s of the 15th International Symposium on Infections in the Immunocompromised Host S17 Conclusions: The results demonstrate that, despite the generally naive CB lymphocytes, influenza HA-specific responses can be generated ex vivo and could be potentially be used to enhance immune reconstitution following allogeneic stem cell transplantation. 37 Harvest and Preparation Techniques of the Blood Stem Cells Dorel Vlad1, Carmen Calugaroiu1, Virginia Mirea1, Ramona Pasare1, Tatiana Puscariu2, Alexandra Dumitrescu2, Jeni Laura Vlad3, Simona Dima4, Irinel Popescu4. 1Transfusions and Medullar Graft Centre, 2Analysis Laboratory Central; 3Microbiology Department; 4General Surgery and Liver Transplantation Centre, Fundeni Clinical Institute Bucharest, Romania Background: The purpose of the study was to obtain a quality graft, which contained the minimum of 2.5x106/kg body stem cells CD34 viable and functional. Objectives: The principle was to base the separation of blood cells using the difference between density gradients. We compared the harvests on patients with: Hodgkin disease, multiple myloma, neuroblastoma, Ewing sarcoma, malignant non-Hodgkins lymphoma, and acute leukemia. Material and Methods: The study was undertaken between 2000 till November 2007 on 116 patients (97 patients and 19 donators) in the Medullar Graft and Transfusions Centre, collaborating with another department from Fundeni Clinical Institute. The total numbers of procedures was 188 (159 patients and 29 donators). The harvest of peripheral blood stem cells were made by: medullar aspiring puncture, citaferesys procedure, and/or umbilical vein puncture, after expelling the afterbirth from uterus. We used devices such as: Haemonetics MCS Plus and Cobe Spectra, and for harvests made for liver and pancreatic transplantation the Clinimacs Plus device system. Results: In the case of harvests for patients with hematological problems, we obtained 42 grafts CD34 5x106/KgC. For patients with diabetes, we obtained 2 grafts CD34 >5x106/KgC. For patients with liver problems we obtained 4 grafts CD34 500/mL on three consecutive measurements. Time to platelet engraftment (PLT_20) was defined as the number of days from stem cell infusion to date of maintaining platelet count (PLT) >20,000/mL for 3 consecutive measurements without any platelet transfusion for at least 7 days from the date of last PLT transfusion. Statistical analysis was done using Fisher' s exact test and the Wilcoxon rank sum test. Results: Thirty-five cases were compared to 35 controls. Demographics and transplant characteristics were similar between cases and controls. The median duration of treatment was 13 days for linezolid (range 5-28) and 18 days for vancomycin (6-43). The cumulative percentage of patients achieving ANC_500 and PLT_20 at each time point examined was similar for the two treatments groups. The p-values from the competing risk analysis were not significant (P=NS). The competing regression model confirmed this conclusion after adjustment for factors know to affect engraftment. WBC, ANC and PLT counts at 30 days after discontinuing treatment were similar between the two groups. Conclusions: Early linezolid administration did not have a negative impact on time to neutrophil or platelet engraftment post HSCT. Compared to controls cases had similar values of WBD, ANC and PLT 30 days after discontinuing treatment. A larger study is needed to validate our findings and assess the hematologic safety profile of linezolid in the period of greatest marrow vulnerability. 39 High Incidence of Human Herpesvirus 6 Reactivation in Adult Recipients of Double Cord Blood Transplants Vicky Kyriazi1, Eirini Grispou2, Aikaterini Manaka1, ConstantineGeorge Balotis1, Zoe Poulopoulou1, Eirini Bika1, Ioannis Baltadakis1, Dimitri Karakasis1, Mary Anagnostopoulou2, Ioannis Apostolidis1, Nicholas Harhalakis1, Olga Paniara2, Emmanuel NIikiforakis1. 1BMT Unit Evaggelismos Hospital, Athens Greece; 2Microbiology Laboratory, Evaggelismos Hospital, Athens Greece Introduction: Human herpesvirus 6 (HHV-6) reactivation may have significant consequences in cord blood transplant recipients (CBR). This study evaluates the incidence of HHV-6 reactivation, its manifestations and treatment in CBR at our center.