T-cell depletion and autologous stem cell transplantation in the management of tumour stage mycosis fungoides with peripheral blood involvement.
Nine patients with tumour stage mycosis fungoides (MF) have been entered into a pilot study of T-cell depletion and autologous stem cell transplantation (SCT). Eight patients had detectable rearrangements of the T-cell receptor (TCR) gamma-gene demonstrated by polymerase chain reaction (PCR)/single-stranded conformation polymorphism (SSCP) in the peripheral blood. The median age was 47 years and the median duration of disease before SCT was 61 months; Peripheral blood progenitor cells were mobilized using high-dose etoposide (1.6 g/m2) and granulocyte colony-stimulating factor (G-CSF). The apheresis products underwent rigorous T-cell depletion with immunomagnetic methods. Double CD34-positive and CD4/CD8-negative selection achieved a median reduction of 3.89 log of T cells. All nine patients have been transplanted. Conditioning included carmustine (BCNU), etoposide and melphalan (BEM) in seven patients and total body irradiation plus etoposide or melphalan in two. Eight patients engrafted promptly and one patient died of septicaemia. All survivors entered complete remission. Seven patients have relapsed at a median of 7 months (2-14) post SCT. However, most patients have relapsed into a less aggressive stage, which has responded to conventional therapy. Four out of seven evaluable patients had detectable TCR rearrangements in the T-cell depleted graft. A T-cell clone was also detected in the peripheral blood before relapse in four cases. Autologous SCT is feasible, safe and can result in complete remission in a significant proportion of patients with tumour stage mycosis fungoides. Despite a short relapse-free survival, most patients achieved good disease control at the time of relapse.