ANTIBODIES TO ANTIGEN A60 IN CEREBROSPINAL-FLUID FROM PATIENTS WITH TUBERCULOUS MENINGITIS

Cerebrospinal fluid (CSF) anti-mycobacterial antigen 60 (A60) IgM, IgG and IgA in patients affected by meningitis of different etiologies we re assayed as a rapid diagnostic test in cases of tuberculous meningit is. A commercial EIA was used to test 127 CSF samples classified as fo llows: tuberculous meningitis (n = 27 CSF samples from 16 patients, 6 of them with AIDS), pyogenic meningitis (n = 13), non-tuberculous asep tic meningitis (n = 43) and 44 normal CSF samples (16 of them from HIV -positive patients, 8 of whom had extraneurological tuberculosis). Ant i-AGO IgM was positive only in two cases (1 tuberculous meningitis and 1 self-resolving aseptic meningitis). Positive CSP anti-AGO IgG and I gA were observed in eight and nine out of 16 patients with tuberculous meningitis, but only in four and five out of 13 samples studied prior to or in the first ten days of treatment, respectively. Most of the p atients with false-positive IgG and IgA (16%) had pyogenic meningitis, but without intrathecal synthesis of antibodies. In patients with ase ptic meningitis, the finding of CSF anti-A60 IgG plus IgA, initially o r during follow-up, can be used as a diagnostic criterion for tubercul ous meningitis, with a specificity of 100%, a positive predictive valu e of 1, and a negative predictive value of 0.81. However, its sensitiv ity is only 50% in immunocompetent patients and 16% in patients with A IDS.