The phytohemagglutinin (PHA) response in the thermally injured rat

Immune suppression after acute ethanol ingestion and thermal injury

Acute alcohol ingestion is commonly associated with burn injury. Both alcohol ingestion and burn injury produce immune suppression, but the combination of these factors on immune function has not been investigated. To study this combined effect, immune function was measured in rats with a 30% burn injury following a single ingestion of 2.4 g/kg of ethanol (EtOH) and compared to that of animals with burn injury only, animals with EtOH only, and animals with neither alcohol nor burn injury. Four days after ethanol and/or burn, animals receiving both ethanol and burn injury had significant suppression of in vivo chemotaxis and lymphocyte responsiveness to lipopolysaccharide (LPS) compared to animals receiving either burn injury alone or EtOH alone (P less than 0.05). There was no difference in responsiveness to concanavalin A (Con A). Serum corticosterone was significantly elevated by burn injury but not EtOH ingestion. EtOH treatment prior to injury caused a further increase in corticosterone level that was significantly associated with a decrease in immune function. These results indicate that a single EtOH exposure prior to burn injury produces greater immune suppression than does burn injury alone. This further decrease in immune function may contribute to increased susceptibility to infection and increased mortality in burn patients with acute EtOH ingestion.

A burn induced Ly-2 suppressor T cell lowers resistance to bacterial infection

Suppressor T cell activity after major burn injury in a murine model has been well characterized. Suppressor cells have also been demonstrated in patients after major burn, and suppressor cell activity has been temporally correlated with septic episodes. A splenic Ly-2 T suppressor effector (Tse) cell appearing 7 days after a 30% full thickness burn has been identified in a murine model. A rat monoclonal antibody (14-8c3-12) directed against a factor produced by the Tse cell (Tsef) can enhance depressed in vitro mixed lymphocyte reaction (MLR) responses of Day 7 burn spleen cells without enhancing control spleen cell activity. Additionally, 14-8c3-12 can block the suppressive effect of these burn T cells on normal T cells. A cecal ligation and puncture (CLP) model using a 25-gauge needle (LD15) was used to assess the contribution of burn T cells to post-CLP mortality. Normal spleen cells injected into syngeneic recipients followed by CLP did not affect mortality (13%). Burn spleen cells injected into normal recipients enhanced mortality sixfold (90%) after CLP. The effect could be reversed by removing Ly-2 T cells (30% mortality) but not Ly-1 T cells (100% mortality) prior to cell transfer. Simultaneous injection of 14-8c3-12 antibody with burn T cells reduced mortality after CLP significantly (20%). Injection of 14-8c3-12 did not improve survival after CLP in control animals not injected with burn T cells (20%). Ly-2 T suppressor effector cells found in the spleens of mice 7 days postburn enhance the lethality of a purely bacterial septic challenge. A monoclonal antibody to the Tsef can reverse this effect in vivo.

The cellular response of T and B dependent areas of the spleen after focal thermocoagulation of liver and kidney

Using 3H-thymidine autoradiography, the cellular response of the white splenic pulp after single or repeated thermolesions on liver and kidney was studied. Sham operations served as controls, and did not induce any significant changes in the splenic white pulp. After single or repeated thermolesions, the labeling index increased distinctly in the B and T cell areas. The central T-dependent periarteriolar lymphatic sheath (PALS) showed an earlier rise of radioactively labeled lymphocytes after repeated thermolesions than after a single lesion. After a single heat coagulation of liver and kidney a dissociation of the germinal centers occurred with consecutive hyperplasia. However, compared with the splenic reaction after other surgical injuries, especially after cryosurgical operations, the response of the B-dependent splenic areas was weaker. The distinct reaction of the central T-dependent PALS supports the conception of a more prominent cell mediated immune response of the peripheral lymphatic system with temporary T cell dysfunctions. Possibly the inflammatory complications of burned patients and the delayed wound healing of thermosurgical tissue lesions may be caused by the alteration of the lymphatic system with a disturbed cooperation of T and B lymphocytes with macrophages.

Longitudinal assay of lymphocyte responsiveness in patients with major burns

Serial blast transformation in vitro was measured in peripheral lymphocytes from 38 patients with major thermal injury. Lymphocytes were tested with the antigens streptokinase-streptodornase (SKSD), mumps and purified protein derivative (PPD), the mitogens concanavalin A (Con A) and phytohemagglutinin (PHA), and in the one-way mixed lymphocyte reaction. Statistically significant suppression by the burn injury was noticed in all measurements except response to PHA. One-time measurements were not significantly different between the patients who survived and the patients who did not survive their burn injuries. However, serial determinations of responsiveness to the three natural antigens SKSD, mumps and PPD, as well as the mixed lymphocyte reaction accurately reflected prognosis.

The burn patient: II. Later care and complications of thermal injury

The care necessary for the extensively burned patient is of an intensity, variety and duration most effectively and economically provided by the multidisciplinary staff of a specialized treatment facility. The organization of burn care in the United States has been well regionalized in recognition of this fact. The burn care given and the research carried out at burn units and burn centers has led to the identification of the pathophysiologic changes, the development of new treatments and the improvement in functional result and survival described in this review.

DNA-synthesis in the rat thymus after focal thermolesions on abdominal organs

The changes in the DNA-synthesis of lymphocytes in the different zones of the rat thymus were autoradiographically studied with 3H-thymidine after focal thermonecroses (740 degrees C/4 sec) on abdominal organs and sham operation (laparotomy). A single thermolesion was performed in separate groups of rats on the liver and spleen, whereas a third group received multiple heat lesions (liver, kidney, stomach wall). A slight decrease of the labeling index occured during the first 36 h after the sham operation and was attributed to an unspecific stress effect leading to an increased release of corticosterones. The most remarkable and contrasting result was the observation that after thermonecroses a decrease of the labeling index of thymus-lymphocytes did not happen during the first 48 h but rather a marked increased with a maximum on the fifth day. It was concluded that the stimulated DNA-synthesis in the thymus might be related to a cell mediated immune response against thermocoagulated tissue components or to an immediate T-cell dysfunction, which is known to develop after burns. In both cases the thymus might react with an increased division and maturation of lymphocytes regulated through a feed-back mechanism.

Granulocyte function and Pseudomonas burn wound infection

Granulocyte function in burn injury has been evaluated with an in vitro animal assay. Bactericidal activity, using this technique, was markedly depressed only when granulocytes from scald burned rats were challenged with each of three strains of Pseudomonas aeruginosa in the presence of autologous postburn serum or heat-inactivated serum. Preincubation of postburn and normal serum at 37 degrees C for 1 h resulted in normal phagocytosis. These studies validate an investigation of plasma and/or granulocyte replacement therapy in the burned patient.

Post-traumatic immunosuppression is due to activation of suppressor T cells

Severe immunosuppression occurs after major thermal burns, accidental injuries, and extensive surgical operations, and probably contributes substantially to patient morbidity and mortality. The mechanism of immunosuppression is unknown and attempts to explain it are contradictory. The contradictions can be resolved by assuming the activation by injury of the suppressor T-cell system, which is involved in normal immunoregulation. If this is true, then generalised, non-specific attempts to bolster the immune response in these patients may be inappropriate.

Cell-mediated immunity after thermal injury

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Selective effects of thermal injury on mouse peritoneal macrophages

Normal mice or mice burned 6 days previously were injected intraperitoneally with either saline or 50 mug of concanavalin A. Four days after the injection the peritoneal macrophages were collected and examined in vitro. Macrophages from concanavalin A-injected mice appeared activated because several in vitro parameters of activity were increased. Examination of macrophages from burned animals revealed a selective depression of macrophage activity.