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Published on: December 1, 2023
Predicting autoimmunity after alemtuzumab treatment of multiple sclerosis
Laura Azzopardi1, Sara A J Thompson1, Katherine E Harding2
1Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
Objective:
We have previously shown that autoimmunity following alemtuzumab treatment of multiple sclerosis can be predicted by high baseline serum interleukin IL-21 (IL-21), as measured using a now 'redundant' enzyme linked immunosorbent assay (ELISA). Here we ask whether currently available ELISAs have similar prognostic value.
Design:
Serum IL-21 from 141 individuals with relapsing remitting multiple sclerosis was measured using the now 'redundant' IL-21 ELISA and five further currently available kits. All patients had been treated with alemtuzumab; 61/141 had developed secondary autoimmunity.
Results:
The 'redundant kit', and one current kit, confirmed higher baseline serum IL-21 in patients with autoimmunity (542 pg/mL vs. 222 pg/mL and 53.1 pg/mL vs. 9.3 pg/mL respectively) and showed positive correlation. However, only the 'redundant' kit had predictive utility.
Conclusions:
Currently available IL-21 ELISA kits should not be used to counsel individuals with multiple sclerosis considering treatment with alemtuzumab.

