L-selectin (CD62L) and anti–John Cunningham virus (JCV) antibody index were both effective biomarkers for progressive multifocal leukoencephalopathy (PML) development in patients undergoing natalizumab therapy for remitting-relapsing multiple sclerosis, according to Dr. Nicholas Schwab and his associates.
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In the CD62L group of 17 pre-PML patients and 1,410 control patients, sensitivity for PML prediction was 86% and specificity was 91%. If a patient had at least one instance of low CD62L, risk of developing PML increased by 55 times. In the JCV index group of 9 pre-PML patients and 1,921 controls, sensitivity was 100% and specificity was 59%.
Both biomarkers have benefits and weaknesses. While JCV index is significantly less specific than CD62L for predicting PML, it is more reliable. CD62L is variable, and while just one low CD62L reading strongly indicates PML, regular screening is necessary. Combining both biomarkers identified nearly 2% of patients at risk for PML.
“The systematic inclusion of both JCV index and CD62L could reduce the risk and occurrence of PML up to 10-fold if applied rigorously during risk stratification,” the investigators concluded.
Find the full study in the Multiple Sclerosis Journal (doi: 10.1177/1352458515607651).