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Biomedical subjects

N E Kay

Publications and source records attributed to N E Kay.

At least 55 records · Page 3Linked to original sources
PubMed1994

Does IL-2 receptor expression and secretion in chronic B-cell leukemia have a role in down-regulation of the immune system?

Recent evidence of cell membrane expression of interleukin-2 receptors (IL-2R) by malignant B cells in hairy cell leukemia (HCL) and B-chronic lymphocytic leukemia (B-CLL) has lead to speculation that growth factors, such as IL-2, may play a role in the pathophysiology of these diseases. However, to date, it is not clear that IL-2 is a consistent growth factor in vitro or in vivo for malignant B cells. What then is the potential significance of membrane IL-2R on the malignant B-cell membrane? Laboratory analysis indicates that the malignant cells are the source of elevated serum levels of soluble Tac protein (sIL-2r alpha) in both diseases. Indeed, these cells spontaneously secrete sIL-2R alpha into culture medium. We speculate that the presence of an expanding mass of malignant B cells possessing high and low affinity membrane IL-2R may contribute significantly to the associated immunodeficiency seen in B-CLL. In particular, it is the cell associated high affinity IL-2R that have the greatest potential for reducing the levels of free IL-2 available to normal immune cells.

B-Lymphocytes↗
PubMed1993

Confirmation of Rb gene defects in B-CLL clones and evidence for variable predominance of the Rb defective cells within the CLL clone.

In 70 B-CLL patients, deletion or translocation, at or near the retinoblastoma (Rb) site, was detected in 20 by cytogenetic analysis. Purified B cell clones from 13 of these B-CLL patients were isolated and studied for Rb gene status, Rb mRNA and the Rb protein product. Southern blot analysis of the Rb site detected internal deletions (N = 1) or a single allele loss (N = 2) in five patients. Northern blots detected reduced Rb mRNA in four patients. Immunoblot of whole cell lysate revealed reduced levels of unphosphorylated Rb protein in six CLL patients. No CLL B cell clone contained phosphorylated Rb species. These molecular studies have confirmed the cytogenetic alteration of 13q12-14 sites in B-CLL cells. In addition, cytogenetic and molecular biologic analysis suggest heterogeneity in the B cell clone for Rb gene abnormality. B-CLL patients with abnormalities in both cytogenetic and Rb DNA/RNA analysis will have a dominance of B cells with an Rb abnormality (N = 5). In patients whose Rb defective CLL cells constitute only a minor subpopulation of the total B cell clone, only cytogenetic defects would likely be detected (N = 7).

Blotting, Northern↗
PubMed1993

Detection of clonal platelet antibodies in immunologically-mediated thrombocytopenias: association with circulating clonal/oligoclonal B cells.

Aware that T and B cells in autoimmune thrombocytopenia are abnormal, including the existence of clonal B cell populations, we sought to characterize this clonal phenomenon in various immunological thrombocytopenias using platelet antibody light chain analysis, flow cytometry, Southern blot analysis, and PCR. Using a monoclonal antibody-antigen capture ELISA, we analysed sera from 21 of 26 patients with autoimmune, alloimmune, or drug-induced immunological thrombocytopenia for the light chain phenotypes of their platelet antibodies. Alloantibodies and drug-dependent antibodies from four and 14 patients, respectively, were found that expressed a predominant type of light chain, suggesting that these platelet-reactive antibodies were monoclonal or oligoclonal in nature. 14 of the 26 patients were available for light chain B cell phenotyping studies. Of these 14 patients, thrombocytopenia was due to autoimmunity in two, drug-induced immunity in four, and alloimmunity in eight. We detected clonal populations of B cells in all 14 patients by flow cytometry. Although six of these latter patients possessed platelet antibodies with clonal characteristics, light chain phenotypes of antibodies in five patients were opposite to those of their B cells. Eight of these patients were further examined for immunoglobulin gene rearrangement using Southern and/or polymerase chain reaction analysis. In all eight patients we detected clonal or oligoclonal B cell populations. Only two of these patients had malignancies (chronic lymphocytic leukaemia) that would be expected to have detectable clonal B cells, and thus the mechanism for clonal expansion in the other six patients did not appear to be related to an obvious neoplastic process. Prior to these studies, detection of clonal B cells in thrombocytopenic patients without known malignancies was limited to individuals with autoimmune thrombocytopenia, prompting the speculation that this particular autoimmune disorder arises from B cell dysregulation, rather than from expansion of specific autoantibody producing B cell clones. In contrast, the current studies provide evidence that clonal B cells are common to patients with any form of immunologically-mediated thrombocytopenia. Moreover, the majority of the platelet antibodies (86%) present in these disorders exhibited monoclonal characteristics in that there was an apparent restriction in light chain usage.

Adult↗
PubMed1993

Malignant B cell CD5 membrane phenotype and B cell colony growth in vivo and in vitro in patients with B-chronic lymphocytic leukemia: analysis with clinical parameters.

Chronic lymphocytic leukemia (CLL), despite an overall good prognosis, has a subgroup of patients with more rapid, aggressive disease. In an attempt to generate additional information about the B cell clones in B-CLL which could be used as predictive parameters, we analysed CD5 membrane phenotype and B cell colony growth in 29 B-CLL patients. CD5, a 67-kd glycoprotein, has been reported to be a consistent feature of the malignant B cell membrane phenotype in CLL. We used an in vitro B cell colony assay to study the in vitro growth, differentiation, and cell surface properties of CLL B cells. Finally, a variety of standard clinical parameters were collated for each patient. Monoclonal antibodies to both CD5 and CD19 (pan B cell marker) were used to perform 2-color flow cytometry on freshly purified CLL B cells and on CLL B cells harvested after 7 days of in vitro culture. We demonstrate here that CLL B cells are heterogeneous with respect to their expression of CD5, and that this expression is not fixed but may vary both in vivo and in vitro. In vitro growth potential, as measured by the B cell colony assay, was also heterogeneous with three subgroups defined as low growth (< 10 colonies), intermediate (10-100 colonies) and high growth (> 100 colonies). Furthermore a T cell conditioned medium was not found to be a requirement for in vitro colony growth in the majority of CLL B cells. In addition, we evaluated the potential correlation of B cell CD5 phenotype or B cell colony growth on standard clinical parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1992

Frequent clonal abnormalities of chromosome band 13q14 in B-cell chronic lymphocytic leukemia: multiple clones, subclones, and nonclonal alterations in 82 midwestern patients.

We performed cytogenetic analyses of peripheral blood lymphocytes from 82 Midwestern B-cell chronic lymphocytic leukemia (B-CLL) patients. The cells were cultured with mitogens for 3-4 days. At least 15 metaphase cells were analyzed in 79 (96%) cases. Fifty (63%) of the 79 patients had clonal chromosomal alterations. Structural modifications of the long arm of chromosome 13 at or near band 13q14 were the most frequent abnormalities, identified in 23 (46%) of the patients with clonal abnormalities. In several patients, the abnormality involving band 13q14 was the sole chromosomal alteration. There was a high incidence of complex karyotypes. Nine patients had multiple subclones that appeared to result from clonal evolution; seven patients had cytogenetically unrelated clones; three patients had both subclones and cytogenetically unrelated clones. Nonclonal abnormalities were also prominent. Our study confirms the high incidence of clonal abnormalities involving chromosome arm 13q and documents the clustering of abnormalities at band 13q14 in B-CLL. The evidence for clonal evolution and the presence of multiple unrelated clones in these patients suggest that B-CLL may not be a karyotypically stable disease.

Aged↗
PubMed1992

B-chronic lymphocytic leukemia cells contain both endogenous kappa immunoglobulin mRNA and critical immunoglobulin gene activation transcription factors.

B-cell chronic lymphocytic leukemia (B-CLL) is a hematologic malignancy characterized by the proliferation and accumulation of mature-looking B lymphocytes. Patients with B-CLL exhibit a number of immune defects including: auto-antibodies, depressed cell-mediated immunity and hypogammaglobulinemia (HG). We investigated the control of Ig production in the malignant CLL B-cell at a transcriptional and translation level. We isolated fresh leukemic B-cells from CLL patients and analyzed for the presence of nuclear factors OCT-1, OCT-2, and NF-KB. Malignant B-cells were purified to greater than 90% B-cells, and total cellular RNA and nuclear proteins were isolated from these cells. Mobility shift assays were probed with 32P-labeled oligonucleotides specific to the immunoglobulin (Ig) enhancer and promotor regions. We detected endogenous OCT-1, OCT-2, and NF-KB in all patients tested (n = 5). We then evaluated whether activation of CLL B cells could augment kappa-mRNA levels. CLL cells (n = 3) exposed to phorbol ester and A23187 were harvested at 0, 2, 4, 8, and 48 min and examined for kappa-mRNA by Northern blot. All CLL patients (n = 3) had easily detectable levels of endogenous kappa-mRNA. However, only one patient had an obvious increase in kappa-mRNA post-induction with TPA/A23187. There was no concomitant increase in this patient's OCT-1, OCT-2, or NF-KB level. This finding prompted us to survey other B-CLL patients (n = 6) for Ig nuclear transcriptional factors pre- and post-induction. In summary, CLL B cells express Ig transcriptional factor OCT-1, OCT-2, and NF-KB constitutively. The endogenous level of NF-KB may account for the basal kappa-mRNA detected in B-CLL cells. However, the inability to augment NF-KB levels may, in part, explain the low levels of Ig synthesis in CLL B-cells.

Base Sequence↗
PubMed1991

Habituation to repeated painful and non-painful cutaneous stimuli: a quantitative psychophysical study.

Repeated stimuli elicit progressively smaller responses and elevated sensory and/or pain thresholds (habituation). The present experiments were designed to determine the rate of habituation of perceptual responses to supraliminal painful and non-painful cutaneous stimuli. Changes in the perceived intensity of electrical stimuli applied to the digital nerves of the index finger were determined by a matching procedure in which subjects set the current applied to the index finger of one hand to match the perceived intensity of a stimulus train (5 pulses at 20 Hz) applied to the other index finger. Twenty-five volunteers took part in 7 experiments in which both non-painful (2.5 times the sensory threshold Ts) and painful (1.2 times the pain threshold Tp) stimulus trains were presented. Subjects were required to match the stimuli at 30 s intervals over a period of 7.5 min. The percentage change in matching current (Y) was fitted by the function Y = -20.7*[1-exp(-0.56*t)] for both painful and non-painful stimuli repeated at 2 Hz. Responses recovered completely within 2 min of cessation of the stimulation. The degree of habituation increased or decreased with the rate of stimulus presentation. These results did not depend on changes in afferent fibre recruitment or fatigue because the afferent volley on the median nerve remained constant throughout the period of stimulation. Thus perceptual responses to the perceived intensity of supraliminal painful and non-painful stimuli delivered to the index finger habituate to the same extent, and the extent of the habituation is a function of the frequency of presentation of the stimulus.

Adult↗
PubMed1990

Expansion of a lymphocyte population co-expressing T4 (CD4) and T8 (CD8) antigens in the peripheral blood of a normal adult male.

Approximately 2% to 3% of circulating human T cells co-express CD4 and CD8 (CD4+, CD8+) T-cell antigens. These CD4+, CD8+ cells may be immature precursors that function to replenish functional T-cell subsets. We detected a very high level of CD4+, CD8+ cells in the peripheral blood lymphocytes of a healthy white male, ranging from 21% to 36%. The morphology of his peripheral blood lymphocytes was normal, and he has maintained an elevated level of CD4+, CD8+ cells without clinical disease over a 19-month observation period. The CD4+, CD8+ cells did not possess thymocyte membrane antigen (CD6), nor did they have increased Tac (CD25) antigen. His intact, purified blood T cells had a normal proliferative response to phytohemagglutinin and interleukin-2 (IL-2), provided help for B-cell proliferation at control levels and exposure to IL-2 resulted in generation of cytotoxic cells. However, the purified blood CD4+, CD8+ cells were deficient in these latter functions except for help in B-cell function. Despite defective function, the isolated CD4+, CD8+ cells co-expressed CD2 and CD3. Prolonged in vitro culture of CD4+, CD8+ cells was possible in the presence of recombinant IL-2. The cultured CD4+, CD8+ cells retained the double antigens (CD4 and CD8) throughout a 4-week period. It is likely these cells are less mature than CD4+, CD8- or CD4-, CD8+ T cells as the CD4+, CD8+ have less in vitro function than the former cells, but it is not yet clear if they mature into either CD4+, CD8-, or CD4-, CD8+ cells. Finally, the presence of an expanded, hypofunctioning CD4+, CD8+ cell population in a normal adult male is apparently compatible with excellent clinical health.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1990

Immunoregulatory cell dysfunction in chronic B-cell leukemias.

Chronic B-cell malignancies are routinely characterized as B-cell clonal diseases that have signs and symptoms primarily related to the continuing expansion of these cells. This review discusses chronic lymphocytic leukemia, multiple myeloma and hairy cell leukemia from the perspective of secondary abnormalities in non-malignant cells. Thus, our main purpose is to elaborate on the alterations/abnormalities of the immunoregulatory (IR) cells in these diseases and focus on the qualitative and quantitative aspects of T-cells, natural killer (NK) cells and monocytes. The relevance of the IR-cell changes to the basic disease process and their complications are emphasized.

Humans↗
PubMed1990

Interaction between endogenous opioids and IL-2 on PHA-stimulated human lymphocytes.

Endogenous opioids exert a variety of extra central nervous system (CNS) functions, including modulation of some human lymphocyte functions. The latter opioid activity may result in elevation of human natural killer (NK) function (i.e. by beta-endorphin), which is reversed by an opioid antagonist, Naloxone. Since recent evidence has suggested both structural and functional similarities between lymphokines known to elevate human NK function (interferon and interleukin-2) and endogenous opioids, we investigated if Naloxone could modulate lymphokine-enhanced human NK activity. Naloxone blunted, in a dose-dependent fashion, the NK-enhancing activity of peripheral blood lymphocytes or large granular lymphocytes by recombinant interferon-alpha (IFN-alpha) or interleukin-2 (IL-2). Naloxone decreased the uptake of radiolabelled IL-2 receptors. beta-endorphin also decreased the binding of radiolabelled IL-2 or IL-2 receptor-positive human lymphocytes. Finally, labelled Naloxone was inhibited from binding to phytohaemagglutinin (PHA)-stimulated lymphocytes by either beta-endorphin or IL-2. These findings strongly suggest that human lymphocyte receptors for opioid, IFN or IL-2 molecules, once occupied, have distinct influences on the alternate receptor. In addition, these data further strengthen the potential role of CNS-mediated influences on the human immune system.

Binding, Competitive↗
PubMed1989

Malignant chronic lymphocytic leukemia B cells elaborate soluble factors that down-regulate T cell and NK function.

To determine if the frequently observed T cell and natural killer dysfunction in B-chronic lymphocytic leukemia might be related to the presence of large numbers of malignant B cells, we studied the effects of secretory or shed products of CLL B cells on normal (control) T cell and NK function. The cell-free supernatants from CLL B cells cultured from 24 to 48 hr inhibited a variety of T cell functions including: PHA-induced proliferation, PHA-stimulated entry of T cells into the cell cycle, and PHA-induced production of interleukin-2. In addition, B-CLL supernatants diminished control NK activity. Purified control B cells and other malignant cell lines produced little or no inhibitory activity toward these T cell or NK functions. The sera from these same B-CLL patients diminished PHA-induced interleukin-2 production by control T cells. Initial molecular characterization of the inhibitory factor(s) revealed it to be of low molecular weight (less than 5000 daltons) with loss of functional activity after treatment with neuraminidase. This suggested that this substance might be either a ganglioside or glycoprotein whose inhibitory activity depends on the presence of a sialic acid moiety. If CLL B cells are capable of secreting or shedding immunosuppressive factor(s), then alteration of this property may result in a more normal immune system for these patients.

B-Lymphocytes↗
PubMed1989

Large granular lymphocytes from B-chronic lymphocytic leukemia patients inhibit normal B cell proliferation.

Large granular lymphocytes (LGL) may exert regulatory influences on B cell immunoglobulin synthesis. We, therefore, investigated the influence of LGL from controls and B cell chronic lymphocytic leukemia patients (B-CLL) on control B cell proliferation to costimulation with the F(ab')2 fragment of goat antihuman mu and B cell growth factor (BCGF). Purified LGL (greater than 90% by morphology) from control and B-CLL peripheral blood were added in various concentrations to purified control B cells and incubated with anti-mu and BCGF for 3 days. [3H]-thymidine uptake of B cells was then measured. There was no proliferation of control or CLL LGL alone to the costimulatory signals of the F(ab')2 fragments of goat antihuman mu chain and BCGF. Addition of control LGL to equal numbers of control B cells did not blunt control B cell responsiveness to BCGF (with control LGL 8,649 +/- 298 cpm vs. control B cells alone 8,336 +/- 556 cpm, mean +/- SEM). When control LGL were increased to 10:1 LGL:B cell ratio, the maximal inhibition by control LGL of control B cell proliferative response to BCGF was 23%. In contrast, addition of CLL LGL at a 1:1 LGL:B cell ratio resulted in marked impairment of the control B cell proliferative response to BCGF (with CLL LGL 3,586 +/- 954 cpm vs. control B cells alone 8,649 +/- 298 cpm). Inhibition by CLL LGL occurred in a cell-concentration-dependent manner. No difference in CLL LGL's inhibitory effect on either resting or activated control B cell responsiveness to BCGF was noted. Inhibition of de novo protein synthesis (by cycloheximide inhibition) of CLL LGL did impair CLL LGL's inhibitory capacity for BCGF-induced B cell proliferation. A possible explanation for these findings includes the possibility that a subgroup of LGL with B cell suppressive activity may have expanded as a host response to the B cell leukemia or as part of the disordered cell regulation in B-CLL.

Agammaglobulinemia↗
PubMed1989

Evidence that large granular lymphocytes from B-CLL patients with hypogammaglobulinemia down-regulate B-cell immunoglobulin synthesis.

B-chronic lymphocytic leukemia (CLL) patients frequently suffer from moderate to severe hypogammaglobulinemia. This complication is a serious cause of morbidity and mortality in this disorder. There is recent evidence that natural killer (NK) cells modulate B-cell immunoglobin (Ig) synthesis/secretion. The authors therefore evaluated the circulating NK cells from B-CLL patients on their ability to regulate mitogen-induced B-cell Ig synthesis. Blood, NK cells (CD16+, CD3-) from three B-CLL patients with hypogammaglobulinemia were able to clearly down-regulate the pokeweed mitogen (PWM)-induced-B-cell Ig secretion. In contrast, CD16+, CD3- cells from age-sex-matched controls or B-CLL patients with normal Ig were either nonregulatory or enhanced mitogen-induced B-cell Ig secretion. An alternative explanation for hypogammaglobulinemia in B-CLL patients is the immunomodulation of B-cell Ig production/secretion by CD16+, CD3- blood cells.

Agammaglobulinemia↗
PubMed1988

Guidelines for clinical protocols for chronic lymphocytic leukemia: recommendations of the National Cancer Institute-sponsored working group.

The National Cancer Institute (NCI)-sponsored Chronic Lymphocytic Leukemia (CLL) Working Group was convened to develop a set of standardized eligibility, response, and toxicity criteria for clinical trials. We recognized the previous efforts in 1967 (published again in 1973 as the report of the Chronic Leukemia-Myeloma Task Force [1] and 1978 of Cancer and Leukemia Group B (CALGB) [2]). We have used these reports for guidance during the current effort. Several noteworthy developments in the past few years have made it necessary to modify the previous guidelines. First, the diagnostic criteria for CLL and its clinical staging have been developed and well defined. Second, although staging systems facilitated entry of comparable and relatively homogeneous groups of patients in clinical trials, the definitions of response (CR) and partial response (PR) were not uniformly adopted from the previous guidelines in the clinical trials (Tables IA, IB); therefore, comparisons of results obtained in different studies became difficult. Third, there has been an improvement in our understanding of the immunology and biology of CLL. Finally, we are witnessing the emergence of several chemotherapy agents that promise impressive activity in CLL (e.g., 2'-deoxycoformycin [3], fludarabine monophosphate [4, 5]), and thereby offer the potential for improving survival time in this disease. To best identify regimens worthy of continued pursuit in large comparative trials, standardized guidelines for evaluation are essential. A number of laboratory investigations are also presented for which scientific interest is high yet relevance remains to be determined; thus, they are presented as companion studies to the clinical trials. This mechanism allows for flexibility in the testing of these questions and for additional ideas in the future without requiring modification of an entire treatment protocol. The following guidelines were developed to be used as a form of standardization for clinical trials, incorporating current technologies, yet remaining relevant to the general hematology/oncology community. Based on the membership of the Working Group, it is expected that these guidelines will serve as the criteria for most clinical trials in the near future.

Antineoplastic Agents↗
PubMed1988

Reduction in perceived intensity of cutaneous stimuli during movement: a quantitative study.

The effect of movement of the index finger on the perceived intensity of trains of electrical stimuli to the digital nerves of the same finger was studied quantitatively using a novel intramodality stimulus-matching task. Subjects consistently were able to match reliably the perceived intensity of stimuli delivered on the 'reference' side with that of stimuli delivered simultaneously to the digital nerves of the index finger on the other ('matching') side. Both active and passive movement of the index finger (on the reference side) in the palmar plane reduced the matched stimulus voltage by about 10% of its control value for stimuli at twice the sensory threshold. This reduction in perceived intensity did not persist beyond the period of stimulation. An isometric contraction of first dorsal interosseous muscle produced a smaller, but statistically significant, reduction in perceived intensity. Non-noxious electrical stimulation of the digital nerves of the ipsilateral thumb or little finger also reduced the perceived intensity of stimuli to the index finger. Perceived intensity of stimuli during movement was also reduced, but to a lesser extent, when the index finger was stimulated at painful levels. Psychophysical studies using open magnitude scaling indicated that the relationship between stimulus intensity and perceived magnitude of electrical stimuli could be described by a power law with an exponent close to 1.0. Therefore, the percentage reduction in matching voltage accurately represents the percentage decline in perceived intensity. These results suggest that the perceived intensity of cutaneous stimuli to the index finger over a range of intensities can be reduced by afferent activity from the hand. The motor command appears to play a relatively minor role in modulating the perceived intensity.

Adolescent↗