Plasma viremia titration and RNA quantitation in ICD-p24 negative HIV type-1-infected patients.

Quantitative culture of human immunodeficiency virus (HIV) was performed on 202 plasma samples obtained from asymptomatic and early symptomatic HIV-1 infected patients (mean CD4+ count: 186/mm3) before antiretroviral therapy was started. HIV could be isolated from 84% of the plasma samples (titers ranging from 10(0) to 10(2.75) TCID50/ml). Immune complex dissociated p24 antigen (ICD-p24) was detected in 66% of the samples. Only 23 samples (11%) were negative for both ICD-p24 as well as HIV culture. Discordant results were obtained in 55 samples, and 45 samples negative for ICD-p24 were positive for HIV culture. A significant proportion (42%) of patients that were negative for ICD-p24 belonged to a very advanced group with very low CD4+ cell count. However, almost 90% of these ICD-p24 negative samples were positive for HIV plasma viremia, stressing the value of this virological marker in patients with low CD4+ cell count and without any detectable ICD-p24 antigenemia. HIV-1 RNA was detected in all ICD-p24 negative plasma samples tested by the branched DNA (bDNA) assay. A very good correlation was found between high RNA copy number and HIV plasma isolation in samples obtained from patients with low CD4+ cell count, suggesting that HIV-1 RNA quantitation may also reflect viral infectivity of plasma.

Progenitor cells purging: negative selection.

Disease relapse after autologous bone marrow transplantation (ABMT) may arise from residual tumor in the recipient and/or from cancer cells that are reinfused. The aim of purging by negative selection is to remove tumor cells from the marrow without adversely affecting the engraftment potential of the normal cell. We report the results of a study on fifty-six patients (pts) with non Hodgkin's lymphoma or acute leukemia submitted to ABMT after immunomagnetobead (IMB) purging (11 pts), Maphosphamide purging (31 pts) and no purging (14 pts). The IBM procedure involved one incubation of 3 monoclonal antibodies (CD10, CD19 and CD22) and two incubations with magnetic beads (Dynabeads M-450). The median recovery of mononuclear cells and CFU-GM was 40% and 45% after IMB purging and 84% and 5% after Maphosphamide purging respectively. The rate of leukocyte, neutrophils and platelets recovery following ABMT was similar in the three groups of pts, although platelet recovery was slow in patients received graft purged with Maphosphamide. Our study confirms the clinical feasibility of the IMB procedure, but only randomized studies will be able to definitely address the question of the clinical utility of purging.

Immunomagnetic purging procedure for autologous bone marrow transplantation in lymphoid malignancies.

In this report we describe the use of the immunomagnetic depletion of tumor cells from harvested bone marrow in two patients with acute lymphoblastic leukemia. The immunomagnetic procedure of purging involved one incubation of the marrow cells with a mixture of 4 monoclonal antibodies which bind to antigens of CD10 (ALB2), CD19 (HD37), CD20 (B1) and CD22 (HD39). Two incubations with magnetic beads (Dynabeads M-450) covered with antimouse antibodies followed by magnetic separation were performed. The bead/target B cell ratio was 50:1. After purging the recovery of mononuclear cells was 56% and 40%, while the recovery of CFU-GM was 45% and 38% respectively. Both patients engrafted rapidly without serious complications. One patient relapsed 4 months after transplant, the other remains in complete remission after 5 months. Our results confirm that the use of immunomagnetic beads is a simple, safe and reproducible technique to remove tumor cells before ABMT in patients with B malignancies using a broad mixture of MoAbs. However only a randomized trial using autologous marrow purged or not will clarify the effective clinical value of the procedure.

A technique for isolation of bone marrow cells using hydroxyethyl starch (HES) sedimentation agent.

Various methods have been investigated to concentrate hemopoietic stem cells before in vitro treatment and cryopreservation. Each procedure requires various degrees of cell manipulation; moreover, the extent of purification of the stem cell fraction depends on the further use of bone marrow. Fifty four bone marrows were treated with hydroxyethyl starch (HES) to isolate the mononuclear cell population. The manipulation with HES permitted to concentrate marrow stem cells in a small volume with removal of unwanted granulocytes, red blood cells and the donor isohemagglutinins in the major ABH incompatibility. We describe here a manual method which permits the transfusion of a very few number of red cells without depletion of progenitor cells and thus delay of engraftment.

Collection of peripheral blood stem cells by apheresis with continuous flow blood cell separator Dideco Vivacell.

In S. Camillo Hospital, Rome, the Apheresis Center (CNTS-CRI) and the Haematological Division, Authors treated 17 patients affected by haematologic malignances and solid tumours with leukoapheresis procedures for PBSC collection. Nine patients were treated with continuous-flow cell separator Dideco Vivacell, performing a total of 50 collection procedures. Mean values of total collected NC and MNC were 6.5 x 10(9) and 5.5 x 10(9), with a mean recovery 24% and 52%. Authors took patient's blood samples during the procedure, in order to analyze the MNC collection and to optimize the separation efficiency. Haemopoietic reconstitution values of the eight patients submitted to APBSCT showed the effectiveness of our method of cell collection.

Blood stem cells autografts in patients with high risk multiple myeloma.

Five patients with high risk multiple myeloma not responsive to standard chemotherapy were treated by high-dose chemotherapy (Melphalan, Cyclophosphamide) (HDC) and total body irradiation (TBI) followed by autografting with blood stem cells. These cells were previously collected by leukaphereses from eight to twelve occasions during hematopoietic recovery following profound aplasia induced by each course of intensive chemotherapy (Vincristine, Adriamycin, Cyclosphosphamide, Prednisone) when the patient reached a neutrophil count of 1,000/microliters and a platelet count of 100,000/microliters. No patients had evidence of tumor plasmacells in leukaphereses products using cytology, immunocytochemistry and immunofluorescence. At this time the patient 5 is not evaluable because of the short follow-up. One died at day 30 from heart failure. All living patients achieved a complete remission which persisted at a follow-up of 300, 261 and 136 days. Autologous blood derived hematopoietic stem cells induced successful and sustained engraftment in all living patients. Our results indicate the feasibility of this therapeutic approach over allogenic or autologous bone marrow transplantation in selected patients with high tumour mass multiple myeloma.