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M F La Via

Publications and source records attributed to M F La Via.

At least 19 recordsLinked to original sources
PubMed1992

Clinical applications of cytometry: 6th annual meeting.

The Sixth Annual Clinical Applications of Cytometry Meeting was held September 11-14, 1991, in Charleston, SC. Attendance reached a record 470. The meeting provides a forum for interactions among investigators who utilize cytometry as a tool in their clinical immunology, cell biology, hematology, and cancer investigations. Clinical laboratory directors and their technical staff find the meeting of practical value because of the presentation of new applications that they can take home to their own laboratories. The emphasis of the meeting is on advances in the application of cytometry to clinical problems. Often, advances result from new dyes or reagents or improved instrumentation. Sometimes they result from advances in biology that make the studies possible. Occasionally a new way of looking at the same data provides a useful answer. In every case, the effort is to provide a reliable, straightforward way to quantitate biologic information in order to provide improved diagnosis or treatment of human disease.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Clinical applications of cytometry: 5th annual meeting.

The 5th annual Clinical Applications of Cytometry meeting was held September 12-15, 1990 in charleston, SC. The theme which emerged repeatedly throughout the meeting was the need to take full advantage of the quantitative power of cytometry to provide the most useful clinically relevant diagnostic and prognostic information. Greater quantitative power is based on careful and reproducible standards and quality control. The same principles, albeit with somewhat different approaches, apply to cell surface immunofluorescence analysis, DNA measurements, and image cytometry assessments. Monoclonal antibody probes against oncogenes, others against lymphokines within the Golgi, and a novel fluorogenic substrate designed to quantitate the activity of a mitochondrial enzyme were exciting developments described at the meeting.

Autoimmune Diseases↗
PubMed1991

Psychoneuroimmunology: where are we, where are we going?

We have reviewed briefly the current status of research on central nervous system-immune system interactions, focusing attention on the neural and humoral pathways by which CNS and IS communicate and interact and on the effects of stress and psychiatric illness on immune function. It is evident that CNS-IS communication occurs by direct innervation of lymphoid organs and by means of hormones, neuropeptides and cytokines. There is also clear evidence that humoral substances each of which were thought to be the product of one specific cell type are elaborated and secreted by a variety of cell types. This observation suggests a new unified concept of CNS-IS interactions with mediators of these interactions being produced ubiquitously and acting on cells of the two systems. In examining the effects of stress on IS it has become apparent that stress of various types can have a depressive effect on immune functions, primarily at the level of T lymphocytes and NK cells. This suggests that the defense mechanisms affected by stress are those which are responsible for cytotoxic effector responses. These findings are interesting in that they support older studies implicating stress in the pathogenesis and/or the clinical course of neoplastic diseases. Further support for a role of stress-induced immunodepression in morbidity comes from a very interesting, recent prospective study showing that stress will affect susceptibility to viruses. Finally, exploration of the mechanisms of stress-induced immunodepression, suggests that a variety of mediators which regulate lymphocyte interactions and activation may be affected, perhaps at the level of gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗
PubMed1990

Immunophenotypic analysis of non-Hodgkin's lymphomas.

Flow cytometric cell analysis with fluorescence-labeled antibodies has become a very useful methodology for the immune phenotyping of lymphocytes. The continued evaluation of lymphocyte cell surface antigens has been of value in this respect by providing a clear picture of lymphocyte differentiation steps. Thus it is now possible to precisely identify lymphocytes of abnormal phenotype which may represent malignant cells. Detection of monotypic populations of lymphocytes represents a monoclonal expansion of a lymphocyte subset which is the hallmark of malignancy. In the case of B cell lymphoma, detection of monotypic populations rests on the finding of a monoclonal expansion of a cell type bearing one type of light chain and of heavy chain and/or one of the specific B lymphocyte differentiation antigens. The diagnosis of T cell malignancy is more difficult to establish and a diagnosis of T cell lymphoma rests on the finding of an abnormal phenotype. Thus flow cytometry in combination with histomorphologic examination is a useful technique for the more precise diagnosis of lymphomas and for the establishment of treatment protocols.

Antibodies, Monoclonal↗
PubMed1988

Subclass specificity of the Fc receptor for human IgG on K562.

The erythroleukemic cell line K562 bears a 40-kDa Fc receptor (Fc gamma RII) serologically related to and with a similar molecular weight as the Fc gamma R present on a broad range of leukocytes. The human IgG subclass specificity of the Fc gamma R on K562 was investigated using IgG aggregates of defined size, obtained from purified human myeloma proteins. The monoclonal antibody IV.3, which reacts with the Fc gamma RII present on various cell types, totally prevented binding of 125I-IgG2 trimers to K562. Experiments with radiolabeled IgG2 trimers showed that K562 cells bound a mean of 156,764 +/- 9895 molecules per cell with an association constant (Ka) of 1.8 +/- 0.7 X 10(8) M-1. Similar results were obtained with IgG3 oligomers. IgG3 and IgG2 trimers were about two- to threefold more effective in inhibiting binding of 125I-IgG2 trimers to K562 than IgG1 and IgG4 trimers. These results were confirmed by inhibition experiments using IgG monomers. The subclass specificity of the Fc gamma RII on K562 (i.e., IgG2 = IgG3 greater than IgG1 = IgG4) is quite distinct from the one reported for the Fc gamma RI and III of human cells (i.e., IgG1 = IgG3 greater than IgG4 and IgG2).

Antibody Specificity↗
PubMed1988

Depression by Fc gamma receptor ligands of SRBC-induced IgM-PFC generation in human blood mononuclear cell cultures.

A tissue-culture system to stimulate human peripheral blood mononuclear cells (PBMC) has been employed in which IgM plaque-forming cell (IgM PFC) generation in response to sheep erythrocytes (SRBC) is dependent on macrophages and T suppressor and helper lymphocytes. In this system PBMC from normal subjects give IgM PFC responses ranging from 26 to 938 PFC/culture. Heat-aggregated human IgG or immune complexes present for the duration of culture induce a significant depression of PFC. Unaggregated IgG has no effect on the response or only a moderate stimulatory effect at the highest dose. The results of these experiments are compatible with previous results in a murine system, which indicated that Fc gamma receptor-positive (Fc gamma R+) cells in the suppressor subset are the target for aggregated IgG and induce depression of the PFC response. A similar mechanism may be operating in the human system described here, although the target cell has not been identified. These results may reflect a mechanism of immunomodulation dependent on interaction of Fc receptor (FcR) ligands with FcR, which may play a role in the pathogenesis of immune complex disorders.

Antibody-Producing Cells↗
PubMed1988

Immunoresponsiveness in hemophilia: lymphocyte- and phagocyte-mediated functions.

Several deficits of immune response have been reported in hemophiliacs. In order to evaluate the overall immune function in this disease, we have investigated peripheral blood mononuclear cells (PBMC) surface phenotype, lymphokine production, B cell responsiveness, monocyte- and polymorphonuclear (PMN) cell-mediated responses in a group of 25 A or B hemophiliac patients. They were treated with concentrates (greater than 30,000 U/year) for at least 8 years, and ten of them were positive for human immunodeficiency virus (HIV) infection. With particular reference to lymphocyte surface markers, a low CD4+/CD8+ ratio and an increased frequency of CD25+ and surface immunoglobulin (sIg) positive lymphocytes were noted in HIV+ subjects. By contrast, CD3+ and CD4+ cell frequency was decreased in HIV- patients, whereas in the same individuals CD11+ and sIg+ cell percentage was augmented. Regardless of HIV infection, a quite variable degree of B-cell response was seen in hemophiliacs with either a T-independent or a T-dependent polyclonal B cell activator. PMN chemotaxis, phagocytosis, and killing were significantly diminished, whereas similar monocyte functions were basically unaffected. Finally, hemophiliacs were characterized by a profound impairment of leukocyte inhibiting factor (LIF) and lymphocyte-derived chemotactic factor (LDCF) production. Our findings clearly indicate an impairment of immune function in hemophiliacs regardless of HIV infection.

Adolescent↗
PubMed1988

Inhibition of E rosetting and of OKT 11 in patients with oral dysplasia and neoplasia.

A group of patients with oral dysplastic or early neoplastic lesions has been followed for 6 years to examine the change in ALS (antilymphocyte serum) induced 25% E rosette inhibition during the course of their disease. Control patients with other oral problems were examined similarly. The E rosette inhibition titer differences seen in our previous studies between control and diseased patients do not appear to persist with a longitudinal examination of these patients. While at early examination the patients exhibit higher inhibition titers than controls, later analysis shows that they seem to return to normal. To improve methodology, inhibition of OKT 11 uptake was substituted for E rosette inhibition and it is clear that both methods measure the same phenomenon. Thus, the former is more accurate and quantitative than the latter and will be used in future work. Continuation of these studies with the examination of more patients will be of value in assessing possible T lymphocyte changes in patients with oral lesions.

Antigens, Surface↗
PubMed1988

Mononuclear cells from rheumatoid arthritis patients exhibit a depressed IgM response to sheep erythrocyte stimulation in vitro.

Human peripheral blood mononuclear cells when cultured for the short term (11 days) produce an optimal IgM plaque-forming cell (PFC) response to sheep erythrocytes, which is dependent on macrophages and T suppressor and helper lymphocytes. With this system we have investigated the PFC response of individuals with rheumatoid arthritis and compared this to the response of normal sex- and age-matched controls and of patients with osteoarthritis. The response of rheumatoid arthritis patients was significantly lower than that of subjects in the other two categories.

Animals↗
PubMed1987

T-lymphocyte polyclonal proliferation: effects of stress and stress response style on medical students taking national board examinations.

This study investigated the effects of stress and stress response style on T-lymphocyte polyclonal proliferation (TLPP). The TLPP levels of 15 medical students taking NBME Part I were compared to those of a matched (on age and sex) sample of students not taking exams and hospital employees. All subjects completed the Impact of Events Scale to measure recent stress levels and style of responding to stress. TLPP data for both experimental and control groups, pre- and post-boards, were analyzed via a 2 X 2 factorial analysis of variance. Results indicated a significant main effect for the NBME stress vs control conditions and a significant interaction between stress response style (avoidance vs intrusion) and NBME stress vs control conditions. TLPP levels were significantly depressed (relative to the controls) for the NBME stress group 1 week after examinations. Furthermore, those students whose stress response style was characterized by intrusion were significantly more immunosuppressed than those characterized by an avoidance stress response style. Four- and six-week follow-up measures of TLPP were taken on 10 and 11 NBME group students, respectively. Follow-up results, analyzed via t tests, indicated that TLPP levels were significantly suppressed for 4 weeks but returned to initial normal levels at 6 weeks. Results are discussed in terms of needed research examining the mechanism of stress intruders' susceptibility to stress-induced immunosuppression and the possible clinical significance of brief periods of stress-induced decrements in TLPP levels.

Adult↗
PubMed1987

Humoral-mediated suppression of interleukin 2-dependent target cell proliferation in acquired immune deficiency syndrome (AIDS): interference with normal IL-2 receptor expression.

Sera from patients with acquired immune deficiency syndrome (AIDS) were analysed for effects on normal lymphocyte interleukin 2 (IL-2) production, IL-2 receptor (IL-2R) expression and levels of IL-2 dependent T cell proliferation. The presence of AIDS serum appeared to reduce significantly IL-2 production by cultures of mitogen-activated normal human peripheral blood mononuclear cells (PBMC). However, dilution analyses of the culture supernatants indicated that the primary inhibitory effect occurred at the level of the IL-2 responsive target cell. Furthermore, eight of nine AIDS sera, but none of the normal human sera (NHS) tested, suppressed the capacity of IL-2-dependent CTL-20 cells to proliferate in response to human IL-2. Fractionation of AIDS sera by gel filtration on Sephacryl S-200 revealed that inhibitory activity coeluted with the immunoglobulin fraction. Pretreatment of human IL-2R+ lymphoblasts with AIDS serum did not interfere with the binding of monoclonal antibody (anti-Tac) specific for the human IL-2R; however, significant reductions in the levels of phytohaemagglutinin-induced IL-2R expression were observed when normal human PBMC were cultured in the presence of AIDS serum. These findings indicate that the inhibitor present in many AIDS sera does not suppress lymphocyte proliferation by interfering directly with the IL-2 receptor, and suggest that inhibition occurs at a later stage of the cell cycle. One of the primary consequences of the activity of this serum inhibitory factor is a decline in the levels of lymphocytic IL-2R expression.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Mononuclear cell phenotypes in patients with psoriasis.

Mononuclear blood cells from 19 patients with psoriasis were stained with a panel of monoclonal antibodies which detect total T lymphocytes, their helper/inducer and suppressor/cytotoxic subsets and Ia-positive lymphocytes and monocytes. Fluorescence-positive cells were enumerated by cell flow cytometry. In these patients, percentages of all mononuclear cell studies were within reference range with few, sporadic exceptions. Statistical analysis of data showed no significant differences between patient values and reference values from a panel of 100 normal subjects.

Adult↗
PubMed1985

Lymphocyte phenotype changes in congenital and acquired perinatal cytomegalovirus infections.

The recognition that the multiple functions of T-lymphocytes are accomplished by separate subpopulations of cells that can be delineated both functionally and by antisera directed against specific cell surface markers is one major advance in immunology. Our study was directed at enumerating lymphocyte subsets in cytomegalovirus (CMV) perinatal infections with monoclonal antibodies and cell flow cytometry. Eight patients ranging in age from 1 week to 2 1/2 months were studied. Except for one term neonate, all of the infants were less than 36 weeks of gestational age, with a mean of 31.5 weeks (range 27-36 weeks) at birth. The mean birth weight of the premature infants was 1,211 gm (range 870-2420 gm). Five patients were 3 weeks old when studied and were classified as congenital CMV by viral isolation. Three were older than 2 months and were classified as acquired CMV. One of the acquired CMV infants was followed from birth to 6 months of age and had normal lymphocyte numbers at 2 weeks with alterations appearing at 8 weeks. The results of these studies indicated that in congenital CMV there is a normal to high helper/suppressor ratio. On the contrary, in acquired CMV this ratio is profoundly depressed because of significant increase in suppressor T-lymphocytes with borderline normal helper T-lymphocytes. In the latter group, the ratio increased with time after the acute infection episode. Our results agree with reported data indicating that in adults with CMV there is a depression of the helper/suppressor ratio during the acute stage with a return toward normal values during convalescence.

Antibodies, Monoclonal↗