Neopterin plasma levels in burn patients

The predictive value of serum neopterin for multiple organ dysfunction syndrome in severe burn patients

Objective To investigate the predictive value of serum neopterin for multiple organ dysfunction syndrome (MODS) in severe burn patients. Methods Seventy-six severe burn patients with burns covering a total body surface area (TBSA) above 70% were included in this study. Of the 76 patients, 29 cases developed MODS (MODS group) and the remaining 47 subjects did not (non-MODS group). From the MODS group, 12 patients died (Death group) and 17 patients survived (Survive group). The serum level of neopterin in the MODS and non-MODS groups were examined by radioimmunoassay on following 1, 3 , 7 , 14 , 21 and 28 post-burn days (PBDs). A receiver operating characteristic (ROC) curve was used to analyse the predictive value of serum neopterin for MODS and death. Results The serum neopterin level in the MODS group was significantly higher than that of non-MODS group between 3~28 PBDs (p<0.001). However, the serum neopterin levels between the MODS and non-MODS groups following 1 PBD were not statistically significant (p>0.05). The best diagnostic performance of serum neopterin for MODS occurred 14 PBDs with the prediction sensitivity and specificity of 75.86% (56.46%~89.70%) and 85.11% (71.69%~93.80%) respectively. However, serum neopterin levels had no clinical value in predicting the death of MODS patients. The area under the ROC curve (AUC) was 0.72 (0.58~0.85), 0.81 (0.71~0.92) and 0.83 (0.72~0.94) for serum neopterin as biomarker in the prediction of MODS after 3, 7 and 14 PBDs, respectively. The AUCs were 0.50 (0.27~0.73), 0.53 (0.30~0.76) and 0.56 (0.33~0.79) for serum neopterin as biomarker in prediction of death for MODS patients after 3, 7 and 14 PBDs, respectively. Conclusion The persistent and significant increase of serum neopterin level is closely related to the development of MODS in patients with severe burns. Serum neopterin is therefore a promising serological marker for MODS early diagnosis, but has little efficacy in the prediction of the likelihood of death in severe burn patients with MODS.

Biomarkers predicting sepsis in polytrauma patients: Current evidence

INTRODUCTION

Major trauma still represents one of the leading causes of death in the first four decades of life. Septic complications represent the predominant causes of late death (45% of overall mortality) in polytrauma patients. The ability of clinicians to early differentiate between systemic inflammatory response syndrome (SIRS) and sepsis is demonstrated to improve clinical outcome and mortality. The identification of an "ideal" biomarker able to early recognize incoming septic complications in trauma patients is still a challenge for researchers.

AIM

To evaluate the existing evidence regarding the role of biomarkers to predict or facilitate early diagnosis of sepsis in trauma patients, trying to compile some recommendations for the clinical setting.

METHODS

An Internet-based search of the MEDLINE, EMBASE and Cochrane Library databases was performed using the search terms: "Biomarkers", "Sepsis" and "Trauma" in various combinations. The methodological quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies Checklist (QUADAS). After data extraction, the level of evidence available for each bio-marker was rated and presented using the "best-evidence synthesis" method, in line with the US Agency for Healthcare Research and Quality.

RESULTS

Thirty studies were eligible for the final analysis: 13 case-control studies and 17 cohort studies. The "strong evidence" available demonstrated the potential use of procalcitonin as an early indicator of post-traumatic septic complications and reported the inability of c-reactive protein (CRP) to specifically identify infective complications. Moderate, conflicting and limited evidence are available for the other 31 biomarkers.

CONCLUSION

Several biomarkers have been evaluated for predicting or making early diagnosis of sepsis in trauma patients. Current evidence does not support the use of a single biomarker in diagnosing sepsis. However, procalcitonin trend was found to be useful in early identification of post-traumatic septic course and its use is suggested (Recommendation Grade: B) in clinical practice.

The value of neopterin and procalcitonin in patients with sepsis

OBJECTIVE

Neopterin (NT) is a compound of low molecule-based pteridine. It is secreted by macrophages as a response to the stimulation of cytokines such as interferon-gamma, interferon-1beta, tumor necrosis factor alpha or bacteria compounds such as lipopolysaccharides. Procalcitonin (PCT) levels may increase in the course of bacterial, parasitic, and fungal infections. Therefore, it can be used for the differential diagnosis of the infection, especially in cases of serious inflammation. In this study, the role of NT, and PCT in sepsis as a prognostic factor, and the relationship between the two parameters are examined.

METHODS

From November 1, 2005 through December 31, 2005, fifty patients with sepsis admitted to the Department of the Infectious Diseases and Clinical Microbiology and/or Department of Anaesthesiology and Reanimation were enrolled in the study. Patients were divided in two subgroups according to their survival: group I (n=23) nonsurviving patients and group II (n=27) surviving patients.

RESULTS

Serum NT levels have been found to be increased in group I (median: 15 ng/mL, range: 2-69) when compared to group II (median: 5 ng/mL, range: 2-130). The difference was statistically significant (P=0.03). Other laboratory parameters and PCT levels (group I median: 0.13; group II median: 0.08; P<0.05) were not different between the two groups.

CONCLUSIONS

NT was found to be a prognostic factor in patients with sepsis.

Elevated systemic IL-18 and neopterin levels are associated with posttraumatic complications among patients with multiple injuries: a prospective cohort study

INTRODUCTION

Posttraumatic systemic inflammatory response syndrome (SIRS), sepsis and their subsequent complication, the multiple-organ dysfunction syndrome (MODS), remain major complications following polytrauma. This prospective clinical study aimed at evaluating the association between these and plasma interleukin-18 (IL-18) and neopterin levels.

METHODS

Inclusion in the series required an Injury Severity Score (ISS) >16, age 16-65 years, admission within 6 h of the accident and survival >48 h; 55 patients were enrolled. Over 14 days, plasma neopterin and IL-18 levels and the clinical course regarding MODS, SIRS and sepsis were recorded daily using the Marshall Score for MODS and the ACCP/SCCM criteria for SIRS and sepsis.

RESULTS

Neopterin and IL-18 plasma levels were increased in +MODS cases as compared with -MODS cases over almost the entire observation period. IL-18 concentrations over days 3-6 were significantly increased among participants with sepsis. These increases were all apparent 2-3 days before the clinical diagnosis of sepsis or MODS was made. In contrast, no significant differences in neopterin and IL-18 plasma levels were observed between participants with and without SIRS.

CONCLUSIONS

Determinations of neopterin and IL-18 concentrations might represent early markers for posttraumatic complications such as MODS and sepsis. They might help to differentiate between SIRS and sepsis and thereby guide the timing of the surgery for polytrauma. Neopterin and IL-18 levels should be used together with the clinical status and other inflammatory markers (IL-6, IL-8, etc.) for prediction of posttraumatic complications.

Clinical laboratory differentiation of infectious versus non-infectious systemic inflammatory response syndrome

OBJECTIVE

To evaluate the accuracy of C-reactive protein (CRP), procalcitonin (PCT), neopterin, and endotoxin in the differential diagnosis of sepsis and non-infectious systemic inflammatory response syndrome (SIRS).

METHODS

A Medline database and references from identified articles were used to perform a literature search relating to the differential diagnosis of sepsis versus non-infectious SIRS.

RESULTS

CRP, PCT, and neopterin are released both in sepsis and in non-infectious inflammatory disease. CRP and PCT are equally effective, although not perfect, in differentiating between sepsis and non-infectious SIRS. However, CRP and PCT have different kinetics and profiles. The kinetics of CRP is slower than that of PCT, and CRP levels may not further increase during more severe stages of sepsis. On the contrary, PCT rises in proportion to the severity of sepsis and reaches its highest levels in septic shock. PCT tends to be higher in nonsurvivor than in survivor. Therefore, PCT demonstrated a closer correlation with the severity of sepsis and outcome than CRP. Unlike CRP and PCT, neopterin is increased in viral infection as well as bacterial infection, and neopterin is also a useful indicator of sepsis. Endotoxemia was detected in no more than half of patients with Gram-negative bacteremia, and Gram-negative bacteremia was detected in half of patients with endotoxemia.

CONCLUSIONS

The diagnostic capacity of PCT is superior to that of CRP due to the close correlation between PCT levels and the severity of sepsis and outcome. Neopterin is very useful in the diagnosis of viral infection. The endotoxin assay in combination with CRP, PCT, or neopterin may help as a diagnostic marker for Gram-negative bacterial infection.

Myocardial function and haemodynamics in extensive burn trauma: evaluation by clinical signs, invasive monitoring, echocardiography and cytokine concentrations. A prospective clinical study

BACKGROUND

The objectives of this study were to (1). describe the haemodynamic profile of patients with extensive burns during the early fluid resuscitation phase, (2). evaluate myocardial performance by invasive monitoring and echocardiography and (3). analyze the relations between serum cytokine (IL-6, IL-8, TNF) and natriuretic peptide (ANP, BNP) concentrations and myocardial function in these patients.

METHODS

Prospective, clinical study in a tertiary care burn centre. Invasive haemodynamic measurements including a pulmonary artery catheter, echocardiography, blood samples for cytokine and atriopeptide analyses. The follow-up time was up to 72 h postinjury.

RESULTS

According to echocardiography, patients were hypovolaemic despite aggressive (median 7,9 ml kg(-1) h(-1), range 3.3-11.7) fluid resuscitation and adequate urine output (median 0.9 ml kg(-1) h(-1), range 0.46-1.35) during the first day postinjury. There were no consistent findings of hyperlactatemia, metabolic acidosis or low mixed venous oxygen saturations. Daily highest and lowest values of cardiac index and stroke volume index increased and the lowest and highest values of systemic vascular resistance decreased. Cardiac performance (stroke volume index) improved during the study period even though there were no initial signs of myocardial depression in echocardiography. Three patients received a dobutamine infusion based on clinical judgement. There was no consistent association between haemodynamic changes and plasma cytokine concentrations.

CONCLUSION

Persisting hypovolaemia is evident in the resuscitation phase of extensive burns despite aggressive fluid therapy and the lack of classic signs of hypoperfusion. Cardiac performance improves during the first days after extensive burn injury without association with plasma cytokine profile.

Procalcitonin and neopterin as indicators of infection in critically ill patients

BACKGROUND

: In critically ill patients, severe infection and systemic inflammation due to non-infectious causes produce very similar clinical presentations, and traditional infection markers do not always differentiate these two conditions. Both procalcitonin and neopterin have been suggested to aid in the early diagnosis of bacterial infections and in differentiating bacterial infections from systemic inflammatory, non-infectious diseases or from viral infections.

METHODS

: Procalcitonin (PCT) and neopterin were analyzed in 208 ICU patients who developed acute fever or septic shock. Blood samples were taken every 8th h within 48 h of the onset of fever or septic shock.

RESULTS

: A total 162/208 of patients had infection, the most common location being the respiratory tract. Mortality was higher in infected patients (31.4% vs. 10.9%; P < 0.01). The optimum cut-off levels in identifying patients with infection of daily peak PCT were 0.8 microg/L on day 1 and 0.9 microg/L on day 2, and both sensitivity (67.7% and 60.9%, respectively) and specificity (47.8% and 63%) were poor. Accordingly, the optimum cut-off values of peak neopterin were 18 and 16 pg/L. The sensitivity was 62.7% on day 1 and 69.3% on day 2, while specificity was correspondingly 78.3% and 67.9%. There were no significant differences between the markers in discriminating between patients with infection or inflammation. Both PCT and neopterin increased with the severity of infection. They were higher in non-survivors.

CONCLUSION

: PCT and neopterin were equally effective, although not very accurate in differentiating between infection and inflammation in critically ill patients. Neopterin was more specific than PCT, suggesting that neopterin is related to the activity of inflammatory response.

Markers for cell-mediated immune response are elevated in cerebrospinal fluid and serum after severe traumatic brain injury in humans

The brain is believed to be an immunologically privileged organ, sheltered from the systemic immunological defense by the blood-brain barrier (BBB). However, there is increasing evidence for a marked inflammatory response in the brain after traumatic brain injury (TBI). Markers for cellular immune activation, neopterin, beta2-microglobulin (beta2M), and soluble interleukin-2 receptor (sIL-2R), were measured for up to 3 weeks in cerebrospinal fluid (CSF) and serum of 41 patients with severe TBI in order to elucidate the time course and the origin of the cellular immune response following TBI. Neopterin gradually increased during the first posttraumatic week in both CSF and serum. Concentrations in CSF were generally higher than in serum, suggesting intrathecal release of this marker. beta2M showed similar kinetics but with higher serum than CSF concentrations. Nonetheless, intrathecal release as assessed by the beta2M index could be postulated for most of the patients. The mean levels of sIL-2R in both CSF and serum were elevated during the whole study period, serum concentrations being up to 2 x 10(4) times higher than in CSF. No significant intrathecal production of sIL-2R could be detected. The present data shows that severe TBI leads to a marked cell-mediated immune response within the brain and in the systemic circulation. In the intrathecal compartment the activated cells appear to be predominantly of the macrophage/microglia lineage, while the immune activation in the systemic circulation seems to involve mainly T-lymphocytes.

Neopterin plasma concentrations predict the course of severe acute pancreatitis

In a prospective, descriptive study in 25 patients with acute pancreatitis neopterin plasma concentrations were found to be associated with the severity of the disease, which was assessed using weights of the worst 17 physiological abnormalities of the APACHE-III score over a 24 h-period after hospital admission. Neopterin concentrations were higher in severe pancreatitis (n = 10) compared to mild disease, and there existed a positive exponential correlation between neopterin and the Acute Physiology Score (r = 0.66). Higher neopterin concentrations were associated with the development of multiple organ failure (p = 0.012) and death (p = 0.019). At a cut-off concentration of 12 nmol/l the sensitivity (80%) and specificity (100%) of neopterin for the discrimination between mild and severe clinical course of pancreatitis was more accurate than C-reactive protein at a risk threshold of 1.2 g/l (70% and 87%). Development of pancreatic necrosis was associated with higher neopterin concentrations than edematous pancreatitis (p < 0.001).

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.