Use of the polymerase chain reaction and direct sequencing analysis to detect cells with the t(14;18) in autologous bone marrow from patients with follicular lymphoma, before and after in vitro treatment.

Between August 1993 and February 1994, 25 patients with follicular or transformed follicular lymphoma had bone marrow harvested at St Bartholomew's Hospital (SBH) with a view to proceeding to high-dose treatment comprising: cyclophosphamide 60 mg/kg x 2 and total body irradiation, 200 cGy x 6, supported by autologous bone marrow transplantation (ABMT). The marrow mononuclear cell fraction was treated in vitro with four anti-B cell antibodies and baby rabbit complement. The aim of this study was to determine whether in vitro treatment of the marrow could remove morphologically undetectable lymphoma cells. PCR analysis for the t(14;18) was used to determine the presence or absence of lymphoma. At the time of the bone marrow harvest, 21/25 bone marrow samples were positive for the t(14;18), in 15/22 patients, the rearrangement could also be demonstrated in peripheral blood. After in vitro treatment, 18/21 samples (86%) remained 'PCR positive'. Sequence analysis of the t(14;18) PCR products was performed on the latter and on lymph node biopsy material taken at diagnosis from 12 patients. The same t(14;18) sequences were found in the bone marrow harvest samples as in the patients' original biopsies. These results suggest that this form of in vitro treatment does not completely eradicate the t(14;18) bearing clone. New and better methods need to be developed.