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Biomedical subjects

B K Pelton

Publications and source records attributed to B K Pelton.

At least 19 recordsLinked to original sources
PubMed1992

Polyclonal origin of rheumatoid synovial T-lymphocytes.

Nineteen T-cell clones from seven patients with RA were obtained by cloning infiltrating lymphocytes from needle synovial biopsies. Southern blot analysis of the T-cell receptor (TCR) beta-chain genes in these clones revealed that there were no T-cell clones with an identical rearrangement of the TCR beta gene. These results do not support the idea that the infiltrating T-lymphocytes in RA are of monoclonal or oligoclonal origin.

Arthritis, Rheumatoid↗
PubMed1992

Activation of IL-6 production by UV irradiation of blood mononuclear cells from patients with systemic lupus erythematosus.

Cultured mononuclear cells from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and normal donors were assayed for their ability to secrete IL-6 both spontaneously and after exposure to UV light. Mononuclear cells from SLE, RA and atopic control patients produced IL-6 spontaneously, while those from normal donors did not. Spontaneous production of IL-6 occurred in the non-adherent cell population. UV light-induced IL-6 production was confined exclusively to the SLE patients and was present only in the macrophage/monocyte fraction. This stimulation was induced by wavelengths in the UVA, UVB but not the UVC portion of the spectrum. These results suggest that cytokine release may be involved in the exacerbations of SLE provoked by photosensitivity.

Humans↗
PubMed1992

Chimeric CD7 monoclonal antibody therapy in rheumatoid arthritis.

Murine monoclonal antibody (Mab) therapy in patients with rheumatoid arthritis (RA) produces an antimouse immunoglobulin response by the recipient. We studied a chimeric (human/mouse) CD7 Mab, in a dose ranging tolerability study in 10 patients with RA. Modest improvements in disease activity occurred with frequent acute adverse effects of malaise, fever and nausea. After treatment, peripheral blood T lymphocyte numbers fell by 50% and CD7 expression fell by 97% for less than 7 days. Our study demonstrates chimeric Mab function in vivo and illustrates the influence of antibody isotype and patient characteristics on adverse effects.

Adult↗
PubMed1991

Cytokine-independent progression of immunoglobulin production in vitro by B lymphocytes from patients with systemic lupus erythematosus.

B lymphocytes from patients with systemic lupus erythematosus (SLE) secreted high levels of immunoglobulin spontaneously when cultured in vitro. Addition of the cytokines interleukin-2, interleukin-4 and interleukin-6 either alone or in combination failed to augment spontaneous immunoglobulin synthesis. Percoll-separated low-density SLE B lymphocytes matured into immunoglobulin-secreting cells also independent of exogenous interleukins. During maturation these cells became enlarged and less dense, and began to express CD23. This was in contrast to normal B cells, which did not secrete immunoglobulin spontaneously but synthesized IgM after interleukin stimulation. These results indicate that in vitro immunoglobulin synthesis by SLE B cells is already initiated in these cells and progresses independently of further stimulatory manoeuvres.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

Herpes simplex virus and the rheumatic diseases.

A viral aetiology for rheumatoid arthritis and inflammatory connective tissue diseases has been sought in general terms first, by studying viral growth patterns in lymphocytes from the blood and lesions of patients affected second, by analysing lymphocyte concentrations of the interferon-induced enzyme 2-5 oligo-adenylate synthetase (2-5 A); and third, by probing Southern blots of lymphocyte DNA with viral probes. Indirect evidence consistent with a viral aetiology has been found in several such diseases, but direct proof has been difficult to adduce. There is some suggestion that herpes simplex viral (HSV) DNA is present in Behcet's blood lymphocytes, but the findings are inconsistent. It is also plausible that viruses such as HSV do not induce these diseases through classic immunopathological mechanisms, but as "promoters" of abnormal lymphoproliferation in individuals with predisposing defects, possibly related to selective DNA repair defects.

Behcet Syndrome↗
PubMed1988

Use of T cell cloning to detect in vivo mutations induced by cyclophosphamide.

By cloning T cells, mutations at the hypoxanthine-guanine phosphoribosyltransferase locus were quantified in peripheral blood lymphocytes of 12 patients with connective tissue diseases receiving long-term cyclophosphamide. Frequency of mutation was higher than in control subjects and was related to the duration of therapy; therefore, some cells with mutations are long-lived, and these cells accumulate in the peripheral circulation. Mutation frequency was also independently related to age. The results indicate that even low doses of cyclophosphamide are mutagenic and may explain, in part, why these patients are at risk of drug-induced malignancy.

Chromosome Mapping↗
PubMed1988

A search for retrovirus infection in systemic lupus erythematosus and rheumatoid arthritis.

Evidence for retroviral infection in general and human immunodeficiency virus (HIV) infection in particular was sought in freshly isolated peripheral blood T cells, B cells, and monocyte-macrophages from patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and also in T cell and B cell lines established from the same source. Similar cells isolated from rheumatoid synovial membrane were also examined. The strategy used for the detection of virus was cocultivation with susceptible cell lines looking for syncytia formation, reverse transcriptase production, and nucleic acid hybridisation with HIV cDNA probes. No evidence for infection was obtained.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Spontaneous production of B cell growth factors by SLE lymphocytes.

Systemic lupus erythematosus blood lymphocytes produce B cell growth factors (BCGF) spontaneously to an extent comparable with pokeweed mitogen-stimulated lymphocytes from normal donors. BCGF production by SLE lymphocytes is not increased by PWM and these cells are refractory to exogenous BCGF. Production requires B cells and irradiated T cells but not accessory cells. The properties of spontaneously synthesized BCGF differ in some respects from those induced by PWM. These findings suggest that the abnormal B cell proliferation characteristic of SLE may result, at least in part, from autostimulatory growth factors.

Growth Substances↗
PubMed1985

Immunoregulatory effects of alpha-interferon. Effects on in-vitro antibody synthesis by lymphocytes from patients with rheumatoid arthritis.

The immunosuppressive effects of alpha-interferon (IFN) on the in-vitro synthesis of specific anti-influenza virus antibody by lymphocytes from 20 healthy donors were compared with those from 12 patients with rheumatoid arthritis. No differences were observed between the two groups. IFN suppressed the induction of in-vitro antibody synthesis by lymphocytes from rheumatoid donors but did not affect antibody synthesis once this had been initiated. Furthermore, the IFN-mediated suppression of antibody synthesised by rheumatoid lymphocytes could also be reversed by B cell helper supernatant. These findings make it unlikely that alpha-IFN affects established B cell responses characteristic of the rheumatic diseases.

Antibody Formation↗
PubMed1985

Immunoregulatory effects of interferon-alpha. I. Interferon-alpha inhibits in vitro antibody synthesis by normal human lymphocytes.

The effects of human interferon-alpha (IFN-alpha) on in vitro synthesis of specific anti-influenza virus antibody were measured in cultures of peripheral blood lymphocytes from normal donors. IFN-alpha suppressed antibody synthesis in a time and dose related manner. This suppression was also produced by monoclonal antibody purified IFN-alpha and was blocked by anti-IFN-alpha antibody. However antibody induced by a combination of antigen and 'B cell helper supernatant' was not suppressed indicating that IFN-alpha inhibits the initial events in antibody synthesis but does not affect cells committed to antibody production.

Adult↗
PubMed1985

The rheumatoid synovial membrane participates in systemic anti-viral immune responses.

Sixteen patients with rheumatoid arthritis were systemically immunized with influenza virus vaccine and in vitro anti-influenza antibody responses by blood lymphocytes and lymphocytes isolated from synovectomy specimens were measured after in vitro challenge with this influenza antigen. Synovial lymphocytes from eight of these patients produced anti-viral antibody, thereby indicating that infiltrating lymphocytes participate in a systemic anti-viral immune response.

Adult↗
PubMed1983

Effects of immunosuppression on herpes simplex virus growth in lymphocytes of patients with connective tissue diseases.

The growth of herpes simplex virus (HSV) was measured in blood lymphocytes isolated from patients with connective tissue diseases receiving immunosuppressive drugs. Whereas lymphocytes from such patients were frequently nonpermissive for HSV before treatment, they became permissive in most patients after treatment. The exception was the persistence of nonpermissiveness in lymphocytes of treated patients whose disease was associated with malignant disease.

Adult↗
PubMed1982

Virus infections and chronic rheumatic disorders.

There is little direct evidence that viruses cause inflammatory arthritis in the sense that infectious agents classically cause disease. However, there are several mechanisms by which virus infections could be implicated in the pathogenesis of such disorders. In particular virus infection of lymphocytes could produce the combination of selective immunodeficiency and immune stimulation that characterizes many rheumatic disorders. In addition re-combination events between integrated pro-viruses in DNA and exogenous infections would account for the lack of any obvious correlation between the appearance of these disorders and any obvious preceding viral infection. Certainly, more sophisticated approaches will be needed to test such hypotheses rather than relying on classical techniques for viral isolation.

Antigens, Viral↗
PubMed1982

Selective immunosuppressive effects of measles virus infection.

The antibody response to diphtheria toxoid by cultured tonsil cells was suppressed by measles virus, which productively infected a small percentage of both T and B lymphocytes. However, infection of cultures spontaneously secreting antibody and immunoglobulin (with Herpes simplex virus) or measles virus did not result in immunosuppression. Immunosuppression by measles virus may thus be attributed to a selective effect on the inductive phase of the response and suggest that infection of immunoglobulin-producing B lymphocytes does not alter the ability of these cells to secrete antibody.

Adolescent↗
PubMed1982

Defective B cell function in systemic lupus erythematosus.

The in vitro synthesis of specific anti-influenza virus antibody was measured in cultures of peripheral blood lymphocytes from 25 patients with systemic lupus erythematosus (SLE) and 23 control subjects. Whilst all cultures derived from normal individuals synthesized specific antibody, cultures from patients with SLE were consistently unable to produce anti-influenza antibody. This defect could not be corrected by manipulating the culture conditions or by in vivo immunization. Co-cultivation of separated SLE-B or control B cells, with SLE-T or control T cells showed that the immunodeficiency exhibited by the SLE peripheral blood lymphocytes resides in the B cells.

Antibodies, Viral↗
PubMed1980

Herpes simplex virus depresses antibody production by affecting T-cell function.

Many viruses enter lympho-reticular cells during pathogenesis and thereby induce immunosuppression, which is of practical importance in that it may be related to overall virulence. Immunosuppression may result from a selective infection, as viruses often show an affinity for different lymphocyte subpopulations: Epstein-Barr virus, for example, infects only a small percentage of B cells. We reported previously that herpes simplex virus (HSV) type 1 suppressed the induction of an antibody response to diphtheria toxoid in cultures of human tonsil cells, and that this seemed to result from the infection of a small percentage of T lymphocytes. However, as fully infectious virus was used in these experiments, it had probably spread from cell to cell in the course of the culture, so complicating the interpretation of the results. Accordingly, we have now reinvestigated the mechanism of immunosuppression using temperature-sensitivity (ts) mutants which fail to complete their growth cycle in the conditions selected for antibody synthesis. In this study, mutants tsB, tsD and tsF, derived from HSV type 1 strain 17, and ts 9, derived from HSV type 2 HG 52, were used. The results suggest that the immunosuppression is due to the selective infection by the viruses of helper T cells.

Antibody Formation↗
PubMed1980

Lymphocyte abnormalities in Behçet's syndrome.

In order to test indirectly the hypothesis that Behçet's syndrome is caused by a virus, lymphocytes from eighty-six patients were evaluated for two parameters consistent with persistent virus infection: chromosomal abnormalities and decreased ability to herpes simplex virus type I (HSV) to grow in lymphocyte cultures stimulated by PHA. Whereas HSV grew in lymphocytes cultured from all normal donors, replication was impaired in lymphocytes from 37% of the patients with Behçet's syndrome. This figure is increased to 57% if patients receiving steroids or cytotoxic drugs were excluded. Lymphocytes were scored as chromosomally abnormal from sixteen of the thirty-eight patients examined, compared with only one of seventeen normal controls. There was damage to specific chromosomes in four patients. The frequency with which chromosomal abnormalities were detected was significantly related to failure to replicate HSV and inversely related to concomitant steroid treatment. The findings are consistent with a viral aetiology for Behçet's syndrome but other explanations are not excluded.

Adolescent↗