Circulating calprotectin as biomarker in neutrophil-related inflammation: Pre-analytical recommendations and reference values according to sample type.

BACKGROUND: Calprotectin (CLP) is a promising biomarker for the evaluation of neutrophil-related inflammation. Our aim was to establish reference values for circulating CLP in different sample types and to study the effect of pre-analytical variables. METHODS: Reference values were determined in 100 healthy individuals. Pre-analytical variables were evaluated in 10 healthy controls and four rheumatoid arthritis patients with active disease and covered sample type (serum with/without gel separator, heparin, EDTA and citrate plasma), pre-centrifugation time (<2 h, 6 h, 24 h), storage condition (2-8 °C, 18-25 °C, 30 °C) and storage time (24 h, 72 h, 7 days). CLP measurements were performed with the EliA™Calprotectin 2 assay on Phadia™200 (Thermo Fisher Scientific). RESULTS: In healthy controls, baseline CLP concentrations in serum were more than double the concentration in EDTA and citrate plasma (0.909 µg/mL versus 0.259 µg/mL and 0.261 µg/mL respectively). Heparin, EDTA and citrate stabilized CLP concentrations for up to 6 h before centrifugation, whereas significant increases in CLP levels were observed when serum was left untreated during that time period. CONCLUSION: Clinical studies on circulating CLP need to apply sample type-specific reference values and decision limits. To obtain reproducible CLP results in serum, more stringent pre-analytical sample handling instructions are needed.

The importance of detecting anti-DFS70 in routine clinical practice: comparison of different care settings.

BACKGROUND: Screening for antinuclear antibodies by indirect immunofluorescence (ANA-IIF) is essential in the diagnostic workup of ANA-associated autoimmune rheumatic diseases (AARDs). However, also healthy individuals may test positive, making the interpretation challenging. Recent reports suggest that dense fine speckled 70 antibodies (anti-DFS70) may facilitate this challenge. Here, we investigate their clinical importance based on data from four Belgian laboratories (one primary, two secondary and one tertiary care). METHODS: At least one specific DFS70 assay (DFS70 IgG ELISA or lineblot [Euroimmun, full length antigen] and/or DFS70 IgG CLIA [Inova Diagnostics, truncated antigen]) was performed on four consecutive cohorts of homogeneous-like ANA-IIF samples (n=697). Co-occurrence with AARD-specific ANA and clinical information were documented in the anti-DFS70-positive samples. RESULTS: Using a combination of solid phase techniques, we found between 7.6% and 26% anti-DFS70 in the different cohorts. Focusing on anti-DFS70 CLIA-positive samples without co-occurrence of AARD-specific ANA, we observed a trend towards lower frequency in tertiary (8% [p=0.0786]) and secondary care (12% [p=0.1275] and 6% [p<0.001]) compared to primary care (21%). Moreover, in this specific subpopulation, AARD was less frequent (0%-50% compared to 6%-77% in the total anti-DFS70-positive group). CONCLUSIONS: Anti-DFS70 prevalence depends on the applied assay and care setting. Our data suggest that, for an ANA-IIF-positive patient, it is rather the absence of AARD-associated ANA and clinical symptoms that contribute to the exclusion of AARD than the presence of anti-DFS70. Nevertheless, isolated anti-DFS70 helps to clarify positive ANA-IIF results, especially if pretest probability for AARD is low.

Wegener's granulomatosis strictly and persistently localized to one organ is rare: assessment of 16 patients from the French Vasculitis Study Group database.

OBJECTIVE: To study the frequency and characteristics of patients with Wegener's granulomatosis (WG) strictly and persistently localized to one organ. METHODS: Retrospective analysis of the French Vasculitis Study Group (FVSG) WG cohort. RESULTS: Sixteen patients (3.2% of the cohort) were identified who had isolated lung nodules, ear-nose-throat, or ocular involvement that did not progress to systemic disease (median followup, 58 mo) over the period of observation. Ten received first-line therapy with cyclophosphamide, which was effective in 4. Cotrimoxazole alone achieved remission in one, combined with corticosteroids in 3. Eight required subsequent treatments because of first-line failure or relapse. CONCLUSION: Strictly and persistently localized WG is uncommon. Optimal treatment remains to be determined.

Characterization of a subset of antigen-specific human central memory CD4+ T lymphocytes producing effector cytokines.

CCR7(+ )central memory (T(CM)) CD4(+) T cells play a central role in long-term immunological memory. Recent reports indicate that a proportion of CD4(+) T(CM) is able to produce effector cytokines. The phenotype and the role of this subset remain unknown. We characterized cytokine-producing human CD4(+) T(CM) specific for cleared protein and persistent viral Ag. Our results demonstrate that the type of Ag stimulation is a major determinant of CD4(+) T(CM) differentiation. CMV-specific T(CM) were significantly more differentiated than protein Ag-specific T(CM) and included higher proportions of IFN-gamma-producing cells. The expression of killer cell lectin-like receptor G1 (KLRG1) by protein Ag- and CMV-specific T(CM) was associated with increased production of effector cytokines. KLRG1(+) T(CM) expressed high levels of CD127, suggesting that they can survive long term under the influence of IL-7. The induction of KLRG1(+) T(CM) may therefore represent an important target of vaccination against pathogens controlled by cellular immune responses.

Improving tetanus prophylaxis in the emergency department: a prospective, double-blind cost-effectiveness study.

BACKGROUND: The choice of tetanus prophylaxis for patients with wounds depends on obtaining their vaccination history, which has been demonstrated to be unreliable. Use of a rapid immunoassay (Tétanos Quick Stick, the TQS), combined with knowledge of certain demographic characteristics, may improve the evaluation of tetanus immunity and thus help to avoid inadequate prophylactic measures and reduce costs. OBJECTIVES: To evaluate the contribution of the TQS in the choice of tetanus prophylaxis and to perform a cost-effectiveness analysis. The final aim was to define the place of the TQS in a modified algorithm for assessment of tetanus immunity in the emergency department. METHOD: In this Belgian prospective, double-blind, multicentre study, 611 adult patients with a wound were included; 498 (81.5%) records were valid. The TQS test was performed by a nurse before the vaccination history was taken and the choice of prophylaxis was made, using the official algorithm (Belgian Superior Health Council), by a doctor who was unaware of the TQS result. RESULTS: The prevalence of protective anti-tetanus immunity was 74.1%. Immunity was lower in older patients and in female patients. The TQS was a cost-effective tool for patients presenting with a tetanus-prone wound and considered from the vaccination history to be unprotected. Use of the TQS would have improved management in 56.9% (95% CI 47.7% to 65.7%) of patients by avoiding unnecessary treatments, leading to a reduction in the mean cost per patient (10.58 euros/patient with the TQS versus 11.34 euros/patient without). The benefits of the TQS use were significantly greater in patients <61 years old: unnecessary treatment would have been avoided in 76.9% (95% CI 65.8% to 85.4%) of cases and the mean cost per patient reduced to 8.31 euros. CONCLUSION: In selected patients, the TQS is a cost-effective tool to evaluate tetanus immunity. An algorithm is proposed for ED assessment of tetanus immunity integrating age and the TQS result.

Seroprotection against tetanus in patients attending an emergency department in Belgium and evaluation of a bedside immunotest.

BACKGROUND: In most emergency departments, tetanus prophylaxis currently relies on vaccination history. Bedside evaluation of tetanus immunity may improve this process. OBJECTIVES: (i) To determine the seroprevalence of tetanus immunity; (ii) to evaluate the accuracy of vaccination history in assessing tetanus immunity; (iii) to identify factors predictive of seroprotection and incorrect history. METHOD: In a prospective observational study, tetanus immunity was assessed in 784 adults using Tétanos Quick Stick (TQS). A questionnaire was completed to obtain vaccination and general histories. Immunity assessed by TQS and by vaccination history were compared with anti-tetanus antibody levels measured by the enzyme-linked immunosorbent assay (seroprotection threshold >0.15 IU/ml). RESULTS: Overall, 64.2% of patients were protected according to TQS results. Four independent predictors of seroprotection were identified: young age, birthplace in Belgium, male sex and occupational medicine consultation. TQS performance was good: kappa=0.71, sensitivity 85.3%, specificity 87.2%, positive predictive value 92.1% and negative predictive value 77.2%. Seven hundred and sixty-two participants responded to the vaccination history: 23.4% said they were protected, 22.1% that they were not and 54.5% did not know. History performance was poor: kappa=0.27, sensitivity 60.3%, specificity 73.3%, positive predictive value 81.8% and negative predictive value 45.8%. Compared with history, TQS offered a significantly better sensitivity, negative and positive predictive values, but specificity was similar. No predictor of an incorrect history was identified. CONCLUSION: Lack of protective immunity against tetanus is frequent but poorly evaluated by history taking. Several demographic characteristics are good predictors of seroprotection. TQS could be a valuable tool in selected patients to improve tetanus prophylaxis in the emergency department.

Antigen-specific central memory CD4+ T lymphocytes produce multiple cytokines and proliferate in vivo in humans.

The function of Ag-specific central (T(CM)) and effector (T(EM)) memory CD4+ T lymphocytes remains poorly characterized in vivo in humans. Using CD154 as a marker of Ag-specific CD4+T cells, we studied the differentiation of memory subsets following anti-hepatitis B immunization. Hepatitis B surface Ag (HBs)-specific memory CD4+T cells were heterogeneous and included T(CM) (CCR7+CD27+) and T(EM) (CCR7(-)CD27(+/-)). HBs-specific T(CM) and T(EM) shared the capacity to produce multiple cytokines, including IL-2 and IFN-gamma. Several years postimmunization, approximately 10% of HBs-specific memory CD4+ T cells were in cycle (Ki67+) and the proliferating cells were CCR7+. These results suggest that the model of functional specialization of T(CM) and T(EM) cannot be applied to protein vaccine Ags and support the concept that T(CM) are capable of self-renewal and contribute to maintain the pool of memory cells.