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R A Dempsey

Publications and source records attributed to R A Dempsey.

At least 37 records · Page 2Linked to original sources
PubMed1990

Anti-tumor necrosis factor antibody enhances allograft survival in rats.

We have recently observed significantly elevated serum tumor necrosis factor-alpha (TNF-alpha) levels during human liver allograft rejection. Although increased TNF activity has been reported in rejecting rat cardiac and renal allografts, this represents the first report of an animal model utilizing immunotherapy directed against TNF. Intraabdominal heart transplants (Buffalo to Lewis) were performed. Cardiac rejection was defined as cessation of a palpable beat and confirmed at laparotomy. Control animals received no immunotherapy and experienced rejection on Postoperative Day 11 +/- 0.4 (mean +/- SEM). Experimental animals received immunotherapy either intraperitoneally (ip) or intravenously (iv) from Days 1 to 10. Intraperitoneally administered anti-TNF-alpha prolonged graft survival to 16 +/- 2.7 days (P less than 0.05 vs controls), iv administration prolonged survival to 15 +/- 1.4 days (P less than 0.004). Animals treated with ip anti-TNF-beta survived 17 +/- 1.7 days (P less than 0.002 vs controls). Conversely, administration of purified TNF-alpha to graft recipients decreased graft survival to 7 +/- 0.4 days (P less than 0.001 vs controls). Serum samples analyzed in an L929 bioassay showed increased cytotoxic activity in control animals, corresponding to an increase in circulating TNF. This activity was partially abrogated in animals receiving immunotherapy. These data demonstrate that circulating levels of TNF are increased during rejection. Immunotherapy with anti-TNF-alpha or anti-TNF-beta prolongs graft survival, suggesting that TNF may play a role in the pathogenesis of acute allograft rejection.

Animals↗
PubMed1990

The role of tumor necrosis factor in allograft rejection. II. Evidence that antibody therapy against tumor necrosis factor-alpha and lymphotoxin enhances cardiac allograft survival in rats.

In the previous study we demonstrated that circulating levels of TNF-alpha are elevated during liver allograft rejection and may precede clinical manifestations. The current study was designed to investigate the efficacy of antibody therapy against tumor necrosis factor-alpha and lymphotoxin (LT) in a rat heterotropic cardiac transplant model utilizing Buffalo donors and Lewis recipients. Control animals received no immunotherapy and experienced rejection on postoperative day 11 +/- 0.4 (mean +/- SEM). Experimental animals received immunotherapy either intraperitoneal or intravenous from days 1 to 10. The i.p. administered anti-TNF-alpha prolonged graft survival to 16 +/- 2.7 days (P less than 0.05 vs. controls); the i.v. administration prolonged survival to 15 +/- 1.4 days (P less than 0.004). Animals treated with i.p. anti-LT survived 17 +/- 1.7 days (P less than 0.002 vs. controls). Combination immunotherapy of anti-TNF-alpha and anti-LT increased function to 21 +/- 2.2 days (P less than 0.001 vs controls). Conversely, administration of purified TNF-alpha or LT to graft recipients accelerated the time to rejection. Mean survival for both treatments was 7 days (P less than 0.001 vs. controls). Histologic examination of the transplanted cardiac tissue showed a typical pattern for acute rejection; there was no evidence of hemorrhagic or coagulative necrosis. In contrast, administration of purified TNF-alpha or LT to recipients of a syngeneic heart did not stimulate rejection. These data suggest that TNF-alpha and LT may play a role in the pathogenesis of acute allograft rejection. In addition, the mechanism appears to be distinct from that seen in TNF-alpha or LT-mediated cytotoxicity of tumor cells.

Animals↗
PubMed1990

The role of tumor necrosis factor in allograft rejection. I. Evidence that elevated levels of tumor necrosis factor-alpha predict rejection following orthotopic liver transplantation.

Plasma levels of tumor necrosis factor-alpha were measured in 50 adult patients following orthotopic liver transplantation. The mean (+/- SEM) plasma concentration of TNF-alpha was significantly higher in patients experiencing a rejection episode (941 +/- 83 pg/ml) than in those with a stable clinical course (240 +/- 6 pg/ml; P = 0.0001). Peak levels of TNF-alpha were usually found at the time of clinically diagnosed rejection, although elevated levels were observed 1-2 days earlier. First-week peak TNF-alpha levels were significantly higher in patients who suffered graft loss (2146 +/- 788 pg/ml) than in those who were discharged from the hospital without clinical evidence of rejection (581 +/- 93 pg/ml; P = 0.004). TNF-alpha levels were not correlated with white blood cell count (r2 = 0.004), cyclosporine levels (0.01), serum creatinine (0.002), serum bilirubin (0.05), serum SGOT (0.03), or SGPT (0.05). TNF-alpha levels were not elevated in four cases of viral hepatitis occurring after transplantation. We conclude that circulating levels of TNF-alpha are elevated during liver allograft rejection and may precede clinical manifestations. First-week TNF-alpha levels are also useful predictors of long-term graft outcome. Further investigation is required to determine whether this monokine is important in the actual pathogenesis of allograft rejection.

Adolescent↗
PubMed1989

In vitro production of IL 1 beta, IL 1 alpha, TNF and IL2 in healthy subjects: distribution, effect of cyclooxygenase inhibition and evidence of independent gene regulation.

Numerous studies have reported altered in vitro cytokine production in various diseases. In the present study we used specific immunoassays to quantitate production of interleukin 1 beta (IL 1 beta), IL 1 alpha, tumor necrosis factor (TNF) and IL 2 from human peripheral blood mononuclear cells (PBMC). The distribution of cell-associated and secreted cytokines was studied in PBMC of 21 individuals; in response to lipopolysaccharide (LPS) the proportion of cell-associated IL 1 beta ranged from 13% to 56%, for IL 1 alpha 29% to 98%, and for TNF 2% to 17%. In a larger cohort of 32 subjects, the total amount of immunoreactive cytokines produced in response to LPS or phytohemagglutinin was normally distributed within the study group. Mean production of IL 1 alpha in response to LPS was 10.1 ng/ml and exceeded production of IL 1 beta (5.6 ng/ml) and TNF (2.2 ng/ml). The distribution pattern was characterized by high intersubject variability extending over two orders of magnitude and the presence of high and low "producers". Production of IL 1 alpha and IL 1 beta correlated (R = 0.69). In contrast, production of IL 1 beta did not correlate with production of TNF or IL 2. Indomethacin present during stimulation of PBMC increased the amount of IL 1 beta produced and showed a high correlation (R = 0.83) compared to cultures without indomethacin. Thus, low production of IL 1 beta in certain subjects appears not to be due to inhibitable levels of cyclooxygenase products. In a retrospective study, PBMC from 12 subjects who had taken oral cyclooxygenase inhibitors during the preceding 7 days produced 43% more IL 1 beta than subjects who did not take these drugs (p less than 0.05). These studies demonstrate that the amount of cytokine synthesized by PBMC (a) is regulated independently for IL 1, TNF and IL 2; (b) correlates for IL 1 beta and IL 1 alpha; (c) is intrinsic for low and high "producers", and (d) production of IL 1 beta increases with the use of oral cyclooxygenase inhibitors.

Adult↗
PubMed1989

Sequential determinations of urinary cytology and plasma and urinary lymphokines in the management of renal allograft recipients.

Urine cytology, plasma (P), and urinary (U) interleukin-2 (IL-2)* and IL-2 receptor (IL-2R) levels were evaluated as immunological monitoring techniques in 65 renal allograft recipients. Normal individuals showed normal urine cytology, IL-2(U) = 0, IL-2(P) = 0.4 +/- 0.1 ng/ml (mean +/- SEM) and IL-2R(P) = 318 +/- 26 U/ml. Stable transplants also showed normal urine cytology, no IL-2(U), IL-2(P) = 0.8 +/- 0.2 ng/ml, and IL-2R(P) = 326 +/- 29 U/ml. Rejection episodes (n = 21) were accompanied by cytologic changes, including lymphocyturia, exfoliation of immature tubular cells, platelet aggregates, and fibrin deposits. The corresponding lymphokine changes were IL-2(U) = 39.6 +/- 1.4 ng/ml, IL-2(P) = 79 +/- 21 ng/ml, and IL-2R = 1884 +/- 202 U/ml, all markedly increased. Successful treatment was associated with return of all parameters to normal; treatment failure was associated with continued abnormalities. Fourteen rejections unresponsive to Solumedrol (500 mg x 5 days) required OKT3 rescue (5 mg x 14 days). In the 11 that were reversed, onset of OKT3 therapy was characterized by markedly increased exfoliation of necrotic cellular debris, lymphocytes, and collecting duct cells. Interestingly, serum creatinine increases of 57.2 +/- 18.9% (range 25-90%) over pre-OKT3 levels were noted. Maximal changes occurred 48-72 hr after the first dose, followed by gradual return to normal. Rejections unresponsive to OKT3 (n = 3) showed no cytologic changes from the pretreatment mean creatinine increase of 13.2 +/- 2.7% (range 9-15%), and maximum change occurred 24 hr after the first dose. Rejections responsive to Solumedrol only (n = 4) showed gradual improvement of all parameters. Rejections treated with Solumedrol following failed OKT3 prophylaxis (n = 3) did not reverse and continued to show rejection associated cytologic changes and abnormal creatinines. Patients experiencing CsA toxicity (n = 12) showed mild creatinine elevations, normal or negative IL-2(P) and IL-2R(P) levels, and no IL-2(U). They showed distinctive cytologic changes consisting of swollen convoluted tubular cells with nuclear pyknosis and cytoplasmic vacuoles. Pretransplant IL-2(P) levels of patients who subsequently rejected were elevated, with 19/21 patients with preoperative IL-2 levels greater than 15 ng/ml having subsequent rejections. In contrast, pretransplant creatinine, urine cytology, and IL-2(U) levels showed no correlation to subsequent clinical course.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1987

Malignant granular lymphoproliferation after Epstein-Barr virus infection: partial immunologic reconstitution with interleukin-2.

This report describes a patient who developed a malignant proliferation of granular lymphocytes following Epstein-Barr virus (EBV) infection. For many months, his illness resembled prolonged infectious mononucleosis with persistent fatigue, fever, leukocytosis, and serologic evidence of recent primary EBV infection. After approximately 1 year, however, he developed progressive granular lymphocytosis and extensive lymphocytic infiltration of the bone marrow and liver. Tests for EBV DNA in pre- and postmortem tissue samples using a sensitive DNA hybridization technique were negative. Southern blot analysis of DNA prepared from blood mononuclear cells demonstrated clonal T-cell antigen receptor gene rearrangement. Despite increased numbers of circulating lymphocytes with the morphology and surface phenotype of normal donor natural killer (NK) cells, the patient's NK activity was consistently depressed in a standard in vitro assay. However, in vitro incubation with interleukin-2 (IL-2), but not with alpha- or gamma-interferon, increased the NK activity of the patient's lymphocytes. Intravenous recombinant IL-2 treatment transiently increased the patient's blood NK activity and was associated with seroconversion to EBV nuclear antigens but failed to affect the progression of his disease. Our findings indicate that clonal granular lymphocytic proliferation may develop after EBV infection and confirm the utility of DNA hybridization analysis in distinguishing monoclonal from benign immunoreactive lymphoproliferation. Furthermore, our results suggest that certain functionally inert neoplastic granular lymphocytes acquire NK activity when exposed to IL-2.

Adult↗
PubMed1986

The development of anti-interleukin-2 antibodies in patients treated with recombinant human interleukin-2 (IL-2).

Approximately 65% (11/17) of cancer patients participating in an ongoing Phase I clinical trial with recombinant interleukin-2 developed nonneutralizing serum IgG anti-interleukin-2 antibodies within 1 month of initiating therapy. These antibodies could be detected using any of several standard techniques including immunoblots and enzyme-linked immunosorbent assays. Western blot analysis and retention experiments with protein A-Sepharose indicate that the antibodies are specific for interleukin-2. The interleukin-2 mutein utilized in this clinical trial (des-ala-ser125 r-IL-2) differs from the major species of the human T cell-derived lymphokine in that it lacks the N-terminal alanine of the native molecule, is not glycosylated, and possesses a serine-cysteine substitution at position 125. Another recombinant interleukin-2, identical to the mutein except that it retains the cysteine at position 125 (des-ala-cys125 r-IL-2), strongly competes with the mutein in competitive enzyme-linked immunosorbent assays, suggesting that the amino acid substitution is not responsible for the recognition of the molecule by serum antibodies. Conversely, nonrecombinant T cell-derived interleukin-2 fails to compete in these assays and is not retained by protein A-Sepharose columns when mixed with high-titer antiserum. These results suggest that the anti-interleukin-2 serum antibodies generated in the course of treatment do not react with the nonrecombinant lymphokine but recognize epitopes peculiar to recombinant forms which are not dependent on the amino acid substitution at position 125. The failure of the antibodies to neutralize the biological activity of recombinant interleukin-2 (IL-2) in lymphocyte proliferation assays and to bind to the native lymphokine suggests that they may not affect IL-2-dependent cellular immune functions in vivo.

Antibody Formation↗
PubMed1986

Phase I evaluation of recombinant interleukin-2 in patients with advanced malignant disease.

Seventeen patients with refractory malignant tumors were treated with recombinant human interleukin-2 (IL-2) administered by weekly bolus intravenous (IV) injection in a phase I dose escalation trial. Patients received 10,000 to 1,000,000 U/m2 per injection over a course of 3 to 33 weeks. Toxicity was dose related and consisted primarily of fever, chills, nausea, and vomiting. Hypotension was observed at doses of 500,000 U/m2 or higher and in one instance was sufficiently severe to require pressors. No tumor regression was seen and all patients eventually developed progressive disease. Blood levels of cortisol, ACTH, prolactin, and growth hormone as well as the acute phase reactant C-reactive protein (CRP) increased after the administration of IL-2 in most patients. Serum IL-2 levels in excess of 250 U/mL were detected five minutes after an IV injection of 1,000,000 U/m2, after which the levels declined with a half-life of approximately 25 minutes. No alteration in lymphocyte surface phenotype or enhancement in natural cell-mediated cytotoxicity against natural killer (NK)-sensitive and resistant tumor cell lines was observed when these parameters were measured weekly just before the IL-2 injections. However, a dramatic but transient decline in circulating lymphocytes and NK activity was noted within hours of receiving IL-2. This effect was independent of fever and was not abrogated by pretreatment with ibuprofen or metyrapone. The majority of patients developed serum IgG antibodies of IL-2 detectable with a sensitive enzyme-linked immunosorbent assay (ELISA) and a nitrocellulose dot blot assay. The development of anti-IL-2 antibodies was not associated with symptoms suggestive of serum sickness, reductions in serum complement levels, or deterioration in lymphocyte tumoricidal activity. This investigation provides insight into the in vivo actions of this potent biological response modifier and will assist in the design of future studies with IL-2 administered alone or in conjunction with other treatment modalities.

Adult↗
PubMed1986

Inhibitory effects of elevated temperature on human cytokine production and natural killer activity.

Febrile reactions often occur in cancer patients given various biological response modifiers such as alpha- or gamma-interferon or interleukin-2. The present studies were undertaken to determine the effects of moderately elevated temperatures (39 degrees C) on various immunological functions related to host defense against malignant cells. The production of the cytokines interleukin-1, interleukin-2, erythroid burst-promoting activity, and granulocyte-macrophage colony-stimulating factor from activated human mononuclear cells was assessed in vitro at 34, 37, and 39 degrees C and found to be reduced at 39 degrees C. The natural killer activity of human mononuclear cells preincubated for 18 h at various temperatures was also significantly reduced (P less than 0.001) at 39 degrees C. Although the addition of recombinant interleukin-1-beta, interleukin-2, and alpha-interferon during the 18-h incubation augmented natural killer activity at all temperatures, the enhancing effects were least apparent at 39 degrees C. Indomethacin increased cytokine-primed natural killer cell activity at all temperatures but did not reverse the inhibitory effects of elevated temperatures. These results suggest that the fever associated with treatment with pyrogenic cytokines may partially offset the direct stimulatory effects of these substances on cellular immune function.

Biological Products↗