Electronic Poster | Session 1

068 – Characterization of the Immunophenotype of Clinically Isolated Syndrome Patients Who Convert or Not To Multiple Sclerosis and the Effect of Cryopreservation

Chieh-Hsin Lee (1) – Maryam Nakhaei-Nejad (2) – David Barilla (2) – Carlos Camara-Lemarroy (3) – Luanne Metz (3) – Claudia Silva (3) – V. Wee Yong (3) – Fabrizio Giuliani (2)
University of Alberta, Neuroscience and Mental Health Institute, Edmonton, Canada (1) – University of Alberta, Department of Medicine, Edmonton, Canada (2) – University of Calgary, Department of Clinical Neurosciences, Calgary, Canada (3)

Clinically isolated syndrome (CIS) is the prodromal phase of multiple sclerosis (MS) disease course, with patients having experienced one neurological episode. Since up to 70% of CIS patients are subsequently diagnosed with MS, it is important to determine who will convert to RRMS later. Multi-colour flow cytometry panels were used to identify up to 50 peripheral blood lymphocyte subpopulations. Samples from two sites were used, with one done on fresh whole blood and the other on cryopreserved peripheral blood mononuclear cells (PBMCs) after recovery. We compared patients with CIS who do (CIS-C) or do not (CIS-N) covert to RRMS (relapsing remitting MS) later. Comparisons were also done between the two sites. This study aims to immunophenotype PBMC subsets in CIS who do or don’t covert; identify biomarkers that predict progression to RRMS; and examine the effect of cryopreservation and recovery on cell populations. In the fresh samples, the T cell subcompartment, CIS-C patients had a higher expression level of CD127 (IL-7 receptor) in the Granzyme B expressing CD8+ T cells (CD8+CCR7-CD27-) than non-converters. A significantly lower dendritic cell population in converters than non-converters was shown as well. Converters also had a significantly higher level of CD56DimCD16+ natural killer cells. Comparisons between fresh blood and cryopreserved samples showed a variety of changes, including a higher population of classical memory and naïve & transitional B cells in the cryopreserved samples. Within the cryopreserved patient samples, no differences were detected between converters and non-converters. Partial least square discriminant analysis (PLS-DA) was used to compare the overall immunophenotypes between CIS-C and CIS-N, with no significant separation in either fresh blood or cryopreserved samples. In conclusion, some immune subpopulations are significantly different between converters and non-converters within fresh blood samples, with no differences detected in cryopreserved samples. Overall comparisons of the immunophenotypes show no separation between the groups in either fresh blood or cryopreserved samples. Our findings also showed that cryopreservation of cells can result in a wide range of differential changes in immune subpopulations, potentially obscuring differences between groups.