MxA for differentiating viral and bacterial infections in adults: a prospective, exploratory study.

PURPOSE: Inappropriate antibiotic prescription in patients with viral infections contributes to the surge of antibiotic resistance. Viral infections induce the expression of the antiviral protein MxA in monocytes, which is a promising biomarker to differentiate between viral and bacterial diseases. In this prospective, exploratory study, we aimed to determine the diagnostic value of monocyte MxA expression in adults with viral, bacterial or co-infections. METHODS: We measured monocyte MxA expression using flow cytometry in a cohort of 61 adults with various viral, bacterial and co-infections including patients receiving immunosuppressive therapy. RESULTS: Monocyte MxA expression in virus-infected patients was significantly higher compared to bacterial infections (83.3 [66.8, 109.4] vs. 33.8 [29.3, 47.8] mean fluorescence intensity [MFI]; p < 0.0001) but not co-infections (53.1 [33.9, 88.9] MFI). At a threshold of 62.2 MFI, the area under the ROC curve (AUC) to differentiate between viral and bacterial infections was 0.9, with a sensitivity and specificity of 92.3% and 84.6%, respectively. Immunosuppressive therapy did not affect monocyte MxA expression in virus-infected patients. CONCLUSION: Our findings corroborate the diagnostic performance of MxA in differentiating viral and bacterial infections but also point to an important caveat of MxA in viral-bacterial co-infections. This study extends previous reports and indicates that MxA is also a useful biomarker in immunocompromised patients.

Active tuberculosis is characterized by an antigen specific and strictly localized expansion of effector T cells at the site of infection.

Mycobacterium tuberculosis (MTB)-specific cytokine responses in the peripheral blood and at the site of infection may differ significantly within the same individual, but the under-lying T-cell subset changes are largely unknown. Here, we measured effector and memory T-cell markers on CD4⁺ T cells (CD45RO, cysteine chemokine receptor (CCR)7, and CD27) in peripheral blood and at the site of active tuberculosis (TB). Additionally, T cells were stimulated overnight with purified protein derivative (PPD) and early secretory antigenic target (ESAT)-6 to determine which T-cell subset produces MTB-specific interferon (IFN)-γ. A striking decrease in CCR7 and CD27 expression on T cells was noted at the site of active TB. Likewise, IFN-γ expressing, ESAT-6 specific CD4⁺CD45RO⁺CD27⁻ T cells were dramatically increased at the site of infection but were not detectable in peripheral blood. An antigen-specific expansion of differentiated T cells at the site of active TB infection was poorly reflected in peripheral blood. Insight in these changes in MTB-specific effector T cells in different compartments of the body could lead to new approaches for immune-based diagnosis and interventions.

Rapid T-cell-based immunodiagnosis of tuberculous peritonitis in a peritoneal dialysis patient.

Tuberculous peritonitis is a rare complication during peritoneal dialysis (PD). This report presents the case of a patient with clinical signs and symptoms indicative of bacterial peritonitis, but without culture growth of conventional bacteria or fungi. Cytokine flow cytometry after overnight stimulation of cells from peripheral blood and the peritoneal dialysate with Mycobacterium tuberculosis (MTB)-specific antigens revealed a 40-fold increase in MTB-specific CD4 + T cells expressing interferon-γ (IFN-γ) in peritoneal fluid compared with blood, which was indicative of active tuberculosis (TB). The presence of TB was later confirmed by polymerase chain reaction and growth of MTB in culture of the dialysate. The case illustrates the usefulness of MTB-specific immunodiagnosis for the rapid identification of peritoneal TB in PD patients.

Specific cytokine patterns of pulmonary tuberculosis in Central Africa.

Different cytokines have been suggested to be involved in the pathogenesis of pulmonary tuberculosis (TB). The frequencies of Mycobacterium tuberculosis (MTB) specific CD4(+) and CD8(+) T cells, CD4(+)CD25(+) Forkhead Box Protein (FoxP)3(+) T cells, interleukin (IL)-6, interferon (IFN)-γ, Tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-ß and IL-10 were assessed in HIV-negative, pulmonary tuberculosis (TB) patients (n=30) and in healthy controls (n=23) in Gabon. Peripheral blood mononuclear cells (PBMC) were stimulated with purified protein derivative (PPD) and early secretory antigenic target-6 (ESAT-6). In patients, a pronounced pro-inflammatory cytokine response with highly significant increased levels of IL-6 and TNF-α accompanied by increased TGF-ß was detectable. Differences in IFN-γ responses between patients and healthy individuals were less pronounced than expected. FoxP3 expression did not differ between groups. A distinct cytokine pattern is associated with active pulmonary TB in patients from Central Africa.

Loss of T cells expressing CD27 at the site of active tuberculosis - A prospective diagnostic study.

The lack of a rapid and reliable diagnostic test for active tuberculosis is still a burden to the control of the infection. The accumulation of Mycobacterium tuberculosis (MTB)-specific CD4+ T cells at the site of infection and the increase of MTB-specific CD27- cells seem to be characteristic for active tuberculosis. We evaluated CD27 expression of non-stimulated T cells at the site of infection compared to peripheral blood of seventy-two patients (n = 72) presenting with symptoms of active MTB-infection. Twenty patients (n = 20, 27.8%) were actually confirmed to have active tuberculosis. Overall, a significant increase of terminally differentiated CD27- CD4+ T cells at the site of disease was noted when compared to peripheral blood (<0.001). However, the loss of CD27 at the site of disease was not restricted to active tuberculosis (p = 0.253). The CD27 expression profile of tuberculosis patients was only discriminative to patients with malignancy.

Prevalence and Outcome of Secondary Hemophagocytic Lymphohistiocytosis Among SIRS Patients: Results from a Prospective Cohort Study.

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening condition clinically presenting as SIRS (Systemic Inflammatory Response Syndrome). However, there is no comprehensive data concerning diagnostic algorithms, prevalence, outcome and biomarker performance in SIRS patients. We conducted a prospective observational cohort study on 451 consecutive patients fulfilling ≥2 SIRS criteria. The Hscore and the HLH-2004 criteria were used to determine the presence of sHLH, and the correlation of the screening-biomarkers ferritin, sCD25, and sCD163 with both scores was assessed. Out of 451 standard-care SIRS patients, five patients had high Hscores (≥169), suggesting incipient or HLH-like disease, and these patients were in urgent need for intensified therapy. However, none of these patients fulfilled five HLH-2004 criteria required for formal diagnosis. From the studied biomarkers, ferritin correlated strongest to both the HLH-2004 criteria and the Hscore (rs = 0.72, 0.41, respectively), and was the best predictor of 30-day survival (HR:1.012 per 100 µg/L, 95% CI: 1.004-1.021), when adjusted for patient's age, sex, bacteremia and malignant underlying-disease. Also, the HLH-2004 (HR per point increase: 1.435, 95% CI: 1.1012-2.086) and the Hscore (HR per point increase:1.011, 95% CI: 1.002-1.020) were independent predictors of 30-day-survival. The Hscore detected patients in hyperinflammatory states requiring urgent therapy escalation. Degrees of hyperinflammation, as assessed by ferritin and both HLH scores, are associated with worse outcomes.

Bone marrow infection with bacillus Calmette-Guérin (BCG) after intravesical immunotherapy.

Instillation of bacillus Calmette-Guérin (BCG) into the urine bladder is an effective treatment of superficial bladder cancer. BCG-mediated anti-tumor activity appears to be a local phenomenon in which cell-mediated immunity, involving cytotoxic T cells, lymphokine-activated killer cells and natural killer cells, is important for the elimination of malignant cells. Serious side-effects of BCG therapy are rare; nevertheless, BCG is a live, attenuated strain of Mycobacterium (M.) bovis and may exhibit invasive properties. Both local and distant or generalized infections have been reported after treatment with BCG. We describe the case of a 68-year-old man who developed bone marrow infection with BCG two years after intravesical instillation of BCG for treatment of superficial bladder cancer. He presented with intermittent fever, weight loss and pronounced pancytopenia. A bone marrow biopsy specimen showed granulomatous inflammation and BCG was cultured from the urine. Anti-mycobacterial treatment with isoniazid, rifampicin and ethambutol (pyrazinamide is inactive against M. bovis) led to full clinical recovery of the patient.

Cross-sectional survey of the seroprevalence of Puumala hantavirus in Austria.

The prevalence of Puumala hantavirus infections in Austria and the occupational exposure of military personnel to this virus were assessed in 2009 in an exploratory nationwide cross-sectional seroprevalence survey in 526 healthy individuals, of which 222 were soldiers and 304 were civilians. In addition, information on possible risk factors for hantavirus exposure, including previous foreign military assignments, residential area, occupational animal contact, and regular outdoor activities, was obtained. Immunoglobulin G antibodies against Puumala hantavirus were examined with a commercial enzyme-linked immunosorbent assay. Overall, 7 (1.3%) individuals, aged 19, 22, 24, 24, 26, 38, and 60 years, tested positive on serologic screening. There were no significant differences between the seroprevalence of the virus and any of the variables surveyed. Our data demonstrate serologic evidence of Puumala hantavirus infection among the Austrian population, with a stable prevalence in the past decade. When compared with the general population, no increased risk of exposure to Puumala hantavirus could be detected for military personnel.

Peripheral T cell cytokine responses for diagnosis of active tuberculosis.

BACKGROUND: A test for diagnosis of active Tuberculosis (TB) from peripheral blood could tremendously improve clinical management of patients. METHODS: Of 178 prospectively enrolled patients with possible TB, 60 patients were diagnosed with pulmonary and 27 patients with extrapulmonary TB. The frequencies of Mycobacterium tuberculosis (MTB) specific CD4(+) T cells and CD8(+) T cells producing cytokines were assessed using overnight stimulation with purified protein derivate (PPD) or early secretory antigenic target (ESAT)-6, respectively. RESULTS: Among patients with active TB, an increased type 1 cytokine profile consisting of mainly CD4(+) T cell derived interferon (IFN)-γ was detectable. Despite contributing to the cytokine profile as a whole, the independent diagnostic performance of one cytokine producing T cells as well as polyfunctional T cells was poor. IFN-γ/Interleukin(IL)-2 cytokine ratios discriminated best between active TB and other diseases. CONCLUSION: T cells producing one cytokine and polyfunctional T cells have a limited role in diagnosis of active TB. The significant shift from a "memory type" to an "effector type" cytokine profile may be useful for further development of a rapid immune-diagnostic tool for active TB.

Low serum levels of cathelicidin LL-37 in leprosy.

The antimicrobial peptide cathelicidin LL-37 possesses antituberculous activity, its association with other mycobacterial diseases, such as leprosy, is unknown. We studied serum cathelicidin and 25OH-vitamin D3 levels in 29 leprosy patients and 19 healthy individuals from Yemen. Cathelicidin levels were significantly lower in both treated (n=15) and untreated leprosy patients (n=14) when compared to controls (P<0.001). Within leprosy patients, levels were lower in those who very recently developed disease (untreated group) when compared to already treated patients (P<0.05). 25OH-vitamin D3 levels were not different between groups. The results suggest a potential association of cathelicidin LL-37 with Mycobacterium leprae infection.

T cells co-producing Mycobacterium tuberculosis-specific type 1 cytokines for the diagnosis of latent tuberculosis.

Patients treated with tumor necrosis factor (TNF)-alpha-antagonizing medication are at increased risk of developing active tuberculosis (TB), brought about mainly by reactivation of latent infection. Thus, screening for latent TB infection (LTBI) prior to administration of anti-TNF-alpha-therapy is required. For a long time, the tuberculin skin test (TST) was the only means of diagnosing LTBI, however, interferon-gamma-release assays (IGRAs), are promising new tools. Fifty two patients with dermatological disorders were included prior to implementation of anti-TNF-alpha therapy. Mycobacterium tuberculosis (MTB)-specific cytokine production, including interferon (IFN)-gamma, TNF-alpha, interleukin (IL)-2 and IL-10, was measured in CD4+ and CD8+ T cells by cytokine flow cytometry following stimulation of peripheral blood mononuclear cells (PBMC) with purified protein derivative (PPD) and early secretion antigenic target (ESAT)-6. Simultaneously, a TST was administered and 11 were TST-positive. Generally, MTB-specific IFN-gamma produced by CD4+ T cells correlated well with TST results. CD4+ T cells co-producing specific IFN-gamma and TNF-alpha after ESAT-6 stimulation showed the highest overall agreement with the TST (Kappa [kappa] = 0.87). Each single cytokine displayed individual patterns, the expression of IFN-gamma, however, showed the highest concordance with the TST (kappa = 0.82). This suggests that the enumeration of MTB-specific CD4+ T cells might introduce greater specificity for the diagnosis of latent TB, compared to the TST.