[Donor cell leukemia (DCL): A prospective study of its identification and treatment]. / Leucemia en células del donador (LCD): un estudio prospectivo de su identificación y tratamiento.

Donor-derived malignancies after allogeneic hematopoietic stem cell transplantation and after solid organ transplantation are considered as rare diseases. We have prospectively searched for donor cell leukemia in a 12-year period, in a single institution, in a group of 106 consecutive patients allografted because of leukemia. We have identified seven cases of donor cell leukemia; six were allografted because of relapsed acute lymphoblastic leukemia and one because of paroxysmal nocturnal hemoglobinuria/aplastic anemia. These figures suggest that the real incidence of donor cell leukemia has been underestimated. The six patients with lymphoblastic donor cell leukemia were treated prospectively with a pediatric-inspired combined chemotherapy schedule designed for de novo acute leukemia. A complete response was obtained in three out of six patients with lymphoblastic donor cell leukemia. It is possible to obtain favorable responses in donor cell leukemia patients employing combined chemotherapy. The long-term donor cell leukemia survivors remain as full chimeras and have not needed a second transplant.

Oral versus intravenous fludarabine as part of a reduced-intensity conditioning for allogeneic stem cell transplantation.

BACKGROUND: In 2003, oral fludarabine was introduced in the USA for the treatment of patients with hematologic malignancies as an alternative to its intravenous (i.v.) formulation; in 2008, it was introduced in México while the i.v. formulation was withdrawn. Accordingly, i.v. fludarabine had to be replaced by oral fludarabine as part of the conditioning regimen employed to conduct allogeneic stem cell transplantation in México. METHODS: Nonrandomized retrospective analysis of 55 patients conditioned with oral fludarabine compared with 113 patients conditioned with the i.v. formulation. In addition to fludarabine, the conditioning regimen included oral busulfan and i.v. cyclophosphamide. Donors were HLA-matched siblings. RESULTS: The clinical features of the two groups were comparable. There were no statistical differences in time to neutrophil engraftment, time to platelet engraftment, acute graft versus host disease rate and nonrelapse mortality at day 100. The overall survival of patients allografted with oral fludarabine was better than those allografted with i.v. fludarabine: 62 and 33% at 67 months, respectively (p = 0.0006). DISCUSSION: Oral fludarabine can replace its i.v. formulation as part of reduced-intensity conditioning regimens with no deleterious effect on any of the early transplantation outcomes.

Poor performance of the total kappa/lambda light chain quantification in the diagnosis and follow-up of patients with multiple myeloma.

BACKGROUND: The gold standard for paraproteinemia screening in plasma cell disorders has been serum protein electro- phoresis (SPE) with immunofixation electrophoresis (IFx); serum total and free light chain quantifications have also been used. OBJECTIVE: To define the role of SPE, IFx and serum total light chain (sLC) determinations in patients with multiple myeloma (MM), both at diagnosis and at maximum response during treatment follow-up. MATERIAL AND METHODS: These serological studies were performed in a group of 62 patients with MM at diagnosis, and in a subset of 29 patients at the point of maximum response to treatment. RESULTS: At diagnosis, we found an abnormal SPE in 58%, an abnormal IFx in 92% and an abnormal sLC in 45% of the 62 patients; 64% had simultaneously abnormal results in all three serological studies. IFx alone proved to be the most sensitive of all three assays, followed by SPE, which was redundant in most instances with sLC and IFx. At maximum response, the abnormal SPE normalized in 7 cases, the abnormal IFx in 7 cases and the abnormal sLC in 7 cases. There were 12 instances in which an abnormal IFx was found despite normal sLC, and one case in which a normal IFx was found in the presence of abnormal sLC. The association between IFx and sLC was highly significant (r = 0.9274611, p < 0.000001), despite instances where a positive result for IFx was associated to a normal sLC. CONCLUSION: All three serological methods should ideally be simultaneously performed in patients with MM both at diagnosis and throughout therapy. In this series, the total sLC assay was not more sensitive than IFx neither at diagnosis nor during follow-up.