Chronic Lymphocytic Leukemia Clone Research Articles

Primary leukemia cells resistant to alpha-interferon in vitro are defective in the activation of the DNA-binding factor interferon- stimulated gene factor 3

Cells from one-third of chronic lymphocytic leukemia (CLL) patients are resistant to alpha-interferon (alpha-IFN) as measured by induction of blast transformation. We have previously shown that all CLL clones express alpha/beta-IFN receptors, but that the resistant cells are defective in the induction of the enzyme 2′,5′-oligoadenylate synthetase (2′,5-A synthetase). Thus, the deficiency in IFN sensitivity is localized somewhere between the interaction of the IFN molecule with its receptor and induction of 2′,5′-A synthetase. We have now further characterized the resistance of CLL clones to IFN by investigating whether it is associated with a defect in the activation of IFN- stimulated gene factor 3 (ISGF3), which is involved in the activation of alpha-IFN-stimulated genes (ISGs). A defect induction of ISGF3 after alpha-IFN treatment was found in 4 of 12 CLL patients. There was a close correlation between defective induction of ISGF3 and a lack of enhancement of 2′,5′-A synthetase as well as induction of blast transformation. Pretreatment with gamma-IFN and mixing experiments with extracts from IFN-sensitive cells indicate that a lack of the gamma- component of ISGF3 was the reason for defect in activation in 2 of the patients. We conclude that a defect in activation of ISGF3 is a possible cause for resistance in CLL cells to IFN-induced blast transformation in vitro.

Primary Leukemia Cells Resistant to α-Interferon In Vitro Are Defective in the Activation of the DNA-Binding Factor Interferon-Stimulated Gene Factor 3

Cells from one-third of chronic lymphocytic leukemia (CLL) patients are resistant to alpha-interferon (alpha-IFN) as measured by induction of blast transformation. We have previously shown that all CLL clones express alpha/beta-IFN receptors, but that the resistant cells are defective in the induction of the enzyme 2',5'-oligoadenylate synthetase (2',5-A synthetase). Thus, the deficiency in IFN sensitivity is localized somewhere between the interaction of the IFN molecule with its receptor and induction of 2',5'-A synthetase. We have now further characterized the resistance of CLL clones to IFN by investigating whether it is associated with a defect in the activation of IFN-stimulated gene factor 3 (ISGF3), which is involved in the activation of alpha-IFN-stimulated genes (ISGs). A defect induction of ISGF3 after alpha-IFN treatment was found in 4 of 12 CLL patients. There was a close correlation between defective induction of ISGF3 and a lack of enhancement of 2',5'-A synthetase as well as induction of blast transformation. Pretreatment with gamma-IFN and mixing experiments with extracts from IFN-sensitive cells indicate that a lack of the gamma-component of ISGF3 was the reason for defect in activation in 2 of the patients. We conclude that a defect in activation of ISGF3 is a possible cause for resistance in CLL cells to IFN-induced blast transformation in vitro.

Genetic relatedness of lymphoid malignancies. Transformation of chronic lymphocytic leukemia as a model.

Studies concerning the genetic relatedness between chronic lymphocytic leukemia and the more aggressive B-cell cancers that develop in about 10% of affected persons were reviewed. These B-cell cancers include large B-cell lymphoma (the Richter syndrome), prolymphocytic transformation, acute lymphoblastic leukemia, and multiple myeloma. Two possible relations were evaluated: development from the chronic lymphocytic leukemia clone (clonal evolution) and development of a genetically unrelated, independent second cancer. An English-language medical literature search was done using MEDLINE (1982 to 1992) and CANCERLIT (1982 to 1992). An extensive manual search of the literature that included meeting abstracts and reports was also done. Approximately 500 articles, abstracts, and book chapters were identified; 102 were selected for detailed analysis. Analysis of genetic relatedness between the two cancers considered concordance for immunoglobulin gene rearrangements, for immunoglobulin isotypes and idiotypes, and for cytogenetic abnormalities. In the case of large B-cell lymphoma, generally thought to arise from the chronic lymphocytic leukemia clone, approximately one half of the patients had genetically unrelated cancers. In prolymphocytic transformation, all cases studied appeared to evolve from the chronic lymphocytic leukemia clone. The few studies of acute lymphoblastic leukemia and multiple myeloma showed genetic relatedness in some cases and unrelatedness in others. These data indicate that progression to more aggressive B-cell cancers in persons with chronic lymphocytic leukemia can result from either clonal evolution or from an independent transforming event.

Heterogeneous immunoglobulin gene rearrangement in a B-chronic lymphocytic leukemia progressing into non-Hodgkin lymphoma (richter syndrome)

The relationship between chronic lymphocytic leukemia (CLL) and supervening non-Hodgkin lymphoma is debated, as is whether a particular genomic pattern is related to the emergence of the terminal lymphoma. To investigate these features, the molecular organization of the immunoglobulin (Ig) gene region in a case during both the B-CLL and Richter transformation phase was studied. B-CLL and non-Hodgkin lymphoma cells were processed for Southern blot analysis of Ig heavy- and light-chain gene configuration. Molecular studies of B-CLL cells revealed the presence of a single Ig heavy-chain rearrangement with both kappa and lambda light-chain rearranged genes, which was consistent with the occurrence of multiple mutational events during the development of the B-CLL clone. Molecular analysis of the lymphoma DNA showed new Ig heavy- and kappa light-chain rearrangements in addition to the original ones related to the CLL phase, indicating that the lymphoma tissue consisted of two genotypically distinct populations of cells. On the basis of the overall molecular configuration, this heterogeneous pattern of Ig gene rearrangement was interpreted as an inherent genetic instability of the CLL clone, in which multiple mutational events allowed a selective pressure toward more aggressive subclones, resulting in the emergence of the terminal lymphoma.

No evidence of trisomy 12 or t(11;14) by molecular genetic techniques in chronic lymphocytic leukemia cells with a normal karyotype

Chromosome analysis of B-cell mitogen-activated cells from patients with B-cell chronic lymphocytic leukemia (CLL) show clonal abnormalities in approximately one half of the cases. Among the most frequent aberrations are trisomy 12 and t(11;14). In the other half, no clonal chromosomal abnormalities are found. We wished to determine whether these CLL clones are cytogenetically normal or whether the apparently normal karyotype results from an inability of the malignant cells to enter metaphase in vitro, leaving only the few remaining normal cells to be karyotypically studied. Probes that can detect restriction fragment length polymorphisms (RFLPs) on chromosome 12, which makes it possible to determine the copy number of this chromosome, as well as bcl-1 probes that can detect t(11;14) were used. Of 13 CLL cases with normal karyotypes, none showed evidence for either trisomy 12 or t(11;14). This finding indicates that CLL cases with an apparently normal karyotype do not have two of the most common clonal chromosomal aberrations and may be karyotypically normal. The study also shows that Southern blot analyses, using probes that can detect RFLPs on chromosome 12, can be used for rapid and simple detection of trisomy 12 in CLL patients.

Analysis With Antiidiotype Antibody of a Patient With Chronic Lymphocytic Leukemia and a Large Cell Lymphoma (Richter’s Syndrome)

A murine monoclonal antibody made against an idiotypic determinant (Id) of surface IgM/IgD lambda molecules on chronic lymphocytic leukemia (CLL) cells of a 71-year-old woman was used for clonal analysis by two-color immunofluorescence. The anti-Id antibody identified IgM+/IgD+/lambda+ B cells as the predominant cell type of her CLL clone. In addition, substantial proportions of the IgG and IgA B cells and most of the IgM plasma cells in her bone marrow and blood were Id+. Six years after diagnosis, the patient died of respiratory failure due to infiltration of lungs by malignant cells. Autopsy revealed a dramatic change in the tumor cell morphology. The lungs, hilar nodes, and liver were infiltrated by a diffuse large cell lymphoma admixed with the leukemic cells. By immunohistologic staining these anaplastic lymphoma cells were IgM+/IgD-/lambda+ B cells expressing the same Id noted earlier on the CLL cells. The immunoglobulin gene rearrangement pattern on Southern blot analysis was also the same in leukemic blood cells and in the tissues involved by the lymphoma. Thus, the combination of antiidiotype and immunoglobulin gene analyses in this patient with Richter's syndrome revealed that a CLL clone, seemingly "frozen" in differentiation, was actually undergoing isotype switching, differentiation into plasma cells, and evolution into a rapidly growing and fetal lymphoma.

Analysis with antiidiotype antibody of a patient with chronic lymphocytic leukemia and a large cell lymphoma (Richter's syndrome)

A murine monoclonal antibody made against an idiotypic determinant (Id) of surface IgM/IgD lambda molecules on chronic lymphocytic leukemia (CLL) cells of a 71-year-old woman was used for clonal analysis by two- color immunofluorescence. The anti-Id antibody identified IgM+/IgD+/lambda+ B cells as the predominant cell type of her CLL clone. In addition, substantial proportions of the IgG and IgA B cells and most of the IgM plasma cells in her bone marrow and blood were Id+. Six years after diagnosis, the patient died of respiratory failure due to infiltration of lungs by malignant cells. Autopsy revealed a dramatic change in the tumor cell morphology. The lungs, hilar nodes, and liver were infiltrated by a diffuse large cell lymphoma admixed with the leukemic cells. By immunohistologic staining these anaplastic lymphoma cells were IgM+/IgD-/lambda+ B cells expressing the same Id noted earlier on the CLL cells. The immunoglobulin gene rearrangement pattern on Southern blot analysis was also the same in leukemic blood cells and in the tissues involved by the lymphoma. Thus, the combination of antiidiotype and immunoglobulin gene analyses in this patient with Richter's syndrome revealed that a CLL clone, seemingly “frozen” in differentiation, was actually undergoing isotype switching, differentiation into plasma cells, and evolution into a rapidly growing and fetal lymphoma.

A study of a patient with chronic lymphocytic leukemia (CLL) which demonstrates that proliferation of the lymphocytic clone in CLL does not include T lymphocytes

A study of a patient with chronic lymphocytic leukemia (CLL) which demonstrates that proliferation of the lymphocytic clone in CLL does not include T lymphocytes

Partial characterization of the shift from IgG to IgA synthesis in the clonal differentiation of human leukemic bone marrow-derived lymphocytes.

An unusual B-cell proliferation was noted in an individual (Tun) which was characterized by the presence of two separate populations of chronic lymphocytic leukemia (CLL) cell staining on the surface and in the cytoplasm for either IgG(k) or IgA(k). Utilizing an idiotypic antiserum prepared from the associated serum monoclonal IgG(k) protein the idiotype was detected on the surface and in the cytoplasm of both the IgG- and IgA-bearing cell populations. These observations are consistent with a common clonal origin and a switch mechanism involving IgG and IgA synthesis. Sequential-labeling of Surface Ig and intracellular Ig with antisera conjugated to opposite fluorochromes documented the progressive maturation of the terminal differentiation of the IgA-bearing cell population at a level before morphologically distinct plasma cells. The distribution and pattern of surface and cytoplasmic IgG and IgA staining in individual cells suggest that the direction of switching is from IgG to IgA synthesis. The demonstration of shared idiotypic specificity between the IgG- and IgA-bearing populations is consistent with a transition in Ig heavy chain synthesis resulting from an alternation in the CH gene. It is concluded that certain CLL clones may manifest a switch from IgG to IgA synthesis at a level of B-cell differentiation which encompasses both the B lymphocyte and the Ig-synthesizing plasma cell.