 blood volumes (±0.31) were processed. Median CD34+ cells yield per leukocytapheresis was 6.52 × 10⁶ /kg (±9.87 × 10⁶ ). CD34+ cell extraction rates were not significantly different between the two apheresis systems. Platelet and magnesium levels were significantly lower after collection (P < .001 and P = .009, respectively).

CONCLUSIONS

Although recommendations are lacking, we have successfully and safely performed leukocytaphereses in children with body weight below 10 kg. The authors believe that a permanent and dynamic comprehensive evaluation of each child is paramount for attaining good results.

Prevention of hypokalaemia and hypomagnesaemia following peripheral stem cell collection - a prospective cohort study

BACKGROUND AND OBJECTIVES

Citrate-based anticoagulation reduces plasma potassium and free magnesium in patients undergoing peripheral stem cell collections. Whether the effects may be mitigated by pre-procedure oral electrolyte supplements has not been previously assessed.

MATERIALS AND METHODS

Results from a historic cohort (2010-2013) guided a systematic prospective intervention in subjects deemed at risk for clinically meaningful hypokalaemia and hypomagnesaemia. From 2015 to 2019, 136 patients were enrolled in the study. Pre- and post-apheresis electrolyte levels were measured, and oral potassium and magnesium supplements were systematically administered based on the pre- electrolyte levels.

RESULTS

We saw a 37% absolute reduction in severe hypokalaemia and 39% absolute reduction in hypomagnesaemia in the prospective intervention cohort when compared to the historic cohort. Multivariate analyses indicated that part of the effect was due to the electrolyte intervention, while part of the effect likely stemmed from other procedure-related changes implemented during the study period.

CONCLUSION

Oral potassium and magnesium prophylaxis appear to reduce hypokalaemia and hypomagnesaemia following peripheral stem cell collection. Whether the effect size is sufficient to motivate the intervention warrants further investigation, preferably in a prospective randomized trial setting.