Quantification of γδ T cells and HLA-DR+ NK cells does not predict emergence of new contrast enhancing lesions in MS patients suspending natalizumab treatment

BACKGROUND: Natalizumab (NTZ) is a drug that has been widely used in the treatment of multiple sclerosis (MS). NTZ is very effective in suppressing inflammation, but if treatment is suspended many patients will experience relapses. OBJECTIVE: To investigate if quantification of γδ T cells and HLA-DR(+) NK cells could predict early disease reactivation after NTZ suspension. METHODS: Absolute counts of γδ T cells and HLA-DR(+) NK cells in whole blood were determined with flow cytometry in fifteen patients treated with NTZ. NTZ treatment was then withdrawn and patients were followed with clinical visits and MR investigations. RESULTS: Patients with recurrent disease had higher absolute counts of γδ T cells 129 (±156) cells/μl in comparison to patients with stable disease 50.0 (±51.0) cells/μl but the difference was not statistically significant and largely driven by outliers. Patients with recurrent and stable disease had similar absolute counts of HLA-DR(+) NK cells. CONCLUSION: Quantification of γδ T cells and HLA-DR(+) NK cells could not predict active disease after NTZ suspension.