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Biomedical subjects

J Sklar

Publications and source records attributed to J Sklar.

At least 109 records · Page 6Linked to original sources
PubMed1987

Clonal T-cell populations in pityriasis lichenoides et varioliformis acuta (Mucha-Habermann disease).

Patients with the skin disorder pityriasis lichenoides et varioliformis acuta (PLEVA) develop recurrent, self-healing papulonecrotic lesions that contain infiltrates of cytologically and antigenically normal T lymphocytes. DNA extracted from the lesions of 3 patients with PLEVA was analyzed for rearrangement of beta-T-cell receptor genes for the purpose of assessing the clonality of T lymphocytes within the tissues of this disease. Lesions from all 3 cases showed clonal gene rearrangements. In each of 2 cases from which two separate lesions were biopsied, identical rearrangements were found in specimens from both sites. DNA from a variety of inflammatory lesions obtained from patients with other types of skin diseases failed to show detectable rearrangements of beta-T-cell receptor genes. These results suggest that PLEVA represents a T-cell lymphoproliferative process, rather than an inflammatory disorder, as had been previously thought.

DNA Restriction Enzymes↗
PubMed1986

Cloning and structural analysis of cDNAs for bcl-2 and a hybrid bcl-2/immunoglobulin transcript resulting from the t(14;18) translocation.

cDNAs for the bcl-2 mRNA were cloned from a human common acute lymphoblastic leukemia cell line. Nucleotide sequence analyses showed that the 6 kb bcl-2 mRNA potentially encodes a 26 kd protein that is homologous to a predicted Epstein-Barr virus protein. Most t(14;18) translocation breakpoints cluster within a narrow region of a 5.4 kb exon that contains a long 3'-untranslated region of the bcl-2 mRNA. As a result of t(14;18) translocation, hybrid bcl-2/immunoglobulin heavy chain transcripts are produced that consist of the 5' half of the bcl-2 mRNA fused to a "decapitated" immunoglobulin heavy chain mRNA. Nucleotide sequence analyses confirmed that the hybrid transcripts continue to encode a normal bcl-2 protein. Our results suggest that t(14;18) translocations alter expression of the bcl-2 gene both by transcriptional activation and by abnormal posttranscriptional regulation of bcl-2 mRNA.

Amino Acid Sequence↗
PubMed1986

Clonal T-cell populations in lymphomatoid papulosis. Evidence of a lymphoproliferative origin for a clinically benign disease.

Lymphomatoid papulosis is a chronic, clinically benign skin disorder that, when examined histologically, is seen to include numerous large, atypical lymphoid cells that display antigenic markers of T lymphocytes. To investigate the disparity between the clinical behavior of this disease and its malignant histologic appearance, we analyzed the DNA from skin lesions of six patients for rearrangements of beta and gamma T-cell receptor genes. Lesions from five of these patients showed between one and three clonal rearrangements for at least one T-cell receptor gene. Three separate biopsy specimens from a single patient showed different patterns of rearrangements for the beta gene in each specimen. Our results indicate that lymphomatoid papulosis is a clonal T-cell lymphoproliferative process that may possibly be multiclonal in origin. We conclude that this disease has both biologic and histologic features consistent with a malignant T-cell neoplasm despite its indolent course.

Adult↗
PubMed1986

Detection of a second t(14;18) breakpoint cluster region in human follicular lymphomas.

Our results indicate that there are two major breakpoint cluster regions in chromosome 18 DNA for t(14;18) translocations in follicular lymphomas. The absence of a pFL-1 homologous transcript in a cell line containing a pFL-2-detectable translocation suggests that there may be two different pathogenetic consequences of t(14;18) translocations. One possibility is that, despite the distances between them (greater than 20 kb), breakpoints in the two cluster regions in some way affect transcription of the same gene product, which has not yet been identified. Alternatively, two separate transcriptional units may be involved. The availability of DNA probes for each of the two t(14;18) breakpoint cluster regions will allow further studies regarding the biologic significance of these two genetically distinct classes of t(14;18) translocations.

Cell Line↗
PubMed1986

Clustering of extensive somatic mutations in the variable region of an immunoglobulin heavy chain gene from a human B cell lymphoma.

Following treatment of a human B cell lymphoma with an anti-idiotype antibody, a subpopulation of tumor cells remained that had lost the tumor-specific heavy chain idiotypic determinant. Nucleotide sequence analyses of eight independent heavy chain variable region isolates showed extensive point mutations, so that no two sequences were identical. Comparison of pretreatment and posttreatment sequences implicated an amino acid in CDR2 as being involved in the idiotypic determinant. Apparently the malignant B cells escaped the therapeutic effects of the anti-idiotype antibody through an ongoing process of somatic mutation in their immunoglobulin genes. Non-random clustering of amino acid replacements in CDR2 suggested that growth of the tumor may have been influenced by endogenous selective forces interacting with the tumor cell-surface immunoglobulin.

Amino Acid Sequence↗
PubMed1986

Immunoglobulin gene rearrangements in Hodgkin's disease.

An initial survey of biopsy specimens from 16 cases of Hodgkin's disease revealed clonal immunoglobulin gene rearrangements in one specimen, which contained large numbers of Reed-Sternberg (R-S) cells. As a result of this finding, the configuration of immunoglobulin and T-cell receptor gene DNA was investigated in biopsy tissues from other cases that were histologically and immunophenotypically consistent with Hodgkin's disease and contained numerous R-S cells. In six of seven such specimens (all of the nodular sclerosing subtype), selected solely on the basis of high R-S cell content and sufficient frozen tissue for study, at least one immunoglobulin gene was found to be rearranged in a clonal manner. Additionally, tissue samples obtained at two different time points from the original patient who showed immunoglobulin gene rearrangements revealed identical patterns of rearrangement. In the majority of cases, only a single gene showed rearrangement, and the rearranged bands in Southern blot autoradiograms were usually considerably less intense than the germline bands. No rearrangements of T-cell receptor DNA were detected in any case with a probe for the beta T-cell receptor gene. The results suggest that clonal cell populations possessing uniform immunoglobulin gene rearrangements are present in tissue in some cases of Hodgkin's disease. It is not possible to determine which cells contain these rearranged genes, but the increased incidence of detectable rearrangements in cases with high numbers of R-S cell raises the possibility that immunoglobulin gene rearrangement occurs in these cells.

Chromosome Aberrations↗
PubMed1986

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.

B-Lymphocytes↗
PubMed1986

Clonal T-cell populations in angioimmunoblastic lymphadenopathy and angioimmunoblastic lymphadenopathy-like lymphoma.

Ten cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) and AILD-like lymphoma were studied by immunophenotypic and immunogenotypic analysis. All specimens were found to have a predominance of T cells by immunophenotypic analysis. DNA hybridization analyses showed three of five specimens of AILD and five of six specimens of AILD-like lymphoma to contain clonal rearrangements of the beta T-cell receptor gene. No rearrangements of the heavy or light chain immunoglobulin genes were seen in any case. A single case showed a progression of AILD with a germ-line pattern of beta T-cell receptor DNA to AILD-like lymphoma with detectable clonal rearrangements for beta T-cell receptor DNA. These results suggest that many, but not all, cases diagnosed histologically as AILD or AILD-like lymphoma contain a clonal proliferation of T-lymphocytes.

Aged↗
PubMed1985

Detection of B-cell lymphoma in peripheral blood by DNA hybridisation.

As an alternative to morphological identification of circulating neoplastic lymphocytes in the blood of patients with non-Hodgkin's lymphoma, DNA of peripheral blood lymphocytes was analysed for clonal immunoglobulin gene rearrangements in 29 patients with low-grade B-cell lymphomas. 76% of the patients showed clonal rearrangements of immunoglobulin genes in their blood, including 58% of those with no other evidence of disease. In seven patients from whom paired samples were available the rearranged bands found in the blood and in lymph-node biopsy specimens containing histologically confirmed lymphoma were identical. Detection of circulating lymphoma cells by use of tumour-specific anti-idiotype antibodies and cytofluorimetry showed complete agreement with the results of DNA analysis.

B-Lymphocytes↗
PubMed1985

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.

Clone Cells↗
PubMed1985

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.

Adult↗
PubMed1985

Individual tumors of multifocal EB virus-induced malignant lymphomas in tamarins arise from different B-cell clones.

Cotton-top tamarins were inoculated with sufficient Epstein-Barr virus to induce multiple tumors in each animal within 14 to 21 days. The tumors consisted of large-cell lymphomas that contained multiple copies of the Epstein-Barr virus genome and generated Epstein-Barr virus-carrying cell lines showing no detectable consistent chromosomal abnormality. Hybridization of tumor DNA with immunoglobulin gene probes revealed that each lymphoma was oligo- or monoclonal in origin and that individual tumors from the same animal arose from different B-cell clones. Thus the virus induced multiple transformation events in tamarins in vivo to cause malignant tumors resembling the Epstein-Barr virus-associated lymphomas of patients with organ transplants.

Animals↗
PubMed1985

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.

B-Lymphocytes↗
PubMed1985

DNA hybridization in diagnostic pathology.

DNA hybridization is becoming an important new adjunct to conventional methods for the diagnosis of infectious diseases, inherited conditions, and neoplasia. Applications of this technology require very small quantities of tissue or body fluids because the DNA probes used in the hybridization assays detect minute amounts of homologous DNA sequence in the test material. Under the proper conditions, these DNA probes are absolutely specific for the pathogen or gene being examined, and hybridization with them usually yields objective answers that require little interpretation. The relatively minor inconveniences currently associated with DNA hybridization are related to the use of radioactivity as a detection signal and the time and labor required to obtain diagnostic data. In the future, technical improvements currently being developed and the preparation of new probes for additional human and microbial genes are likely to create an increasingly larger role for DNA hybridization in diagnostic pathology.

Communicable Diseases↗
PubMed1985

Nucleotide sequence of a t(14;18) chromosomal breakpoint in follicular lymphoma and demonstration of a breakpoint-cluster region near a transcriptionally active locus on chromosome 18.

The t(14;18)(q32;21) chromosomal translocation characteristic of follicular lymphomas is the most common cytogenetic abnormality known to be associated with any specific type of hematolymphoid malignancy. A fragment of DNA containing the crossover point between chromosomes 14 and 18 was cloned from the tumor cells of a patient with a follicular lymphoma carrying this translocation. Nucleotide sequence analysis of the breakpoint DNA revealed that the break in chromosome 14 occurred in joining region 4(J4) of the nonfunctional immunoglobulin heavy chain allele. This finding and other structural similarities of the breakpoint with the functional diversity region-joining region (D-J) joint in this lymphoma suggest that D-J recombination enzymes played a role in the mechanism of the t(14;18) translocation. Hybridization analysis of DNA from 40 follicular lymphomas showed that the majority of t(14;18) translocations occur on chromosome 18 DNA within 4.2 kilobases of the cloned breakpoint. A DNA probe from this breakpoint-cluster region detects transcription products in the tumor cells from which it was cloned and in a B-lymphoma cell line containing a t(14;18) translocation.

Alleles↗
PubMed1985

Leukemia with Down's syndrome: translocation between chromosomes 1 and 19 in acute myelomonocytic leukemia following transient congenital myeloproliferative syndrome.

A girl with Down's syndrome was born with a myeloproliferative disorder. The child had spontaneous regression of the myeloproliferation, with acute leukemia developing at a later date. Morphologic, cytochemical, immunologic, and immunoglobulin gene configuration studies all supported the diagnosis of acute nonlymphocytic leukemia. High-resolution chromosome studies revealed that the leukemic cells consistently contained a translocation between chromosomes 1 and 19: der(19)t(1;19)(q25;p13). Spontaneous regression of the transient myeloproliferative syndrome of the newborn with Down's syndrome may not always be permanent, and the transient myeloproliferative syndrome may sometimes represent an early sign of acute nonlymphocytic leukemia.

Antibodies, Monoclonal↗