Pediatric Sibling Donor Complications of Hematopoietic Stem Cell Collection: EBMT Pediatric Diseases Working Party Study.

The analysis of donor safety and early side effects related to hematopoietic stem cells (HSC) collection from bone marrow (BM) or peripheral blood (PB) in pediatric HLA-identical sibling donors.

From 2005 to 2009, data regarding pediatric (<18 years) sibling donors undergoing HSC collection from 38 participating EBMT Centers were registered on specific forms sent to the PDWP Office. Data were centrally analyzed as of July 2009. A multiple logistic regression was performed to express an estimate of the relative risk of BM versus PB donation for the following variables: pain, blood transfusion, prolonged hospital stay, and need for iron supplementation.

A total number of 410 pediatric sibling donors with median age of 9 (range; 0.3-18) years were enrolled into the study; including 12% aged <4 yrs and 64% with body weight <40 kg. Children donated BM in 272 (66%), and PB in 138 (34%) cases. The criteria used by transplant centers for PB-HSC collection in children were: discrepancy between donor and recipient body weight, parents decision, undergoing clinical trial (pediatric centers), or transplant protocol (adult centers). Consents for donation were given by parents (49%), court (23%), ethical committee (28%) or social board (0.4%). All BM and 56% of PB donors had general anesthesia (PB donors for central catheter placement), for a median 90 (range; 30-300) and 30 (range 8-285) minutes, respectively. One (0.2%) serious adverse event (SAE) was reported (pneumothorax+hydrothorax) after catheter placement for PB collection. Tachycardia, decrease of blood pressure, sore throat or vomiting after anesthesia occurred in 5-11% cases. Autologous blood transfusion was done in 26% of BM and 7% of PB donors, at median age of 12 years (range 2.8-18). Erythropoietin was administered in 23 BM donors. BM was collected in median volume 18.8 (range; 2-49) ml/kg of donor weight and no severe complications of BM collection were observed. G-CSF priming was performed in all PB donors with median G-CSF dose of 10 (range; 5-20) mcg/kg/day. Median WBC count before collection was 46 (range; 24-101) G/L. Muscle/bone pain, fever, headache, abdominal or back pain, nausea or vomiting related to G-SCF were reported only in 6% of PB donors. Median number of apheresis was 1 (range; 1-3), which lasted for a median of 4 (range; 2-8) hrs. 21% donors experienced hypocalcemia. Thrombocytopenia <70G/L occurred in 3% of PB donors, however platelet transfusion was not required in any case. Blood allotransfusion was done in 23% of BM and 2.6% of PB donors. Iron was supplemented in 73% of BM and 31% of PB donors (p<0.001). Pain after collection occurred in 64% of BM and 15% of PB donors (p<0.001) and persisted for median of 1 day (range; 1-21 for BM and 1-3 for PB donors, respectively). No infections or thrombotic events were reported. Median number of nights spent in hospital before collection was 1 (range; 0-14) for BM and 3 (range; 0-7) for PB donors; while after collection 1 (range; 0-7) for BM and 0 (range; 0-6) for PB donors (p<0.001). Donors felt helpful, happy and proud in most cases, irrespectively of stem cell source. They felt responsible for recipient in 58% of BM and 53% of PB of donors (ns). Willingness to donate again was expressed by 86% and 71% of the BM and PB of donors, respectively (p=0.007). In multiple logistic regression analysis following complications and risk factors were determined: pain (BM collection, OR=12.3, p<0.001; age >4 yrs, OR=9.9, p<0.001), blood allotransfusion (BM collection, OR=22.7, p<0.001; body weight <40 kg, OR=4, p=0.004), prolonged hospital stay (BM collection, OR=3.5, p<0.001), and need for iron supplementation (BM collection, OR=6.9, p<0.001).

BM or PB HSC collection in pediatric sibling donors is safe, however there is a risk of mild, short-term and easy to prevent or control early side effects. The risk of SAE in healthy pediatric donors exists, although it is small. Donors and parents must be informed about the risk of possible complication. There is a need of donor outcome and follow-up registry.

No relevant conflicts of interest to declare.