Hematology and cell therapy最新文献

There is evidence indicating that autoreactive B cells constitute a substantial part of the B-cell repertoire. This autoreactive repertoire secrete the so called natural autoantibodies characterized by their broad reactivity mainly directed against very well conserved public epitopes. They fulfill the definition of an autoantibody since they are self-reactive, but they are not self-specific. As yet, NAA directed against determinants of polymorphism have not been reported. Their germinal origin is suggested by their early appearance during ontogeny, their expression of cross-reactive idiotopes and structural studies of their sequence. As for the physiological role of the repertoire, we can assume that it may play a major role as a first barrier of defense. It is presently unknown whether these polyreactive B cells could constitute a pre-immune template which through an antigen driven process may be involved in the production of immune high affinity antibodies. This autoreactive B cell repertoire frequently undergoes malignant transformation, although there is controversy concerning the reasons accounting for this. It has been postulated that the continuous challenge of this autoreactive repertoire by self-antigens could create propitious conditions for malignant transformation to occur. However, it can be alternatively postulated, that overexpression of certain genes reflect what happens during ontogeny, since V genes expression is a developmentally regulated phenomenon and not all V genes are expressed during fetal life. Some of the genes that are recurrently expressed by these malignancies are also over-expressed in fetal repertoires and even in the adult normal B cell repertoire. We do not know whether it is the challenge by self-antigens or whether alternatively this over-expression simply reflects what happens with the fetal repertoire which could have selective advantages for malignization.

A new automated erythrocyte sedimentation rate (ESR) system, the SEDISYSTEM was evaluated for its stability and accuracy. It offers automated mixing of vacuum-collected blood for 5 minutes (min) and reading of the ESR for 20 min to generate values comparable with those of the Westergren method at 1 hour (h) and 2 h. The benefits are (1) simplified procedure, (2) reduction of biohazard and, (3) shortening of examination time. To evaluate the basic performance of this system, the stability of ESR values was first evaluated by keeping samples at room temperature for up to 20 h, during which time no remarkable change was observed. Next, a comparison between this system and the standard method of Westergren was conducted and good agreement was obtained. To determine the factors affecting ESR values, correlations were analyzed between the ESR obtained by SEDISYSTEM and the standard Westergren method for red blood cell concentration, hematocrit, and plasma proteins including fibrinogen, albumin and globulins (alpha1, alpha2, beta and gamma). Multiple regression analysis showed significant correlation with RBC, fibrinogen and gamma globulin. It is concluded from these results that SEDISYSTEM is a useful new tool for the measurement of ESR.

This review attempts 1) to enonciate recent observations made on the effects of phorbol esters on megakaryocyte cell lines, 2) to examine these effects taking into account megakaryocytopoiesis in vivo and 3) to demonstrate that phorbol esters stimulated megakaryocyte cell lines provide a good model to study the mechanisms governing megakaryocyte maturation.

There is increasing interest in dendritic cells (DC) that are capable of initiating antitumor immune responses. An in vitro cell differentiation method has recently been developed that uses GM-CSF and IL-4 to generate human DC from adherent blood mononuclear cells cultured on tissue culture plastic. These cells are competent for antigen uptake but express relatively low levels of co-stimulatory molecules and thus correspond to immature resident tissue DC. We have adapted this method to consider some variables that are pertinent to clinical use, including a large scale differentiation of functional DC in a culture system suitable for clinical use. We report here that sizable numbers of monocytes purified by elutriation from blood leukocytes and cultured in Teflon bags develop with high efficiency into typical DC, as defined by morphology and membrane phenotype. When compared with usual adherent DC, cells generated under our adherent-free conditions exhibited lower CD1a expression and antigen capture capacity, but maintained the ability to present soluble antigens to T cells. They neoexpressed a high level of the co-stimulator molecule B7-2 (CD86) and was potent accessory cells for T cell proliferation, but they lacked the CD83 marker of DC full maturation. This study may constitute a prerequisite step for clinical investigations in tumor immunotherapy.

Hepatitis due to Herpes Simplex Virus (HSV) is a rare and severe infection in patients with impaired immunity, as bone marrow transplanted. The antemortem diagnosis is often difficult to establish because the clinical features are nonspecific. We report an uncommon cause of fulminant hepatic failure in a neutropenic patient, 14 days after bone marrow transplantation. HSV-2 fulminant hepatitis occurred during acyclovir prophylactic treatment. No observation of HSV hepatitis in this context has been reported since prophylaxis is used. Because of the extremely high apparent mortality associated with HSV hepatitis, and the improved survival noted among the non-marrow-transplant recipients and prolonged survival seen in one marrow transplant recipient, it seems reasonable to urge early and aggressively acyclovir therapy. A liver biopsy seems to be indispensable in the case of hepatic failure in post-marrow-transplantation in order to make rapidly a diagnosis.

Because recent reports have suggested that non plasmacytic tumor B cells are very rare in Multiple Myeloma (MM), we tried to characterize the B lineage in this disease by comparing by flow cytometry in the PB and BM of MM patients and of controls the proliferative activity (BrdU incorporation) and the Bcl-2 expression of different B cell subsets defined by cytoplasmic light chain, CD19 or CD10 antigen expression. The labelling indices (LI) of CD19+ and CD10+ BM cells in treated patients were higher than in controls and untreated patients. Plasma cell LI (PCLI) were close to previously published values of PCLI flow assays and did not correlate with the LI of BM B cells. Bcl-2 expression by BM CD19+ and CD10+ cells in patients was inferior to controls. These results agree with previously published data about the likely polyclonal nature of most pre PC B cells in MM.

We studied platelet recovery in relation to graft content in CFUs and CD34+ cells in 31 patients with multiple myeloma (21) or non-Hodgkin lymphoma (10) receiving marrow-ablative therapy followed by autologous transplantation with G-CSF mobilized CD34+ cells purified from leukapheresis products. Twelve patients had prolonged post-transplantation thrombopenia (> or = 14 days): their graft contents in CD34+ cells, CFU-GM and BFU-E were significantly inferior to those of patients with rapid platelet recovery. Although numbers of infused CD34+ cells and CFU-GM or BFU-E were well correlated, the graft content in CD34+ cells was the only parameter predictive of platelet recovery (r = -0.38, p = 0.04), with a threshold of 2.5 x 10(6) CD34+ cells/kg. However, because rapid platelet reconstitution was obtained for 4 of 16 patients re-infused with < 2.5 x 10(6) CD34+ cells/kg, we investigated whether the graft CFU-MK content might be a better predictor of platelet reconstitution than the CD34+ cell content. Eighteen CD34 grafts were studied for CFU-MK content: CD34 and CFU-MK contents were weakly correlated (r = 0.52, p = 0.03), but there was no correlation between numbers of infused CFU-MK and time to platelet recovery. We conclude that, for autologous CD34 grafts, CFU-MK assays, like CFU-GM or BFU-E assays, cannot be used to predict platelet recovery. A CD34+ cell content > or = 2.5 x 10(6)/kg remains the only reliable indicator of the platelet reconstitution capacity of a CD34 graft.

A variety of T, B and natural killer (NK) cell subsets defined by surface markers were analyzed by double immunofluorescence flow cytometry in the peripheral blood of patients following autologous bone marrow transplantation (ABMT, n = 14), autologous peripheral blood stem cell transplantation (PBSCT, n = 10) and allogeneic bone marrow transplantation (allo-BMT, n = 6). Patients following ABMT were divided in 2 groups, those who did not received G-CSF post-transplant (ABMT, n = 6) and those who did (ABMT + G, n = 8). All patients following PBSCT or allo BMT received G-CSF. In all the groups prolonged significant decreases with respect to normal numbers were observed for the T CD3+, CD2+ and CD25+ subsets, more profound for the CD4+ subset but less for the CD8+ subset, especially following PBSCT (only decreased at 1 month). A significant expansion of the CD3+CD57+ and CD8+CD57+ phenotypes was noticed between 9 and 12 months following ABMT, the group of longer follow-up. Long-lasting expansion of the NK-like CD3+CD56+ and CD3+CD16+ subsets was also observed. The B CD19+ and CD20+ subsets had a significant overexpression from 4 months after ABMT, showing a normally balanced Igk+:Ig1+ ratio. Concordantly, the HLA-DR+ and HLA-DQ+ subsets showed significant increases. The NK CD56+ and CD16+ subsets had a faster recovery than the T or B subsets in all the groups. However, the CD3-CD56+, CD3-CD16+, CD16+CD56+, CD3-CD8+, and especially the CD3-CD57+, CD16+CD57+, and CD56+CD57+ subsets had a slower recovery than the global CD56+, CD16+, or CD57+ subsets. The biological and clinical implications of these findings are discussed.

We report on two cases of central nervous system (CNS) relapse after high-dose chemotherapy and autologous stem cell transplantation. A 55-year-old man received two courses of vincristin, doxorubicin and dexamethasone (VAD) as an induction treatment for stage IIIB IgG kappa multiple myeloma. Bone marrow stem cell collection was performed after a high-dose melphalan (HDM) course (140 mg/m2). Autologous bone marrow transplantation (ABMT) was performed with this cryo-preserved unpurged bone marrow sample after a second HDM course. Three months after ABMT, the patient presented with signs of central nervous involvement with plasma cells and monoclonal IgG kappa in the cerebral fluid. The patient died despite systemic and intrathecal chemotherapy. A 50-year-old man was initially treated with 3 courses of VAD for a stage IIIA IgD lambda multiple myeloma. Blood stem cell were collected after a course of high-dose etoposide and cyclophosphamide. ABMT was performed after total body irradiation (TBI) and HDM. Three months later, he presented with right leg palsy and a lumbar puncture showed numerous plasma cells and the presence of the IgG lambda. The patient died of neurological complications three months later. Extramedullary occurred prior to medullary relapse in the two cases, suggesting the presence of an extramedullary clone of plasma cells with a high degree of chemo-resistance. Although high-dose chemotherapy appears promising, this therapeutic approach could allow the occurrence of presently unobserved complications. Wether CNS prophylaxis is indicated in this context, as recommended in leukemia, remains an open question.