A simple and highly efficient method of IFI44L methylation detection for the diagnosis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex heterogenous autoimmune disease that can be challenging to diagnose. We previously identified the IFN-induced protein 44-like (IFI44L) methylation marker for SLE diagnosis, which can be detected by pyrosequencing. Although the previous technique has high sensitivity and specificity, it requires special equipment and high cost for detection. Here, we established a high-resolution melting-quantitative polymerase chain reaction (HRM-qPCR) assay to detect the methylation of IFI44L promoter for the diagnosis of SLE. The result was determined according to the standard melting curve of the methylation level of the IFI44L promoter region. The sensitivity was 88.571% and the specificity was 97.087%. The HRM-qPCR and pyrosequencing results presented good consistency when both methods were used to detect the methylation of the IFI44L promoter for SLE diagnosis. Furthermore, the HRM-qPCR method can be used to distinguish SLE from other autoimmune diseases, infectious diseases and virus-related cancers.