Identification of new sensitive biomarkers for the in vivo response to interferon‐β treatment in multiple sclerosis using DNA‐array evaluation

Abstract

Objective: Neutralizing antibodies (NAbs) occur in a proportion of multiple sclerosis (MS) patients treated with interferon (IFN)-b. NAbs impair the effect of treatment. The biological effect of IFN-b can be measured as the induction of the myxovirus resistance protein A (MxA) molecule. However, other markers could be more sensitive for evaluating the response to IFN-b. We used DNA array analysis to identify genes that are strongly induced in blood cells by IFN-b, and measured their expression in MS patients with different NAb levels. Methods: Gene expression was studied on DNA arrays in untreated patients, in NAb negative patients, and in MS patients with varying NAb levels 9-12 h and 36-48 h after IFN-b administration. The expression of selected genes was measured by realtime PCR. NAb levels were assessed by a cytopathic effect assay. Results: Several hundred genes were induced 9-12 h after an injection of IFN-b. The molecules CXCL10, CCL2 and IFI27 were among the most strongly induced. Gene induction was generally much less pronounced after 36-48 h, but IFI27 remained strongly induced. The strong induction of these molecules and MxA was confirmed by real-time PCR. Induction of MxA, CCL2, CXCL10 and IFI27 was reduced in patients with low NAb levels and lost in patients with intermediate/high NAb levels. Conclusion: We identify IFI27, CCL2 and CXCL10 as sensitive biomarkers for the response to IFN-b. The expression of these markers adequately reflects bioactivity of IFN-ß as documented by the decreased induction in low NAb-positive patients and the lost induction in patients with moderate/high NAb levels.

Early detection of neutralizing antibodies to interferon-beta in multiple sclerosis patients: binding antibodies predict neutralizing antibody development

“…Further evidence comes from a recent study, which reports fully abrogated CXCL-10 gene expression in patients with low NAb titers and remaining MxA expression. 13 One could conclude that some IFN-b stimulated genes are less affected by anti-IFN-b antibodies than others, a factor that might contribute to the "grey zone" of NAb assays; however, in the present study comparison is limited, as MxA was determined at the RNA and CXCL-10 at the protein level.…”

Biomarkers of disease activity in multiple sclerosis

“…Currently identified and validated biomarkers are useful in initial diagnosis of MS versus NMO (aquaporin-4 antibody), predicting conversion to RRMS after CIS (CSF OCB) and interpreting treatment failure in patients on IFN-β therapy (IFN-β neutralizing antibodies), but are clearly not infallible (Table 10). It is possible that multiplex arrays and statistical algorithms that examine multiple biomarkers simultaneously may provide better sensitivity and specificity [10,62,85,[138][139][140][141][142]. Reliable biomarkers of disease activity and therapeutic response would assist in guiding treatment decisions and improving long-term outcomes in MS. …”

“…Serum levels of CXCL8, CXCR3, CCL5 and IP-10 increase during relapse with MRI activity, while levels of CCL2 (MCP1) decline [82][83][84]. CCL2 and CXCL10 levels are strongly induced by IFN-β treatment and lost in the presence of IFN-β neutralizing antibodies, but their correlation with disease activity is unknown [85]. Serum levels of the chemokine IL-8 in the first trimester of pregnancy have been shown to predict patients at risk of post-partum relapse [86].…”

Endogenous Interferon-β-Inducible Gene Expression and Interferon-β-Treatment Are Associated with Reduced T Cell Responses to Myelin Basic Protein in Multiple Sclerosis

“…Gene expression levels are given as normalization ratio (NR) calculated by: NR = 2 -ΔCt(sample) - ΔCt(pool) [23]. Gene expression in PBMCs was analyzed on the Affymetrix Human Genome Focus Gene Chip as previously described [24]. …”