Hematologic pathology最新文献

Variant translocations involving either chromosome 9, chromosome 22, or both with other chromosomes have been reported in about 8% of chronic myelogenous leukemia (CML) patients. In the 22 Ph+ patients studied in our laboratory, two showed variant translocations: t(9;22;11) (q34;q11;q13), and t(9;11) (q34;q11). We compared the pattern of involvement of different chromosomes (and bands) in secondary structural changes in CMLs carrying the t(9;22) (q34;q11) and in the variant translocations. Analysis showed significant differences in the pattern of involvement of different chromosomes and chromosome sites in the secondary structural changes in classic CMLs. This study, thus identifies nonrandomly involved chromosome sites that may be targeted for detailed molecular analysis to obtain an understanding of their role in disease progression. In the variant translocations chromosomes and chromosome bands were nonrandomly involved. Breakpoint cluster region (bcr) of the BCR gene was found to be rearranged in our two cases. We compared the location of molecular breaks within the bcr in classic and variant translocations. We found that translocation breaks occurred more frequently in the 5' region, and less frequently in the 3' region of bcr in variant translocations as compared with classic translocations. The significance of these findings in the etiology of CML is discussed.

Molecular genetic analysis was exploited to determine the lineage of the neoplastic cells in nine patients affected by hairy cell leukemia (HCL). In all cases the B-lineage of the cells was confirmed at the molecular level. In four cases a relatively advanced maturation stage was suggested by the expression of lambda light chain genes. Surprisingly, in two patients lambda light chain gene rearrangement was observed in spite of a germ-line kappa light chain gene. In at least one case the rearrangement was productive, as a full length messenger RNA (mRNA) was shown by Northern blot analysis and lambda light chain-restricted surface immunoglobulins (sIg) were found. These data suggest that exceptions to the hierarchy that regulates light chain gene rearrangements are not uncommon in this type of leukemia and that molecular genetic analysis should include lambda gene locus to determine more precisely the lineage origin of some leukemic cell populations.

The estimated S-phase fraction (%S) of non-Hodgkin's lymphomas has been demonstrated to be of prognostic value. The %S can be determined by labeling index (LI) techniques or by various mathematical models applied to DNA content histograms. We performed DNA content analysis and a slide-based bromodeoxyuridine immunofluorescence LI on split samples from 117 biopsy specimens suspicious for lymphoma. The LI was compared with the %S determined by two computer models (rectangular and polynomial) with and without debris subtraction, and a manual gates computer model. In the 93 DNA diploid cases, the rectangular models had the highest correlation with the LI (R = 0.88). In the 24 aneuploid cases, the manual gates model was the most useful because of a high correlation with the LI (R = 0.70) and its ability to be used in most cases (23/24). The polynomial models had limited usefulness because they generally gave a higher %S than the LI and could be fitted in less than half of the DNA aneuploid histograms. These results suggest that in situations where the LI is not possible, an accurate %S estimate can usually be obtained with either a rectangular or manual gates model.

A functional analysis of an expanded T-cell subpopulation was studied in a patient with pure red cell aplasia who had no evidence of malignancy. In the time of an aggravation of the anemia, an expanded population of large granular lymphocytes (LGL) with T-cell receptor (TCR) alpha beta +CD3+CD8+ phenotype was noted, which reverted to normal with remission. These T cells displayed a polyclonal pattern in DNA analysis. Functionally, the T cells, with suppressor/cytotoxic phenotype exhibited normal capabilities for transducing the signals of the proliferative response, and of interleukin-2R (IL-2R) expression and IL-2 production via the TCR-CD3 complex structure. While they suppressed erythroid colony formation in vitro, neither non-major histocompatibility complex-restricted cytotoxic activity, cytotoxic T-cell activity, nor suppressive activity for immunoglobulin synthesis by B cells was detected. Pretreatment by anti-CD3 or anti-T-cell receptor antibody generated cytotoxicity for FcR+ target cells in the patient cells, but no such augmentation was found with other monoclonal antibodies of FcR- target cells. These findings indicated that the expanded T cells are functionally relevant to antigen-specific cytotoxic T lymphocytes.

Vascular endothelial cells do not constitutively produce significant quantities of hematopoietic growth factors, interleukins, or adhesion molecules, but they can be induced to do so by a variety of stimuli including the inductive cytokines, interleukin-1 (IL-1), and tumor necrosis factor-alpha, as well as phorbol esters, bacterial proteins, endotoxin, certain viruses, and modified low-density lipoproteins. Recently, some groups have begun to investigate the molecular mechanism by which expression of these genes is regulated. Because induced expression of the gene products is always prefaced by an increase in mRNA the focus of attention has been largely upon the mechanisms involved in the process of transcript accumulation. Certain inducing agents drive transcription of these genes, others may induce both transcription and transcript stability. In the case of the inducing factor IL-1, it was recently demonstrated that accumulation of G-CSF, GM-CSF, and interleukin-1 beta mRNAs induced in vascular endothelial cells occurs as a result of transcript stabilization. Based on preliminary studies in a cell-free system, it is proposed that the inductive capacity of interleukin-1 results, at least in part, from its capacity to activate cytoplasmic inhibitors of selective ribonucleases and hypothesize that this may be a mechanism that has been conserved throughout evolution. Because other inducing agents also incite IL-1 gene expression, transcript stabilization may be a common ingredient of most inductive stimuli.

Abnormalities of the short arm of chromosome 12 have been detected in a wide variety of hematopoietic disorders. Seven cases of non-Hodgkin's lymphoma (NHL) are reported with various rearrangements involving bands 12p13 or 12p11, associated with other chromosome changes. A review of the literature confirms that rearrangements of 12p, mainly at band 12p13, are nonrandom chromosomal abnormalities in all subtypes of NHL, as in other malignant blood disorders. No common translocation could, however, be detected, and 12p abnormalities may be considered as secondary chromosomal events. Most of the 12p rearrangements involving translocation of genetic material of unknown origin, suggest that they result in loss of 12p segment.

To determine the growth requirement of leukemic blast progenitors in acute myeloblastic leukemia (AML), leukemic cells from the peripheral blood of eight AML patients were cultured in the serum-free culture system. Blast progenitors made colonies in methylcellulose culture and showed exponential growth in suspension culture, although the growth of blast progenitors in the absence of fetal calf serum (FCS) in some patients was inferior to that in the FCS-enhanced culture system. Recombinant human granulocyte colony-stimulating factor (rhG-CSF) stimulated the growth of blast progenitors in a dose-responsive manner. When cells were cultured at high cell density, blast colonies were formed even in the absence of CSF. Irradiated blasts also supported the growth of intact blast progenitors. These results confirm the finding noted in the FCS-enhanced culture studies that granulopoietic factor, G-CSF, plays an important role on the leukemic growth. The importance of cell to cell interaction for the growth of blast progenitors was also confirmed.

A method involving simultaneous demonstration of the immunophenotype and the karyotype was applied to a case of angioimmunoblastic lymphadenopathy (AILD), in which the standard chromosome preparation revealed an aberrant clone with trisomy 3 and additional changes. The aberrant mitoses showed a positive reaction with the monoclonal T-cell antibody Leu 4 (CD3). This new method thus provides definite evidence that the malignant clone with trisomy 3, a characteristic finding in AILD, belongs to the T-cell population. Nevertheless, cytogenetically normal T cells were also found. Moreover, a cell from the same clone was found in the phytohemagglutinin-stimulated blood lymphocytes. This finding demonstrates that AILD may have a leukemic variant.