Altered expression of lymphocyte Il-2 receptors in burned patients

Alterations of acute phase reaction and cytokine production in patients following severe burn injury

To determine the acute immunologic reaction, mediated by cytokines, interleukines (ILs) and growth factors and the susceptibility to infections and sepsis after severe burn injury a prospective, single unit, longitudinal study of acute phase reactants and mediators who performed. After approval by the ethics committee of our hospital, we investigated the plasma concentrations of IL-2, -6, -8, -10, and -13, the soluble IL-2 receptor (sIL-2R), and the acute phase proteins procalcitonin (PCT) and C-reactive protein (CRP) at admission and every 3 days in 24 patients over a time course of 28 days after thermal injury and categorized by percent burn: < or =30% (group 1; n=12) and >30% (group 2; n=12). Shortly after burn injury we found higher concentrations of IL-2, -6, -10 and PCT in those patients >30% TBSA. During the study period, we found significant higher levels of acute phase proteins, IL-6 and -8 in patients >30% TBSA. The incidence of SIRS and MODS was three times increased in patients >30% TBSA. Our results show different patterns of cytokines and acute phase proteins in patients with different burned surface areas over a long time and continuous monitoring of a more distinct inflammatory response in these patients.

Inhibiteur de rejet de greffe alpha2-macroglobulin in burn injury: a suppressive activity on complement

A subform of alpha2-macroglobulin, (inhibiteur de rejet de greffe (IRG), present at a low rate in healthy rat, increased with rate-related suppressive activity on complement during inflammatory processes. In human serum, a molecule with such properties was described. Serum and blister IRG from burn patients belonging to a selected population was purified under gentle conditions. Serum IRG increased quickly within the first day after hospitalization and continued to increase until day 6. Although absent in whole serum, the rate-related activity of IRG varied according to the surface area and the degree of burns. A rate-related activity was also revealed in whole blister fluid and in purified blister IRG. We report a new site and a new suppressive activity of IRG in its native form from serum and blister fluid during inflammatory processes of burned patients. The suppressive activity of IRG on complement is discussed, and it appears to play a role in the development of inflammatory processes.

Pathophysiology of the burn wound and pharmacological treatment. The Rudi Hermans Lecture, 1995

The body's reaction to thermal injury is much more than an initial, local inflammatory response. The burn wound is a continuous, severe threat against the rest of the body due to invasion of infectious agents, antigen challenge and repeated additional trauma caused by wound cleaning and excision. The inflammatory mediators which control blood supply and microvascular permeability in the wound have been extensively studied and are largely understood. Attempts to suppress the inflammatory reaction by different drugs, have, however, been less successful. Extensive thermal injury and sepsis also results in immunosuppression. The defects causing immunosuppression are still very much under consideration. An understanding of these defects is essential for the development of therapies. The increasing interest in the control of the inflammatory reactions by cytokines may, in the near future, be of great importance.

Immunosuppression after endotoxin shock: the result of multiple anti-inflammatory factors

OBJECTIVES

Endotoxin induced suppression of cellular immune function is thought to contribute to septic complications in trauma patients. A rabbit model of endotoxemia was used to determine the relative roles of the anti-inflammatory factors interleukin-4 (IL-4), interleukin-10 (IL-10), transforming growth factor beta1 (TGFbeta1), and prostaglandin E2 (PGE2) in addition to other factors, in inducing immunosuppression.

DESIGN

T-cell suppressive factors (TSF) in serum ultrafiltrates were separated and tested for the presence of the known suppressive factors PGE2, IL-4, IL-10, and TGFbeta1.

MATERIAL AND METHODS

New Zealand rabbits were injected with 50 microg/kg of purified Escherichia coli lipopolysaccharide. Animals were exsanguinated after 48 hours and serum was separated by ultrafiltration (cutoff 50 kd), TSK HW-40 size exclusion chromatography, and Q-Sepharose anion exchange chromatography. TSF activities of chromatographic fractions and serum samples were measured with a mitogen induced in vitro T-cell proliferation assay. Levels of PGE2, IL-4, IL-10, and TGFbeta1 were measured with enzyme immunoassays.

MEASUREMENTS AND MAIN RESULTS

Serum TSF activity, and levels of PGE2, IL-4, IL-10, and TGFbeta1 were increased after endotoxemia. Size exclusion chromatography revealed three major fractions (TSF1-3) with up to 600 times more TSF activity compared with controls. IL-4 and IL-10 were found in TSF1 and TSF3. Further separation of TSF1 by anion exchange chromatography revealed a total of eight different T-cell suppressive factors. TGFbeta1 probably remained in the retentate after ultrafiltration, while PGE2 eluted at a higher retention time. The known anti-inflammatory factors TGFbeta1, IL-10, IL-4, and PGE2 only accounted for 13% of the total serum TSF activity of 614 U/mL.

CONCLUSIONS

Lipopolysaccharide shock results in the release of multiple T-cell suppressive factors in addition to known immunosuppressive factors, all of which contribute to the anti-inflammatory response.

T lymphocytes and immunosuppression in the burned patient: a review

Extensive thermal trauma results in impaired immune function which has been attributed to a reduction in T lymphocyte numbers, increased suppressor cell activity, serum suppressive factors and altered cytokine synthesis and receptor expression on T cells. Numeric and phenotypic changes in T lymphocytes, T cell proliferation and functional responses of T lymphocytes in recent studies using murine models and patients are described.

Translocation. Incidental phenomenon or true pathology?

OBJECTIVE

This study was conducted to determine if reduction of early postburn endotoxemia influences the cytokine cascade, clinical manifestations of sepsis, and mortality rate.

SUMMARY BACKGROUND DATA

Translocational endotoxemia has been demonstrated postburn in animals and humans. Endotoxin is known to induce the cytokine cascade, which leads to the clinical manifestations of sepsis. Whether reduction of postburn endotoxemia could influence the induction of cytokines has not been demonstrated.

METHODS

In a prospective, randomized study, 76 burn patients were given polymyxin intravenously or served as control subjects. Polymyxin B was given intravenously for 1 week postburn in doses designed to neutralize circulating endotoxemia.

RESULTS

In the polymyxin group, there was a statistically significant reduction in the plasma endotoxin concentration. There was, however, no reduction in the sepsis score or the interleukin-6 levels, and no differences in mortality rates were seen between the two groups.

CONCLUSIONS

Early postburn translocational endotoxemia can be treated with anti-endotoxin agents such as polymyxin B. This, however, does not influence the cytokine cascade or the mortality rate. The systemic inflammatory response syndrome is caused by cytokine induction from the injury and is unaffected by a reduction in the plasma endotoxin concentration.

Glycosylation of acute phase proteins and interleukins following hip arthroplasty. Inflammation parameters studied in 10 patients

We analyzed changes in glycosylation and serum concentrations of alpha 1-acid glycoprotein (AGP), antichymotrypsin (AC), interleukin-6 (IL-6), soluble interleukin-2 receptor (sIL-2R) and C-reactive protein (CRP) following hip arthroplasty. Glycosylation of AGP and AC showed an increased reactivity to concanavalin A between postoperative Day 2 and Day 5 and Day 10, respectively. Serum levels of AGP and AC increased at the earliest on Day 5. The AC levels returned to baseline by Day 10. AGP, however, exhibited increased values beyond Day 14. CRP levels were elevated at Day 2 and remained increased beyond Day 14. sIL2R showed increased values at Days 5, 10 and 14. IL-6 was the first parameter to increase, and it returned to baseline in less than 5 days.

IL-2 regulation of soluble IL-2 receptor levels following thermal injury

In the immunosuppressed burn patient serum levels of both IL-2 and a soluble form of IL-2 receptor alpha (sIL-2R alpha) are significantly elevated. Strikingly, the production of these markers by the in vitro activated patients' cells is decreased. This study examines the role of IL-2 in the decreased production of the sIL-2R alpha in vitro in patients with major burns (n = 18, 30 to greater than 70% total body surface area). Peripheral blood mononuclear cell (PBMC) cultures from patients with highly elevated serum sIL-2R alpha, and from healthy controls (n = 12) were activated with concanavalin A (Con A) at initiation. In patients' cultures mitogen-induced increments of sIL-2R alpha levels were significantly lower. There was a significant negative correlation (r = 0.64, P less than 0.001) between a high serum sIL-2R alpha level and a decreased lectin-induced sIL-2R alpha release in vitro. Low levels of sIL-2R alpha in patients' samples were not normalized by increasing the number of T lymphocytes. Also exogenous rIL-1 was without effect, whereas rIL-3 increased sIL-2R alpha release in some cultures. However, sIL-2R alpha levels were significantly increased in patients' cultures by (i) addition of exogenous IL-2; (ii) removal of adherent cells; (iii) addition of cyclooxygenase inhibitor, indomethacin; (iv) bypassing cell surface activation by the combination of the calcium ionophore A23187 and the phorbol ester 12-o-tetradecanoyl acetate. The cyclic AMP-elevating drug, forskolin, abrogated the ability of exogenous IL-2 to increase sIL-2R alpha production. Thus, in the burn patient, the reduced in vitro sIL-2R alpha release appears to relate to abnormalities in IL-2 production and action mediated through its functional surface receptor. Elevated levels of sIL-2R alpha in vivo may, therefore, reflect systemic activation of T lymphocytes in response to biologically active IL-2.

The role of mediators in the response to thermal injury

Inflammatory mediators play a major role in both the local burn wound and the systemic response to burn injury. Oxidant and arachidonic acid metabolites are involved in the initial burn edema process. The mediators as well as the cytokines released from activated macrophages also result in an early generalized inflammatory response. The later postburn hyper-metabolism is initiated and perpetuated by these same mediators, especially the cytokines, tumor necrosis factor, interleukin-1, and interleukin-2. Circulating endotoxin from the wound or the gut also appears to be involved. The postburn septic response is now recognized to be the result of inflammation; infection is not necessary. Mediator induced priming of the inflammatory cells by the burn itself results in an exaggerated response to infection in the postburn period. Defining the specific mechanism of injury and mediators involved can result in a major improvement in burn care, especially since many mediator inhibitors are already available for clinical use. It is essential that the clinician understand this pharmacologic manipulation in order to be able to optimally utilize these future advances.

Monitoring of elastase in plasma of burned patients in relation to other inflammation parameters

Twenty burned patients divided in three groups according to the severity of the lesions were investigated at 1- or 2-day intervals for up to 5 weeks after injury. Plasma elastase levels were elevated during the first day after injury and were correlated with the area of the burns. However, plasma elastase was rapidly bound and inactivated by protease inhibitors. Leucocyte counts, fever and the concentration of alpha-1-proteinase inhibitor were not correlated with the extent of the burn. The rise of plasma elastase was not accompanied by consumption of the elastase inhibitory capacity (EIC) of plasma, which increased to a plateau around day 5. The EIC values were in accord with the rise of alpha-1-proteinase inhibitor, the major anti-elastase agent in plasma. Studies of blister fluid in eight patients showed that the elastase content was higher than that of corresponding plasma, while the concentration of alpha 1-proteinase inhibitor and the EIC were comparable with those of plasma. Measurements of the levels of tumour necrosis factor released by stimulated macrophages in five patients with major burns showed no significant increase compared with controls.

Influence of burn-induced lipid-protein complex on IL2 secretion by PBMC in vitro

Normal peripheral blood mononuclear cells (PBMC) were incubated with the lectins PHA and ConA to stimulate IL2 release into the culture supernatants. In the added presence of the lipid-protein complex (LPC) derived from burned skin, PHA and ConA produced much less bioavailable IL2, the combination with PHA being more inhibitory of its production than that with ConA at concentrations of 1 microgram and 5 micrograms lectin/ml. As LPC alone also elicited IL2 production the inhibition of active IL2 production with these lectins was seen as a synergistic reaction with LPC. This was not altered by incubating cells with PHA alone, followed later by LPC, suggesting that LPC affects later molecular events which develop in T-cell activation. However, after incubating LPC first and washing it from the cells, both lectins were able to stimulate secretion of higher levels of bioavailable IL2, but again, less IL2 was produced with PHA than with ConA. Since PHA and ConA are reported to react with the T-cell receptor (TCR) and CD3 T-cell surface antigens, respectively, although both react additionally with CD2, it appears that LPC interfered more directly with TCR-related reactions than those involving CD3, although the two antigens have been considered to be interdependent. LPC is a trimer of a complex of six proteins from skin cell membranes, which had coalesced under the influence of thermal energy. The six proteins have relative molecular weights of 40, 50, 65, 110, 120 and 160 kDa. By coincidence 40 kDa and 51 kDa are the weights of the heterodimer subunits of TCR alpha/beta, and CD2 is 50 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)

Soluble interleukin-2 receptors in cerebrospinal fluid from individuals with various neurological disorders

Soluble interleukin-2 (IL-2R) levels in the cerebrospinal fluid (CSF) were studied in infectious, inflammatory, degenerative, and neoplastic disorders to evaluate their usefulness as a marker for the presence of activated T cells, thus indicating an inflammatory process. CSF from control subjects and patients with stationary, progressive, and treated multiple sclerosis (MS); aseptic meningitis; lymphoid and nonlymphoid central nervous system (CNS) tumors; Alzheimer's disease, as well as serum from MS patients and control subjects were studied for levels of soluble IL-2R. A significant increase in CSF IL-2R levels was observed in patients with MS, meningitis, and lymphoid CNS tumors; the MS group showed the highest values. CSF from individuals with Alzheimer's disease and from patients with nonlymphoid tumors did not show significantly elevated values. Serum IL-2R levels were significantly higher in MS patients than in control subjects, but there was no significant correlation between individual serum and CSF IL-2R levels. This study suggests the presence of activated T-lymphocytes in the CNS of patients with MS.

Increased levels of circulating interleukin 6 in burn patients

The serum levels of interleukin 6 (IL-6) were determined in a population of burn patients. In all patients, IL-6 levels were increased over a 3-week interval with peak concentrations reached during the first week after injury. Patients receiving intravenous polymyxin B therapy according to a regimen designed to reduce endotoxemia manifested greatly reduced levels of both circulating endotoxins and IL-6. Certain patients not treated with polymyxin B showed extraordinarily large increases in IL-6 which were associated with lethal or life-threatening clinical complications. Increased IL-6 levels were also associated with decreased percentage of circulating T cells and corresponding increases in B cells. However, IL-6 did not produce any direct inhibitory effects in vitro on T cell representation or function.