Agreements and uncertainties in autologous haematopoietic stem cell mobilization and collection. A Spanish consensus document.

Although many experts position statements on autologous stem cell mobilization have been published, there are some aspects that are still under discussion. A Spanish Hematologist expert group was summoned to settle on agreements and uncertainties on PBSCs mobilization, including factors not always considered; as apheresis and cytometry key factors that determine a successful PBSC collection. This document reviews critical factors that define poor mobilizer patients and the tools to better collect the desired stem cells for a successful autologous haematopoietic stem cell transplant.

Guillain-Barré syndrome associated with cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation.

The association between cytomegalovirus (CMV) infection and the development of Guillain-Barré syndrome (GBS) in the setting of allogeneic hematopoietic stem cell transplantation (alloSCT) has been reported only occasionally. We describe here a 23-year-old patient diagnosed with acute myelogenous leukemia who underwent a partially HLA-mismatched alloSCT and soon after developed GBS along with a CMV infection. Serum autoantibodies to several ganglioside antigens were concomitantly detected. Despite therapy with ganciclovir and plasma exchanges, the patient's clinical condition rapidly deteriorated, and he died 3 weeks later with persisting CMV antigenemia. Although a coincidental association cannot be excluded, it could be speculated that a pathogenetic link exists between the 2 disorders. In this sense, molecular mimicry between viral antigens and neural host tissues could be postulated as the hypothetical mechanism underlying the triggering of the autoimmune disease in the present case.

Impact of different strategies of second-line stem cell harvest on the outcome of autologous transplantation in poor peripheral blood stem cell mobilizers.

The optimal approach to obtain an adequate graft for transplantation in patients with poor peripheral blood stem cell (PBSC) mobilization remains unclear. We retrospectively assessed the impact of different strategies of second-line stem cell harvest on the transplantation outcome of patients who failed PBSC mobilization in our institution. Such patients were distributed into three groups: those who proceeded to steady-state bone marrow (BM) collection (group A, n = 34); those who underwent second PBSC mobilization (group B, n = 41); those in whom no further harvesting was carried out (group C, n = 30). PBSC harvest yielded significantly more CD34+ cells than BM collection. Autologous transplantation was performed in 30, 23 and 11 patients from groups A, B and C, respectively. Engraftment data and transplantation outcome did not differ significantly between groups A and C. By contrast, group B patients had a faster neutrophil recovery, required less platelet transfusions and experienced less transplant-related morbidity, as reflected by lower antibiotics needs and shorter hospital stays. In conclusion, remobilization of PBSC constitutes an effective approach to ensure a rapid hematopoietic engraftment and a safe transplantation procedure for poor mobilizers, whereas unprimed BM harvest does not provide any clinical benefit in this setting.

Prophylaxis of early bacterial infections after autologous peripheral blood stem cell transplantation (PBSCT): a matched-pair study comparing oral fluoroquinolones and intravenous piperacillin-tazobactam.

The safety and efficacy of early bacterial prophylaxis with piperacillin-tazobactam were prospectively evaluated in 51 autologous peripheral blood stem cell transplantation (PBSCT) recipients. The results were compared with those obtained in 51 control patients receiving oral fluoroquinolones in a retrospective matched-pair control study. Overall, 76% of the study group and 98% of the control group developed at least one febrile episode during neutropenia (P=0.002). Time from neutropenia to the first febrile episode (FFE) was significantly longer in the study group than in the control group (P=0.04). Once a febrile episode appeared, the duration of fever was significantly longer in cases than in controls (median of 5 and 2 days respectively, P<0.001), and led to a more frequent use of empirical amphotericin B (AmB), not statistically significant (P=0.13). However, the total time of antibiotic administration was significantly greater in the control than in the study group (P=0.05). The duration of AmB treatment shows a trend toward a longer duration in the control than in study group (P=0.2). Overall, 86% of the Gram-positive bacteremia and 85% of the Gram-negative bacteria were susceptible to the tested antibiotics. Our study suggests that a subgroup of patients could benefit from prophylaxis with piperacillin-tazobactam without increasing toxicity or bacterial resistance.