Optimizing pediatric peripheral blood stem cell collection.

INTRODUCTION: Pediatric PBSC harvests pose specific challenges during apheresis and a knowledge of the same and variables affecting PBSC collection are very important in planning these procedures. In the present study safety profile of pediatric PBSC procedures and variables influencing the successful collection were analyzed. METHOD: Pediatric PBSC harvest data for 3 years was reviewed for donor, procedural and product parameters and any specific challenges faced during the procedures. Successful PBSC collection was defined when CD34 dose obtained was ≥2 × 106 cells/Kg of recipients' body weight. RESULTS: 85 PBSC collections performed on 46 children (age range 1.5-15 years) were included. Sixty-two procedures were on autologous donors and 23 on allogenic donors. The median CD34+ cell dose in the PBSC product per procedure was 2.12 × 106 cells/Kg for autologous procedures and 4.6 × 106 cells/Kg for allogenic procedures. Systemic adverse reaction was observed during only one procedure (0.01 %) and was managed conservatively. Successful dose was collected in 52 procedures (61.17 %) and was significantly associated with CD34+ count of more than 19.7/µL, monocyte count of more than 1.65 × 106/µL, allogenic collection and female gender (p = 0.00001, p = 0.011, p = 0.00052, and p = 0.0001, respectively). CONCLUSION: PBSC collection is safe in pediatric age groups and pre-procedure CD34 count of ≥20/µL on the day of collection may result in successful collection of stem cell dose. It is important to identify factors associated with failed collection for appropriate counselling and justifying pre-emptive use of stem cell mobilizing agents.

Red cell antibodies resulting in false-positive complement-dependent cytotoxicity cross-match: A unique case.

A false-positive complement-dependent cytotoxicity cross-match (CDC XM) has a negative impact in donor selection process obliterating healthy, donor compatible population. A 47-year-old male with chronic kidney disease was planned for ABO-compatible renal transplantation from his sister. CDC and donor-specific antibody (DSA) lysate XM were negative 10 days before transplant. The pretransplant CDC XM showed 40% positivity. DSA lysate XM and HLA antibody screen were negative. Patient's Indirect antiglobulin test (IAT) was positive and anti-M antibody (IgG + IgM) was identified. Therapeutic plasma exchange, intravenous immunoglobulin, and rituximab were used for desensitization. Decrease in positivity of CDC XM and anti-M titer was seen. The transplant was performed successfully. Red cell alloantibody should be considered in differential diagnosis of a positive CDC XM. The utility of DSA lysate XM as a pretransplant monitoring tool is immense in such situations. Institutional policies regarding plan of action in the event of positive CDC XM and negative DSA lysate XM and vice versa should be formed.

Anti-M antibodies: Biphasic (reactive at room temperature and at 37°C): A case series.

Anti-M antibody, which is not reactive at 37°C, is not clinically significant. Reports of clinically significant anti-M antibodies causing hemolytic disease of the fetus and the newborn (HDFN) and delayed hemolytic transfusion reaction (DHTR) are available. We report 13 cases of anti-M antibodies reactive at room temperature (RT) and at 37°C. These were found in patients of varied age groups (11 months to 85 years) with varied clinical diagnosis. All the female patients were multigravida. In all cases, antibody screening was positive at RT as well as at the indirect antiglobulin test (IAT) phase. Providing "M"-antigen negative transfusions is the best therapy in this situation. Provision of red blood cell (RBC) antigen phenotyped donor registry shall ensure quick provision of antigen-negative blood for transfusion in emergency situations.