AB Deisseroth

Relapse after autologous bone marrow transplantation for chronic myelogenous leukemia (CML) can be due either to the persistence of leukemia cells in systemic tissues following preparative therapy, or due to the persistence of leukemia cells in the autologous marrow used to restore marrow function after intensive therapy. To help distinguish between these two possible causes of relapse, we used safety-modified retroviruses, which contain the bacterial resistance gene NEO, to mark autologous marrow cells that had been collected from patients early in the phase of hematopoietic recovery after in vivo chemotherapy. The cells were then subjected to ex vivo CD34 selection following collection and 30% of the bone marrow were exposed to a safety-modified virus. This marrow was infused after delivery of systemic therapy, which consisted of total body irradiation (1,020 cGy), cyclophosphamide (120 mg/kg), and VP-16 (750 mg/m2). RT PCR assays specific for the bacterial NEO mRNA, which was coded for by the virus, and the bcr-abl mRNA showed that in two evaluable CML patients transplanted with marked cells, sufficient numbers of leukemia cells remained in the infused marrow to contribute to systemic relapse. In addition, both normal and leukemic cells positive for the retroviral transgenome persisted in the systemic circulation of the patients for at least 280 days posttransplant showing that the infused marrow was responsible for the return of hematopoiesis following the preparative therapy. This observation shows that it is possible to use a replication-incompetent safety-modified retrovirus in order to introduce DNA sequences into the hematopoietic cells of patients undergoing autologous bone marrow transplantation. Moreover, this data suggested that additional fractionation procedures will be necessary to reduce the probability of relapse after bone marrow transplantation in at least the advanced stages of the disease in CML patients undergoing autologous bone marrow transplantation procedures.

Plasma exchange has been proposed as a treatment for multiple disorders. Three patients with amyotropic lateral sclerosis, who were hemostatically normal, were studied through a total of 11 4-liter exchanges. Plasma was replaced by an equal volume of 5% albumin or 5% plasma protein fraction. Serial studies revealed that immediately after the exchange transfusion, there was significant prolongation of the prothrombin, partial thromboplastin, and thrombin times with reduction of the fibrinogen and antithrombin III levels. Factors V, VII-X, IX, and X were all significantly decreased, as were the factor VIII antigen, procoagulant, and the ristocetin cofactor activities. Platelet counts were obtained before and after exchanges and revealed significant decreases. Four hours after exchange, all parameters remained abnormal except the factor IX, ristocetin cofactor, and factor VIII procoagulant activities. By 24 hr, all hemostatic parameters had returned to normal. These studies indicate that plasma-exchange transfusion with material devoid of coagulation factors results in a coagulation defect that may be of clinical significance in a hemostatically compromised patient.

To clarify the relationship between recipient presensitization and response to granulocyte (PMN) transfusion, we tested 187 non-HL-A matched donor-recipient pairs for the presence of antileukocyte antibody using granulocytotoxicity (G), lymphocytotoxicity (L), microleukoagglutination (M), and capillary leukoagglutination (C) assays. PMN increments per 10(11) transfused PMNs per square meter of body surface area, ascertained one hour following termination of transfusion, and the occurrence of nonhemolytic transfusion reactions, were correlated with the assay results. Although circulating anti-donor-leukocyte antibody was detected in 52 per cent of recipients, there was no statistically significant relationship between the presence of these antibodies and either PMN recovery or incidence of transfusion reaction. We conclude that the prospective use of these assays is of little value in predicting the recipient's response to PMN transfusion.

Although HLA-matched platelet transfusions are of value in the support of some alloimmunized thrombocytopenic patients, poor posttransfusion increments can be observed following HLA-matched platelet transfusions and conversely good posttransfusion increments may result after HLA-mismatched platelet transfusions. We have explored the possibility that in vitro assays in addition to HLA typing might better select compatible donors for refractory recipients. Our studies suggested that a platelet migration inhibition assay is predictive of platelet transfusion responses in HLA-compatible and incompatible donor-recipient pairs, while lymphocytotoxicity is predictive of posttransfusion increments only in HLA-incompatible donor-recipient pairs. Granulocytotoxicity, microleukoagglutination, and capillary leukoagglutination showed no value in predicting platelet transfusion increments, either in HLA-compatible or incompatible donor-recipient pairs.