Serum procalcitonin in systemic autoimmune diseases--where are we now?

Procalcitonin for the early discrimination of fever etiology in patients with systemic autoimmune diseases attending the emergency department

In febrile patients with known systemic autoimmune disease, early discrimination between infection and disease flare often represents a clinical challenge. This study aimed at evaluating the efficacy of procalcitonin (PCT) and other common inflammatory biomarkers in discriminating disease flare from bacterial infections in the Emergency Department (ED). In a cross-sectional observational retrospective study, we identified consecutive febrile patients with a known diagnosis of systemic autoimmune disease, admitted to the ED, and subsequently hospitalized. Flare vs infective disease was defined on clinical records at hospital discharge. Dosage of common inflammatory markers was performed at ED admission. Out of 177 patients, those with infection were most commonly elderly, frail, and with reduced peripheral oxygen saturation at admission. When compared to C-reactive protein (CRP) and white blood count (WBC), PCT showed the best performance in discriminating infections vs flare. However, only at a very high threshold value of 2 ng/ml, the PCT had a satisfactory negative predictive value of 88.9%, although with a very low specificity of 13.6% and a positive predictive value of 35.8%. Our data suggest that in the ED setting, the early PCT determination has low accuracy in the differentiation of disease flare from infection in patients with known rheumatologic disease. However, the PCT could be useful in elderly and comorbid subjects, in supporting clinical assessment and in recognizing those febrile patients needing prompt antibiotic treatment.

Markedly elevated procalcitonin due to anaphylactic shock, a case report

Procalcitonin (PCT) is a well-known biomarker that is directly connected to bacterial infection especially when it reaches significantly high levels. It is extremely rare to be witnessed in non-bacterial infections such as viral or parasitic. It may be elevated in other conditions such as trauma and autoimmune diseases. We present a rare case of a young gentleman, who had an extremely high PCT level that appeared to be a result of anaphylaxis due to worm infestation.

Serum procalcitonin and C-reactive protein levels as diagnostic markers for distinguishing bacterial infections from lupus flares in systemic lupus erythematosus: A systematic review and meta‑analysis

PURPOSE

To systematically evaluate the diagnostic performance of procalcitonin (PCT) and C-reactive protein (CRP) for distinguishing bacterial infections from lupus flares in systemic lupus erythematosus (SLE) via meta-analysis.

METHODS

Electronic databases were comprehensively searched. The pooled standard mean difference (SMD) and 95% confidence interval (CI) were calculated to estimate the differences of serum PCT and CRP levels between bacterial infections and flares in SLE. Sensitivity, specificity and summary receiver operating characteristics (SROC) curve were used to assess the diagnostic values of PCT and CRP. The use of fixed or random effects model depended on heterogeneity.

RESULTS

Fifteen studies were included in the analysis. Serum PCT and CRP levels were significantly higher in SLE patients with bacterial infections compared to SLE patients with flares (PCT: SMD = 1.035, 95 %CI = 0.708 to 1.362; CRP: SMD = 1.000, 95 %CI = 0.758 to 1.242). The overall sensitivity, specificity, area under the SROC curve, positive likelihood ratios (PLR) and negative likelihood ratios (NLR) of PCT were 0.62, 0.88, 0.862, 6.63 and 0.36, respectively, while the same indicators for CRP were 0.72, 0.70, 0.784, 2.45 and 0.38, respectively.

CONCLUSION

Serum PCT and CRP levels were significantly increased in SLE with bacterial infections. PCT had a better diagnostic performance than CRP. PCT had a high value of PLR and could serve as a rule-in marker, while CRP testing may result in a high false-positive rate due to low PLR; both markers had a suboptimal value of NLR and are not appropriate for ruling out bacterial infections.

Effective use of monoclonal antibodies for treatment of persistent COVID-19 infection in a patient on rituximab

As we are over a year into the COVID-19 pandemic, we have made many forward strides in therapeutics. These treatments, such as monoclonal antibodies, have help mitigate the detrimental and often fatal consequences of COVID-19. The current indication for the use of monoclonal antibodies is mild to moderate COVID-19 infection within 10 days of symptom onset in those who are at high risk of progression to severe disease. However, their role in patients with prolonged symptoms is not clear. We present a unique case of monoclonal antibodies use after 54 days of symptom onset in an immunosuppressed patient with persistent COVID-19 infection despite standard treatment. This case illustrates the potential use of monoclonal antibodies outside of the current recommended therapeutic window in immunosuppressed patients, who may have difficulty with viral clearance.

Modestly Elevated Serum Procalcitonin Levels in Patients with Rheumatoid Arthritis Free of Active Infection

Background and objectives: To investigate the serum procalcitonin (PCT) levels among patients with rheumatoid arthritis (RA) without active infection compared with healthy controls and to understand the relationship of PCT with RA disease activity, and treatment received by patients. Materials and Methods: Patients aged 20 years and above with clinician-confirmed diagnosis of RA and healthy volunteers were included during regular outpatient visits, and those with active infection symptoms and signs were excluded. RA disease activity was measured using the Disease Activity Score-28 for Rheumatoid Arthritis with erythrocyte sedimentation rate (DAS28-ESR). Medications received by the patients were also recorded. Results: A total of 623 patients with RA and 87 healthy subjects were recruited in this study. The mean PCT were significantly higher in patients with RA (6.90 ± 11.81 × 10⁻³ ng/mL) compared with healthy controls (1.70 ± 6.12 × 10⁻³ ng/mL) (p < 0.001) and the difference remained statistically significant after adjusting for age and sex. In addition, multiple linear regression analysis showed that a lower rank-transformed PCT serum level was significantly correlated with the use of biologics (p = 0.017) and a high DAS28-ESR score (p = 0.028) in patients with RA. Conclusion: Patients with RA have a significantly higher serum PCT levels compared with healthy controls. The use of biologics and an active RA disease activity were associated with a lower level of PCT in patients with RA. Further investigation is required to determine the optimal cutoff value of PCT among patients with RA and its association with disease activity and biologic usage.

Procalcitonin: A promising tool or just another overhyped test?

Sepsis is the leading cause of death worldwide. Timely administration of antibiotics is recognized as the cornerstone in the management of sepsis. However, inappropriate use of antibiotics may lead to adverse effects and the selection of drug-resistant pathogens. Microbiological cultures remain the gold standard to diagnose infection despite their low sensitivity and the intrinsic delay to obtain the results. Certain biomarkers have the benefit of rapid turnover, potentially providing an advantage in timely diagnosis leading to accurate treatment. Over the last few decades, there is an ongoing quest for the ideal biomarker in sepsis. Procalcitonin (PCT), when used alone or alongside additional clinical information, has shown to be a promising tool to aid in the diagnosis and management of patients with sepsis. In February 2017, the Food and Drug Administration (FDA) approved the use of PCT to guide antibiotic treatment in lower respiratory tract infections and sepsis. Despite a good negative predictive value for bacterial infection, the utility of PCT-guided antibiotic initiation is conflicting at best. On the other hand, the use of PCT-guided antibiotic discontinuation has shown to reduce the duration of antibiotic use, the associated adverse effects, and to decrease the overall mortality. The current review discusses the history and pathophysiology of procalcitonin, synthesizes its utility in the diagnosis and management of sepsis, highlights its limitations and compares it with other biomarkers in sepsis.

[Cancer patients in operative intensive care medicine]

Die Prävalenz onkologischer Erkrankungen ist in den vergangenen Jahrzehnten stetig angestiegen. Durch neue Therapieoptionen können immer mehr Patienten mit einem kurativen Therapieansatz behandelt werden. Diese individualisierten und teilweise sehr aggressiven Therapien können jedoch auch zu schweren Nebenwirkungen führen. Diese sollten als wichtige Differenzialdiagnosen zu anderen vitalbedrohlichen Krankheitsbildern auch dem im OP und als Intensivmediziner tätigen Anästhesisten bekannt sein. Krebspatienten werden häufig auf operativen Intensivstationen aufgenommen, um Komplikationen der malignen Grunderkrankung oder auch Nebenwirkungen einer operativen oder konservativen Therapie zu behandeln. Aktuelle Untersuchungen zeigen, dass die maligne Grunderkrankung entgegen bisheriger Annahme keinen wesentlichen Einfluss auf das Intensivüberleben hat. Bei der Aufnahme eines onkologischen Patienten sollte daher die akut vorliegende Organdysfunktion zunächst im Vordergrund stehen. Bei der Therapiezielplanung gilt es, nicht zu übersehen, wann ein kuratives in ein palliatives Konzept übergehen muss. Hierfür müssen neue Aufnahmestrategien und -kriterien entwickelt und evaluiert werden. In diesem Übersichtsartikel werden Diagnosen und Therapien häufiger intensivmedizinischer Krankheitsbilder von onkologischen Patienten sowie Nebenwirkungen moderner onkologischer Therapien dargelegt und Aufnahmestrategien für Patienten mit malignen Erkrankungen vorgestellt.

Laboratory Assessment of Patients with Suspected Rheumatic Musculoskeletal Diseases: Challenges and Pitfalls

Current patient care in rheumatology relies primarily on a combination of traditional clinical assessment and standard laboratory tests. Investigators seek to discover new biomarkers and novel technologies to boost the research in this field. Mechanistic biomarkers such as cytokines, cell types, antibodies, signaling molecules, are rooted in the mechanism underlying the disease and can guide the clinical management of the disease. Conversely, descriptive biomarkers are byproducts of the disease process, depict the state of a disease but are not involved in its pathogenesis. In this article, we reviewed the field of common laboratory biomarkers in rheumatology, highlighting both their descriptive or mechanistic value as well as their role in clinical practice.

The use of procalcitonin in the determination of severity of sepsis, patient outcomes and infection characteristics

Objective

The primary objective of this study was to determine the correlation between procalcitonin values and illness severity by evaluating the degree of end organ dysfunction using the Sequential Organ Failure Assessment score, length of stay and the severity of sepsis (sepsis alone vs. septic shock), The hypothesis that procalcitonin values would be higher in sicker patients was formulated before data collection began. Secondary outcomes studied in relation to procalcitonin levels included infection characteristics such as the site of infection, microbial agent and dialysis dependent CKD.

Design

Unblinded retrospective cohort study. September 2014-December 2016.

Setting

364 patients with a diagnosis of sepsis or severe sepsis who were admitted to the general medical ward and ICU at Methodist Medical Center and Proctor Hospital in Peoria, Illinois, USA.

Results

This study demonstrates the following: Weak positive correlation between procalcitonin and SOFA score. Negligible correlation with length of stay. Higher values in patients who died than in patients who survived to discharge (p = 0.058). Sensitivity and specificity of procalcitonin for septic shock was 63 and 65% respectively. Sites typically infected by gram negative bacteria have higher procalcitonin values than sites infected by gram positive bacteria (p = 0.03). Higher procalcitonin in bacteremia than non-bacteremic infections (p = 0.004). Higher procalcitonin in dialysis-dependent CKD patients (p = 0.020).

Conclusions

Procalcitonin has a higher specificity for bacterial infections than other acute phase reactants. Although initial procalcitonin value may be helpful in the determination of illness severity, it is not always a reliable prognostic indicator and carries little significance as a standalone value. Procalcitonin values may be influenced by preexisting comorbid conditions such as chronic kidney disease, which are associated with higher procalcitonin values at baseline. Procalcitonin can provide invaluable information when viewed as one piece of a clinical puzzle, and is most powerful when the interpreting physician is aware of how values are influenced by the different clinical scenarios presented in this article.

Combination of procalcitonin, C-reaction protein and carcinoembryonic antigens for discriminating between benign and malignant pleural effusions

Pleural effusion (PE) is a common manifestation associated with certain chest diseases. However, there is no effective diagnostic marker with high sensitivity and specificity. The aim of the present study was to evaluate the diagnostic performance of several biomarkers in the use of detecting malignant pleural disorder. One hundred and fifty patients with a specific diagnosis of exudative PE were enrolled in this study and were divided into the benign PE group (n=93) and the malignant PE group (n=57). Thoracoscopy was conducted to identify the reasons for the PE. Biomarkers in pleural fluid and in sera were determined either by microparticle enzyme immunoassay [carcinoembryonic antigen (CEA)], fluorescence immunoassay [procalcitonin (PCT)] or light-scattering turbidimetric immunoassay [C-reaction protein (CRP)]. Then, correlation analysis and receiver-operating characteristic (ROC) curve analysis individually or in combination were performed. The CRP and PCT levels were higher in benign PE than they were in malignant PE (PCT: P=0.017, P=0.032; CRP: P=0.001, P<0.001, respectively), while CEA levels were lower in benign PE than in malignant PE (CEA: P=0.001, P=0.001, respectively). During the ROC curve analysis, an optimal discrimination was identified by combining pleural CRP, pleural CEA and serum (s)PCT with an area under the curve of 0.973 (sensitivity, 98.9%; specificity, 89.5%). In the diagnosis of PE, there was no single biomarker that appeared to be adequately accurate. The combination of pleural CRP, pleural CEA and sPCT may represent an efficient diagnostic procedure for guiding the patient towards follow-up clinical treatment.

Diagnostic and predictive values of procalcitonin in bloodstream infections for nosocomial pneumonia

PURPOSE

We evaluated the diagnostic accuracy of PCT to distinguish between gram-negative (GN) and gram-positive (GP) bloodstream infections nosocomial pneumonia (NP) patients and compared PCT levels with the pneumonia severity index (PSI) for predicting mortality.

METHODS

Data were collected retrospectively for blood culture-positive NP patients between January 2014 and August 2016. PCT levels were compared between patients with GN versus GP infections. Outcome variables included 28- and 60-day mortality.

RESULTS

PCT level was higher in GN infections than in GP infections. PCT could differentiate between GN and GP infections with an AUC value of 0.706. At a PCT cutoff of 5.4 ng/mL, the specificity for GN infections were 80.3%. The AUCs for 28- and 60-day mortality were 0.758 and 0.759 for PSI, and 0.620 and 0.634 for PCT. Serum PCT level was less predictive of mortality in GN NP patients compared with that for GP NP patients. There was a significantly positive correlation between PCT and PSI, and the correlation in GP NP patients was better than that in GN NP patients.

CONCLUSIONS

PCT could differentiate between GN and GP bloodstream infections in patients with NP. However, PCT levels were less predictive of mortality compared with the PSI.

[Cancer patients in operative intensive care medicine]

Die Prävalenz onkologischer Erkrankungen ist in den vergangenen Jahrzehnten stetig angestiegen. Durch neue Therapieoptionen können immer mehr Patienten mit einem kurativen Therapieansatz behandelt werden. Diese individualisierten und teilweise sehr aggressiven Therapien können jedoch auch zu schweren Nebenwirkungen führen. Diese sollten als wichtige Differenzialdiagnosen zu anderen vitalbedrohlichen Krankheitsbildern auch dem im OP und als Intensivmediziner tätigen Anästhesisten bekannt sein. Krebspatienten werden häufig auf operativen Intensivstationen aufgenommen, um Komplikationen der malignen Grunderkrankung oder auch Nebenwirkungen einer operativen oder konservativen Therapie zu behandeln. Aktuelle Untersuchungen zeigen, dass die maligne Grunderkrankung entgegen bisheriger Annahme keinen wesentlichen Einfluss auf das Intensivüberleben hat. Bei der Aufnahme eines onkologischen Patienten sollte daher die akut vorliegende Organdysfunktion zunächst im Vordergrund stehen. Bei der Therapiezielplanung gilt es, nicht zu übersehen, wann ein kuratives in ein palliatives Konzept übergehen muss. Hierfür müssen neue Aufnahmestrategien und -kriterien entwickelt und evaluiert werden. In diesem Übersichtsartikel werden Diagnosen und Therapien häufiger intensivmedizinischer Krankheitsbilder von onkologischen Patienten sowie Nebenwirkungen moderner onkologischer Therapien dargelegt und Aufnahmestrategien für Patienten mit malignen Erkrankungen vorgestellt.

Distinguishing infections vs flares in patients with systemic lupus erythematosus

SLE is a chronic autoimmune disease involving multiple systems. Patients with SLE are highly susceptible to infections due to the combined effects of their immunosuppressive therapy and the abnormalities of the immune system that the disease itself causes, which can increase mortality in these patients. The differentiation of SLE activity and infection in a febrile patient with SLE is extremely difficult. Activity indexes are useful to identify patients with lupus flares but some clinical and biological abnormalities may, however, make it difficult to differentiate flares from infection. Several biological markers are now recognized as potential tools to establish the difference between SLE activity and infection, including CRP and procalcitonin. It is possible, however, that the use of only one biomarker is not sufficient to confirm or discard infection. This means that new scores, which include different biomarkers, might represent a better solution for differentiating these two clinical pictures. This review article describes several markers that are currently used, or have the potential, to differentiate infection from SLE flares.

Utility of cytokines to predict neonatal sepsis

BACKGROUND

Sepsis is an important cause of neonatal morbidity and mortality worldwide. Diagnosis and treatment of neonatal sepsis relies on clinical judgment and interpretation of nonspecific laboratory tests. In a prospective cohort, we measured inflammatory cytokines as a potential biomarker for neonatal sepsis.

METHODS

Serum inflammatory cytokine levels were evaluated in the early stage of neonatal sepsis and after antimicrobial treatment. Receiver operating characteristic curves assessed the diagnostic value of cytokines. We performed multiple logistic regression analysis to characterize the role of each cytokine independently for infants with culture proven sepsis.

RESULTS

C-reactive protein, interleukin (IL)-6, IL-10 and IL-6/IL-10 levels were significantly elevated in neonatal sepsis when compared with the control group and there were 1.4 (95% confidence interval (CI): 1.2-1.5), 4.9 (95% CI: 4.6-5.1), 5.1 (95% CI: 4.5-5.6), and 10.2 (95% CI: 9.2-11.1) fold greater odds, respectively, to predict neonatal sepsis when increased. After effective treatment, median IL-6 (pretreatment value: 263.0 pg/ml and post-treatment value: 7.4 pg/ml) and IL-6/IL-10 levels (pretreatment value: 16.6 and post-treatment value: 1.4) significantly decreased. The areas under the curve for IL-6, IL-10, IL-6/IL-10 and C-reactive protein for differential diagnosis were 0.98, 0.82, 0.90, and 0.88, respectively.

CONCLUSION

IL-6 and IL-6/IL-10 outperformed C-reactive protein to diagnose neonatal sepsis. Of the cytokines studied, IL-6 was the most sensitive, whereas IL-6/IL-10 was the most specific predictor of neonatal sepsis.

The relationship between procalcitonin and thyroid autoantibodies in patients with autoimmune thyroiditis

BACKGROUND

The aim of this study is to investigate the serum levels of procalcitonin and its association with autoantibodies in patients with euthyroid Hashimoto's thyroiditis.

METHODS

A total of 80 participants were included in the study; 40 of which were newly diagnosed with Hashimoto's thyroiditis, aged over 18, and 40 of which were healthy volunteers. The serum levels of procalcitonin were measured by enzyme-linked immunosorbent assay kit. Thyroid function tests were analyzed in hormone laboratory with Electro-chemiluminescence immunoassay.

RESULTS

Hashimoto's thyroiditis patients had higher median procalcitonin levels than those of the control group (34.3 pg/mL vs 27.8 pg/mL respectively; P=.037). Also, male patients had higher median procalcitonin levels as compared to female patients (37 pg/mL vs 27 pg/mL respectively; P=.013). In the Hashimoto's thyroiditis group, procalcitonin level was positively correlated with anti-thyroglobulin and anti-thyroid peroxidase levels (r=.559, P<.001; r=634, P<.001, respectively). The procalcitonin and anti-thyroid peroxidase levels were identified to be an independent predictor in diagnosis of Hashimoto's thyroiditis.

CONCLUSIONS

The fact that procalcitonin was found to be correlated with thyroid autoantibodies and found to be an independent risk factor for Hashimoto's thyroiditis in the regression analysis in the framework of this study urges us to think that procalcitonin may be associated with the autoimmunity.

Discontinuation of Hemodialysis in a Patient with Anti-GBM Disease by the Treatment with Corticosteroids and Plasmapheresis despite Several Predictors for Dialysis-Dependence

A 26-year-old man highly suspected of having antiglomerular basement membrane (GBM) disease was treated with corticosteroid pulse therapy 9 days after initial infection-like symptoms with high procalcitonin value. The patient required hemodialysis the next day of the treatment due to oliguria. In addition to corticosteroid therapy, plasmapheresis was introduced and the patient could discontinue hemodialysis 43 days after the treatment. Kidney biopsy after initiation of hemodialysis confirmed anti-GBM disease with 86.3% crescent formation. Physician should keep in mind that active anti-GBM disease shows even high procalcitonin value in the absence of infection. To pursue recovery of renal function, the challenge of the immediate and persistent treatment with high-dose corticosteroids plus plasmapheresis for highly suspected anti-GBM disease is vitally important despite the presence of reported predictors for dialysis-dependence including oliguria and requiring hemodialysis at presentation.

Procalcitonin levels in bloodstream infections caused by different sources and species of bacteria

OBJECTIVE

The aim of this study was to evaluate procalcitonin (PCT) diagnostic accuracy in discriminating gram-negative (GN) from gram-positive (GP) bloodstream infections and determining the relationship between PCT levels, infection sites, and pathogen types.

METHODS

Clinical and laboratory data were collected from patients with blood culture (BC)-positive sepsis between January 2014 and December 2015. PCT levels at different infection sites were compared, as was the presence of GN and GP bloodstream infection. A receiver operating characteristic (ROC) curve was generated to assess diagnostic accuracy.

RESULTS

Of the 486 monomicrobial BCs, 254 (52.26%) were positive for GN bacteria (GNB), and 202 (42.18%) for GP bacteria (GPB). Median PCT levels were higher in BCs positive for GN (2.42ng/ml, IQR: 0.38-15.52) than in those positive for GPB (0.49ng/ml, IQR: 0.13-5.89) (P<0.001). In the ROC analysis to differentiate between GNB and GPB, the area under the curve was 0.628 (95% CI: 0.576-0.679). When the cutoffs for PCT were 10.335 and 15.000ng/ml, the specificity of GNB infection was 80.2% and 84.2%, respectively. PCT levels caused by GNB differed between Escherichia coli and Acinetobacter baumanni/Burkholderia cepacia, Klebsiella pneumonia and Acinetobacter baumanni. PCT levels caused by GPB differed between Staphylococcus epidermidis/Staphylococcus aureus and Staphylococcus hominis/Staphylococcus haemolyticus, Enterococcus faecium and Enterococcus faecalis/S.hominis/S. haemolyticus. Among patients with known infection sites, there were statistical differences in PCT levels between abdominal infection and pneumonia/infective endocarditis, urinary tract infection and pneumonia/catheter-related infection/infective endocarditis.

CONCLUSION

PCT can distinguish between GNB and GPB infection, as well as between different bacterial species and infection sites.

Comparison of soluble urokinase plasminogen activator receptor, soluble triggering receptor expressed on myeloid cells 1, procalcitonin and C-reactive protein in distinguishing concurrent bacterial infection from idiopathic inflammatory myopathy

The aim of the study was to measure the diagnostic values of biomarkers of bacterial infection in idiopathic inflammatory myopathy (IIM) patients. The serum and clinical data of 82 IIM patients with/without bacterial infection were collected. Concentrations of soluble urokinase plasminogen activator receptor (suPAR), soluble triggering receptor expressed on myeloid cells 1 (sTREM-1), procalcitonin (PCT) and C-reactive protein (CRP) were measured in IIM patients and healthy controls. There were no significant differences in serum suPAR and sTREM-1 levels between healthy controls and non-infection IIM patients. Serum levels of suPAR, sTREM-1, PCT and CRP measured in this study were significantly higher in the IIM patient group with concurrent infection than in the non-infection IIM patient group (p < 0.05). The biomarker suPAR showed the highest diagnostic value with sensitivity, specificity, positive predictive value and negative predictive value of 81.6, 77.3, 75.6 and 82.9%, respectively. Combining suPAR negative and CRP negative to rule out bacterial infection in IIM patients provides a very high specificity of 97.4%. Both suPAR and CRP positive to confirm bacterial infection give the specificity of 90.9%. The inflammatory biomarkers suPAR, sTREM-1, PCT and CRP offer diagnostic accuracy in detecting bacterial infection in IIM patients. Particularly, suPAR is the most sensitive and specific biomarker to predict bacterial infection in IIM patients. Combination of suPAR and CRP serum levels provides an even better confirmation of bacterial infection.

Serum Procalcitonin as a Useful Serologic Marker for Differential Diagnosis between Acute Gouty Attack and Bacterial Infection

PURPOSE

Patients with gout are similar to those with bacterial infection in terms of the nature of inflammation. Herein we compared the differences in procalcitonin (PCT) levels between these two inflammatory conditions and evaluated the ability of serum PCT to function as a clinical marker for differential diagnosis between acute gouty attack and bacterial infection.

MATERIALS AND METHODS

Serum samples were obtained from 67 patients with acute gouty arthritis and 90 age-matched patients with bacterial infection. Serum PCT levels were measured with an enzyme-linked fluorescent assay.

RESULTS

Serum PCT levels in patients with acute gouty arthritis were significantly lower than those in patients with bacterial infection (0.096±0.105 ng/mL vs. 4.94±13.763 ng/mL, p=0.001). However, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels showed no significant differences between the two groups. To assess the ability of PCT to discriminate between acute gouty arthritis and bacterial infection, the areas under the curves (AUCs) of serum PCT, uric acid, and CRP were 0.857 [95% confidence interval (CI), 0.798-0.917, p<0.001], 0.808 (95% CI, 0.738-0.878, p<0.001), and 0.638 (95% CI, 0.544-0.731, p=0.005), respectively. There were no significant differences in ESR and white blood cell counts between these two conditions. With a cut-off value of 0.095 ng/mL, the sums of sensitivity and specificity of PCT were the highest (81.0% and 80.6%, respectively).

CONCLUSION

Serum PCT levels were significantly lower in patients with acute gouty attack than in patients with bacterial infection. Thus, serum PCT can be used as a useful serologic marker to differentiate between acute gouty arthritis and bacterial infections.

Prospective Evaluation of Procalcitonin, Soluble Triggering Receptor Expressed on Myeloid Cells-1 and C-Reactive Protein in Febrile Patients with Autoimmune Diseases

Background

Both procalcitonin (PCT) and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) have been investigated separately as indicators of infection in patients with autoimmune diseases. Our study simultaneously evaluated both PCT and sTREM-1 along with C-reactive protein (CRP) in febrile patients with autoimmune diseases.

Methods

Fifty-nine patients were enrolled in the study. The patients were categorized into the infection group (n = 24) or the disease flare group (n = 35). sTREM-1, PCT and CRP concentrations at fever onset were compared between the two groups of patients.

Results

sTREM-1 and CRP did not differ between the two groups. PCT [median (range), ng/ml] was higher in the infection group than in the disease flare group [0.53 (0.02–12.85) vs. 0.12 (0.02–19.23), p = 0.001]. The area under the receiver-operating characteristic (ROC) for diagnosis of infection was 0.75 for PCT (p = 0.001), 0.63 for CRP (p = 0.09) and 0.52 for sTREM-1 (p = 0.79). Using 0.2 ng/ml as the cutoff value for PCT, sensitivity was 0.75 and specificity was 0.77. Negative predictive values for PCT were 92%, 87% and 82% for a prevalence of infection of 20%, 30%, and 40%, respectively. Neither immunosuppressants nor biomodulators affected the level of the three biomarkers. However, in patients treated with corticosteroids, the levels of sTREM-1 and CRP were significantly decreased compared with the untreated patients.

Conclusions

Setting PCT at a lower cutoff value could provide useful information on excluding infection in febrile patients with autoimmune diseases. The possible effect of corticosteroids on the level of sTREM-1 as an infection marker deserves further study.

Sometimes There Is More Than One Puzzle on the Table: Pneumococcal Bacteremia as a New Systemic Lupus Erythematosus Presentation

Infection is common and a leading cause of death in patients with systemic lupus erythematosus (SLE). SLE is associated with a diverse spectrum of immune impairments including humoral defects and hypocomplementemia that contribute to a lupus patient's increased susceptibility to infection with encapsulated bacteria. Nonetheless, there are only few reports of severe invasive bacterial infection as the initial presentation of SLE in the literature. Here, we report a rare case of SLE presenting with pneumococcal bacteremia. Based on the high resolution chest computed tomography and the result of blood cultures, the bacteremia was assumed to be secondary to pneumococcal pneumonia.

Diagnostic Value of Procalcitonin in ANCA-Associated Vasculitis (AAV) to Differentiate Between Disease Activity, Infection and Drug Hypersensitivity

Objective:

Procalcitonin (PCT) is considered to be a specific marker for severe bacterial infections and sepsis. Elevated PCT levels have been reported in active autoimmune diseases without infection.

The aim of this study was to assess the diagnostic value of PCT serum levels in ANCA-associated vasculitis (AAV) patients with respect to infection, disease activity and drug fever using a high sensitive PCT detection method.

Methods:

In 53 AAV patients with elevated C-reactive protein (CRP) PCT was determined by the Thermo Scientific BRAHMS PCT sensitive KRYPTOR assay. Patients underwent standardized diagnostic procedures for evaluation of disease activity and infection.

Results:

53 patients with AAV and elevated CRP (7.7±6.9 mg/dl, PCT 0.34±1.02 ng/ml) were assessed, 10 had infection with elevated CRP levels of 11.2±10.2 mg/dl and PCT levels of 1.06±2.07 ng/dl. 43 patients had no evidence of infection, 36 of them were presented with AAV with normal or only slightly positive PCT levels in active disease (n=36) (PCT 0.06±0.06 ng/ml). 7 patients had increased PCT levels due to azathioprine hypersensitivity (0.76±1.01 ng/ml). For discrimination between infection and vasculitis activity PCT was more useful than CRP with the best cut-off at 0.1 ng/ml (sensitivity 60%, specificity 92%).

Conclusion:

In contrast to previous studies using semiquantitative PCT assays, the KRYPTOR performs better with respect to discrimination of infection from active AAV. In all patients assessed with active AAV (and without infection) PCT levels remained below the PCT reference limit (0.5 ng/ml) for infections. Drug hypersensitivity seems to be an important differential diagnosis in the setting of elevated CRP and PCT in patients who receive azathioprine.

The utility of initial procalcitonin and procalcitonin clearance for prediction of bacterial infection and outcome in critically ill patients with autoimmune diseases: a prospective observational study

Background

The diagnostic value of procalcitonin (PCT) for patients with autoimmune diseases (AID) remains controversial and few studies focused on ICU patients. We sought to determine its diagnostic and prognostic values in this clowd.

Methods

A prospective observational study was conducted in AID patients admitted to the ICU. Serum PCT levels were measured on ICU admission and subsequently at days 1, 3, 5 and 7, and peak PCT levels within 24 h (PCT_peak) were analyzed the utility for bacterial infection. The relationship of PCT_peak and SOFA score and severity of sepsis was performed correlation analysis. The change of PCT over time reflected as PCT clearance was compared to ICU 28-day mortality.

Results

One hundred twelve patients were divided into bacterial infection group (group I, n = 54) and nonbacterial condition group (group II, n = 58). The median PCTpeak (range, μg/L) was higher in the group I than that in the group II (1.95 [0.38–37.56] vs. 0.64 [0.05–7.83], p = 0.002). PCTpeak had the best single predictor of bacterial infection (area under the curve [AUC], 0.902, p < 0.001) with a sensitivity of 79.6 % and a specificity of 89.6 % at the threshold of 0.94 μg/L. PCTpeak was also positive correlation with severity of sepsis (r = 0.731, p = 0.002), but its correlation with SOFA score was only found in subjects with bacterial infection (r = 0.798, p < 0.001). Importantly, the 5-day PCT clearance (PCTc-d5), rather than absolute PCT values, could earlier discriminate survivors (n = 73) from nonsurvivors (n = 39) (68.8 ± 9.8 vs. 21.8 ± 17.5 %, p < 0.001, respectively). PCTc-d5 < 50 % was an independent predictor of mortality (odds ratio 5.1, 95 % confidence interval 3.5 to 7.5; p = 0.001).

Conclusions

In critically ill patients with AID, elevated PCT levels are valuable for bacterial infection and are significantly positive correlation with the septic severity. Five-day PCT clearance may provide independent prognostic information. Larger, prospective trials are warranted to confirm the benefit.

Electronic supplementary material

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Clinical significance of serum procalcitonin in patients with ulcerative colitis

AIM: To investigate the association of serum procalcitonin (PCT) level with disease activity and inflammatory markers in ulcerative colitis (UC).

METHODS: Serum PCT levels, white blood cell count, platelet count, erythrocyte sedimentation rate (ESR), albumin, C-reactive protein (CRP) and interleukin-6 (IL-6) levels were analyzed in 31 patients with UC and 18 healthy volunteers. Severity assessments were based on the Truelove and Witts' severity index. Spearman's rank correlation and receiver operating characteristic (ROC) analysis were used to evaluate correlations between variables and diagnostic accuracy, respectively.

RESULTS: Serum PCT level in severe UC patients (n = 11, 0.426 μg/mL ± 0.506 μg/mL) was significantly higher than those in mild-to-moderate UC patients (n = 20, 0.079 μg/mL ± 0.085 μg/mL) and healthy volunteers (n = 18, 0.03 μg/mL ± 0.01 μg/mL) (P = 0.047, 0.027, respectively). Serum PCT level in UC patients was positively correlated with CRP levels, IL-6 levels and ESR, negatively with albumin levels (P < 0.05), but showed no statistically significant correlation with white blood cell count or platelet count (P > 0.05). PCT performed well in the prediction of UC, and was superior to CRP, ESR and white blood cell count for diagnosing severe UC. The area under the ROC curve was 0.895 (95%CI: 0.782-1.000, P < 0.001), 0.727 (95%CI: 0.548-0.906, P = 0.041), 0.856 (95%CI: 0.721-0.992, P = 0.001) and 0.665 (95%CI: 0.463-0.867, P = 0.138), respectively. A threshold of 0.1 μg/L for PCT may detect the most severe form of UC, and the sensitivity, specificity, predictive positive value and negative predictive value predictive were 90.91%, 80.00%, 71.43% and 94.12%, respectively.

CONCLUSION: Serum PCT level correlates with disease activity markers ESR and CRP in UC, and a cut-off of 0.1 μg/L could distinguish the most severe form of UC.

Sepsis biomarkers

Sepsis is the most frequent cause of death in non-coronary intensive care units (ICUs). In the past 10 years, progress has been made in the early identification of septic patients and in their treatment and these improvements in support and therapy mean that the mortality is gradually decreasing but it still remains unacceptably high. Leaving clinical diagnosis aside, the laboratory diagnostics represent a complex range of investigations that can place significant demands on the system given the speed of response required. There are hundreds of biomarkers which could be potentially used for diagnosis and prognosis in septic patients. The main attributes of successful markers would be high sensitivity, specificity, possibility of bed-side monitoring, and financial accessibility. Only a fraction is used in routine clinical practice because many lack sufficient sensitivity or specificity. The following review gives a short overview of the current epidemiology of sepsis, its pathogenesis and state-of-the-art knowledge on the use of specific biochemical, hematological and immunological parameters in its diagnostics. Prospective approaches towards discovery of new diagnostic biomarkers have been shortly mentioned.

Serum procalcitonin levels in patients with ankylosing spondylitis

AIM

Procalcitonin is a marker of bacterial and fungal infection and sepsis. The present study evaluated the relationship between serum procalcitonin levels and disease activity in patients with ankylosing spondylitis (AS).

METHOD

A total of 61 patients who met the 1984 New York criteria for AS were studied. Twenty-four age- and sex-matched healthy volunteers were recruited to this study as a control group. Disease activity was assessed by the Bath AS Disease Activity Index (BASDAI). The functional status of patients was evaluated by the Bath AS Functional Index (BASFI). Spinal mobility was measured by the Bath AS Metrology Index (BASMI). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and serum procalcitonin levels were measured.

RESULTS

Thirty patients were on anti-tumor necrosis factor-alpha treatment and 31 patients were on conventional treatment. Seventeen (28%) of the AS patients were active (BASDAI > 4) and 44 (72%) of the AS patients were in remission. The median ESR was 14 (34-6) mm/h and 4 (7-2) mm/h (P < 0.001) for the patient and control groups, respectively. The median CRP level was 0.91 (2.72-0.37) mg/dL and 0.15 (0.25-0.07) mg/dL in the patient and control groups, respectively (P < 0.001). Median BASDAI, BASFI and BASMI scores for all AS patients were 3.6 (5.25-2.29), 2.5 (4.22-0.91) and 3 (5-1), respectively. Serum procalcitonin levels were normal (< 0.05 ng/mL) for all patients and controls.

CONCLUSION

Serum procalcitonin levels were not high in AS patients and controls, and the levels were independent of disease activity and medications. If bacterial or fungal infection is suspected in an AS patient, serum procalcitonin level may be useful for diagnosis.

Reactive oxygen species induce procalcitonin expression in trigeminal ganglia glia

OBJECTIVE

To examine calcitonin gene-related peptide (CGRP) gene expression under inflammatory conditions using trigeminal ganglia organ cultures as an experimental system. These cultures have increased proinflammatory signaling that may mimic neurogenic inflammation in the migraine state.

BACKGROUND

The trigeminal nerve sends peripheral pain signals to the central nervous system during migraine. Understanding the dynamic processes that occur within the trigeminal nerve and ganglion may provide insights into events that contribute to migraine pain. A neuropeptide of particular interest is CGRP, which can be elevated and play a causal role in migraine. However, most studies have overlooked a second splice product of the Calca gene that encodes calcitonin (CT), a peptide hormone involved in calcium homeostasis. Importantly, a precursor form of CT called procalcitonin (proCT) can act as a partial agonist at the CGRP receptor and elevated proCT has recently been reported during migraine.

METHODS

We used a trigeminal ganglion whole organ explant model, which has previously been demonstrated to induce pro-inflammatory agents in vitro. Quantitative polymerase chain reaction and immunohistochemistry were used to evaluate changes in messenger ribonucleic acid (mRNA) and protein levels of CGRP and proCT.

RESULTS

Whole mouse trigeminal ganglia cultured for 24 hours showed a 10-fold increase in CT mRNA, with no change in CGRP mRNA. A similar effect was observed in ganglia from adult rats. ProCT immunoreactivity was localized in glial cells. Cutting the tissue blunted the increase in CT, suggesting that induction required the close environment of the intact ganglia. Consistent with this prediction, there were increased reactive oxygen species in the ganglia, and the elevated CT mRNA was reduced by antioxidant treatment. Surprisingly, reactive oxygen species were increased in neurons, not glia.

CONCLUSIONS

These results demonstrate that reactive oxygen species can activate proCT expression from the CGRP gene in trigeminal glia by a paracrine regulatory mechanism. We propose that this glial recruitment pathway may occur following cortical spreading depression and neurogenic inflammation to increase CGRP nociceptive actions in migraine.

Clinical utility of procalcitonin as a marker of sepsis: a potential predictor of causative pathogens

OBJECTIVE

Sepsis is one of the leading causes of mortality in critically ill patients, and providing a timely diagnosis and early intervention is necessary for successful treatment. Procalcitonin (PCT) may be a better marker of sepsis than conventional inflammatory markers. The aim of this study was to evaluate the clinical utility of the PCT level as a marker of sepsis.

METHODS

Forty-five patients with sepsis, 24 patients with pneumonia who did not meet the SIRS criteria (PN) and 56 controls were enrolled in this study. The levels of PCT and other serum markers were measured, and their utility as markers of sepsis was assessed.

RESULTS

The serum PCT levels exhibited statistically significant differences between the three groups (p<0.0001). The PCT levels in the sepsis group (29.3 ± 85.3 ng/mL) were significantly higher (p<0.001) than those observed in the PN group (0.34 ± 8.6 ng/mL) and the control group (0.74 ± 2.1 ng/mL), according to a post hoc analysis. There were no differences in the white blood cell (WBC) counts or C-reactive protein (CRP) levels between the three groups. Fourteen of the 45 patients with sepsis had positive microbiological blood cultures (Gram-positive cocci [GPC] in seven patients, Gram-negative rods [GNR] in six patients, other types of bacteria in one patient). The 13 patients with GNR or GPC were categorized into the GNR group or GPC group according to the identified pathogens. The serum PCT levels were significantly higher in the GNR group (149.8 ± 199.7 ng/mL) than in the GPC group (19.1 ± 41.8 ng/mL) (p<0.05), although there were no differences in the WBC counts or CRP levels between these groups. When the cut-off value for the PCT level was set at 16.9 ng/mL, the sensitivity and specificity for the detection of GNR infection were 85.7% and 83.3%, respectively.

CONCLUSION

The PCT level is a potentially useful marker of the type of causative pathogen in patients with sepsis whose measurement may facilitate the selection of appropriate empiric antibiotic treatment.

Procalcitonin is a specific marker for detecting bacterial infection in patients with rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic inflammatory disease accompanied by many complications, and serious infections are associated with many of the advanced therapeutics used to treat it. We assessed serum procalcitonin (PCT) levels to distinguish bacterial infection from other complications in patients with RA.

METHODS

One hundred eighteen patients experiencing an RA flare, noninfectious complication of RA or its treatment, nonbacterial infection, or bacterial infection were studied. Serum PCT concentrations were determined with a chemiluminescent enzyme immunoassay.

RESULTS

All patients experiencing an RA flare showed negative PCT levels (≤ 0.1 ng/ml; n = 18). The PCT level was higher in the bacterial infection group (25.8% had levels ≥ 0.5 ng/ml) than in the other 3 groups (0.0-4.3% had levels ≥ 0.5 ng/ml) and the difference was significant among groups (p = 0.003). Conversely, no statistically significant difference was observed among the groups with C-reactive protein (CRP) concentration ≥ 0.3 mg/dl (p = 0.513), white blood cell (WBC) count > 8500/mm(3) (p = 0.053), or erythrocyte sedimentation rate (ESR) > 15 mm/h (p = 0.328). The OR of high PCT level (≥ 0.5 ng/ml) for detection of bacterial infection was 19.13 (95% CI 2.44-149.78, p = 0.005). Specificity and positive likelihood ratio of PCT ≥ 0.5 ng/ml were highest (98.2% and 14.33, respectively) for detection of bacterial infection, although the sensitivity was low (25.8%).

CONCLUSION

Serum PCT level is a more specific marker for detection of bacterial infection than either CRP, ESR, or WBC count in patients with RA. High PCT levels (≥ 0.5 ng/ml) strongly suggest bacterial infection. However, PCT < 0.5 ng/ml, even if < 0.2 ng/ml, does not rule out bacterial infection and physicians should treat appropriately.

C-reactive Protein Is a More Sensitive and Specific Marker for Diagnosing Bacterial Infections in Systemic Lupus Erythematosus Compared to S100A8/A9 and Procalcitonin

Objective.

C-reactive protein (CRP), S100A8/A9, and procalcitonin have been suggested as markers of infection in patients with systemic lupus erythematosus (SLE). We investigated the clinical significance of these factors for indication of infection in SLE.

Methods.

Blood samples were prospectively collected from 34 patients with SLE who had bacterial infections and 39 patients with SLE who had disease flares and no evidence of infection. A second set of serum samples was collected after the infections or flares were resolved.

Results.

CRP levels of SLE patients with infections were higher than those with flares [5.9 mg/dl (IQR 2.42, 10.53) vs 0.06 mg/dl (IQR 0.03, 0.15), p < 0.001] and decreased after the infection was resolved. S100A8/A9 and procalcitonin levels of SLE patients with infection were also higher [4.69 μg/ml (IQR 2.25, 12.07) vs 1.07 (IQR 0.49, 3.05) (p < 0.001) and 0 ng/ml (IQR 0–0.38) vs 0 (0–0) (p < 0.001), respectively]; these levels were also reduced once the infection disappeared. In the receiver-operating characteristics analysis of CRP, S100A8/A9, and procalcitonin, the area under the curve was 0.966 (95% CI 0.925–1.007), 0.732 (95% CI 0.61–0.854), and 0.667 (95% CI 0.534–0.799), respectively. CRP indicated the presence of an infection with a sensitivity of 100% and a specificity of 90%, with a cutoff value of 1.35 mg/dl.

Conclusion.

Our data suggest that CRP is the most sensitive and specific marker for diagnosing bacterial infections in SLE.

Calcitonin gene-related peptide in migraine: intersection of peripheral inflammation and central modulation

Over the past two decades, a convergence of basic and clinical evidence has established the neuropeptide calcitonin-gene-related peptide (CGRP) as a key player in migraine. Although CGRP is a recognised neuromodulator of nociception, its mechanism of action in migraine remains elusive. In this review, we present evidence that led us to propose that CGRP is well poised to enhance neurotransmission in migraine by both peripheral and central mechanisms. In the periphery, it is thought that local release of CGRP from the nerve endings of meningeal nociceptors following their initial activation by cortical spreading depression is critical for the induction of vasodilation, plasma protein extravasation, neurogenic inflammation and the consequential sensitisation of meningeal nociceptors. Mechanistically, we propose that CGRP release can give rise to a positive-feedback loop involved in localised increased synthesis and release of CGRP from neurons and a CGRP-like peptide called procalcitonin from trigeminal ganglion glia. Within the brain, the wide distribution of CGRP and CGRP receptors provides numerous possible targets for CGRP to act as a neuromodulator.