S in the diagnosis of pleural TB [25]. In this study we
S in the diagnosis of pleural TB [25]. In this study we have quantified TB specific and unspecific immune responses in the pleural cavity of patients with HIV and TB co-infection by using the commercial available QFT-TB test. Further, we have evaluated the utility of this test as a diagnostic tool of TB pleuritis in a high TB and HIV endemic area.MethodsStudy participants Patients presenting with pleural effusion and clinical symptoms of TB pleuritis admitted to the Dr. George Mukhari Hospital (DGM), Ga-Rankuwa, Pretoria, South Africa in the period 2004?005 were recruited into the study.The patients were categorised as; (i) ‘confirmed TB’ pleuritis (AFB microscopy or culture positive pleural fluid), (ii) ‘probable TB’ pleuritis (AFB microscopy and culture negative pleural fluid, ADA 30 U/L and/or strong clinical evidence consistent with active TB followed by a decision by a clinician to treat with tuberculosis chemotherapy [26]) and (iii) ‘non-TB’ pleuritis when diagnosed as malignancy or another non-TB condition. Patients with recent TB therapy (< 1 year) or treated with corticosteroids, immunosuppressive or antiretroviral therapy (ART) were not included. HIV testing was done routinely at the hospital in pleural effusion patients with suspected TB. The demographic Avasimibe biological activity PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/27107493 and clinical data, HIV status and CD4 cell count were recorded for each patient. Thoracocentesis and pleural biopsies (for only two patients) were obtained according to clinical practice at the hospital. Peripheral blood was obtained in parallel and before initiation of anti-tuberculosis therapy. The QFT-TB results were not available for the clinicians and did not influence the classification of patients or decisions concerning treatment. The study was evaluated and approved by the Research, Ethics and Publications Committee at the DGM Hospital, University of Limpopo, South Africa (2003) and the Regional Committee for Ethics in Medical Research in Bergen, Norway (2003, REK Vest nr.185.02). All thePage 2 of(page number not for citation purposes)BMC Infectious Diseases 2008, 8:http://www.biomedcentral.com/1471-2334/8/patients received written and oral information of the study and all gave informed consent.Specimen preparation and culture The pleural fluid and sputum specimens were processed according to standard laboratory routines for AFB staining of smears and culture for up to four weeks (BacT-alert, Organon, Teknika). The pleural fluid was also sent for cytological examination and analysis of ADA, using a commercial colorimetric assay kit (Diazyme General Atomics, CA) with a cutoff value for positive test of 30 U/ L [27]. Pleural fluid mononuclear cells (PFMCs) were isolated from approximately 200 ml pleural fluid by density gradient centrifugation (Ficoll histopaque 1077, Sigma), washed and resuspended in RPMI media (1640, Lglutamine and HEPES supl., Sigma) to make a final concentration of 1 ?106 cells/ml. QuantiFERON?TB Gold In-Tube assay One ml of blood and 1 ml of PFMC suspension were added to each of the three ‘QuantiFERON?TB Gold (QFTTB) In-tubes’; TB antigen (ESAT-6, CFP-10 and TB 7.7), positive mitogen control (phytohemagglutinin [PHA]) and negative control (Nil), as provided PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28724915 by the manufacturer (Cellestis Ltd., Victoria, Australia), mixed well and incubated at 37 for 20 hours. The tubes were centrifuged and 500 l of the supernatants were harvested and stored at -70 . until the IFN- was measured in duplicates simultaneously in an ELISA reader. The IFN- concentratio.