Mycolic acids are attractive diagnostic markers for tuberculosis (TB) infection because they are bacteria-derived, contain information about bacterial species, modulate host–pathogen interactions and are chemically inert. Here, we present a novel approach based on mass spectrometry. Quantification of specific precursor → fragment transitions of approximately 2000 individual mycolic acids (MAs) resulted in high analytical sensitivity and specificity. We next used this tool in a retrospective case–control study of patients with pulmonary TB with varying disease burdens from South Korea, Vietnam, Uganda and South Africa. MAs were extracted from small volume sputum (200 µl) and analysed without the requirement for derivatization. Infected patients (70, 19 of whom were HIV+) could be separated from controls (40, 20 of whom were HIV+) with a sensitivity and specificity of 94 and 93%, respectively. Furthermore, we quantified MA species in lung tissue of TB-infected mice and demonstrated effective clearance of MA levels following curative rifampicin treatment. Thus, our results demonstrate for the first time the feasibility and clinical relevance of direct detection of mycobacterial lipids as biomarkers of TB infection.
Background
Systemic lupus erythematosus (SLE) valvulopathy can manifest as a spectrum of pathologies and treatment of severe valvular dysfunction thus far has been surgical. However, surgery in patients with SLE is frequently associated with high morbidity and mortality due to the presence of significant co-morbidities.
Case summary
We report the case of a 41-year-old woman with SLE and anti-phospholipid syndrome with extensive co-morbidities including lupus nephritis, pancytopaenia, cerebrovascular accident, and severe airway obstruction from ipsilateral lung collapse and bronchiectasis. She had severe mitral regurgitation (MR) from Libman–Sacks endocarditis and in recent months developed heart failure with progressive exertional dyspnoea from New York Heart Association (NYHA) functional Class from New York Heart Association (NYHA) functional class II to III. In addition, there was progressive left ventricular dilatation and reduction in left ventricular ejection fraction. In view of the high surgical risk, she underwent transcatheter edge-to-edge repair (TEER) of the mitral valve with the MitraClip system. At 1-month follow-up, she was back to NYHA functional Class II with mild MR.
Discussion
Our case demonstrates that in select patient with suitable anatomy, TEER is a potential treatment option for severe MR from SLE valvulopathy.
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