Residual juvenile chronic myelogenous leukemia cells detected in peripheral blood during clinical remission

At diagnosis peripheral blood (PB) or bone marrow from patients with juvenile chronic myelogenous leukemia (JCML) have shown two reproducible abnormalities when studied in cell culture: impaired growth of normal hematopoietic progenitors and excessive proliferation of malignant monocyte-macrophage elements. We used these findings to assess quality of treatment response by serially studying PB specimens from four JCML patients (patients 5, 7, 8, and 9) in complete chemotherapy-induced remission. PB readily yielded high numbers of monocyte-macrophage colonies in CFU-C and CFU-GEMM assays when cultured in early remission, and the colonies were cytogenetically proven to have arisen from a malignant clone in patient 9. When studied later in remission, the abnormal cell proliferation persisted in three of the four patients, but in patient 8 PB colony growth resembled controls. Similarly, when PB from patient 8 was studied in liquid culture without using added growth factor, cell proliferation declined identical to controls, whereas PB from the other three patients showed exuberant growth of monocyte-macrophage elements. Patient 8 successfully completed therapy and has been in a long-term, disease-free remission. The other three had recurrent, ultimately fatal disease. The cell cultures have allowed detection of residual abnormal cells that circulate in PB of JCML patients in remission. Although patient numbers were small because of the rarity of JCML, the data suggested that persistence of leukemia cells in these patients had a bearing on clinical outcome.     

Evidence that multiple myeloma Ig heavy chain VDJ genes contain somatic mutations but show no intraclonal variation

To investigate whether somatic hypermutation occurs in multiple myeloma (MM) Ig VH region genes, we have cloned and sequenced the expressed VH genes from five cases of MM. The sequences were obtained after polymerase chain reaction (PCR) on total RNA isolated from the bone marrow, using 5' VH family-specific leader and 3' C gamma- or C alpha- specific primers. MM-specific CDR3 oligonucleotides were produced to isolate VH genes expressed by the malignant plasma cells. In all five cases, the productive Ig gene used the VH3 family. Extensive sequence analysis of multiple independent M13 clones showed no intraclonal variation with no evidence for ongoing somatic hypermutation in MM VH region genes. We were able to identify possible germline counterparts of the expressed VH genes in two cases. Comparison of these genes shows that the MM VH region genes have somatic mutations characteristic for an antigen-driven process. In the other three cases, no close homology could be found with published VH3 sequences. These findings implicate that, in MM, clonal proliferation takes place in a cell type that has already passed through the phase of somatic hypermutation.     

Haematopoietic marrow hyperplasia simulating transarticular skip metastasis in osteosarcoma

A case is presented of osteosarcoma with haematopoietic marrow hyperplasia simulating transarticular skip metastasis on computed tomography and magnetic resonance imaging.