Immunoglobulin production in burned patients

The effect of severe burn injury on proinflammatory cytokines and leukocyte behavior: its modulation with granulocyte colony-stimulating factor

Severe injury causes immunosuppression. The main contributors are impaired leukocyte function and a cytokine dysbalance. GCSF increases PMN count, function and modulates the inflammatory response. However GCSF may overactivate leukocytes. The purpose of this study is to investigate whether GCSF is able to restore immune competence after severe injury. Lewis rats were divided into three groups: 30% TBSA burn + vehicle; 30% TBSA burn + GCSF (150 microg rhGCSF); Control. Blood samples were taken for total white cell count, PMNs, TNFalpha and IFNgamma. Leukocyte rolling and sticking were measured in the cremaster muscle microcirculation. Leukocyte diapedesis was investigated by lavage of the abdominal cavity and the lungs. Total white cell and PMN counts in the burn + GCSF group were significantly higher (P<0.001) than in burn+vehicle animals. Leukocyte adherence and diapedesis were not elevated in the burn + GCSF group as compared to the burn + vehicle group. TNFalpha (P<0.05) and IFNgamma (P<0.001) levels were significantly increased in the burn + vehicle animals compared to the burn + GCSF animals. GCSF modifies the immune system, as shown by an increase in white cell and PMN counts and by balancing the overall immune response from proinflammatory to normal, as shown by decreased TNFalpha and IFNgamma levels. GCSF does not overactivate PMNs.

Transforming growth factor-beta impairs postburn immunoglobulin production by limiting B-cell proliferation, but not cellular synthesis

BACKGROUND

Transforming growth factor-beta (TGF-beta) has been shown to be an inhibitor of immunoglobulin (Ig) synthesis and may contribute to decreased Ig synthesis after burn injury. This study investigated the relationship between TGF-beta and Ig synthesis after burn injury.

METHODS

Twenty-four BALB/c mice received either a 30% body surface area full-thickness contact burn or no burn. Splenocytes were isolated 8 days after burn and were cultured with 0, 0.05 or 0.5 ng/mL TGF-beta. After culture, total IgG and total IgM were measured by enzyme-linked immunosorbent assay. The number of IgM-secreting cells per 10(5) cells was measured by enzyme-linked immunoabsorbent spot forming assay. Total IgM per IgM-secreting cell (pg/cell) was calculated.

RESULTS

Total IgG, IgM, IgM-secreting cells, and B-cell number after culture were decreased by burn injury, and the decrease was exacerbated by the presence of TGF-beta. The total IgM per IgM-secreting cells, however, was significantly increased by TGF-beta at 0.5 ng/mL.

CONCLUSION

These data demonstrates that TGF-beta does not specifically impair IgM secretion by committed IgM B cells but appears to decrease B-cell proliferation or clonal expansion.

Levels of antibodies to endotoxin and cytokine release in patients with severe trauma: does posttraumatic dysergy contribute to organ failure?

BACKGROUND

We conducted a prospective study in patients with multiple injuries investigating the time course of trauma-related changes of systemic immunologic defense mechanisms.

METHODS

Patients with multiple injuries with Injury Severity Scores of more than 20 were included if they survived for more than 4 days after injury. Further inclusion criteria were no local or systemic infection (pneumonia, sepsis, soft-tissue infection, acquired immunodeficiency syndrome, tuberculosis, etc.) at the time of injury and no history of liver disease, bowel disease, or abdominal surgery. Serum endotoxin levels were measured from peripheral venous blood, as were the immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies against lipid A and against the core polysaccharide of endotoxin (lipopolysaccharide [LPS]), during the course of intensive care management. Serial central venous levels of interleukin-6 were determined as a marker of the inflammatory response.

RESULTS

The patients were grouped according to their survival, with the survivors belonging to group S (48 patients) and the nonsurvivors belonging to group N (16 patients). The time of death for the nonsurvivors was between days 10 and 32 after the initial trauma. Thirteen of these patients (81%) died of multiple organ failure between days 12 and 17, two died of head trauma, and one died of sepsis. In patients who died of multiple organ failure, a significantly lower production of the IgM and IgG antibodies (AB) against lipid A and LPS was found before death (lipid A IgM-AB, day 11: group N, 29 +/- 11 U/mL; group S, 106 +/- 16 U/mL; p = 0.008; lipid A IgG-AB, day 11: group N, 18 +/- 9 U/mL; group S, 57 +/- 18 U/mL; p = 0.007; LPS IgM-AB, day 11: group N, 36 +/- 14 U/mL; group S, 122 +/- 23 U/mL; p = 0.009; LPS IgG-AB, day 11: group N, 17 +/- 12 U/mL; group S, 56 +/- 19 U/mL; p = 0.03). Interleukin-6 levels were significantly increased in the nonsurvivors (day 1: group N, 1,095 +/- 112 pg/mL; group S, 393 +/- 67 U/L; p = 0.008).

CONCLUSION

In patients who died of severe trauma and in whom the cause of death was multiple organ failure, a significantly lower production of antiendotoxin antibodies was measured shortly before death. An insufficient immune defense (dysergy) may be involved in the pathomechanisms leading to the development of organ dysfunction.

Effects of prophylactic intravenous immunoglobulin-G therapy on humoral and cellular immune components and their functions in burned patients

In this study on patients with thermal trauma, we examined the effects of standard therapy plus prophylactic polyclonal immunoglobulin G (IgG) treatment on humoral and cellular contents, cell phenotype and function of the immune system, and compare these with those found in patients receiving only standard therapy. The quantitative, peripheral-blood mononuclear cell panel shows a decrease in the total number of T-lymphocytes and an increase in the natural killer (NK) cells of standard therapy patients 3 weeks following the burn. We found that intravenous IgG treatment does not have an important effect on T lymphocytes and the proportion of their subpopulations, but rather causes a significant decrease in the number of B lymphocytes and an increase in the number of NK cells. When comparing the DNA synthetic response to mitogenic and antigenic stimuli in patient's T and B lymphocytes using phytohaemagglutinin, pokeweed mitogen or allogenic mixed cells in separate in vitro cell cultures, the highest suppressive effect of thermal trauma is seen in the cells derived from the patients who had been given prophylactic IgG therapy. The presented data confirm that thermal trauma causes an immunosuppressive effect and indicate that prophylactic polyclonal IgG therapy increased the quantitative and functional suppression of the specific immune system while additionally increasing the cellular levels of the non-specific immune system, each system having been previously stimulated by thermal trauma.

Early wound excision and skin grafting restores cellular immunity after severe burn trauma

Suppression of cellular immunity following thermal injury may contribute to the high incidence of postburn sepsis. Early excision and skin grafting may remove deleterious local wound factors and prevent immunosuppression. The effect on cellular immunity of early burn wound excision and skin grafting was investigated in an animal model using female Wistar rats. The development of immunosuppression shortly after burn injury was shown by popliteal lymph node assay and a 2,4-dinitrofluorobenzene skin reaction test. Excision and skin grafting 2 days after burn trauma restored parameters to normal. Burned tissue suppresses cellular immunity; this effect is preventable by early excision and skin grafting.

The interaction of burn injury and zinc nutriture as assessed by the humoral response to sheep red blood cells in a burn rat model

Clinical and animal studies suggest that burn injury induces alterations in zinc metabolism. It also has been established that zinc nutriture can cause alterations in the immune response, but there is a paucity of information concerning the interrelationship between burn injury, zinc nutriture and the immune response. In the present study, rats were subjected to full skin thickness dorsal scald injuries covering 30 per cent of the total body surface and then maintained on sufficient or deficient zinc intake. The rats were immunized with sheep red blood cells (SRBC) on day 6 postburn and killed 4 days later. The spleens were excised and spleen lymphocytes isolated and used in a Jerne plaque assay to determine the number of plaque-forming cells (PFC). The burn/zinc-sufficient regimen significantly increased (P less than 0.01) the PFC response when compared to unburned zinc-sufficient or zinc-deficient control rats. Burned rats that were maintained on a zinc-deficient regimen showed a significant decrease (P less than 0.05) in PFC when compared to burned rats maintained on a zinc-sufficient regimen. This study indicates an interaction of zinc in the primary humoral immune response following thermal injury.

Regulation of IgM production in thermally injured patients

This report examines the capacity of autologous and exogenous interleukin-2 (IL2) to regulate and/or induce immunoglobulin M (IgM) production in these patients. Pokeweed mitogen (PWM)-induced lymphocyte proliferation and PWM- and IL2-induced IgM secretion were monitored in vitro during the postburn period (10 to over 60 days) in 40 patients aged 16-72 years, with burns 20-90 per cent TBSA. PWM-induced IgM secretion fluctuated considerably during this period. Twelve of 40 patients demonstrated no IgM production and a significant (P less than 0.001-0.05) proportion of them had profoundly suppressed levels. Of the survivors, restoration of IgM secretion to normal levels was achieved in only 60 per cent at time of discharge. Even more consistently suppressed was exogenous IL2-driven production of IgM. In contrast, PWM-induced lymphoproliferation was normal in over 70 per cent of the patients. Thus, the T-cell-dependent antibody response was suppressed for long periods of time, possibly from some deficiency in IL2-regulated secretion or reception of helper T-cell-derived factors necessary for B cell differentiation into Ig-secreting cells.

Antibody formation after murine injury

To determine the effect of burn injury on humoral immunity, we followed the murine primary and secondary antibody responses to sheep erythrocytes (SRBC), a T-cell dependent antigen, and lipopolysaccharide (LPS), a T-cell-independent antigen, after 25% TBSA burn. Splenic B-cell-specific antibody synthesis was measured by a hemolytic plaque assay. Simultaneous measurements of specific and nonspecific immunoglobulins were performed by a hemagglutination assay and radial immunodiffusion, respectively. Numbers of splenic primary anti-SRBC-plaque forming cells (PFC) were generally equal in burn and control groups. Numbers of splenic secondary IgG anti-SRBC and anti-LPS PFCs were significantly increased in the burn group with a peak at 5 and 16 days after secondary immunization. There were no differences in serum anti-SRBC or anti-LPS antibody titers between burn-injured and control mice. Nonspecific serum IgG levels were depressed on Days 5 and 10 following injury but had returned to normal by Day 10. Due to the discrepancy between increased secondary PFCs and normal or decreased serum immunoglobulin levels, we measured clearance of exogenously administered IgG. The half-life of IgG in burn mice was 2.5 days compared to 7.1 days in control (P less than 0.05). In conclusion, the antibody response is enhanced after burn injury in the mouse, but this is not reflected in serum levels of specific antibody or immunoglobulins probably due to increased clearance from the circulation.

Immunoglobulin E (IgE) in patients with severe burns

The concentrations of immunoglobulin E (IgE) were measured serially in 30 patients with severe burn injury. A characteristic finding was a rapid and dramatic increase of IgE in the serum of all patients, some of whom showed up to 20-fold increases. IgE was also found in considerable amounts in blister fluid and pleural effusions. In some patients raised IgE values were the only indicator of an anamnestic immediate allergic state. No correlation was found between the IgE levels and clinical characteristics of individual patients but significant changes seemed to be present only in patients with a burn covering more than 20 per cent of the body surface area.