Aims/background: To assess the presence of bcl-2/JH rearrangements in bone marrow and peripheral blood lymphocytes from patients affected by diseases other than malignant lymphomas. The t(14;18) (q32;q21) translocation, which juxtaposes the bcl-2 oncogene on chromosome 18 and the JH segment of the immunoglobulin heavy chain (IgH) genes on chromosome 14, is found frequently in follicular lymphomas.
Methods: A sensitive semi-nested polymerase chain reaction (PCR) was used to detect t(14;18) translocation in bone marrow aspirates and peripheral blood lymphocytes from 48 patients. In 137 additional individuals peripheral blood lymphocytes only were tested.
Results: Cells carrying bcl-2/JH rearrangements were detected in about a quarter of the bone marrow samples and half of the peripheral blood lymphocyte samples. In seven patients, t(14;18) positive cells were found in both the bone marrow and peripheral blood lymphocyte samples. The size of the PCR products and bcl-2/JH DNA sequence analysis showed that the same t(14;18) carrying clone was present in the bone marrow and the corresponding peripheral blood lymphocyte samples in three of these seven patients. Some patients had more than one bcl-2/JH rearrangement. There was no significant correlation between age and the translocation incidence. Cells carrying the t(14;18) translocation were present in peripheral blood lymphocyte samples with a similar incidence--between 47% and 52% in all age groups from 20 to 79 years. Patients older than 80 years had a lower (37%) but not significantly different incidence.
Conclusions: These findings suggest that patients affected by non-lymphoid diseases may have several t(14;18) carrying cells and some of them undergo a clonal expansion. Whether individuals with t(14;18) positive cells are at a higher risk of lymphoid malignancies remains unanswered and further epidemiological studies are required.