Two potential markers for diagnosis of relapse and remission phases in patient with relapsing-remitting MS

This study focused on microRNA-326 (miR-326) and micro R26a (miR-26a) as Th17-associated miRNAs whose expression levels elevate in peripheral blood lymphocytes (PBLs) of multiple sclerosis patients during relapsing phase compared with remitting phase and healthy individuals.

Th-17 cells are known to produce numerous cytokines (i.e. IL-17, IL-21, IL-22 and GM-CSF) involved in tissue injuries of various auto-immune diseases such as multiple sclerosis.

The aim of the present study was the evaluation of miR-326 and miR-26a levels in PBLs of relapsing–remitting MS (RR-MS) patients in relapse and remitting periods separately. Discrimination between the two periods is important for analysis of the progress of MS disease and effectiveness of drug therapy evaluation.

Forty RR-MS patients including 20 patients in relapsing phase and 20 patients in remitting phase were studied during a course of eight months. Their blood was collected in EDTA and this was accompanied by collecting 20 healthy blood samples without any infectious or allergic diseases which result in active immune system. All relapsing phase patients were new RR-MS cases with a severe attack, and without any previous consumption of immunomodulatory drugs, whereas all remitting phase patients were using immunomodulatory β-interferon. However, for all remitting patients, drug adjustment was performed in such a way that blood taking was accomplished one week after previous interferon injection and just before the next shot, when the amount of drug and so its effect were in its minimal state.

Immediately after collecting blood samples, PBLs were isolated and RNA was extracted. In order to eliminate any potential contamination with unwanted DNA, total RNA samples undergone RNA-free Dnase treatment. cDNA synthesis for miR-326 and miR-26a was obtained and real-time quantitative PCR reactions were carried out. miR-326 expression level was significantly elevated in the relapsing phase patient group compared with remitting phase patients and healthy groups.

No statistically significant difference was observed between remitting phase patients and healthy subjects. In addition, no significant difference was observed in miR-326 expression level of all patients together (including remitting and relapsing patients) compared to the healthy group. miR-26a exhibited an average of 4.5 fold up-regulation in relapsing phase of multiple sclerosis patients compared with remitting phase and healthy specimens. However no statistically significant differences were observed either between remitting phases and healthy subjects or all patients (including remitting and relapsing patients) and healthy group.

Authors: Honardoost MA, Kiani-Esfahani A
Source: Gene. 2014 Apr 30. pii: S0378-1119(14)00511-3. doi: 10.1016/j.gene.2014.04.069. [Epub ahead of print]
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