Marker sequences for diagnosing and stratifying SLE patients
The present invention relates to methods for identifying markers for systemic lupus erythematosus (SLE) and to the markers identified with the aid of this method, which can differentiate between SLE and other autoimmune diseases on the one hand and between different SLE subgroups on the other hand. The invention also relates to panels, diagnostic devices and test kits which comprise these markers, and to the use and application thereof, for example for the diagnosis, prognosis and therapy control in SLE. The invention also relates to methods for screening and validating active substances for application in SLE subgroups.
1. A method for identifying markers for systemic lupus erythematosus (SLE), comprising:
a) bringing serum samples of SLE patients into contact with more than 5000 antigens coupled to beads, measuring the binding of each individual antigen to autoantibodies in the serum samples of the SLE patients using an immunofluorescence assay, and determining the median fluorescence intensity (MFI) for each individual antigen;
b) bringing serum samples of patients with rheumatoid arthritis (RA) into contact with the more than 5000 antigens coupled to beads, measuring the binding of each individual antigen to autoantibodies in the serum samples of the RA patients using said immunofluorescence assay, and determining from this—the median fluorescence intensity (MFI) for each individual antigen;
c) bringing serum samples of healthy individuals into contact with the more than 5000 antigens coupled to beads, measuring the binding of each individual antigen to autoantibodies in the serum samples of the healthy individuals using said immunofluorescence assay, and determining the median fluorescence intensity (MFI) for each individual antigen;
d) statistically evaluating the MFI for each individual antigen obtained from a), b), and c) using a univariate analysis and identifying marker candidate antigens with which SLE patients can be differentiated from RA patients and from healthy individuals;
e) bringing serum samples of patients with early RA into contact with the marker candidate antigens identified in d) coupled to beads, measuring the binding of each individual marker candidate antigens to autoantibodies in the serum samples of patients with early RA using said immunofluorescence assay, and determining the median fluorescence intensity (MFI) for each individual marker candidate antigen;
f) bringing serum samples of patients with systemic sclerosis (SSc) into contact with the marker candidate antigens identified in d) coupled to beads, measuring the binding of each marker candidate antigen to autoantibodies in the serum samples of SSc patients using said immunofluorescence assay, and determining the median fluorescence intensity (MFI) for each individual marker candidate antigen;
g) bringing serum samples of patients with ankylosing spondylitis or Bekhterev's disease (SPA) into contact with the marker candidate antigens identified in d) coupled to beads, measuring the binding of each marker candidate antigen to autoantibodies in the serum samples of SPA patients using said immunofluorescence assay, and determining the median fluorescence intensity (MFI) for each individual marker candidate antigen;
h) statistically evaluating the MFI for each individual marker candidate antigen obtained from e), f), and g) using an univariate analysis and identifying a marker for SLE when a threshold value of 3 standard deviations above the mean value of the healthy samples is not reached; and
i) identifying a SLE patient for stratification and administering at least one therapeutic agent to the SLE patient for treatment or monitoring the SLE patient for control of the SLE patient's therapy;
wherein the marker for SLE is selected from the sequences of SEQ ID NO: 1-11, 13, 15, 16, 18, 19, 20-24, 28, 29, 31, 46, 61, 95, 126, 128, 134, 136, 143, 152, 163, 169, 171, 173, 188, 191, 213, 214, 241, 258, 270, 302, 348, 349, 367-370, 372-375, 378-391, 403, 406, 408, 415, and 423-433.
2. The method of claim 1 for identifying markers for SLE, comprising selecting a marker for SLE which, in the univariate analysis, has an adjusted p-value for the non-parametric mean value comparison between the groups of less than 0.05 and at the same time have a fold change of greater than 1.5 and an AUC resulting from the ROC analysis of greater than 0.75.
3. The method of claim 1 , wherein the marker for SLE is selected from proteins encoded by SEQ ID NO: 1-11, 13, 15, 16, 18, 19, 20-24, 28, 29, 31, 46, 61, 95, 126, 128, 134, 136, 143, 152, 163, 169, 171, 173, 188, 191, 213, 214, 241, 258, 270, 302, 348, 349, 367-370, 372-375, 378-391, 403, 406, 408, 415, and 423-433.
4. The method of claim 2 , wherein the marker for SLE is selected from proteins encoded by SEQ ID NO: 1-11, 13, 15, 16, 18, 19, 20-24, 28, 29, 31, 46, 61, 95, 126, 128, 134, 136, 143, 152, 163, 169, 171, 173, 188, 191, 213, 214, 241, 258, 270, 302, 348, 349, 367-370, 372-375, 378-391, 403, 406, 408, 415, and 423-433.