Integrated analysis of lncRNAs expression profiling in systemic lupus erythematosus

To the Editor,Systemic lupus erythematosus(SLE)is a chronic autoimmune disease with serious harm to human health and various clinical manifestations,which is characterized by over-activity of lymphocytes,production of autoantibodies,and effects on multiple organs.1 So far,the pathogenesis of SLE remains unclear;it is believed that genetic,environmental,infectious,and other factors participate in the pathogenesis of SLE.With the gradual in-depth study of transcriptomics,genetic factors may be the root cause of SLE,2 and epigenetics plays an important role in genetic factors of SLE.3 Epigenetics means heritable changes in gene expression without shifting the DNA sequence.The principal mechanisms of epigenetic regulation include histone modification,DNA methylation,and regulation of noncoding RNA.In the past,studies of transcriptomics mainly focused on protein-coding genes.However,protein-coding genes that encode exons account for 1.5%of the genome,and genes without protein-coding capability account for more than 80%of the human genome.4 Therefore,studies of transcriptomics began to pay attention to long noncoding RNAs(lncRNAs),which play key roles in transcription control,posttranscriptional processing,protein metabolism,immune cell differentiation,and immune responses.5 However,knowledge of related lncRNAs in SLE remains limited.

Expression of SALL4 in the synovial tissue of refractory rheumatoid arthritis patients

To the Editor,Rheumatoid arthritis(RA)synovitis is characterized by synovial inflammation,characterized by synovial proliferation,neovascularization,and leukocyte infiltration into the joint space,1 leading to irreversible cartilage and bone damage.2 This synovial inflammation stimulates the formation of pannus,which is an invasive tumor-like mass,ultimately contributing to the pathogenesis of RA.RA shares several similarities with cancer,including joint pain,swelling,and stiffness,which are accompanied by hypoxia in the synovial tissue and tumor environment.3 Spalt-like transcription factor 4(SALL4)plays an essential role in the occurrence and development of tumors.4 However,SALL4 expression in synovial tissue of RA is yet to be investigated.This study aimed to investigate SALL4 expression in synovial tissue derived from patients with RA,using immunohistochemical techniques.