M. Siddiqi

Depressed interleukin-12-producing activity by monocytes correlates with adverse clinical course and a shift toward Th2-type lymphocyte pattern in severely injured male trauma patients

OBJECTIVE To determine the effect of major trauma on the cytokine-producing activity of monocytes and CD4+ T cells in a homogeneous cohort of patients as well as to determine the relationship between monocyte and T-lymphocyte responses and clinical outcome. SETTINGS Surgical intensive care units of a trauma center and flow cytometry and experimental laboratories at a teaching hospital. DESIGN Prospective cohort clinical study with measurements of white cell cytokine-producing activity on days 2, 5, and 10 postinjury. The number of cytokine-producing CD14+ monocytes, CD4+, and CD8+ T cells were determined in whole blood using flow cytometry combined with the intracellular cytokine staining method. Basal and lipopolysaccharide-stimulated interleukin (IL)-12, tumor necrosis factor-alpha, IL-6, and IL-1alpha production by monocytes as well as basal and phorbol 12-myristate 13-acetate plus ionomycin-stimulated interferon-gamma, IL-4, and tumor necrosis factor-alpha production by T cells were determined on days 2, 5, and 10 postinjury and compared with similar measurements made in healthy control subjects. PATIENTS Twelve randomly selected black, male patients were enrolled in the study: mean injury severity score, 26; mean age, 35 yrs; mean Glasgow Coma Scale score, 13; systemic inflammatory response syndrome, 92%; sepsis, 42%; bronchial infection, 42%; and adult respiratory distress syndrome 25%. MAIN RESULTS After lipopolysaccharide stimulation, the number of IL-12-, tumor necrosis factor-alpha-, IL-1alpha-, and IL-6-producing CD14+ monocytes was 40% to 70% lower in trauma patients on postinjury days 2, 5, and 10 than in healthy control subjects. After phorbol 12-myristate 13-acetate stimulation, the number of IL-4-producing CD4+ cells increased three-fold in the trauma patients compared with healthy control subjects. In contrast, the number of interferon-gamma- or tumor necrosis factor-alpha-producing CD4+ and CD8+ T cells was not different between the patients and control subjects. The Th1/Th2 ratio was significantly lower in patients on all postinjury days than in the control subjects. A statistically significant inverse correlation was found between the number of IL-12-producing monocytes and IL-4-producing CD4+ T cells in trauma patients (p =.007, r2 =.47). This correlation was absent in control subjects. The degree of depressed capacity of monocyte IL-12 production on day 2 postinjury showed a statistically significant correlation with the development of adult respiratory distress syndrome, sepsis, or infections and also with the duration of systemic inflammatory response syndrome and sepsis. CONCLUSIONS Major trauma results in an early and marked decrease in monocyte cytokine-producing activity. The trauma-induced depression in IL-12 production by the mononuclear phagocyte system may promote T-cell commitment toward a Th2 pattern early after trauma. The appearance of the Th2 pattern is the result of elevated numbers of IL-4-producing cells without major alterations in T-cell interferon-gamma-producing capacity. The degree of alterations in monocyte and T-cell responses on day 2 postinjury correlates with the development of adverse clinical outcomes and the subsequent duration of the inflammatory response.

Increased incidence of sepsis and altered monocyte functions in severely injured type A- glucose-6-phosphate dehydrogenase-deficient African American trauma patients.

ObjectiveTo determine whether trauma patients with the common, type A− glucose-6-phosphate dehydrogenase (G6PD) deficiency have an aggravated inflammatory response, increased incidence of septic complications, and/or more profound alterations in leukocyte functions compared with nondeficient trauma patients. SettingsIntensive and surgical care units of a trauma center and flow cytometry and experimental laboratories at a teaching university hospital. DesignProspective cohort clinical study with measurements on days 2 and 5 postinjury. Monocyte and neutrophil oxidant content, apoptosis, and CD11b expression and plasma cytokine levels were compared between G6PD-deficient and nondeficient patients. PatientsA total of 467 male African American trauma patients were screened for the deficiency. Forty-four type A−202/376 G6PD-deficient patients were identified and enrolled in the study; 43 nondeficient patients were also enrolled and were matched by age, clinical criteria of injury severity, and type of trauma. Main ResultsAfter severe injury (Injury Severity Score, ≥16), 50% of the deficient and 6.2% of nondeficient patients developed sepsis with positive bacterial blood cultures. In deficient patients, the frequency of bronchial (75%) and wound infections (25%) was also increased compared with nondeficient patients (32% and 0%). The durations of systemic inflammatory response syndrome, Sepsis Syndrome, and days on antibiotics were three times longer in deficient than in nondeficient individuals. However, adult respiratory distress syndrome occurred in 37% of both groups. Anemia was more severe in the deficient than nondeficient patients from day 10 posttrauma. On day 5, the peroxide content was doubled, apoptosis was decreased, and CD11b expression was increased in monocytes from deficient patients compared with cells from nondeficient patients. On day 5, the plasma interleukin (IL)-10 concentration was significantly lower in deficient than nondeficient patients, whereas tumor necrosis factor-&agr;, IL-6, and IL-8 levels were similar. After moderate injuries (Injury Severity Score, 9–16), the deficiency was not associated with adverse clinical effects, and the trauma-induced changes in leukocyte function were similar in deficient and nondeficient patients. ConclusionsThe common type A− G6PD deficiency predisposes septic complications and anemia in trauma patients after severe injuries as defined by an Injury Severity Score of ≥16. This adverse clinical course is accompanied by altered monocyte functions manifested as augmented oxidative stress, a decreased apoptotic response, increased cell adhesion properties, and a diminished IL-10 response.

Augmented TNF‐α and IL‐10 production by primed human monocytes following interaction with oxidatively modified autologous erythrocytes

The presence of dysfunctional/damaged red blood cells (RBCs) has been associated with adverse clinical effects during the inflammatory response. The aim of this study was to elucidate whether oxidatively modified, autologous RBCs modulate monocyte cytokine responses in humans. Monocyte tumor necrosis factor α (TNF‐α) and IL‐10 production was measured in whole blood from healthy volunteers using ELISA and flow cytometry. Oxidatively modified RBCs (15 mM phenylhydrazine, 1 h, OX‐RBC) or vehicle‐treated RBCs (VT‐RBC) opsonized by autologous serum were administered alone or in combination with one of three priming agents: E. coli lipopolysaccharide (LPS, 0.2 ng/ml), zymosan A (1 mg/ml), or phorbol 12‐myristate 13‐acetate (PMA, 50 ng/ml). OX‐RBC or VT‐RBC alone did not result in the release of TNF‐α or IL‐10. LPS, zymosan, and PMA caused marked and dose‐dependent increases in TNF‐α and IL‐10 production. Addition of OX‐RBC augmented the LPS‐, zymosan‐, and PMA‐induced TNF‐α release by approximately 100%. OX‐RBC augmented LPS‐ and zymosan‐induced IL‐10 release by 400–600%. Flow cytometry analyses showed that monocytes were responsible for TNF‐α and IL‐10 production in whole blood. The presence of OX‐RBC alone increased the complexity of CD14+ monocytes but caused no cytokine production. LPS alone induced cytokine production without altering cell complexity. After the combined (OX‐RBC+LPS) treatment, monocytes of high complexity were responsible for TNF‐α production. The presence of mannose or galactose (at 10–50 mM) did not alter the observed augmentation of cytokine production by OX‐RBC, suggesting that lectin receptors are not involved in the response. These studies indicate that the interaction between damaged autologous erythrocytes and monocytes has a major impact on the cytokine responses in humans. An augmented cytokine production by the mononuclear phagocyte system may adversely affect the clinical course of injury and infections especially in genetic or acquired RBC diseases or after transfusions.

Attenuated monocyte IL-10 production in glucose-6-phosphate dehydrogenase-deficient trauma patients.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the worlds most common known human genetic polymorphisms, but the pathophysiology of the defect remains largely unknown. In the present study, we compared hematology parameters and ex vivo monocyte cytokine responses in non-deficient and G6PD-deficient trauma patients. Deficient and non-deficient, moderately injured, trauma patients exhibited similar hematology profiles at the time of hospital admission. In contrast to non-deficient patients, G6PD-deficient patients were anemic 2 days post-injury. Monocytes from deficient individuals produced 50% less interleukin 10 (IL-10) in response to LPS and >90% less IL-10 in response to PMA, compared with non-deficient patients, 2 days post-injury. The presence of phenylhydrazine-treated, opsonized, autologous RBC (OX-RBC), alone had no effect on IL-10 production by non-deficient or deficient monocytes, whereas IL-10 responses to lipopolysaccharide (LPS) were augmented by OX-RBC in both groups. However, IL-10 production was markedly lower by monocytes from G6PD-deficient than non-deficient patients after stimulation with LPS plus OX-RBC. TNF-&agr; production following PMA was similar in deficient and non-deficient patients, and the differences following LPS or LPS plus OX-RBC stimulation were moderate between deficient and non-deficient samples. Interferon (IFN)-&ggr; production ex vivo was doubled by OX-RBC treatment alone, but it was not stimulated by LPS treatment. IFN-&ggr; production was similar in non-deficient and G6PD-deficient patients. These data suggest that the observed differences in IL-10 responses between G6PD-deficient and non-deficient patients are not attributable to differences in TNF-&agr; or IFN-&ggr; production. Taken together, our data suggest that a reduction in the capacity to produce IL-10 may be an intrinsic characteristic of G6PD-deficient monocytes. An attenuated IL-10 production may be a contributing mechanism in the previously observed augmented inflammatory response in severely injured G6PD-deficient compared with non-deficient trauma patients.