Steve E. Calvano

The effect of granulocyte-macrophage colony-stimulating factor on myeloid cells and its clinical applications

Granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) is a naturally occurring growth factor produced by several cell types in response to a variety of stimuli. GM‐CSF has potent stimulatory effects on the growth and maturation of hematopoietic cells and has profound effects on mature circulating effector cells. Clinical applications of GM‐CSF include ameliorating chemotherapy‐induced neutropenia and enhancing hematopoietic recovery after bone marrow transplantation. This review evaluates the effect of GM‐CSF on myeloid cells and its clinical applications.

Autologous and allogeneic mixed-lymphocyte responses following thermal injury in man: The immunomodulatory effects of interleukin 1, interleukin 2, and a prostaglandin inhibitor, WY-18251☆

A group of 30 burn patients with 36-87% total body surface area (TBSA) burns was studied at 24-48 hr postburn. These included studies of (1) autologous and allogeneic mixed-lymphocyte reactions (MLR); (2) the immunoregulatory influence of mitomycin C-treated T cells, non-T cells, and unfractionated peripheral blood lymphocytes (PBL) on allogeneic MLR; and (3) correlation between the proportions of T-cell subsets defined with monoclonal antibodies (OKT4 and OKT8) and autologous MLR. Studies concerning adherent cell production of thromboxane, prostaglandin E2, and prostaglandin F2a and the immunomodulatory effects of Interleukin 1 (IL-1), Interleukin 2 (IL-2), and a prostaglandin inhibitor, WY-18251, on autologous MLR are presented. The autologous mixed-lymphocyte reaction was depressed in 60% of the burn patients tested. This depressed response correlated closely to the extent of third-degree injury (P less than 0.025) and to TBSA injury greater than 60% (P less than 0.025). A linear correlation was observed between the depression in autologous MLR and a decrease in both the percentage of OKT4+ T cells and the OKT4+/OKT8+ ratio. The response of T cells from burn patients in allogeneic MLR was normal. Age, sex, TBSA of the burn, and size of second-degree burn did not correlate with the abnormalities observed in MLR. Mitomycin C-treated mononuclear cells, purified T cells, or non-T cells from burned patients did not demonstrate any suppressive influence on MLR in normals. Monocyte number and arachidonic acid metabolism were investigated. In addition to increased numbers of monocytes following thermal injury, adherent cells produced increased quantities of thromboxane, prostaglandin E2, and prostaglandin F2a. The effects of Interleukin 1, Interleukin 2, and a prostaglandin inhibitor, WY-18251, were studied in autologous MLR (AMLR) of burned and normal patients. Interleukin 1 and WY-18251 did not induce any significant changes in proliferation in burned patients or normal controls. When compared to cultures without exogenous IL-2, an increase in AMLR was observed following the addition of IL-2 to burn patient cultures at Day 6 and Day 7 of culture. Although the addition of IL-2 did increase proliferation in AMLR of normal controls at Day 6 and Day 7, the enhancement observed for the burn patient cultures represented a restoration to the level of normal control cultures without IL-2. A dose-dependent increase in AMLR was observed in T cells isolated from normal and burned patients in the presence of purified Interleukin 2.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of the mitogenic effects of toxic Shock toxin on human peripheral blood mononuclear cells in vitro

It has been shown previously that the staphylococcal enterotoxins A and B are T-cell mitogens and also cause inhibition of murine plaque-forming cells generated in vitro. Similarly, toxic shock toxin, a 24,000-MW protein produced by toxic shock-associated strains of Staphylococcus aureus, is mitogenic and inhibits the generation of both murine and rabbit plaque-forming cells. In this study, an analysis of the T-cell response to toxic shock toxin was performed. Human peripheral blood mononuclear cells responded to toxic shock toxin over a broad dosage range (1 ng/ml to 5 micrograms/ml) with maximum proliferation at day 4 (96 hr) of culture. Heat treatment (100 degrees C for 60 min) of toxic shock toxin attenuated its mitogenic effects by only a small amount, and this attenuation could be reversed with increasing concentration of the toxin. By cytofluorography, both untreated and toxic shock toxin-treated small lymphocytes manifested normal percentages of OKT3+, OKT11+, OKT4+, OKT8+, HLA/DR+, and Leu-7+ cells. However, toxic shock toxin-induced blasts were 99% OKT11+ and expressed the receptor for interleukin 2 (89%-100% TAC+). Approximately 85% of the blasts were OKT4+, and 25% of the blasts were OKT8+. Proliferation of purified, double-rosetted T cells was enhanced monotonically by the addition of irradiated non-T cells. Irradiated, monocyte-enriched non-T cells were 2.5 times more potent than unfractionated non-T cells in producing quantitatively similar proliferation by toxic shock toxin-stimulated, autologous T cells. In addition, preincubation of non-T cells for 24 hr with toxic shock toxin, followed by extensive washing and irradiation, induced substantial proliferation by unexposed, autologous T cells. These data show that toxic shock toxin is mitogenic for T cells and requires accessory cells for maximal activity. Further, this substance appears to induce both a subset of OKT4+ (Class II MHC-restricted) and OKT8+ (Class I MHC-restricted) blasts.

Beneficial effect of enteral glycine in intestinal ischemia/reperfusion injury

It has been shown in vitro that glycine can protect renal tubules and hepatocytes from hypoxic injury. Glycine also attenuates ischemic injury in transplanted livers. The present study investigated the effect of enteral glycine in a murine model of ischemia/reperfusion injury of the small intestine. Mice (n = 12 in each group) were randomized to receive two gastric gavages of either a 20% glycine (Gly) or 23% balanced amino acid (AA) solution with a 6-hour interval between each gavage. One hour after the second gavage, mice underwent superior mesenteric artery clamping for 20 minutes. The clamp was then released for reperfusion. Another group of mice (n = 8) underwent a sham operation and served as additional control animals. Six hours after ischemia/reperfusion, the mice were killed in order to assess the intestinal injury (intestinal protein content, mucosal disaccharidase activity, and intestinal histologic findings) and the systemic consequences (bacterial translocation, serum interleukin-6, and lung myeloperoxidase activity). A second set of mice (n = 55) underwent identical gavages and ischemia/reperfusion and they were followed for survival. Compared to AA, enteral glycine administered prior to intestinal ischemia/reperfusion injury significantly preserved mucosal indices and intestinal histology and decreased lung myeloperoxidase activity. Survival was also significantly increased in animals receiving glycine compared to AA control mice. These data suggest that enteral glycine supplementation may be beneficial in attenuating intestinal ischemia/reperfusion injury and its related systemic effects in this murine model.

Epinephrine attenuates down-regulation of monocyte tumor necrosis factor receptors during human endotoxemia.

Epinephrine inhibits lipopolysaccharide (LPS) ‐induced tumor necrosis factor (TNF) production by increasing intracellular cAMP concentrations. Because agents that increase cAMP levels can enhance TNF receptor expression in vitro, granulocyte and monocyte TNF receptors were determined by FACS analysis in 7 normal humans who were receiving a constant 24‐h infusion of epinephrine (30 ng/kg/min), and in 15 normal subjects after intravenous injection of LPS (2 ng/kg), while they were receiving a continuous infusion of epinephrine started either 3 h (EPI‐3) or 24 h (EPI‐24) before LPS injection or an infusion of normal saline (LPS; n = 5 per group). Infusion of epinephrine per se did not influence TNF receptor expression. LPS induced a transient decrease in monocyte TNF receptors and a more sustained decrease in granulocyte TNF receptors (both P < 0.05). EPI‐3 partly prevented LPS‐induced down‐modulation of monocyte TNF receptors (P < 0.05 vs. LPS only), but did not affect LPS‐induced down‐modulation of granulocyte TNF receptors. EPI‐24 had no effect on TNF receptor expression. These data suggest that epinephrine not only influences the bioavailability of TNF by an effect on the production of this proinflammatory cytokine, but also by modulating the expression of its receptors. J. Leukoc. Biol. 61: 156–160; 1997.

The decrease in peripheral blood CD4+ T cells following thermal injury in humans can be accounted for by a concomitant decrease in suppressor-inducer CD4+ T cells as assessed using anti-CD45R

Using single- and two-color fluorescence flow cytometry, 10 thermally injured human subjects were assessed over time for both percentages and absolute numbers of lymphocytes comprising peripheral blood lymphocyte subpopulations. The CD3+ lymphocyte percentage decreased significantly in the early postburn period, and this decrease could be accounted for entirely by a concomitant decrease in the CD4+ lymphocyte percentage. Further, the decline in CD4+ percentage was due to a specific decrease in the suppressor-inducer subset of CD4 as defined using anti-CD45R. No change in the helper-effector subset of CD4 was noted. The percentage of CD8+ lymphocytes did not change significantly at any time postburn nor did subsets of CD8 as defined using anti-CD11. Numerical changes in lymphocyte subsets were dominated by a general lymphopenia occurring on Day 4 following injury. However, suppressor-inducer (CD4+/CD45R+) T cells also decreased significantly on postburn Day 1. These results further elucidate phenotypic changes in immunoregulatory subsets following major injury and suggest a possible basis for depressed autologous mixed lymphocyte responsiveness of burn patient T cells, one of the functional immunologic defects associated with severe injury.

Changes in Free and Total Levels of Plasma Cortisol and Thyroxine Following Thermal Injury in Man

Changes in endocrine status are known to occur following thermal injury. Therefore, the effect of burn injury on plasma corticosteroid and and thyroid hormones and their respective binding proteins was examined. Thirty-one subjects with 18%-99% TBSA burn were compared to 50 normal controls with respect to plasma levels of total cortisol, free cortisol, total thyroxine (T4), free thyroxine index (FTI), corticosteroidbinding globulin capacity ICBGC), tri-iodothyronine uptake (T3U), and albumin. Compared to controls, plasma concentrations of total and free cortisol in thermally injured patients were elevated at all time points tested. However, there was no significant difference in total or free cortisol values for survivors and nonsurvivors. Both total T4 and the FTI were significantly decreased compared to normal, and nonsurvivors in turn had significantly lower T4 and FTI values than did survivors. In nonsurviving patients, values of T4 and the FTI were about 50% of the mean value for normal controls, and these levels showed only a slight increase by postburn day (PBD) 21. For both survivors and nonsurvivors, CBGC was decreased relative to normals in the 48-hour period following burn, but by PBD 7 survivors and nonsuivivors had mean levels of CBGC within the normal range. Plasma albumin was uniformly decreased throughout, and there was no difference in levels for survivors and nonsurvivors. These data confirm that thermally injured human beings have increased levels of free and total corticosteroids and decreased levels of T4, and that these changes are more extreme in patients with greater illness who eventually die.

Granulocyte contamination of Ficoll-Hypaque preparations of mononuclear cells following thermal injury may lead to substantial overestimation of lymphocyte recovery

During ongoing flow cytometric studies of burned patient blood leukocytes, it was noted frequently that large numbers of granulocytes were present along with the mononuclear cells at the plasma/Ficoll-Hypaque (F-H) interface following centrifugation over F-H. Since differential WBC counts are not routinely performed on F-H interface cells, it is possible that many previous immunologic studies of burned patients have greatly overestimated numbers of lymphocytes recovered. The present study sought to quantify the extent to which granulocyte contamination of F-H separated cells occurs following burn injury. Blood from 15 thermally injured patients (7-55% total body surface area burn) was studied serially at 24 hr, 48 hr, and weekly thereafter through 6 weeks postburn (PB). Controls were age-matched normals (No. of control bloods = 59). Three-part differential cell counts (lymphocytes, monocytes, and granulocytes) were performed on both F-H interface cells and RBC-lysed whole blood. Counts were performed by light scatter analysis on a flow cytometer. Except at 48 hr, at every time studied through 4 weeks PB, there was significant contamination of F-H interface cells with granulocytes. At 24 hr PB, 41 +/- 9% of the interface cells were granulocytes while at 4 weeks, PB 24 +/- 8% of the interface cells were granulocytes. The data did not support the interpretation that this increase in F-H interface granulocytes was simply reflective of the granulocytosis commonly observed after burn. Thus artificial generation of granulocytosis by addition of extra normal leukocytes to normal blood resulted in complete separation of granulocytes from mononuclear cells following centrifugation over F-H.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid corticosterone pulses: Confirmation by an alleged disconfirmation?

Data from a paper reporting a failure to confirm our report of rapid corticosterone pulses and suggesting that our data were artifactual were reanalyzed and reevaluated. It is shown that these data actually appear to confirm our original report. Artifacts in their procedure tend to introduce smearing that minimizes the observed effect. In addition, their method of data presentation combined with the lack of appropriate data analysis apparently led to their failure to draw the proper conclusions.