CCL2 and bacterial meningitis: Notably, patients with PM exhibit elevated levels of Interferon-gamma (IFN-γ), Chemokine (C-C motif) ligand 2 (CCL2), and Matrix Metalloproteinase 9 (MMP-9) in their cerebrospinal fluid (CSF) compared to those with other aetiologies of bacterial meningitis, indicating a more intense inflammatory response (4).