The astrocyte-specific marker glial fibrillary acidic protein (GFAP), measured in serum, can predict relapses in neuromyelitis optica spectrum disorders (NMOSD) during remission. Two other biomarkers, S100B and neurofilament light chain (NfL) failed to do so .
In acute phases of NMOSD, the astrocyte-specific biomarkers GFAP and S100B are elevated in cerebrospinal fluid (CSF) and serum or plasma, as is the neuron-specific biomarker NfL. GFAP is already used to set appropriate treatment regimens and monitoring response. In a new study, the prognostic potential of these 3 biomarkers for future relapses in NMOSD with aquaporin-4-IgG was evaluated. Median baseline biomarker values were determined from 47 serum samples from 18 patients in remission. Cut-off levels were established for “high” and “low” GFAP (141.6 pg/mL), S100B (8.6 pg/mL), and NfL (33.9 pg/mL). When a patient relapsed, another serum sample was taken and analysed. In total, 25 post-relapse samples were analysed (11 patients had 1 relapse, 7 had 2 relapses).
Patients with high baseline GFAP had earlier future relapses (after a median of 922 days) than those with low GFAP levels (3,710 days; P=0.0047). They were also at higher risk of future relapses (adjusted HR 9.5; P=0.0061). These differences were absent in the high versus low S100B and NfL groups.
Presenting author Prof. Mitsuru Watanabe (Kyushu University, Japan) suggested that S100B may have failed in this study because it is not specific to astrocytes and because it has a short half-life compared to GFAP. The failure of NfL may be explained by the pathogenesis of NMOSD, in which astrocytopathy is of primary and neuro-axonal damage only of secondary importance.
- Watanabe M, et al. Serum glial fibrillary acidic protein, but not S100B or neurofilament light chain predicts future relapses in neuromyelitis optica spectrum disorders. MSVirtual 2020, PS03.04.
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