The invention discloses a biomarker for diagnosing
systemic lupus erythematosus and
lupus nephritis and application of the biomarker, and relates to the technical field of biological medicines. The biomarker is an ISG15hiCD16 < + > mononuclear
cell. According to the application disclosed by the invention, the ISG15hiCD16 + mononuclear
cell subpopulation is found to be obviously increased in an SLE (
systemic lupus erythematosus) patient. The invention also finds that the expression level of the ISG15hiCD16 + mononuclear
cell subpopulation is positively correlated with the
disease activity of the SLE patient, and the expression level of the ISG15hiCD16 + mononuclear cell subpopulation of the SLE patient with the
kidney enduring expression is obviously higher than that of the SLE patient without the
kidney enduring expression. The working characteristic
curve analysis of a subject shows that the ISG15hiCD16 + mononuclear cell subset has better sensitivity and specificity for diagnosing the SLE and the LN, and has important significance for clinical auxiliary diagnosis of the SLE and the LN and illness state evaluation.