High-dose therapy and autologous stem cell transplantation in patients with diffuse large B-cell lymphoma in first complete or partial remission.

Improved survival has been observed in poor-risk diffuse large B-cell lymphoma (DLBCL) patients treated with high-dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) in first complete remission. Retrospective studies have suggested that HDT with ASCT can improve survival also in partial responders but some doubts about the advantage of intensive therapy in such patients still remain. We evaluated retrospectively the results of HDT and ASCT in 55 patients with confirmed DLBCL treated between May 1999 and July 2006. Thirty-six patients (65%) showed partial remission (PR) and 19 patients (35%) reached complete remission (CR) after induction treatment with (44%) or without (56%) concomitant rituximab (R) immunotherapy. After HDT and ASCT, 69% of patients fulfilled the criteria of CR, 22% had unconfirmed CR (CRu), 7% remained in PR and 1 patient (2%) relapsed. Twenty patients in PR after the induction treatment reached CR after ASCT, 12 other PR patients achieved CRu. The 5-year event-free survival (EFS) of the 55 transplanted patients was 76% (95% confidence interval /CI/, 63% to 89%) and the 5-year overall survival (OS) was 85% (95% CI, 73% to 97%). The EFS and OS rates differed significantly only between patients younger than 40 years and older groups (p=0.022 and p=0.046, respectively). On univariate analysis of prognostic factors, EFS and OS were not affected by any of the following: age, sex, stage, subtype of DLBCL, initial lactate dehydrogenase, beta-2-microglobulin and serum thymidine kinase levels, International Prognostic Index (IPI) and age-adjusted IPI scores, induction treatment with or without rituximab and type of primary therapeutic response (CR vs PR). These results show that first-line HDT and ASCT for adults up to the age of 65 years with poor-risk DLBCL is a feasible and effective treatment option even in the era of R-chemotherapy in CR as well as for patients in PR.

Presence of cytochrome P450 enzymes in human CD34+ haematopoietic progenitor cells.

Human CD34+ cells (haematopoietic stem and progenitor cells separated from peripheral blood) were shown to express CYP2E1 protein by Western blotting. For the first time, the specific CYP2E1 activity (chlorzoxazone 6-hydroxylation) was also detected. No CYP3A4 protein neither the CYP3A-specific nifedipine oxidase activity were detectable. The results obtained indicate differences in content of active CYP proteins in populations of stem and progenitor cells from different species as the CYP3A2 (a rat form similar to human CYP3A4) was shown to be expressed in bone marrow derived cells by RT-PCR (Avital et al. 2001).

Polymerase chain reaction detection of cells carrying t(14;18) in bone marrow of patients with follicular and diffuse large B-cell lymphoma: the importance of analysis at diagnosis and significance of long-term follow-up.

The t(14;18) is the most frequent chromosomal aberration observed in follicular lymphoma (FL), and is less frequent in diffuse large cell lymphoma (DLCL). The bcl-2/IgH rearrangement constitutes good target for polymerase chain reaction (PCR) detection that allows to find out one tumor cell in 100,000 normal cells. The PCR assay was used to detect bcl-2-rearranged cells in blood and bone marrow (BM) in 63 previously untreated patients with DLCL and in 53 patients with FL. Twenty five FL patients (47%) and 9 DLCL patients (14%) had PCR-detectable lymphoma cells in BM and peripheral blood. Minimal residual disease (MRD) was evaluated in 17 FL and 5 DLCL patients undergoing first-line chemotherapy. Three DLCL patients (60%) but only 1 FL (6%) patient achieved molecular response (PCR-negative status in BM). Two PCR bcl-2/IgH positive patients with FL were treated with rituximab (anti-CD20 antibody) and had no PCR-detectable lymphoma cells in BM after the therapy. Peripheral blood stem cells (PBSC) were harvested in 5 FL (1 PCR-negative) and in 2 DLCL (1 PCR-negative) patients. PCR-positive lymphoma cells contamined PBSC in all patients with BM PCR-positivity before harvesting. Five FL patients underwent autologous transplantation (AT). No bcl-2/IgH positive cells were detected in 4 patients (80%) at any point after AT. One patient achieved molecular response after rituximab treatment. All the patients are in CR 6, 22, 30, 31 and 42 months respectively, after AT. On the other hand, 4 FL patients in clinical complete remission, but with persistent PCR positivity in BM relapsed with median of 21 months (interval, 14-28 months) from the end of a first-line chemotherapy. Thus, the results show that PCR detection of the bcl-2/IgH rearrangement is a very useful method in evaluating the BM infiltration by lymphoma cells especially in the situation of MRD. Conventional chemotherapy did not eradicate bcl-2 positive cells in BM in most of lymphoma patients, but autologous transplantation or rituximab immunotherapy can induce molecular response in a significant proportion of them. Our results support the previous observations of the molecular response importance in view of better disease free and probably also overall survival.