No abstract

We report on a bone-marrow biopsy of a 61-year-old female patient that was performed because of the clinical suspicion of a myeloproliferative disease. The trephine biopsy showed morphological features that were consistent with an essential thrombocythaemia (ET). The diagnosis of a myeloproliferative disease could be corroborated by demonstration of the V617F mutation of JAK2. Besides the histological features of ET, the marrow showed a peculiar infiltrate that consisted of multivacuolated cells that were immunohistochemically identified as brown adipose tissue with a hibernoma-like picture. To the best of our knowledge, this is the first report on brown adipose tissue in the bone marrow.

Residual leukemic cells are detectable at frequencies as low as 1 in 10(6) normal cells in patients with Philadelphia chromosome/BCR-ABL-positive leukemias in complete remission (CR) using reverse-transcriptase polymerase chain reaction (RT-PCR) with specific nested primers. The level of minimal residual disease (MRD) in the bone marrow (BM) and the peripheral blood (PB) may favor one of the two as the source for an autologous graft. In order to quantify MRD with RT-PCR we analyzed patients ficolled cells after limiting logarithmic dilutions in normal ficolled buffy-coat cells. In six patients with BCR-ABL-pos ALL who were in CR by conventional criteria (5 in CR1 and 1 in CR2), we studied a total of nine paired BM and PB samples prior to scheduled ABMT. A positive RT-PCR signals was detectable in all samples up to dilutions ranging from 1:10(1) to 1:10(3) in PB, and at higher titers ranging from 1:10(3) to 1:10(5) in the BM. The BM titers exceeded the corresponding PB titers in all nine sample pairs by at least 1 log. The mean difference was 1.55 log (geometric mean, n = 9) and is statistically significant (p < 0.03). We conclude that residual leukemia in BCR-ABL-positive ALL preferentially locates in the BM compartment, and we assume that PB may yield autologous grafts with significantly less leukemic contamination.

No abstract

We examined the configuration of the immunoglobulin genes in the leukemic blast cell DNA of 20 adults with precursor B-cell acute lymphoblastic leukemia (ALL), treated according to the BMFT protocol. Sixteen of 20 (80%) patients expressed HLA-DR antigens and lacked detectable T-cell antigens. Eleven of the 20 patients (55%) were positive for the CD10 antigen and therefore classified as common ALL. Six patients were classified by immunological phenotyping as null-ALL (30%). Three patients (15%) expressed both immature B-cell markers CD19, CD22, or CD24 and myelomonocytic markers CDw65 or CD15, suggesting precursor B-ALL with cross-lineage expression of myeloid markers. In 18 of the 20 patients (90%), rearrangements and/or deletions of the immunoglobulin heavy-chain (IgH) gene locus were found. In none of the patients was a light-chain gene rearrangement observed. Two patients (10%) had a rearrangement of one allele for the J beta 1 gene region of the TCR-beta gene. In four patients (20%) more than two hybridizing bands for the IgH genes were detected. Two of these four patients with multiple hybridizing bands for the IgH genes had a t (4;11) translocation. Two of five patients with the t (4;11) translocation co-expressed both B-cell antigens and the myeloid antigens CD15 or CDw65. No correlation was found between the immunophenotype of the ALL and the arrangement pattern of their IgH genes. Kaplan-Meier plot analysis revealed no significant difference between adult precursor B-ALL patients with monoclonal or oligoclonal IgH gene rearrangements and their disease-free survival rates.