Use of pleural fluid levels of adenosine deaminase and interferon gamma in the diagnosis of tuberculous pleuritis:

Immune responses in the lungs of patients with tuberculous pleural effusion without pulmonary tuberculosis

Background

Tuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis. Because most studies of TPE focused on the pleural space, little information regarding lung parenchyma is available. We therefore aimed to investigate immune responses in the lung parenchyma of TPE patients without pulmonary tuberculosis.

Methods

Patients with any evidence of pulmonary tuberculosis, either from radiologic or bacteriologic evaluation, were excluded. Bronchoalveolar lavage fluid (BALF) was collected from 10 newly diagnosed, untreated, HIV-negative TPE patients and 10 healthy controls. We analyzed T-lymphocyte subpopulations and measured 10 cytokines in BALF. Cytokine levels in BALF were standardised using urea.

Results

The concentrations of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), vascular endothelial growth factor (VEGF), and the CD4+/CD8+ ratio of T-lymphocytes were significantly higher in TPE patients without pulmonary tuberculosis than in the controls. Of the cytokines measured in BALF, VEGF showed the highest concentration. No difference was observed in T-helper type 2 cytokines between the 2 groups.

Conclusion

There were significant immune responses and increases in IFN-γ, TNF-α, and VEGF in the lung parenchyma of TPE patients without pulmonary tuberculosis. This result suggests that TPE may induce a significant immune response in lung parenchyma.

Serum adenosine deaminase may predict disease activity in rheumatoid arthritis

To determine the relationship between serum adenosine deaminase (ADA) and disease activity, and to develop a new disease activity index based on serum ADA in rheumatoid arthritis (RA). Seventy RA patients were included. Disease activity based on Disease Activity Score 28-ESR (DAS28-ESR) and Disease Activity Score 28-CRP (DAS28-CRP) and serum ADA were measured. There were correlations when serum ADA compared with DAS28-ESR and DAS28-CRP. (R (2) = 0.014, 0.175, respectively, P values < 0.00). New disease activity index was developed by replacing ADA with ESR and CRP in DAS28-ESR and DAS28-CRP. There were strong correlations when new model compared with DAS28-ESR and DAS28-CRP. (R (2) = 0.94 and 0.95, respectively, P values < 0.00) The best new model values corresponding to DAS28-ESR values of 2.6, 3.2, and 5.1 were 2.79, 3.4, and 4.82, respectively; and new model values corresponding to DAS28-CRP values of 2.3, 2.7, and 4.1 were 2.1, 2.9, and 4, respectively. There were agreements when the new model compared with DAS28-ESR and DAS28-CRP for determination of patients in different disease activity categories. (Kappa = 0.81 and 0.71, respectively, P values < 0.00). The new disease activity index that applies serum ADA may help in predicting disease activity in RA.

Diagnostic accuracy of adenosine deaminase and lymphocyte proportion in pleural fluid for tuberculous pleurisy in different prevalence scenarios

Background

Tuberculous pleural effusion (TPE) is a paucibacillary manifestation of tuberculosis, so isolation of Mycobacterium tuberculosis is difficult, biomarkers being an alternative for diagnosis. Adenosine deaminase (ADA) is the most cost-effective pleural fluid marker and is routinely used in high prevalence settings, whereas its value is questioned in areas with low prevalence. The lymphocyte proportion (LP) is known to increase the specificity of ADA for this diagnosis. We analyse the diagnostic usefulness of ADA alone and the combination of ADA ≥40 U/l (ADA₄₀) and LP≥50% (LP₅₀) in three different prevalence scenarios over 11 years in our area.

Materials and Methods

Biochemistry, cytology and microbiology studies from 472 consecutive pleural fluid samples were retrospectively analyzed. ADA and differential cell count were determined in all samples. We established three different prevalence periods, based on percentage of pleural effusion cases diagnosed as tuberculosis: 1998–2000 (31.3%), 2001–2004 (11.8%), and 2005–2008 (7.4%). ROC curves, dispersion diagrams and pre/post-test probability graphs were produced. TPE accounted for 73 episodes (mean prevalence: 15.5%). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for ADA₄₀ were 89%, 92.7%, 69.2% and 97.9%, respectively. For ADA₄₀+LP₅₀ the specificity and PPV increased (98.3% and 90%) with hardly any decrease in the sensitivity or NPV (86.3% and 97.5%). No relevant differences were observed between the three study periods.

Conclusions/Significance

ADA remains useful for the diagnosis of TPE even in low-to-intermediate prevalence scenarios when combined with the lymphocyte proportion.

[Extrapulmonary tuberculosis]

Extrapulmonary tuberculosis represents an increasing proportion of all cases of tuberculosis reaching 20 to 40% according to published reports. Extrapulmonary TB is found in a higher proportion of women, black people and immunosuppressed individuals. A significant proportion of cases have a normal chest X-Ray at the time of diagnosis. The most frequent clinical presentations are lymphadenitis, pleuritis and osteoarticular TB. Peritoneal, urogenital or meningeal tuberculosis are less frequent, and their diagnosis is often difficult due to the often wide differential diagnosis and the low sensitivity of diagnostic tests including cultures and genetic amplification tests. The key clinical elements are reported and for each form the diagnostic yield of available tests. International therapeutic recommendations and practical issues are reviewed according to clinical presentation.

Highly accurate diagnosis of pleural tuberculosis by immunological analysis of the pleural effusion

Pleural TB is notoriously difficult to diagnose due to its paucibacillary nature yet it is the most common cause of pleural effusions in TB endemic countries such as The Gambia. We identified both cellular and soluble biomarkers in the pleural fluid that allowed highly accurate diagnosis of pleural TB compared to peripheral blood markers. Multi-plex cytokine analysis on unstimulated pleural fluid showed that IP-10 resulted in a positive likelihood ratio (LR) of 9.6 versus 2.8 for IFN-γ; a combination of IP-10, IL-6 and IL-10 resulted in an AUC of 0.96 and positive LR of 10. A striking finding was the significantly higher proportion of PPD-specific IFN-γ+TNF-α+ cell population (PPD-IGTA) in the pleural fluid compared to peripheral blood of TB subjects. Presence of this pleural PPD-IGTA population resulted in 95% correct classification of pleural TB disease with a sensitivity of 95% and specificity of 100%. These data suggest that analysis of the site of infection provides superior diagnostic accuracy compared to peripheral blood for pleural TB, likely due to the sequestration of effector cells at this acute stage of disease.

Alterations of blood parameters after intramuscular administration of imidocarb in healthy lambs

The aim of this study was to determine the safety of imidocarb dipropionate in sheep. Imidocarb dipropionate (IMDP) was administered (2.4 mg/kg, intramuscular; i.m.) to 10 sheep, and blood samples were obtained 0, 1, 6, and 9 days after treatment. Hemacell counts, serum biochemical values, coagulation values, and serum oxidative status were measured. IMDP caused transient decreases in pH, actual bicarbonate, standard bicarbonate, total carbon dioxide, base excess in vivo, base excess in vitro, oxygen saturation, lactate dehydrogenase, and retinol levels and transient increases in serum creatine kinase-MB, blood urea nitrogen, and creatinine levels. IMDP decreased adenosine deaminase activity, antithrombin III, and superoxide dismutase activity and increased white blood cell counts. In conclusion, IMDP may change serum oxidative status and cause coagulation disorders during treatment in sheep.

Immunological biomarkers of tuberculosis

Currently there are no sufficiently validated biomarkers to aid the evaluation of new tuberculosis vaccine candidates, the improvement of tuberculosis diagnostics or the development of more effective and shorter treatment regimens. To date, the detection of Mycobacterium tuberculosis or its products has not been able to adequately address these needs. Understanding the interplay between the host immune system and M. tuberculosis may provide a platform for the identification of suitable biomarkers, through both unbiased and targeted hypothesis-driven approaches. Here, we review immunological markers, their relation to M. tuberculosis infection stages and their potential use in the fight against tuberculosis.

In-hospital outcome of patients with culture-confirmed tuberculous pleurisy: clinical impact of pulmonary involvement

BACKGROUND

Outcomes for hospitalized patients with tuberculous pleurisy (TP) have rarely been reported, and whether or not pulmonary involvement affects outcomes is uncertain. This study aimed to analyze the in-hospital mortality rate of culture-confirmed TP with an emphasis on the clinical impact of pulmonary involvement.

METHODS

Patients who were hospitalized for pleural effusion (PE) of unconfirmed diagnosis and finally diagnosed as TP were identified. We classified them according to the disease extent: isolated pleurisy (isolated pleurisy group) and pleurisy with pulmonary involvement (pleuro-pulmonary group).

RESULTS

Among the 205 patients hospitalized before the diagnosis was established, 51 (24.9%) belonged to the isolated pleurisy group. Compared to the pleuro-pulmonary group, patients in the isolated pleurisy group were younger, had fewer underlying co-morbidities, and presented more frequently with fever and chest pain. Fewer patients in the isolated pleurisy group had hypoalbuminemia (< 3.5 g/dL) and anemia. The two groups were similar with regards to PE analysis, resistance pattern, and timing of anti-tuberculous treatment. Patients who had a typical pathology of TP on pleural biopsy received anti-tuberculous treatment earlier than those who did not, and were all alive at discharge. The isolated pleurisy group had a lower in-hospital mortality rate, a shorter length of hospital stay and better short-term survival. In addition, the presence of underlying comorbidities and not receiving anti-tuberculous treatment were associated with a higher in-hospital mortality rate.

CONCLUSION

In culture-confirmed tuberculous pleurisy, those with pulmonary involvement were associated with a higher in-hospital mortality rate. A typical pathology for TP on pleura biopsy was associated with a better outcome.