LC-MS/MS targeted analysis of amino acids in CSF of pediatric tuberculous meningitis

Tuberculous meningitis (TBM) is the most severe manifestation of tuberculosis (TB) and is associated with high mortality and long-term neurological morbidity. Diagnosis is challenging due to a nonspecific clinical presentation overlapping with other forms of meningitis. Delayed diagnosis and subsequent delays in treatment initiation remain major contributors to poor outcomes, highlighting the need for improved diagnostic approaches. Untargeted cerebrospinal fluid (CSF) metabolomics studies have revealed perturbed amino acid (AA) metabolism in TBM. Here, we applied liquid chromatography-tandem mass spectrometry (LC-MS/MS) for targeted profiling of AAs in CSF from a pediatric patient cohort (≤ 13 years old) in the Western Cape Province, South Africa. This study included children with TBM, viral meningitis (VM), and non-meningitis controls (NMC). CSF AA concentrations were markedly elevated in TBM, with most measured AAs significantly increased compared with both VM and NMC; however, serine did not show any significant difference. Lysine, glycine, alanine, proline, tyrosine, and methionine showed the strongest discriminatory potential. Despite elevated CSF protein levels in TBM, AA concentrations did not correlate with total protein. Instead, glycine correlated with leucocyte and lymphocyte counts, suggesting a link between AAs and inflammatory responses. No AAs significantly differentiated VM from NMC. These findings demonstrate substantial AA perturbations in pediatric TBM and highlight the potential of AA profiling to inform future diagnostic biomarker development.