Pediatric apheresis with a novel apheresis device with electronic interface control

BACKGROUND: Cancer in children, and specifically cancer requiring autologous stem cell transplantation, is rare. As a consequence, though, experience with pediatric stem cell apheresis collections is limited. Challenges of apheresis in small children (<20 kg) include small total blood volume, issues with venous access, concerns about tolerable anticoagulant doses, and limitations in product volumes that can safely be collected. STUDY DESIGN AND METHODS: This article presents a small series of autologous “stem cell” apheresis procedures in infants and toddlers weighing between 5.5 and 20 kg, the first ones performed with a novel leukapheresis device (Spectra Optia MNC v.3.0, Terumo BCT) to be reported. Some features of the system are described that can be used to achieve favorable apheresis outcomes in small children. RESULTS: Apheresis procedures were uneventful and successful with similar extraction efficiencies (median preapheresis collection efficiency [CE2], 36%) as in adult patients. At 58%, platelet attrition was considerable. CONCLUSION: Our data indicate that stem cell apheresis with the Spectra Optia MNC v.3.0 in very small donors is feasible, safe, and associated with very small product volumes.     

Impaired natural killer cell function in hemophiliacs with or without continuous substitution

Summary In the present study, 28 hemophiliacs substituted continuously and 5 hemophiliacs who had received almost no blood products were investigated. Cells of OKT 3⁺, OKT 4⁺, and OKT 8⁺ subsets were counted. Percoll separated fractions of peripheral blood mononuclear cells were examined by morphological criteria and were tested for NK cell activity. We found that the NK cell activity of both groups of hemophiliacs was decreased on testing Ficoll separated cells or low density Percoll separated cells. Normal NK cell activity was found in medium density cells of hemophiliacs. Two possible explantations are discussed: first, the NK cell activity may be suppressed in hemophiliacs and secondly, there may be a block in maturation of NK cell activity. It is unlikely that chronic substitution by blood products counts for these alterations. The possible role of chronic infections is discussed.     

Perceptual learning in temporal discrimination: asymmetric cross-modal transfer from audition to vision

This study assessed possible cross-modal transfer effects of training in a temporal discrimination task from vision to audition as well as from audition to vision. We employed a pretest–training–post-test design including a control group that performed only the pretest and the post-test. Trained participants showed better discrimination performance with their trained interval than the control group. This training effect transferred to the other modality only for those participants who had been trained with auditory stimuli. The present study thus demonstrates for the first time that training on temporal discrimination within the auditory modality can transfer to the visual modality but not vice versa. This finding represents a novel illustration of auditory dominance in temporal processing and is consistent with the notion that time is primarily encoded in the auditory system.     

Recipients potentially infected with parvovirus B19 by red blood cell products

BACKGROUND: Since 2000, blood donor screening for parvovirus B19 (B19) by nucleic acid testing (NAT) at the Ulm Institute has been conducted 6 to 8 weeks postdonation, that is, after transfusion of cellular blood products, whereas at the Frankfurt Institute all donations are screened before releasing any blood product. In this study, we evaluated the infectivity of B19‐positive blood products in relation to the virus concentration in the transfused blood component. STUDY DESIGN AND METHODS: Recipients were classified into two groups (A, transfused with blood products with B19 virus load less than 10⁵ IU/mL; and B, transfused with blood products with B19 virus load greater than 10⁵ IU/mL). Phylogenetic analyses were done for B19 DNA–positive donor and recipient pairs in the variant VP‐1u genome region. All samples were investigated for immunoglobulin (Ig)M and IgG B19 antibodies. RESULTS: B19 DNA was detected in 9 of 18 recipients of red blood cells (RBCs) from Group B, whereas none of the 16 recipients of RBCs from Group A were positive for B19 DNA (p = 0.016). Phylogenetic analysis demonstrated identical genomic sequences between the donors and recipients. Because recipient B19 DNA and antibody results were not available before transfusion, we interpret our overall data to indicate equivocal evidence of B19 transmission by RBC transfusion. CONCLUSION: B19 transmission by cellular blood products correlates with the virus concentration and the concentration of neutralizing antibodies. Thus, blood donor screening for B19 by minipool NAT should be done to supply at‐risk patients (e.g., immunosuppressed patients) with B19‐negative blood components.