Chronic obstructive pulmonary disease in South Africa: Under-recognised and undertreated

No Abstract

Clinical diagnostic utility of IP-10 and LAM antigen levels for the diagnosis of tuberculous pleural effusions in a high burden setting

Background: Current tools for the diagnosis of tuberculosis pleural effusions are sub-optimal. Data about the value of new diagnostic technologies are limited, particularly, in high burden settings. Preliminary case control studies have identified IFN-γ-inducible-10kDa protein (IP-10) as a promising diagnostic marker; however, its diagnostic utility in a day-to-day clinical setting is unclear. Detection of LAM antigen has not previously been evaluated in pleural fluid. Methods: We investigated the comparative diagnostic utility of established (adenosine deaminase [ADA]), more recent (standardized nucleic-acid-amplification-test [NAAT]) and newer technologies (a standardized LAM mycobacterial antigendetection assay and IP-10 levels) for the evaluation of pleural effusions in 78 consecutively recruited South African tuberculosis suspects. All consenting participants underwent pleural biopsy unless contra-indicated or refused. The reference standard comprised culture positivity for M. tuberculosis or histology suggestive of tuberculosis. Principal Findings: Of 74 evaluable subjects 48, 7 and 19 had definite, probable and non-TB, respectively. IP-10 levels were significantly higher in TB vs non-TB participants (p<0.0001). The respective outcomes [sensitivity, specificity, PPV, NPV %] for the different diagnostic modalities were: ADA at the 30 IU/L cut-point [96; 69; 90; 85], NAAT [6; 93; 67; 28], IP-10 at the 28,170 pg/ml ROC-derived cut-point [80; 82; 91; 64], and IP-10 at the 4035 pg/ml cut-point [100; 53; 83; 100]. Thus IP-10, using the ROC-derived cut-point, missed ~20% of TB cases and mis-diagnosed ~20% of non-TB cases. By contrast, when a lower cut-point was used a negative test excluded TB. The NAAT had a poor sensitivity but high specificity. LAM antigendetection was not diagnostically useful. Conclusion: Although IP-10, like ADA, has sub-optimal specificity, it may be a clinically useful rule-out test for tuberculous pleural effusions. Larger multi-centric studies are now required to confirm our findings

Feasibility and Diagnostic Utility of Antigen-Specific Interferon-γ Responses for Rapid Immunodiagnosis of Tuberculosis Using Induced Sputum

Background: The diagnosis of smear-negative or sputum-scarce tuberculosis (TB) is problematic as culture takes several weeks and representative biological samples are difficult to obtain. RD-1 antigen-specific interferon-c release assays (IGRAs) are sensitive and specific blood-based tests for the diagnosis of M. tuberculosis infection. The feasibility and diagnostic utility of this rapid immunodiagnostic assay, using cells from induced sputum, is unknown.Methodology/Principal Findings: Cells isolated from induced sputum were co-cultured with ESAT-6 and CFP-10 antigens using a standardized enzyme-linked immunospot (ELISPOT) assay (T-SPOT (R).TB) in 101 consecutively recruited TB suspects or non-TB controls. An optimization phase using 28 samples was followed by a validation phase using samples from 73 participants (20 with definite or probable TB, and 48 with non-TB). Despite optimization of sputum processing 65/73 (89%) of the IGRAs in the validation phase were inconclusive. 44/73 (60%) tests failed due to sputum induction-related factors [sputum induction-related adverse events (n = 5), inadequate sputum volume (n = 8), non-homogenisable sputum (n = 7), and insufficient numbers of cells to perform the assay (n = 24)], whilst 20/73 (27%) tests failed due T-SPOT (R).TB assay-related factors [excessive debris precluding reading of spots in the ELISPOT well (n = 6), failure of the positive control (n = 11), or high spot count in the negative control (n = 3)]. Only 8/73 (11%) of the available samples could therefore be correctly categorized (7 definite or probable TB, and 1 non-TB patient). Thus, 13/20 (65%) of the definite or probable TB cases remained undiagnosed.Conclusions/Significance: Rapid immunodiagnosis of pulmonary TB by antigen-specific IFN-gamma ELISPOT responses, using cells from induced sputum, is possible. However, the test, in its current ELISPOT format, is not clinically useful because the majority of the assays are inconclusive

HIV associated Lymphocytic Interstitial Pneumonia: a clinical, histological and radiographic study from an HIV endemic resource-poor setting

Background: There is a paucity of clinical and histopathological data about HIV-associated lymphocytic interstitial pneumonitis (LIP) in adults from HIV endemic settings. The role of Ebstein-Barr virus (EBV) in the pathogenesis remains unclear. Methods: We reviewed the clinical, radiographic and histopathological features of suspected adult LIP cases at the Groote Schuur Hospital, Cape Town South Africa, over a 6 year period. Archived tissue sections were stained for CD3, CD4, CD8, CD20 and LMP-1 antigen (an EBV marker). Results: 42 cases of suspected LIP(100% HIV-infected) were identified. 75% of patients were empirically treated for TB prior to being referred to the chest service for further investigation. Tissue samples were obtained using trans-bronchial biopsy. 13/42 were classified as definite LIP (lymphocytic infiltrate with no alternative diagnosis), 19/42 probable LIP (lymphocytic infiltrate but evidence of anthracosis or fibrosis) and 10 as non-LIP (alternative histological diagnosis). Those with definite LIP were predominantly young females (85%) with a median CD4 count of 194 (IQR 119–359). Clinical or radiological features had poor predictive value for LIP. Histologically, the lymphocytic infiltrate comprised mainly B cells and CD8 T cells. The frequency of positive EBV LMP-1 antigen staining was similar in definite and non- LIP patients [(2/13 (15%) vs. 3/10 (30%); p = 0.52]. Conclusions: In a HIV endemic setting adult HIV-associated LIP occurs predominantly in young women. The diagnosis can often be made on transbronchial biopsy and is characterized by a predominant CD8 T cell infiltrate. No association with EBV antigen was found

Mometasone/Indacaterol/Glycopyrronium (MF/IND/GLY) and MF/IND at Different MF Strengths versus Fluticasone Propionate/ Salmeterol Xinafoate (FLU/SAL) and FLU/SAL+ Tiotropium in Patients with Asthma

Background: Once-daily, single-inhaler mometasone furoate/indacaterol acetate/glycopyrronium bromide (MF/IND/GLY, an ICS/ LABA/LAMA) and MF/IND (an ICS/LABA) via Breezhaler® have been approved for the maintenance treatment of patients with asthma inadequately controlled with medium-or high-dose ICS or medium-or high-dose ICS/LABA treatment. Objective: Once-daily (o.d.) formulations of MF/IND/GLY and MF/IND at different MF dose strengths have been compared with twice-daily (b.i.d.) fluticasone propionate/salmeterol xinafoate (FLU/SAL), and b.i.d. FLU/SAL+ o.d. tiotropium (TIO) in the PALLADIUM, IRIDIUM and ARGON studies. Methods: The similarity in study design and consistent outcomes in these studies prompted the pooling of data in this review to better characterise these novel once-daily controller formulations. Results: Pooled data from PALLADIUM and IRIDIUM studies showed comparable or greater efficacy with o.d. MF/IND formulations versus b.i.d. FLU/SAL. The o.d. MF/IND/GLY was superior to b.i.d. FLU/SAL in the IRIDIUM study, and similar to, if not more efficacious than b.i.d. FLU/SAL + o.d. TIO in the ARGON study. Conclusion: These formulations therefore provide novel once-daily treatment options for patients across asthma severity and flexibility for clinicians to step-up or step-down the treatment using the same device and formulations.</p

Mometasone/Indacaterol/Glycopyrronium (MF/IND/GLY) and MF/IND at Different MF Strengths versus Fluticasone Propionate/ Salmeterol Xinafoate (FLU/SAL) and FLU/SAL+ Tiotropium in Patients with Asthma

Background: Once-daily, single-inhaler mometasone furoate/indacaterol acetate/glycopyrronium bromide (MF/IND/GLY, an ICS/ LABA/LAMA) and MF/IND (an ICS/LABA) via Breezhaler® have been approved for the maintenance treatment of patients with asthma inadequately controlled with medium-or high-dose ICS or medium-or high-dose ICS/LABA treatment. Objective: Once-daily (o.d.) formulations of MF/IND/GLY and MF/IND at different MF dose strengths have been compared with twice-daily (b.i.d.) fluticasone propionate/salmeterol xinafoate (FLU/SAL), and b.i.d. FLU/SAL+ o.d. tiotropium (TIO) in the PALLADIUM, IRIDIUM and ARGON studies. Methods: The similarity in study design and consistent outcomes in these studies prompted the pooling of data in this review to better characterise these novel once-daily controller formulations. Results: Pooled data from PALLADIUM and IRIDIUM studies showed comparable or greater efficacy with o.d. MF/IND formulations versus b.i.d. FLU/SAL. The o.d. MF/IND/GLY was superior to b.i.d. FLU/SAL in the IRIDIUM study, and similar to, if not more efficacious than b.i.d. FLU/SAL + o.d. TIO in the ARGON study. Conclusion: These formulations therefore provide novel once-daily treatment options for patients across asthma severity and flexibility for clinicians to step-up or step-down the treatment using the same device and formulations.</p

Clinical diagnostic utility of IP-10 and LAM antigen levels for the diagnosis of tuberculous pleural effusions in a high burden setting

BACKGROUND: Current tools for the diagnosis of tuberculosis pleural effusions are sub-optimal. Data about the value of new diagnostic technologies are limited, particularly, in high burden settings. Preliminary case control studies have identified IFN-γ-inducible-10kDa protein (IP-10) as a promising diagnostic marker; however, its diagnostic utility in a day-to-day clinical setting is unclear. Detection of LAM antigen has not previously been evaluated in pleural fluid. METHODS: We investigated the comparative diagnostic utility of established (adenosine deaminase [ADA]), more recent (standardized nucleic-acid-amplification-test [NAAT]) and newer technologies (a standardized LAM mycobacterial antigen-detection assay and IP-10 levels) for the evaluation of pleural effusions in 78 consecutively recruited South African tuberculosis suspects. All consenting participants underwent pleural biopsy unless contra-indicated or refused. The reference standard comprised culture positivity for M. tuberculosis or histology suggestive of tuberculosis. Principal FINDINGS: Of 74 evaluable subjects 48, 7 and 19 had definite, probable and non-TB, respectively. IP-10 levels were significantly higher in TB vs non-TB participants (p<0.0001). The respective outcomes [sensitivity, specificity, PPV, NPV %] for the different diagnostic modalities were: ADA at the 30 IU/L cut-point [96; 69; 90; 85], NAAT [6; 93; 67; 28], IP-10 at the 28,170 pg/ml ROC-derived cut-point [80; 82; 91; 64], and IP-10 at the 4035 pg/ml cut-point [100; 53; 83; 100]. Thus IP-10, using the ROC-derived cut-point, missed ∼20% of TB cases and mis-diagnosed ∼20% of non-TB cases. By contrast, when a lower cut-point was used a negative test excluded TB. The NAAT had a poor sensitivity but high specificity. LAM antigen-detection was not diagnostically useful. CONCLUSION: Although IP-10, like ADA, has sub-optimal specificity, it may be a clinically useful rule-out test for tuberculous pleural effusions. Larger multi-centric studies are now required to confirm our findings