Biomedical subjects

D M Knowles

Publications and source records attributed to D M Knowles.

At least 163 records · Page 9Linked to original sources

PubMed1987

Immunoglobulin and T cell receptor beta chain gene rearrangement analysis of ocular adnexal lymphoid neoplasms: clinical and biologic implications.

We investigated the organization of the immunoglobulin heavy chain (IgH) and the T cell receptor beta chain (T beta) gene loci in 20 ocular adnexal and four extraocular lymphoid neoplasms obtained from 18 patients presenting with an ocular adnexal lymphoid neoplasm. Fifteen ocular adnexal and four extraocular lymphoid neoplasms occurring in 13 patients were classified by morphological examination and immunophenotypic analysis as monoclonal B cell lymphomas. Each one of these 19 lymphoid neoplasms exhibited clonal IgH gene rearrangements upon hybridization of EcoRI- or HindIII-digested DNA to a heavy-chain joining region (JH)-specific DNA probe. The bilateral ocular adnexal monoclonal B cell neoplasms occurring simultaneously in two individuals exhibited identical clonal IgH gene rearrangements, which indicated their derivation from an identical B cell clone. The ocular adnexal and the extraocular monoclonal B cell neoplasms occurring in two of three patients also exhibited identical clonal IgH gene rearrangements, which suggested that they too were derived from an identical B cell clone. Five ocular adnexal lymphoid neoplasms were classified by morphological examination and immunophenotypic analysis as benign, polyclonal pseudolymphomas. Three of these five ocular adnexal lymphoid neoplasms exhibited clonal IgH gene rearrangements, which suggested the presence of monoclonal B cell populations that escaped detection by morphological and immunophenotypic examination. None of the 24 pathological samples exhibited clonal T beta gene rearrangements upon hybridization of EcoRI- or BamHI-digested DNA to a T beta gene DNA probe. The results of these studies demonstrate the value of Southern blot hybridization analysis for clonal IgH and T beta gene rearrangements in the diagnosis, classification, and investigation of extranodal lymphoid neoplasms originating and/or presenting in the ocular adnexa.

Aged↗

PubMed1986

Multiple monoclonal B cell expansions and c-myc oncogene rearrangements in acquired immune deficiency syndrome-related lymphoproliferative disorders. Implications for lymphomagenesis.

AIDS (acquired immune deficiency syndrome) and ARC (AIDS-related complex) are associated with a spectrum of lymphoproliferative disorders ranging from lymphadenopathy syndrome (LAS), an apparently benign polyclonal lymphoid hyperplasia, to B cell non-Hodgkin's lymphoma (B-NHL), i.e., malignant, presumably monoclonal B cell proliferations. To gain insight into the process of lymphomagenesis in AIDS and to investigate a possible pathogenetic relationship between LAS and NHL, we investigated the clonality of the B or T lymphoid populations by Ig or T beta gene rearrangement analysis, the presence of rearrangements involving the c-myc oncogene locus, and the presence of human immunodeficiency virus (HIV) sequences in both LAS and B-NHL biopsies. Our data indicate that multiple clonal B cell expansions are present in a significant percentage of LAS (approximately 20%) and B-NHL (60%) biopsies. c-myc rearrangements/translocations are detectable in 9 of our 10 NHLs, but not in any of the LAS cases. However, only one of the B cell clones, identified by Ig gene rearrangements carries a c-myc gene rearrangement, suggesting that only one clone carries the genetic abnormality associated with malignant B cell lymphoma. Furthermore, the frequency of detection of c-myc rearrangements in AIDS-associated NHLs of both Burkitt and non-Burkitt type suggest that the biological alterations present in AIDS favor the development of lymphomas carrying activated c-myc oncogenes. Finally, our data show that HIV DNA sequences are not detectable in LAS nor in NHL B cell clones, suggesting that HIV does not play a direct role in NHL development. Taken together, these observations suggest a model of multistep lymphomagenesis in AIDS in which LAS would represent a predisposing condition to NHL. Immunosuppression and EBV infection present in LAS can favor the expansion of B cell clones, which in turn may increase the probability of occurrence of c-myc rearrangements leading to malignant transformation.

AIDS-Related Complex↗

PubMed1986

T-cell receptor beta chain gene rearrangements: genetic markers of T-cell lineage and clonality.

We have performed a series of investigations involving T-cell receptor beta chain (T beta) gene rearrangements in benign and malignant nonhematopoietic, B-cell, and T-cell proliferations. These studies provide the conceptual basis and the operational approach for the use of T beta gene rearrangements as markers of T-cell lineage, clonality, and differentiation, analogous to immunoglobulin gene rearrangements in B cells. Southern blot hybridization analysis for T beta gene rearrangements can now be utilized to identify and distinguish between non-T cells, polyclonal T cells, and monoclonal T cells. Determination of T beta gene rearrangements will play an important role in the further investigation and classification of T-cell neoplasia. However, the identification of a genetic marker of clonality for T cells has significant diagnostic and prognostic value as well. For example, determination of the T beta gene rearrangement unique to a particular malignant T-cell clone provides a specific genetic marker for that clonal T-cell proliferation. This genetic marker of the T-cell clone may provide a useful tool for monitoring the patient's therapeutic response and clinical course for early signs of relapse. Nonetheless, our studies demonstrate that the lineage specificity of immunoglobulin and T beta gene rearrangements is not absolute. It appears that only a multiparametric approach combining extensive monoclonal antibody immunophenotypic analysis, in vitro testing for functional help and suppression, and Southern blot hybridization analysis for immunoglobulin and T beta gene rearrangements allows the conclusive and unequivocal demonstration of the B- or T-cell derivation of all lymphoid neoplasms. Lymphoid malignancies that cannot be assigned to the B- or T-cell lineage following this extensive multiparametric analysis are exceedingly uncommon.

Cell Line↗

PubMed1986

The human T-cell leukemias: clinical, cytomorphologic, immunophenotypic, and genotypic characteristics.

The distribution of the conventional lymphoid cell markers on T lymphocytes and the principal panels of monoclonal antibodies used to recognize distinctive T-lymphocyte-associated differentiation antigens are discussed. These reagents have been used to probe the early and late stages of T-cell differentiation, and a hypothetical schema of T-cell differentiation has been constructed. Application of these reagents to the investigation of neoplastic T cells has resulted in the determination of the subset of origin and the stage of differentiation of the neoplastic cells in T-cell-derived lymphoproliferative malignancies. Recent advances in molecular biology have made possible the Southern blot hybridization analysis of DNA extracted from neoplastic T cells for patterns of T-cell-receptor gene rearrangements. Examination of these patterns in benign and malignant T and non-T cell has provided the basis for the use of T-cell-receptor gene rearrangements as specific genetic markers of T-cell lineage, clonality, and differentiation. These and other advances have resulted in the delineation of a new category of T-cell neoplasia, the adult T-cell leukemia/lymphoma syndrome. They have also demonstrated that the majority of clinically indolent neoplasms composed of large granular lymphocytes in so-called T gamma-lymphoproliferative disease are monoclonal proliferations. Further phenotypic, functional, and genotypic analyses of the T-cell malignancies should provide better understanding of T-lymphocyte differentiation and heterogeneity. Such studies should also lead to better clinicopathologic correlations and greater understanding of the basis for the clinical diversity of the T-cell-derived lymphoproliferative malignancies.

Adult↗

PubMed1986

Familial erythrophagocytic lymphohistiocytosis: immunophenotypic, immunohistochemical, and ultrastructural demonstration of the relation to sinus histiocytes.

Familial erythrophagocytic lymphohistiocytosis (FEL), a rare, rapidly fatal childhood disease, is characterized by fever, hepatosplenomegaly, pancytopenia, and widely disseminated lymphohistiocytic infiltrates with prominent erythrophagocytosis. Immunophenotypic, immunohistochemical, and ultrastructural studies of two siblings with FEL were performed in an effort to determine the nature of the proliferating histiocyte of FEL. These studies demonstrated that the FEL histiocytes lack S-100 protein, T6, and Birbeck granules, which are found in Langerhans and interdigitating dendritic cells. The FEL histiocytes express alpha 1-antichymotrypsin, Leu-M3, HLA-DR, and, variably, lysozyme and Leu-M1. Thus, the proliferating histiocyte of FEL is a member of the mononuclear phagocytic system and has a phenotype similar to that of the histiocytes that normally populate the sinuses of benign and reactive lymph nodes. These studies suggest that FEL may represent uncontrolled proliferation of sinusoidal histiocytes.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1986

Ocular adnexal monoclonal lymphoid tumors with a favorable prognosis.

Fourteen patients with well- or intermediately differentiated monoclonal B-lymphocytic tumors of the conjunctiva or orbit had a favorable prognosis with follow-ups of 4 to 9 years (mean and median, 7.5 years). The lesions were, for the most part, diffuse proliferations of small lymphocytes, either with round or minimally indented nuclear outlines. Mitotic activity was sparse to nonexistent; occasionally there were scattered small abortive or residual germinal centers, and some lesions exhibited lymphoplasmacytoid features and dispersed multinucleated giant cells (polykaryocytes). None of the six patients with conjunctival lesions had extraocular manifestations. An identical tumor of the submandibular gland developed in one of eight patients with orbital lesions and another patient had multiple extranodal involvements of the oropharynx, liver, and both kidneys, but after chemotherapy the patient has survived for 8 years from orbital presentation and is currently in remission. The authors believe that these low-grade tumors share many biologic resemblances to extranodal lymphoepithelial tumors of other organs (lung, gut, parotid, thyroid), which as a group have been aggregated together as mucosa-associated lymphoid tumors (MALT) and which can often remain localized to their sites of origin.

Aged↗

PubMed1986

Lymphocytic subpopulations in the normal human conjunctiva. A monoclonal antibody study.

Monoclonal antibodies were used to analyze the lymphocytic subpopulations in frozen tissue sections of normal human conjunctiva (epibulbar, tarsal, and forniceal). The overwhelming majority of lymphocytes were T-cells (Leu1+ and OKT8+). In the epithelium, the predominant cell type was the OKT8+ cytotoxic/suppressor cell, whereas in the substantia propria, helper T-cells (Leu3a/3b+) equalled suppressor T-cells. T-cells outnumbered B-cells 20-fold; the letter cells were detected only in the substantial propria, particularly in the fornices, and not in the epithelium. Plasma cells, as identified by OKT10 staining, were completely absent except in the accessory lacrimal glands of Krause. Langerhans' cells, identified by OKT6 and HLA-DR (la) staining, were observed in the epithelium of all conjunctival regions. Our findings suggest that the reactivity of B-lymphocytes and plasma cells is heavily damped down by T-lymphocytes, thus allying the conjunctiva to other mucosal membranes and the skin as heavily immunoregulated tissues.

Aged↗

PubMed1986

A comparison of conjunctival and nonocular dendritic cells utilizing new monoclonal antibodies.

Langerhans cells belong to the dendritic cell family. Their presence in the conjunctiva and cornea has been demonstrated by means of various membrane and cytoplasmic markers. Utilizing OKT6, a monoclonal antibody that specifically binds to Langerhans cells in conjunction with la histocompatibility antigens (HLA-DR), and a new panel of monoclonal antibodies, we compared the population density and characteristic phenotypes of Langerhans cells in normal conjunctiva with those in normal epidermis. A greater density of Langerhans cells was noted in epidermis in comparison with conjunctiva. Various areas of the conjunctiva and cornea were mapped for Langerhans cell distribution. The T6/la ratio of Langerhans cells in conjunctiva was notably different from that in skin. Utilizing the Prolm2 marker, we identified non-Langerhans dendritic cells in the substantia propria and in the basilar epithelium of the conjunctiva, antigen-processing cells probably identical to the interdigitating dendritic cells of lymph nodes.

Antibodies, Monoclonal↗

PubMed1986

Monoclonal antibody identification of infiltrating mononuclear leukocytes in lupus nephritis.

Populations of mononuclear inflammatory cells infiltrating the renal interstitium in LN were studied by means of an avidin-biotin immunoperoxidase technique applied to cryostat sections of 26 renal biopsies (3 WHO class IIb; 4 class III; 8 class IV; 4 class V; 4 class III and V; and 3 class IV and V). The majority of interstitial leukocytes were T cells (mean 65.7 +/- 14.1). The number of cells reactive with OKT8 (47.3 +/- 11.0) exceeded the number of OKT4 positive cells (32.5 +/- 11.3) in 22 of 26 biopsies. Cells reactive with antimonocyte antibodies OKM1 and OKM5 (6.7 +/- 5.9 and 7.9 +/- 5.9, respectively) and B lymphocytes (OKB2 3.9 +/- 3.5) were a minor component of the interstitial infiltrates. Monocytes were the predominant cell type among stained cells in glomerular tufts and crescents. Tissue T4/T8 ratios varied widely (range 0.31 to 1.81), and were less than 1 in 22 of 26 patients. There was no correlation between tissue T4/T8 ratios and simultaneous peripheral blood T4/T8 ratios. Using stepwise multivariate linear regression, tissue T4/T8 ratio was found to correlate highly with renal histologic activity (P less than 0.001) but was not independently predictive of any other histopathologic or clinical variable studied. Mean tissue T4/T8 ratio in LN was significantly lower than that of other glomerular and interstitial diseases studied (P less than 0.001), a finding which may reflect differences in the pathogenesis of renal injury. These findings suggest that local cellular immune mechanisms may be important in the modulation of disease activity in LN.

Adolescent↗

PubMed1986

Immunoglobulin and T-cell receptor beta-chain gene rearrangement analysis of Hodgkin's disease: implications for lineage determination and differential diagnosis.

The lineage and clonality of Hodgkin's disease (HD) were investigated by analyzing the organization of the immunoglobulin and T-cell receptor beta-chain (T beta) gene loci in 18 cases of HD, and for comparison, in a panel of 103 cases of B- and T-cell non-Hodgkin's lymphomas (NHLs) and lymphoid leukemias (LLs). Sizable clonal B- or T-cell populations, representing greater than or equal to 10% of the pathologic sample, were readily detectable by immunogenotypic analysis in all 103 NHLs and LLs but not in any of the 18 cases of HD. However, extremely minor clonal populations (less than or equal to 1%) were detectable in 3 of 18 cases of HD. We demonstrated that these minor clonal populations do not correspond to Reed-Sternberg (RS) cells since clonal immunoglobulin or T beta gene rearrangements are not detectable in cases of HD containing greater than 25% RS cells. The number of RS cells present in these samples appeared to correlate directly with the pattern of gene rearrangements characteristic of polyclonal T cells. These studies demonstrate that Southern blot hybridization analysis for clonal immunoglobulin and T beta gene rearrangements represents an accurate, objective tool in the differential diagnosis between HD and NHL; that HD is predominantly composed of polyclonal B and T cells; that minor clonal B- or T-cell populations unrelated to RS cells occasionally can be found in HD; and that RS cells do not represent clonal B- or T-cell expansions. Finally, our data preliminarily suggest that RS cells may represent polyclonal T-cell populations.

Adolescent↗

PubMed1986

Chromosomal breakpoints and structural alterations of the c-myc locus differ in endemic and sporadic forms of Burkitt lymphoma.

We have examined the position of the chromosomal breakpoint relative to the human c-myc gene (MYC) and the presence of other structural alterations of the same locus in 19 fresh samples of Burkitt lymphoma (BL) and 13 BL-derived cell lines. This panel includes the two pathogenetic forms of BL: the endemic (African-type) BL (eBL) and sporadic (American-type) BL (sBL). In all cases tested, including fresh samples and cell lines, structural alterations of the 5' portion of the gene were detected, suggesting that they may be necessary for c-myc activation. However, the site of chromosomal breakpoint and the type of structural alterations differ in eBL and sBL. In 16 of 18 sBL cases, chromosomal translocation truncates the gene within a 5' region that includes the first intron, the first exon, and 5' flanking sequences. Conversely, in 14 of 14 eBL samples, the chromosomal breakpoint is located outside the c-myc locus, yet the same 5' sequences are affected by several mutations identifiable by restriction enzyme polymorphisms. Different genetic mechanisms may therefore be involved in chromosomal translocation/c-myc activation, and these differences may be a function of differences in the stage of differentiation of eBL versus sBL.

Burkitt Lymphoma↗

PubMed1986

Leu-M1 antigen expression in advanced (tumor) stage mycosis fungoides.

The authors describe two patients with clinically and histopathologically documented advanced (tumor) stage mycosis fungoides. In each case the large, pleomorphic neoplastic cells lacked the monoclonal antibody-defined cell surface antigens commonly associated with immature and mature T-cells, i.e., T11, Leu-1, T3, T4, T6, T8, and T10, but expressed various T-cell-associated activation antigens, such as HLA-DR, Tac, and T21. Leu-M1, a monocyte-associated antigen, was not expressed by the small, cerebriform neoplastic cells in the plaque stage lesions of either patient. However, Leu-M1 was expressed by most of the large, pleomorphic neoplastic cells present in the nodular lesions of both patients. The pattern of Leu-M1 antigen expression was identical to that previously reported in the Reed-Sternberg cells of Hodgkin's disease. Identification of these two patients suggests using caution in the interpretation of the results of immunophenotypic analysis of cutaneous lymphoid neoplasms and that Leu-M1 should not be used as a diagnostic indicator of Hodgkin's disease or a histiocytic-derived neoplasm. These studies also suggest that Leu-M1 may be preferentially expressed on a subpopulation of activated, rapidly proliferating, and/or dedifferentiated neoplastic T-cells that proliferate in the advanced (tumor) stages of mycosis fungoides.

Aged↗

PubMed1986

Accessory function of thymic and tonsillar dendritic cells in interferon gamma production by T lymphocytes.

Human dendritic cells (DC) were purified from tonsils and thymus by a three-step procedure. Over 85% of cells in the purified DC preparations were identified as DC based on their characteristic morphology, presence of HLA-DR, Pro-Iml and Pro-Im2 antigens, and absence of macrophage associated antigens OKM1 and OKM5. To study the accessory function of DC in IFN-gamma production, T lymphocytes and T4+ or T8+ subsets were purified from peripheral blood and tonsils. Addition of autologous or allogeneic tonsillar DC to cultures of purified T cells caused up to a fifteen-fold increase in phytohemagglutinin (PHA)-induced IFN-gamma production and up to a seven-fold augmentation of IFN-gamma induction by interleukin 2 (IL 2). Thymic DC also showed a similar potent accessory activity on IFN-gamma production with concanavalin A (Con A) or PHA. Marked enhancement of IFN-gamma production by T cells was seen in the presence of as little as 0.3% thymic DC.

Antibodies, Monoclonal↗

PubMed1986

Presence of chromosomal abnormalities and lack of AIDS retrovirus DNA sequences in AIDS-associated Kaposi's sarcoma.

The frequent occurrence of Kaposi's sarcoma (KS) in association with the acquired immune deficiency syndrome (AIDS) could be due to the fact that the etiological agent of this tumor is the same retrovirus causing AIDS, to another oncogenic virus frequently found in AIDS patients, or to the unmasking of the tumorigenic potential of KS cells by immunosuppression. We have therefore investigated the presence of DNA sequences homologous to the AIDS retrovirus, cytomegalovirus (CMV), and hepatitis B virus in 13 KS necropsies and biopsies from AIDS patients. All KS DNA samples were negative for AIDS retrovirus or hepatitis B DNA sequences. Two DNAs from necropsies contained CMV DNA, but the data suggested the presence of replicating CMV DNA due to generalized infection. We have also studied cell cultures derived from KS skin biopsies of AIDS patients. These cultures had a short lifetime in vitro and expressed some markers of endothelial cells. The cells were not tumorigenic in nude mice but contained a number of chromosomal rearrangements which were often monoclonal within the same culture. However, these abnormalities were different from culture to culture and even in cultures from the same biopsy. The presence of these chromosomal abnormalities seemed to correlate with the cell positivity for endothelial markers. Taken together these results indicate that neither the AIDS retrovirus, CMV, or hepatitis B virus is directly responsible for the altered growth of KS cells, that KS may be polyclonal even within the same lesion, and that KS cells have a tendency to karyotypic rearrangements.

Acquired Immunodeficiency Syndrome↗

PubMed1986

Analysis of T-cell receptor beta chain (T beta) gene rearrangements demonstrates the monoclonal nature of T-cell chronic lymphoproliferative disorders.

We investigated the rearrangement patterns of the gene coding for the beta chain of the T cell receptor (T beta) in 11 patients with T-cell derived chronic lymphoproliferative disorders, including T-cell prolymphocytic leukemia (T-PLL) and T-cell chronic lymphocytic leukemia (T-CLL). We found that all five cases of T-PLL, and five of six cases of T-CLL, displayed T beta-gene rearrangements, clearly establishing their monoclonal nature. Clonality could not be determined in one case of T-CLL where the T beta gene was found unrearranged. Our results demonstrate that the majority of cases of both clinically aggressive T-PLL and clinically indolent T-CLL are monoclonal. These results suggest that the analysis of T beta gene rearrangements represents a valid tool for the differential diagnosis and clinical monitoring of T-cell derived chronic lymphoproliferative diseases.

Humans↗

PubMed1986

The expression of endothelial cell surface antigens by AIDS-associated Kaposi's sarcoma. Evidence for a vascular endothelial cell origin.

The authors investigated 19 cases of Kaposi's sarcoma (KS) obtained from patients with the acquired immune deficiency syndrome (AIDS) for their expression of Factor VIII-related antigen (FVIIIRAg), HLA-DR (Ia) antigens, OKM1, and three distinctive vascular, but not lymphatic, endothelial-cell-associated antigens, E92, OKM5, and HCl. Antigen expression was demonstrated by immunoperoxidase staining of cryostat sections. FVIIIRAg is strongly expressed by the cells lining the vascular spaces (VCs) but is absent, weakly or focally, and variably expressed by the spindle cell (SC) component of KS. The VC component of each KS lesion examined strongly expressed E92, moderately expressed HCl, and weakly expressed OKM5. In contrast, the entire SC component of each KS lesion studied strongly expressed E92 and OKM5 and weakly expressed HCl. Neither the VCs nor the SCs expressed OKM1. These studies provide strong and compelling evidence for the vascular endothelial cell histogenesis of both the vascular and spindle cell components of KS, demonstrate the intertumor and intratumor phenotypic heterogeneity of KS, and suggest that monoclonal antibodies OKM5 and anti-E92 are the best currently available immunohistochemical markers for identifying the spindle cell component of AIDS-associated KS in cryostat sections.

Acquired Immunodeficiency Syndrome↗

PubMed1985

T cell receptor beta chain gene rearrangements in lymphoproliferative disorders of large granular lymphocytes/natural killer cells.

Twelve cases of T gamma LPD (lymphoproliferative disorders of Fc gamma receptor-bearing T cells) involving an expansion of large granular lymphocyte/natural killer (LGL/NK) cells were investigated for the expression of LGL/NK-associated markers and for T beta gene rearrangement. All the cases selected were classified as T gamma LPD on the basis of morphology, function, and phenotype of the circulating cells. 10 to 12 cases displayed clonal rearrangements of the T beta locus and expression of the T3 antigen, whereas the 2 remaining cases displayed the germline configuration of the T beta gene and no expression of the T3 antigen. T8, Mol, B73.1, and N901 antigens were variably expressed among both T beta+T3+ and T beta-T3- T gamma LPD cases. We suggest that individual T gamma LPD cases represent the clonal expansion of cells frozen at different stages of differentiation/activation within an individual hematopoietic LGL/NK lineage.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1985

Lymphoid tumors displaying rearrangements of both immunoglobulin and T cell receptor genes.

Ig and T beta gene rearrangements can be used as genetic markers of lineage and clonality in the study of B and T cell populations. We have addressed the issue of the respective B and T lineage specificity of these rearrangements by analyzing a panel of 63 lymphoid tumors representative of the various clinicopathologic categories of both B and T neoplasias. We report that approximately 10% of the cases tested displayed rearrangements of both Ig and T beta genes. Despite their dual genotypic pattern, these tumors retain a pure immunophenotype, i.e. they display either B or T cell lineage-restricted cell surface antigens. The implications of these findings for both normal and neoplastic lymphoid differentiation are discussed.

Antibodies, Monoclonal↗