OBJECTIVE: To investigate the protein-to-protein interaction of 
interferon-induced protein with tetratricopeptide repeats 1 (IFIT1), a newly 
discovered systemic lupus erythematosus (SLE) related up-regulated gene, and its 
possible function.
METHODS: Peripheral blood of 40 SLE patients was obtained to extract total RNA 
and synthesized cDNA. Real-time PCR was used to determine the IFIT1 expression 
at transcript level. Peripheral blood of another 10 SLE patients was extracted 
to obtain specimens of white blood cell lysate. Molecular cloning and a modified 
gluthion S-transferase (GST)-pull down assay were used to capture the protein 
interacting with IFIT1 in the specimens of white blood cell lysate. MALDI-TOF 
mass spectrometry (MS) was preformed to identify the captured protein that could 
interact with IFIT1. Twenty-nine sex and age-matched healthy persons were used 
as controls.
RESULTS: By real-time PCR showed that the IFIT1Delta Ct value (x +/- s) was 
2.344 +/- 1.200 in the SLE patients and was 3.734 +/- 1.274 in the controls (P < 
0.001), showing a significant up-regulation in SLE patients. IFIT1 was cloned 
and GST-IFIT1 fusion protein was expressed in Escherichia coli. GST-IFIT1 fusion 
protein was further purified using Glutathione Sepharose 4B column, and was 
treated as bait to capture prey from peripheral white blood cell lysate of SLE 
patients. MALDI-TOF MS detected protein interaction between Rho/Rac guanine 
nucleotide exchange factor and IFIT1.
CONCLUSION: IFIT1 may interact with Rho/Rac guanine nucleotide exchange factor, 
and regulate the activation of Rho/Rac proteins, thus being involved in the 
pathogenesis of SLE.