RT-qPCR is the accepted technique for the quantification of microRNA (miR) expression: however, stem-loop RT-PCR, the most frequently used method for quantification of miRs, is time- and reagent-consuming as well as inconvenient for scanning. We established a new method called ‘universal stem-loop primer’ (USLP) with 8 random nucleotides instead of a specific sequence at the 3′ end of the traditional stem-loop primer (TSLP), for screening miR profile and to semi-quantify expression of miRs. Peripheral blood samples were cultured with phytohaemagglutinin (PHA), and then 87 candidate miRs were scanned in cultured T cells. By USLP, our study revealed that the expression of miR-150-5p (miR-150) decreased nearly 10-fold, and miR-155-5p (miR-155) increased more than 7-fold after treated with PHA. The results of the dissociation curve and gel electrophoresis showed that the PCR production of the USLP and TSLP were specificity. The USLP method has high precision because of its low ICV (ICV<2.5%). The sensitivity of the USLP is up to 103 copies/µl miR. As compared with the TSLP, USLP saved 75% the cost of primers and 60% of the test time. The USLP method is a simple, rapid, precise, sensitive, and cost-effective approach that is suitable for screening miR profiles.

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Objective Dermatomyositis with different myositis-specific autoantibodies has distinctive clinical presentations. Pathological variation of patients with different antibodies has not been fully understood. Methods A retrospective review of muscle pathological features was performed in dermatomyositis patients with known myositis-specific antibodies. Results A total of 46 dermatomyositis patients with one myositis-specific autoantibody (anti-MDA5 11, anti-Mi-2 10, anti-NXP2 13, anti-TIF1γ 8, anti-SAE 4) were included and the pathological severity score was evaluated. Patients with anti-Mi-2 demonstrated higher pathological severity scores and apparent sarcolemmal complement deposition, which was in consistency of more severe muscle weakness and higher level of muscle enzymes. In contrast, patients with anti-MDA5 generally had minimal pathological changes in muscle with less inflammatory cell infiltration, fewer membrane attack complex deposition, and milder myxovirus resistance protein A upregulation. Patients with anti-SAE had more inflammatory cell infiltration and MAC deposition compared to anti-MDA5 group. Muscle pathological scores varied largely in patients with anti-NXP2 and anti-TIF1γ. Conclusion The muscle pathological features varies among dermatomyositis with different autoantibodies, which further indicates the heterogeneity of dermatomyositis.