FISH is better than BIOMED-2 PCR to detect IgH/BCL2 translocation in follicular lymphoma at diagnosis using paraffin-embedded tissue sections.

The most common genetic aberration in follicular lymphoma (FL) is the t(14;18)(q32;q21) translocation that juxtaposes the antiapoptotic BCL2 gene with the promoter of the immunoglobulin heavy chain (IgH) gene. Our aim was to test the usefulness of two different techniques, fluorescence in situ hybridization (FISH) and PCR to detect t(14;18) in FL at diagnosis in paraffin-embedded tissue sections. A total of 51 patients diagnosed of FL were analyzed. FISH was performed with dual color dual fusion commercial probes (VYSIS) and in PCR experiments, the BIOMED-2 primers covering MBR, mcr and 3'MBR regions were applied. FISH showed positivity for the IgH/BCL2 translocation in 96% of patients and PCR in 59% of patients. FISH was able to detect variant translocations involving light chain Ig, or showing variant patterns such as deletions of the IgH portion involved in translocation. In 4% of cases, the IgH/BCL2 translocation was not detected by any of the two techniques tested. Our results show that FISH represents the best technique to detect t(14;18) at diagnosis.

Host cell-derived cardiomyocytes in sex-mismatch cardiac allografts.

BACKGROUND: Mesenchymal precursor cells are able to respond to tissue signals and differentiate into a phenotype characteristic of mature cells of that tissue. We sought to investigate whether adult human cardiomyocytes can be derived from recipient precursor cells in sex-mismatched cardiac allografts. METHODS: We studied four male patients who received hearts from female donors, and four female patients who received an allograft from a male donor. Four sex-matched transplant patients, two of each sex served as controls. Combined fluorescence in situ hybridization with probes specific for X- and Y-chromosomes and immunohistochemistry with alpha-actin was used to identify cardiac muscle cells 4 and 12 months after transplantation. Slides were examined with a fluorescence microscope to detect the presence of male cells with one X and one Y signal in the nucleus, and female cells containing two X signals. RESULTS: Mature cardiomyocytes from the host (1-2%) were found in five endomyocardial biopsy specimens at 4 months, and in three specimens at 12 months. In addition, recipient cells negative for cytoplasmic alpha-actin were also identified (1-21% per slide). The number of infiltrating recipient cells was not associated with the degree of rejection of the sample or with the number of prior rejection episodes. Echocardiographic evaluation showed no improvement in cardiac performance in hearts from patients with more than 10% chimeric recipient cells. CONCLUSIONS: Our data confirm the existence of mature cardiomyocytes derived from host cells, likely mesenchymal precursors, in the adult cardiac allograft in vivo.