Platelet-to-lymphocyte ratio differs between MS and NMOSD at disease onset and predict disability.

BACKGROUND

We aimed to assess platelet-to-lymphocyte (PLR) and neutrophil-to-lymphocyte ratios (NLR) for differentiating multiple sclerosis (MS) from aquaporin-4-antibody-positive neuromyelitis optica spectrum disorders (NMOSD) at disease onset.

METHODS

We retrospectively enrolled and reviewed the medical records of patients with MS (N = 50) and NMOSD (N = 33) followed in specialized MS/NMOSD centers from Argentina. Demographical and clinical (manifestation and disability) data and neuroradiological features (new/enlarging or contrast-enhancing lesions) were assessed at baseline, 1 and 2 years. Serum samples were obtained during the first relapse without a previous acute or chronic treatment, at 1 and 2 years. Mixed-effects model was used to identify independent associations between the log-transformed NLR or PLR and MS/NMOSD outcomes.

RESULTS

PLR is increased in NMOSD when compared to MS (229.4 ± 86.74 vs. 186.6 ± 70.17, P = 0.01), but no significant differences were found for NLR (3.51 ± 1.29 vs. 3.30 ± 1.17, P = 0.43). PLR was the only independent predictor of poor physical disability score (EDSS ≥ 4) in NMOSD patients at 2 years (β=0.28, p = 0.02) after applying multivariate mixed-effects regression analysis. Additionally, multivariate logistic regression analysis showed that the PLR was the only independent predictor of EDSS ≥ 4 at 2 years (OR 28.8, p = 0.041) in the NMOSD group. The area under the receiver-operating characteristic curve was 0.841.

CONCLUSION

PLR could be potentially useful as additional diagnostic tool in differentiating these two neuroinflammatory conditions at presentation. PLR can predict severity of neurological disability at 2 years in NMOSD patients.