CD79b expression in B cell chronic lymphocytic leukemia: its implication for minimal residual disease detection.

The surface expression of CD79b, using the monoclonal antibody (Mab) CB3-1, on B lymphocytes from normal individuals and patients with B cell chronic lymphocytic leukemia (CLL) has been analyzed using triple-staining cells for flow cytometry. In addition, the clinical significance of CD79b expression in CLL patients and its possible value for the evaluation of minimal residual disease (MRD) was explored. A total of 15 peripheral blood (PB) samples from healthy blood donors, five bone marrow (BM) samples from normal donors and 40 PB samples from CLL untreated patients were included in the study. In addition we studied the expression of CD79b in B lymphocytes from five CLL patients after fludarabine treatment in order to support our method. The expression of CD79b in B lymphocytes from PB was analyzed by flow cytometry, using simultaneous staining with the Mabs CD22, CD79b, CD19 and CD5, CD79b and CD19. Since normal immature bone marrow B cells are CD79b-/dim+ on their surface, in BM samples we used the combination CD45, CD79b and CD19 selecting mature B lymphocytes according to their bright CD45 intensity. Cell acquisition was performed in two consecutive steps using a live gate drawn on SSC/CD19+ cells. For data analysis, the PAINT-A-GATE PRO software (Becton Dickinson) was used. Dilution experiments of CD79b- CLL cells and CD79bdim+ CLL cells with normal PB and BM cells were performed in order to assess the sensitivity level of the technique for detection of CD79b-/dim+residual CLL cells. All B lymphocytes from normal samples showed reactivity for the CD79b antigen. In contrast, CD79b was absent in 18/40 CLL patients (42.5%) and 20/40 CLL cases (50%) exhibited a low CD79b expression. Therefore, CD79b- B lymphocytes would be restricted to the CLL population and thus could be considered a 'tumor phenotype' for monitoring MRD in CLL patients. Dilution experiments indicate that the detection limit with this marker almost reaches the levels obtained by molecular biology methods as the PCR technique. All cases studied after fludarabine presented leukemic cells in their PB or BM samples detected by flow cytometry. Upon comparing the clinical and morphological characteristics of CD79b- and CD79b+ cases, all atypical CLL cases included in the present study were CD79b+ and advanced clinical stage (B and C Binet stage) was most frequently observed in CD79b+ cases than in CD79b- cases.

Acute myeloid leukemia M2 and t(8;21)(q22;q22) with an unusual phenotype: myeloperoxidase (+), CD13 (-), CD14 (-), and CD33(-).

Cases of myeloid surface antigen-negative acute myeloid leukemia (AML) are rare. We describe the morphological, cytochemical, immunologic, and cytogenetic features of two patients with AML with maturation (FAB M2) and the phenotype MPO+, CD13 (-), CD33(-), CD56(+). Cytogenetic studies demonstrated t(8;21)(q22;q22). These findings suggest an association between the lack of CD13 and CD33 in myeloperoxidase-positive AML and the presence of t(8;21).

Umbilical cord blood banking for unrelated transplantation: evaluation of cell separation and storage methods.

Cost-efficient umbilical cord blood (UCB) banking requires well-standardized methods of volume reduction and storage. To compare UCB fractionation using a technique of hydroxyethyl starch (HES) sedimentation with the Ficoll (double) and Percoll methods, 50 whole units was allocated randomly to each procedure. HES resulted in a significantly better recovery of mononuclear cells (87.5%), granulocyte/macrophage colony-forming units (CFU-GM) (88.4%), and CD34- cells (87.4%) and lesser volume reduction (85.5%). HES was the least laborious, time consuming, and expensive of the three procedures, costing 3.4- and 4.4-fold less than the Ficoll and Percoll methods, respectively. Five units processed by each method was frozen in 4.5-mL cryotubes under optimal conditions. After thawing, the greatest degree of recovery of viable nucleated cells and number of CFU-GM per unit were obtained using the HES procedure. Using 4.5-mL cryotubes, the calculated number of units that could be stored in 600-L containers was 3.8- and 2.2-fold higher for Ficoll- and Percoll-separated than for HES-separated units, respectively. Nevertheless, the higher direct costs of the density gradient separation procedures outweighed their lower storage cost. For long-term cryopreservation, we assessed the freezing of HES-processed units in 50-mL cryobags and their specifically designed canisters. We found cell recoveries similar to those obtained with cryotubes, but storage capacity was decreased. Special racks designed for these canisters resulted in a 5-fold increase over the number of units stored in standard cryobags. This system also is feasible for Percoll- and Ficoll-separated units, resulting in comparable storage costs for the three separation methods. We conclude that this HES procedure and the 50-mL cryobags constitute a cost-efficient system for large-scale UCB banking.

Splenic peliosis with spontaneous splenic rupture in a patient with immune thrombocytopenia treated with danazol.

We present a 79-year-old man diagnosed with immune thrombocytopenia (ITP), treated with danazol, who died as a result of a spontaneously ruptured spleen. The histopathological diagnosis was splenic peliosis. This patient presents a chronological association between the treatment with danazol and the development of peliosis, which suggests a clear cause-effect relationship. Facing an individual patient with ITP, clinicians should weigh the potential benefits of danazol with the possible development of serious complications, such as hepatic failure or splenic rupture due to peliosis.

Detection of maternal DNA in umbilical cord blood by polymerase chain reaction amplification of minisatellite sequences.

One of the concerns about the use of cord blood as a source of hematopoietic stem cells for allogeneic transplantation is the possibility of contamination by maternal cells which could cause life-threatening GVHD. We have assessed cord blood contamination using PCR analysis of several minisatellite regions to detect maternal DNA. Eighty mother-cord pairs were obtained for this study. In one case there were no specific maternal alleles at any loci and, therefore, cord blood could not be evaluated. Thus, there was a total of 79 informative cases for the detection of maternal cells in the fetal circulation. In most cases, the level of detection was between 0.5 and 1%. We detected maternal DNA in the cord blood sample in only one case (1.26%), and the analysis of dilution experiments led to an estimate of 0.5-1% maternal cells. In conclusion, using PCR amplification of hypervariable regions, maternal DNA is very rarely detected in the cord blood collected at birth, although this approach has a relatively low level of sensitivity.

[Treatment with interferon alfa-2a in the chronic phase of Philadelphia-positive chronic myeloid leukemia]. / Tratamiento con interferón alfa-2a de la leucemia mieloide crónica Ph1 positiva en fase crónica.

PURPOSE: To evaluate the cytologic and cytogenetic response attained with interferon alpha-2a (IFN, Roferon*A) in patients with Ph '-positive chronic myelogenous leukaemia (CML) in the chronic phase. MATERIAL AND METHODS: A prospective study was carried out on 22 CML patients diagnosed in the Haematology Service at the Princesa Hospital in Madrid. The therapeutic regime consisted of two phases: A) Hydroxyurea was given until the white-cell count was reduced to 15-20 x 10(9)/L. B) Roferon*A was then given subcutaneously at a doses of 5 MU/m2 per day. The follow-up was performed weekly, and monthly once the leucocyte count had stabilized. The cytologic and cytogenetic response was assessed by bone marrow aspiration performed after 6, 9, 12 and 18 months. The toxicity was evaluated in accordance with the WHO recommendations. RESULTS: The median follow-up is 263 days (21-930). Thirteen patients (65%) had initial complete haematological response and 3 (15%) had partial response. The mean time to achieve response was 42 days (0-321). In the last evaluation, 69% of the patients were in sustained haematological remission (53% complete and 16% partial) with median follow-up of 232 days (21-930). The cytogenetic response was evaluable in 13 patients (follow up > or = 6 months): three attained complete response (23%) and three others partial response (23%). The commonest untoward effects were hypertriglyceridaemia (100%) and myelosuppression (86%). Grade-III thrombocytopenia was seen in 19% of the patients and grade-III anaemia or leucopenia in 5%. No infectious or haemorrhagic complications have appeared. Therapy was discontinued in 3 patients (14%), two due to severe flu-like syndrome and one for parkinsonism after 809 days of treatment. At the moment of evaluation two patients had died, one in lymphoid blastic crisis on day 217 and the other in the immediate post-BMT period. CONCLUSION: Treatment with interferon-alpha 2A is useful in the chronic phase of CML. An important number of responses can be attained, even in patients in the late chronic phase, and the toxicity seems acceptable.

Allogeneic bone marrow transplantation for high risk acute lymphoblastic leukemia. Results from a single institution.

We present our experience with bone marrow transplantation (BMT) in 30 consecutive patients with high risk acute lymphoblastic leukemia. With a median follow-up of 4 years the disease-free survival (DFS) was 44% for the whole group, with a significant difference between patients in first or second complete remission (CR 1 and 2, as one group), compared with patients with more advanced disease (greater than CR2), 69.5% versus 15.4% (p less than 0.01). The main cause of BMT failure was leukemic relapse, with a relapse rate of 15% for patients in CR 1 and 2 and of 77% for patients with greater than CR2 (p less than 0.01). Among patients with active disease at BMT those who had 15% blast cells or less in the marrow fared better than those with more advanced disease or extramedullary relapse. Transplant-related death was 17%. Graft-versus-host disease (GVHD) was associated with an antileukemic effect; the DFS for patients with acute and/or chronic GVHD was better than for patients with no GVHD at all.