No abstract

Virions were extracted directly from the brain of a patient with progressive multifocal leukoencephalopathy (PML). They were treated with antiserum to SV40, with rabbit antiserum to previous PML isolates, or with serum from another patient with the same disease and observed directly by electron microscopy. This procedure could be used for the rapid identification of the antigenic nature of virions in cases of PML.

Summary:Autologous transplantation in CML has been a focus of interest over the last few years. Determining the indications, optimal timing and method for this procedure remains controversial. One approach has been the mobilisation of Philadelphia chromosome negative (Ph؊) peripheral blood stem cells following high-dose chemotherapy as a method of purging the graft. We have described a mobilisation regimen of 7 days of hydroxyurea followed by G-CSF and have shown it to be substantially less toxic than other methods. We now report further experience with this technique in a total of 18 patients and the outcome of transplantation in seven patients using cells so-derived. Following mobilisation, approximately a third of patients had 100% Ph؊ collections and half had less than 50% Ph+ collections. All patients were 100% Ph+ prior to mobilisation. Six out of seven transplanted patients showed sustained engraftment and two of these patients became 18 and 34% Ph+ 3 months post-transplant. Five patients remain alive and well 13 to 25 months post-autograft. In conclusion, we have developed a well-tolerated regimen for Ph؊ PBSC mobilisation and have demonstrated that such cells are capable of sustained engraftment and of producing significant cytogenetic responses. Keywords: blood stem cells; chronic myeloid leukaemia; autologous stem cell transplantation; hydroxyurea; G-CSF Treatment for the majority of patients with chronic myeloid leukaemia (CML) remains unsatisfactory. The only potentially curative approach is allogeneic bone marrow transplantation which is only available to a minority of patients. Alpha-interferon (IFN) has been shown to reduce the size of the Philadelphia positive (Ph+) clone in some patients leading to a survival advantage but the ability of IFN to prolong survival in patients not achieving a major cytogenetic response remains controversial. [1][2][3] Autografting with blood-or bone marrow-derived stem 4,6,7 The evidence from IFN responders and transplanted patients implies that reduction of the Ph+ clone may correlate with improved survival. The rationale for selecting PhϪ cells for autologous transplantation in CML is based on the presence of residual PhϪ cells in the marrow of many patients with CML especially in the early stages of their disease 8 and by the demonstration that malignant cells present in autografts can contribute to relapse. 9,10 Purging approaches have included in vitro techniques using chemotherapy, antisense oligonucleotides and long-term liquid cultures. 11-13 An alternative in vivo approach is to take advantage of the preferential mobilisation of PhϪ cells during the early regenerative phase following myelosuppressive therapy and to collect them by apheresis. 14 This approach is however associated with considerable morbidity and some mortality. We have investigated the use of a less toxic regimen for PhϪ PBSC mobilisation using oral hydroxyurea and G-CSF. 15 We now report further experience with this technique in a total of 18 patients and the outcome of transplantation in...