Identification and monitoring of systemic lupus erythematosus

Abstract

A method for identifying or monitoring SLE in an individual is provided. The method includes quantitating complement component C4 d on the surfaces of platelets and comparing the amounts of C4 d to reference levels of C4 d on platelets of individuals without SLE and/or on platelets of the individual obtained at a different time. Kits for use in the above-described methods are provided along with computer readable media tangibly embodying executable instructions to perform the methods.

1 . A method for identifying systemic lupus erythematosus in an individual, the method comprising:
 quantitating complement C4d associated with platelets obtained from the individual; and   comparing the quantity of complement C4d associated with platelets obtained from the individual with quantities of complement C4d associated with platelets obtained from individuals not having systemic lupus erythematosus;   wherein greater quantities of C4d associated with platelets obtained from the individual as compared to quantities of C4d associated with platelets obtained from individuals not having systemic lupus erythematosus identifies systemic lupus erythematosus in the individual.   
     
     
         2 . The method of  claim 1 , further comprising quantitating CD42b associated with platelets obtained from the individual. 
     
     
         3 . The method of  claim 1 , wherein quantitation of complement C4d is conducted by a method comprising
 contacting platelets from the individual with a conjugate of an antibody specific for complement C4d and a first labeled moiety; and   quantitating the first labeled moiety.   
     
     
         4 . The method of  claim 3 , wherein the first labeled moiety is a first fluorescent moiety. 
     
     
         5 . The method of  claim 4 , wherein the first fluorescent moiety is quantitated by flow cytometric analysis. 
     
     
         6 . The method of  claim 3 , further comprising contacting the platelets from the individual with a conjugate of an antibody specific for CD42b and a second labeled moiety that is detectably different from the first labeled moiety; and
 quantitating the second labeled moiety.   
     
     
         7 . The method of  claim 6 , wherein the second labeled moiety is a fluorescent moiety. 
     
     
         8 . The method of  claim 7 , wherein the second labeled moiety is quantitated by flow cytometric analysis. 
     
     
         9 . A method of monitoring disease activity of systemic lupus erythematosus in an individual comprising:
 quantitating complement C4d associated with platelets obtained from the individual; and   comparing the quantity of complement C4d associated with platelets obtained from the individual with quantities of complement C4d associated with platelets obtained from either the individual at one or more different times or obtained from individuals not having systemic lupus erythematosus;   wherein greater quantities of C4d associated with platelets obtained from the individual as compared to quantities of C4d associated with platelets obtained from either the individual at one or more different times or obtained from individuals not having systemic lupus erythematosus correlates with the presence of systemic lupus erythematosus in the individual.   
     
     
         10 . A kit for use in identifying systemic lupus erythematosus in an individual, comprising
 a package containing a conjugate of an antibody specific for complement C4d and a first labeled moiety; and   instructions for to use of the conjugate to identify complement C4d associated with platelets.   
     
     
         11 . The kit of  claim 10 , further comprising
 a conjugate of an antibody specific for CD42b with a second labeled moiety that is detectably different from the first labeled moiety.   
     
     
         12 . A computer readable medium tangibly embodying executable instructions to perform a method for identifying systemic lupus erythematosus in an individual, the method comprising:
 quantitating complement C4d associated with platelets obtained from the individual; and   comparing the quantity of complement C4d associated with platelets obtained from the individual with quantities of complement C4d associated with platelets obtained from individuals not having systemic lupus erythematosus;   wherein greater quantities of C4d associated with platelets obtained from the individual as compared to quantities of C4d associated with platelets obtained from individuals not having systemic lupus erythematosus correlates with the presence of systemic lupus erythematosus in the individual.   
     
     
         13 . The computer readable medium of  claim 11 , further comprising executable instructions for quantitating CD42b associated with platelets obtained from the individual. 
     
     
         14 . The computer readable medium of  claim 12 , further comprising executable instructions for conducting a quantitation of complement C4d by binding the C4d to a conjugate of an antibody specific for complement C4d with a first labeled moiety and quantitating the first labeled moiety. 
     
     
         15 . The computer readable medium of  claim 14 , wherein the first labeled moiety is a fluorescent moiety. 
     
     
         16 . The computer readable medium of  claim 15 , wherein the first fluorescent moiety is quantitated by flow cytometric analysis. 
     
     
         17 . The computer readable medium of  claim 14 , further comprising executable instructions for: binding CD42b to a conjugate of an antibody specific for CD42b with a second labeled moiety that is detectably different from the first labeled moiety; and quantitating the second labeled moiety. 
     
     
         18 . The computer readable medium of  claim 17 , wherein the second labeled moiety is a fluorescent moiety. 
     
     
         19 . The computer readable medium of  claim 18 , wherein the second fluorescent moiety is quantitated by flow cytometric analysis. 
     
     
         20 . A computer readable medium tangibly embodying executable instructions to perform a method for monitoring disease activity of systemic lupus erythematosus in an individual, the method comprising:
 quantitating complement C4d associated with platelets obtained from the individual; and   comparing the quantity of complement C4d associated with platelets obtained from the individual with quantities of complement C4d associated with platelets obtained from either the individual at one or more different times or individuals not having systemic lupus erythematosus;   wherein greater quantities of C4d associated with platelets obtained from the individual as compared to quantities of C4d associated with platelets obtained from either the individual at one or more different times or individuals not having systemic lupus erythematosus correlates with the presence of systemic lupus erythematosus in the individual.