Abstract 5: Decontamination of Two Umbilical Cord Blood Grafts Prior to Autologous Administration

Abstract Introduction The contamination rate of umbilical cord blood (UCB) grafts is estimated to vary in public and family banking in the range of 3-10%, mostly by skin commensals which are not considered pathogenic. Contamination of grafts is not considered to be problematic when used in marrow transplant, with patients being already on a combination of broad-spectrum antibiotics; however the expanding use of cord blood for non-transplant procedures – mostly in neurology and regenerative medicine – brings this issue to the forefront. Objectives We aimed to decontaminate the UCB grafts prior to intravenous administration, while keeping stem cells viable. We report two different scenarios when the decontamination of cord blood grafts was successfully performed. Practically we have added antibiotic in order to achieve in the thawed and treated UCB (ttUCB) an antibiotic concentration approximately 10 times higher than MIC100; (minimal inhibitory concentration of the antibiotic in mg/L at which 100% of the bacteria treated are killed); available from literature for the specific geographical area of the patient. Methods In first case, pathogen identification with the respective antibiogram was done before cryogenation, allowing easier preparation by adding the known antibiotic to the decryogenated graft immediately after thawing and after correcting the graft osmolarity by adding dextrane and albumin according to the Rubinstein protocol. In the second situation, before cryogenation and storage, pathogen identification was performed but not antibiogram, so a sample of the cryogenated graft was used for antibiogram and confirmation blood culture before the graft was decryogenated. Results Cultures from ttUCB - both aerobic and anaerobic - were negative; CD34+ viability was 90%.The decontamination of cord blood grafts was successfully performed, with negative blood cultures and stem cell viability remaining around 90% and also clinical response recorded as improvement in levels of inflammation markers and patient functioning Discussion This work shows that decontamination of cord blood grafts can be safely performed after decryogenation and with good results, and the poster has details of the steps involved in the decontamination procedure used by us.