Lack of involvement of the c-fms and N-myc genes by chromosomal translocation t(2;5)(p23;q35) common to malignancies with features of so-called malignant histiocytosis

We report the molecular, cytogenetic, and immunologic characterization of three hematologic malignancies that contained characteristic t(2;5) chromosomal translocations. The clinicopathologic features in all three cases fit the disease spectrum of so-called malignant histiocytosis (MH). All cases expressed activation antigens including Ki-1 (CD 30), but no lineage-restricted pattern of cellular antigen expression was observed. Cell lines SUP-M2 and SU-DHL-1 established from two of the cases showed rearranged beta T-cell receptor (beta TCR) genes nonproductive of full-length beta TCR mRNA and therefore not helpful in unequivocal establishment of lineage derivation. The common cytogenetic feature was a reciprocal translocation between chromosomes 2 and 5, involving bands 2p23 and 5q35 near the reported chromosomal locations of the N-myc and c-fms genes, respectively. Normal-sized and truncated c-fms RNAs were observed in both cell lines, whereas no N-myc transcripts were detected. Sequence analysis of the truncated fms RNA showed that it consisted of the 3' half of the c-fms mRNA, but its derivation was not the result of a structural alteration of the c-fms gene. Our studies show that the t(2;5) does not involve the N-myc and c-fms protooncogenes and that this cytogenetic abnormality may be characteristic of a subset of primitive malignancies with an indeterminate lineage but with clinicopathologic features of so-called MH.

Clinical and biologic characterization of T-cell neoplasias with rearrangements of chromosome 7 band q34

In T cell malignancy, rearrangements of chromosome 14 have been observed with a break in the band that contains the alpha chain gene for the T cell receptor (TCR). Because the beta chain TCR gene is in chromosome band 7q34, we searched for and report finding specific rearrangements of 7q34 exclusively in T cell malignancies. The rearrangements were reciprocal translocations between 7q34 and other points: 1p34, 9q32, 9q34, 15q22, and 19p13. The malignancies containing a 7q34 translocation were either T cell acute lymphoblastic leukemias or T cell lymphoblastic lymphomas that had similarities in clinical, enzyme, immunologic, and cellular characteristics. Hybridization using a probe to the beta-TCR gene disclosed unique rearrangements consistent with clonality in every case. A common pattern with chromosome breakpoints involving TCR genes may be emerging in T cell neoplasia.

Monoclonal antibodies reactive in routinely processed tissue sections of malignant lymphoma, with emphasis on T-cell lymphomas

The immunoreactivity of eight monoclonal antibodies was evaluated on 45 routinely processed lymphomas (22 T-cell lymphomas, 11 B-cell lymphomas, and 12 cases of Hodgkin's disease). Two antibodies reactive with leukocyte common (T200) antigens (PD7/26 and 2B11) stained most of the B- and T-cell lymphomas but did not stain the Reed-Sternberg cells and variants in Hodgkin's disease. Two antibodies known to stain B cells (LN-1 and LN-2) reacted with some of the B-cell lymphomas, but LN-2 also reacted with the neoplastic cells in six of 22 T-cell lymphomas and with the Reed-Sternberg variants in eight of 12 cases of Hodgkin's disease. The granulocyte antibody anti-Leu M1 reacted with most cases of Hodgkin's disease but also reacted with two of 11 B-cell non-Hodgkin's lymphomas. An antibody to epithelial membrane antigen (anti-EMA) stained some cases of T-cell lymphoma, B-cell lymphoma, and Hodgkin's disease. Leu 7 was expressed in one T-cell lymphoma and in one case of Hodgkin's disease. A novel antibody reactive with T cells (L60) stained all cases of T-cell lymphoma but also stained some cases of B-cell lymphoma and one case of Hodgkin's disease. We conclude that none of these antibodies, when used alone on routinely fixed paraffin-embedded material, is completely sensitive and specific for T-cell lymphoma, B-cell lymphoma, or Hodgkin's disease. However, a panel of antibodies is useful in distinguishing Hodgkin's disease from non-Hodgkin's lymphoma and in suggesting the B- or T-cell phenotype of non-Hodgkin's lymphomas.

Non-Hodgkin's lymphoma containing both B and T cell clones

We describe a patient in whom two lymph node biopsies removed 18 months apart disclosed histologic and immunophenotypic evidence of a non-Hodgkin's lymphoma containing neoplastic lymphocytes of both B and T type. Analyses of immunoglobulin and T cell receptor genes confirmed the presence of separate B and T cell clones. In addition, immunogenotyping revealed the possibility of a second B cell clone within the patient's tumor. Development of a multiclonal lymphoma in this patient may relate to the carcinogenic effects of chemotherapy or to a predisposition for neoplastic transformation of lymphocytes due to a previously diagnosed autoimmune condition. Another possible explanation is that the lymphoma implies the existence in this patient of a transformed lymphocyte-committed stem cell that is capable of generating both B and T lineage clones.

Studies on B lymphoid tumors treated with monoclonal anti-idiotype antibodies: correlation with clinical responses

Monoclonal anti-idiotype antibodies can be made which are exquisitely specific for B lymphocytic malignancies. We have conducted a clinical trial in which some patients' tumors regressed after infusion of such antibodies. Here, we evaluated characteristics of the antibodies, the tumors, and the patients to determine which features best correlated with the clinical response. Neither the isotype of the murine antibodies, nor their avidity were predictive of clinical outcome. The specific epitope to which the antibodies bound was characterized by immunochemical techniques. Reactivity with a heavy-light chain combinatorial determinant correlated somewhat with clinical effect. Variations in the characteristics of the individual tumors such as antigen sites per cell and ability to modulate the surface immunoglobulin were not predictive of response. In one patient with prolymphocytic leukemia the anti-idiotype antibody had a direct antiproliferative effect on tumor cells in vitro. This patient's tumor response was explainable by such a direct mechanism. In the other patients, who had lymphomas, therapeutic outcome correlated with the number of host nontumor cells infiltrating the tumor. The vast majority of these nontumor cells were mature T lymphocytes of the Leu 4, Leu 3 (T3, T4) phenotype. Thus, a preexistent host-tumor interaction seems to be important in the in vivo effect of anti-idiotype antibodies in B cell tumors.

Idiotype variant cell populations in patients with B cell lymphoma

Using isolated idiotype (Id) protein we generated panels of antibodies in two patients with follicular lymphoma, one of whom had never received prior chemo-or radiotherapy. Flow cytometry and frozen section tissue staining of tumor with these monoclonal antibodies (mAb) revealed multiple subpopulations within each tumor. Individual mAb stained between 7% and 83% of surface Ig+ cells in the tumor samples. These subpopulations were overlapping and no single antibody recognized all the tumor cells. However, combinations of antibodies seemed to capture total tumor in both cases. In some instances, the percentage of tumor stained by a single mAb varied over time, and differed between lymph nodes sampled at the same time. Because a single species of Id protein was used to generate mAb in each case, it appears that the antibodies were directed against idiotopes variably shared by different populations within each tumor, and this was confirmed by crossblocking studies. Tumor cells from one patient were fused to a nonsecreting heteromyeloma line K6H6/B5, and most of the resulting hybrids secreted Id protein. Four mAb were used to screen the Id proteins secreted by these hybrids, and 11 different variants (16 maximal) were found. Southern blot analysis of rearranged Ig genes was done in two hybrids and biopsy material. Identically rearranged light-chain genes were seen but it appeared as though extensive somatic variation had occurred in heavy chain genes. These studies indicate that: striking Id variation can exist at diagnosis in untreated patients, the percentage of tumor represented by an individual variant may change with time and may differ between tumor sampled from different anatomical locations, and somatic variation appears to be responsible for the observed heterogeneity. Although this degree of variation makes anti-Id antibody therapy more difficult, appropriate combinations of mAb should be more efficacious than single antibodies in such cases.

Diagnosis of B cell lymphoma by analysis of immunoglobulin gene rearrangements in biopsy specimens obtained by fine needle aspiration

Histologic diagnosis of lymphoma is far more difficult in the disaggregated cells obtained by percutaneous aspiration of lymph nodes than in tissue sections prepared from excisional biopsy specimens. However, the simplicity, economy, and safety of aspiration biopsy makes this an attractive diagnostic option in certain situations. In the present study, we demonstrate that lymph node aspirates provide material that is both suitable and sufficient for accurately detecting clonal proliferations of B cells by analysis of immunoglobulin gene rearrangements. The rearrangements detected in aspirated tissue serve as clonal markers that can be directly compared with the rearrangements found in histologically confirmed lymphoma removed by open biopsy. The application of gene rearrangements to aspirated material therefore offers a useful method of diagnosing lymphoma, particularly for the purposes of more thorough staging at initial presentation or the evaluation of tissues for possible relapse.

Most null large cell lymphomas are B lineage neoplasms

DNA of immunoglobulin and the beta T cell receptor genes was analyzed for rearrangements in 34 diffuse large cell lymphomas that failed to express immunoglobulins or T cell antigens. Twenty-eight cases had both heavy and light chain immunoglobulin rearrangements, two cases had only heavy chain gene rearrangements, three cases had only light chain gene rearrangements, and one case failed to show rearrangements for any of the immunoglobulin genes. None of the cases showed rearrangements for the beta T cell receptor gene. These results indicate that the vast majority of diffuse large cell lymphomas that lack definitive B or T cell phenotypic markers are actually B cell in origin.

Clonal rearrangements of T-cell receptor genes in mycosis fungoides and dermatopathic lymphadenopathy

Histologic diagnosis of mycosis fungoides may be difficult, especially in lymph nodes that show changes frequently associated with chronic skin disease. As an alternative approach to diagnosis, we have analyzed the configuration of DNA for the beta T-cell receptor genes in biopsy tissues from 14 patients with mycosis fungoides. Clonal rearrangements of these genes were found in each specimen tht contained histologically unambiguous mycosis fungoides. Clonal rearrangements were also found in seven of nine lymph nodes removed from patients with mycosis fungoides and considered histologically to contain only benign lymphadenopathy. Matching rearrangements of beta T-cell receptor genes were detected in benign lymph nodes and histologically involved tissues when paired specimens were available from the same cases. Our findings provide molecular evidence for the clonal T-cell origin of mycosis fungoides and indicate the high incidence of extracutaneous disease in patients with palpable lymphadenopathy. In addition, this study demonstrates that the detection of rearranged T-cell receptor genes can be a sensitive and practical method for the diagnosis and characterization of T-cell neoplasms.

Emergence of idiotype variants during treatment of B-cell lymphoma with anti-idiotype antibodies

We studied two patients with malignant B-cell lymphoma that manifested resistance to the therapeutic effects of anti-idiotype antibody because of the emergence of subclones with changes in their immunoglobulin idiotypes. In both patients, tumor-cell populations arose that were unreactive with anti-idiotype antibody but that retained surface immunoglobulin. One of the patients had an additional subpopulation of tumor cells that had switched from mu to gamma heavy-chain expression. Study of the immunoglobulin genes in the tumors confirmed that the subpopulations were derived from the same original clone of neoplastic B cells in each patient. The available data suggest that the idiotypic variation observed was the result of somatic mutation in the variable region of the active immunoglobulin genes. The fact that such mutations became evident over a short time and in the context of a partial tumor response suggests that the antibody therapy exerted a strong selective force against tumor cells that expressed the idiotype determinant. Multiple anti-idiotype antibodies may therefore be needed to identify all cells of a malignant clone, and some patients may require treatment with more than one monoclonal antibody.

A clinical trial of anti-idiotype therapy for B cell malignancy

Eleven patients with B lymphocytic malignancy were treated with mouse monoclonal anti-idiotype antibodies. All but one of the patients in this study had received extensive prior treatment with conventional lymphoma therapy. All antibodies were prepared against, and uniquely reactive with, the patient's own tumor. Ten patients were treated with a single antibody, but one patient received three antibodies concurrently. The treatment protocol initially used an escalating dose schedule that was intended to evaluate toxicity, pharmacokinetics and, eventually, to achieve appreciable levels of free mouse antibody in the circulation. The last two patients received substantial initial doses. Tumor sampling was performed before and during therapy to evaluate tissue penetration by antibody. None of the patients had serum paraproteins by routine clinical testing, but six had idiotype protein detectable by a sensitive immunoassay at levels greater than 1 microgram/mL, two of which were greater than 200 micrograms/mL. Plasmapheresis was capable of reducing these levels temporarily. However, the presence of serum idiotype increased the requirement for mouse antibody to achieve tumor penetration. Another obstacle to treatment was immune response to mouse Ig, which occurred in five of the 11 patients. Once an immune response had begun, further infusions of antibody were not capable of reaching the tumor or inducing tumor regression and were associated with toxicity. Our initial patient remains in an unmaintained complete remission 42 months after receiving antibody. Five of ten additional patients have had objective remissions that were also clinically significant. However, these remissions were not complete and were of relatively short duration. This therapy shows promise as an alternative modality for the treatment of B cell malignancy. Further study will be needed to determine the mechanisms of the antitumor effect and to improve the clinical results.

Frequent biclonality and Ig gene alterations among B cell lymphomas that show multiple histologic forms

Configurations of Ig gene DNA were examined in multiple biopsy specimens from seven cases of human B cell lymphoma that showed histologic differences among the specimens within each case. Analysis by Southern blot hybridizations with DNA probes for each of the three Ig loci revealed that the configurations of DNA within these loci were identical among the specimens in two of the cases. This result indicated the monoclonality of these lymphomas, despite differences in histology between biopsy specimens. In contrast, no common nongermline configurations of Ig gene DNA were detected among multiple biopsies in each of three other cases. Therefore, different histologies correlated with separate clones of proliferating B cells in these cases. In the last two cases, the configurations of light chain gene DNA were the same among biopsies in each case, consistent with a monoclonal origin in both lymphomas. However, differences were detected in the configuration of the heavy chain gene DNA. Analysis with a series of DNA probes of the mu heavy chain region indicated that the differences in the DNA configurations of the heavy chain genes from the biopsies probably arose from postrearrangement deletions of either the switch or constant regions of the mu gene. These studies indicate that, contrary to the conventional belief, individual tumors that contain different histologic types of lymphoma within the same patient frequently arise from separate clones of neoplastic cells. Furthermore, the heavy chain genes of monoclonal tumors may show postrearrangement deletions, often resulting from instability of DNA sequences within or around the mu switch region.

Monoclonal antibody and enzymatic profiles of human malignant T-lymphoid cells and derived cell lines

Recently, four distinct cell lines were established from patients whose malignancies had been defined by immunological and biochemical markers. Each patient had a distinct subtype of a T-cell cancer, and each possessed elevated adenosine deaminase and reduced nucleoside phosphorylase activity. Cell lines cultured in vitro possessed the same basic immunophenotype and biochemical enzyme activity as the patients' original malignant cells. In a direct comparison of the immunophenotype of the cell lines and the patients' malignant cells, full concordance existed for 48 of 52 paired antibody tests performed. However, when compared to the corresponding patient's sample, each cell line showed some minor changes in antigen expression or enzyme level. Antigen loss, de novo antigen expression, or elevated adenosine deaminase levels occurred in the cell lines, and these changes were stable on repeated analysis. While there was good general concordance between the patient's cancer and the established cell line, minor biological differences in the cell lines may reflect cellular maturation or subpopulation selection in vitro.

Biclonal B-cell lymphoma

The cells of most tumors are considered to be genetically homogeneous because they are assumed to represent a single clone descended from one abnormal cell. We have discovered three cases of B-cell lymphoma for which this generalization is not true. In each case, the tumor was composed of two subpopulations of cells, each expressing a different immunoglobulin molecule. Antibodies directed against these immunoglobulins were used to separate the two cell subpopulations of each tumor on a fluorescence-activated cell sorter. DNA extracted from the original tumor and the two fractionated subpopulations was analyzed to determine the configuration of immunoglobulin genes. Differences were found in the arrangement of DNA in at least one immunoglobulin gene for each of the two subpopulations. Thus, biclonality of these tumors was revealed by examination of both protein markers (cell-surface immunoglobulin) and DNA markers (immunoglobulin-gene rearrangements). Our results indicate that the incidence of biclonal B-cell lymphoma may be higher than previously recognized, possibly as high as 10 per cent of all B-cell lymphomas. Furthermore, our findings may have important implications for the diagnosis and therapy of lymphoid cancers.

Immunoglobulin gene rearrangements in hairy cell leukemia

Studies of hairy cell leukemia have yielded conflicting data about the cell of origin in this disease. To investigate this issue, we have examined the state of immunoglobulin genes in the cells of 11 randomly selected spleens showing histologic involvement with hairy cell leukemia. DNA was extracted from splenic tissue samples and digested with restriction endonucleases. Following agarose gel electrophoresis and transfer to nitrocellulose filters or activated nylon membranes, splenic DNA was hybridized with radiolabeled DNA fragment probes specific for the constant regions of the immunoglobulin heavy chain and kappa and lambda light chain genes. Autoradiograms of the hybridized DNA in each case revealed rearrangements of a heavy chain gene and at least one light chain gene. In addition, immunophenotyping of cellular immunoglobulin polypeptides was carried out on frozen tissue sections from all but one case. In each case in which an immunoglobulin polypeptide could be detected, a rearrangement was present in the DNA of the corresponding immunoglobulin gene. These studies offer strong evidence for endogenous immunoglobulin synthesis in hairy cells and for the B lymphocytic character of this leukemia.

Monoclonality of lymphoproliferative lesions in cardiac-transplant recipients. Clonal analysis based on immunoglobulin-gene rearrangements

Whether lymphoproliferative disorders arising in immunosuppressed recipients of organ transplants are primarily neoplastic or hyperplastic in nature is a matter of controversy. Reports of polyclonal B-cell proliferations in these lesions suggest the presence of hyperplasia, but these disorders resemble lymphoma histologically and are clinically aggressive and often rapidly fatal, as expected of a malignant neoplastic disease. We examined tissue specimens from 10 cases of lymphoproliferative disease that occurred in immunosuppressed recipients of cardiac transplants. Specimens from nine of these patients lacked cellular immunoglobulin; however, analysis of DNA extracted from these tissues revealed that each lesion contained large numbers of cells possessing uniform, clonal rearrangements of immunoglobulin-gene DNA. Therefore, when first seen clinically these proliferations contained a notable monoclonal-cell population typical of conventional B-cell lymphomas that are not associated with immunosuppression. We therefore suggest that lymphoproliferative disorders in recipients of cardiac transplants are neoplastic at the earliest stages of detectable disease.

Immunoglobulin gene rearrangement as a diagnostic criterion of B-cell lymphoma

We describe the use of the Southern blot hybridization technique to diagnose B-cell lymphoma by detecting clonal immunoglobulin gene rearrangements in lymph node and other biopsy tissues. DNA was isolated from a wide variety of neoplastic and non-neoplastic specimens and analyzed for the presence of rearranged immunoglobulin genes using radiolabeled DNA probes specific for the heavy- and light-chain immunoglobulin constant region genes. Among the specimens examined, clonal immunoglobulin gene rearrangements were found only in biopsy samples of B-cell lymphoma and not in samples containing reactive lymphoid processes or non-B-cell cancers. In lymphomas, the presence of rearrangements for either the kappa or lambda light-chain gene correlated with expression of one or the other of these chains when cellular immunoglobulins could be detected by frozen-section immunophenotyping techniques. The analysis of immunoglobulin gene rearrangements offers several advantages over conventional diagnostic methods for lymphomas, including improved sensitivity in detecting minor populations of neoplastic lymphocytes composing as little as 1% of the total cell population. In addition, clonal immunoglobulin gene rearrangements are demonstrable in a subset of lymphomas that lack detectable surface or cytoplasmic immunoglobulin, thus offering positive evidence for both malignancy and the B-cell origin of these tumors. Our studies indicate that detection of immunoglobulin gene rearrangements is a valuable method for diagnosis and classification of various lymphoproliferative disorders that are difficult to evaluate histologically or that lack distinctive antigenic markers.

A unique human B lymphocyte antigen defined by a monoclonal antibody

We produced a hybridoma designated 4G7 from a mouse immunized with chronic lymphocytic leukemia cells. The 4G7 hybridoma secretes an IgG1 antibody that is specific for normal and malignant B lymphocytes. Using dual color immunofluorescence staining, this antibody reacted with all immunoglobulin-positive cells but no T cells in normal peripheral blood. There was no detectable 4G7 antigen on monocytes, platelets, red cells, granulocytes, or phytohemagglutinin-activated T cells. When PBL were depleted of 4G7 positive cells and stimulated with pokeweed mitogen, secreted immunoglobulin levels fell to less than 10% of control values on Day 5 and less than 1% of control on Day 7. This antibody was reactive with 155 of 176 B lineage neoplasms on which it was screened. Thirty-five cases of myeloid or T-lymphoid malignancy were negative. Our studies show that the 4G7 antigen modulates in the presence of excess antibody. Free 4G7 antigen was not found circulating in human serum. The cell surface antigen identified by 4G7 was sensitive to pronase proteolysis but resistant to trypsin and chymotrypsin digestion. A comparison of 4G7 with other known B-cell antibodies indicates that the 4G7 antigen has not been previously identified. This antibody is of use for the identification of normal B lymphocytes, the study of B-cell differentiation, and the characterization of lymphoid malignancies.

A single monoclonal antibody identifies T-cell lineage of childhood lymphoid malignancies

Immunophenotyping studies with monoclonal antibodies have revealed the heterogeneity of childhood acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). The lymphoid malignancies of T-cell lineage are particularly heterogeneous and, until now, no single monoclonal antibody has been found to identify all cases of T-ALL and T-NHL. A monoclonal antibody, 4H9, recognizes an antigen of 40,000 molecular weight on normal and malignant T cells. Thirty-six cases of childhood T-ALL and T-NHL were tested, and in all cases, the malignant blast cells were reactive with 4H9, whereas malignant cells from 61 cases of non-T ALL and NHL were not reactive with 4H9. Monoclonal antibody 4H9 is a sensitive and specific reagent for the identification of childhood T-cell ALL and NHL and should be extremely useful in immunophenotyping studies of lymphoid malignancies.

Histochemistry of Hodgkin's disease

The histochemistry of Hodgkin's cells is controversial. Limited numbers and the variety of techniques used make comparisons difficulty. Acid phosphatase and nonspecific esterase have been the two enzymes most frequently tested because the presence of these enzymes has been thought to be characteristic of histiocytes. Despite the controversial results, these studies have frequently figured prominently in arguments about the cell of origin in Hodgkin's disease. Authors identifying the presence of acid phosphatase and nonspecific esterase have generally favored a mononuclear phagocyte origin; those with negative results have favored a lymphoid origin. We have evaluated a series of 21 cases of Hodgkin's disease using tissues embedded in plastic and tested for acid phosphatase and nonspecific esterase. We found that Hodgkin's cells were frequently positive for acid phosphatase (20 to 21 cases) and/or nonspecific esterase (18 of 21). The reactions are weak and sensitive to inhibition by processing procedures. The reaction patterns are unusual for lymphoid cells and histiocytes. The finding is similar to that seen in interdigitating reticulum cells, a specialized cell found in the paracortex of human lymph nodes.

Suppression of endogenous avidin-binding activity in tissues and its relevance to biotin-avidin detection systems

As biotin-avidin systems continue to be developed for applications involving single cells, cell suspensions, and especially tissue sections, the need arises for a method of blocking endogenous avidin-binding activity. One such method is described and its proposed mechanism is discussed. Utilizing this method, endogenous avidin-binding activity was detected and suppressed in selected human and murine tissues, thus facilitating the interpretation of specific immunohistochemical staining utilizing hybridoma monoclonal antibodies in a biotin-avidin-horseradish peroxidase detection system.

Studies of a human T lymphocyte antigen recognized by a monoclonal antibody

A monoclonal antibody (designated L17F12) detects an antigen present on 95-100% of human peripheral T lymphocytes, the majority of thymocytes, and acute lymphocytic leukemia T cells but not B cells, B-cell lines, or monocytes. Examination of frozen tissue sections by the immunoperoxidase method revealed that the cells expressing this antigen were found predominantly in the medulla of thymus and in T-cell zones of lymph node and spleen. The antigen recognized by L17F12 was associated with a cell-surface glycoprotein of 67,000 daltons. L17F12 was used to isolate this molecule from human thymocytes, normal peripheral T cells, leukemic T cells, and T-cell lines. Expression of this antigen on normal T cells was not diminished by prolonged exposure in vitro to various T-cell stimuli. In the absence of complement, L17F12 bound to T cells without altering proliferative functions, thus enabling rapid purification of functionally intact T cells. In the presence of complement, L17F12 was cytolytic for T cells, providing the basis for depletion of T cells from heterogeneous populations. These data suggest that the monoclonal antibody L17F12 recognizes a specific T-cell differentiation protein. This antibody will be useful in studies of the human immune system.