Pretreatment of a biological sample from an autoimmune disease subject

Abstract

The present application describes a method for pretreating a biological sample from an autoimmune disease subject in order to avoid interference, especially where the sample is to be subjected to a cell-based biological activity assay, such as a neutralizing antibody assay.

1 . A method of treating a subject with an autoimmune disease comprising:
 (a) administering a therapeutic antibody or immunoadhesin to the subject to treat the autoimmune disease;   (b) obtaining a biological sample from the subject;   (c) affinity purifying immunoglobulins in the biological sample; and   (d) subjecting the purified immunoglobulins to a neutralizing antibody assay.   
     
     
         2 . The method of  claim 1  wherein the sample in step (b) comprises human serum. 
     
     
         3 . The method of  claim 1  wherein the autoimmune disease is rheumatoid arthritis, systemic lupus erythematosis (SLE) or Sjogren's disease. 
     
     
         4 . The method of  claim 1  wherein the sample in step (b) comprises interference. 
     
     
         5 . A diagnostic kit comprising:
 (a) delipidation reagent;   (b) buffers for affinity purification of immunoglobulins; and   (c) instruction manual instructing the user of the diagnostic kit to practice a method of treating a biological sample from an autoimmune disease subject comprising:
 (i) delipidating the sample; 
 (ii) affinity purifying immunoglobulins in the sample; 
 (iii) concentrating the purified immunoglobulins; and 
 (iv) subjecting the concentrated immunoglobulins to a cell-based biological activity assay. 
   
     
     
         6 . The diagnostic kit of  claim 5  further comprising any one or more of: drug reference material, positive control neutralizing antibody, complement serum, assay diluent for cells, and cell labeling reagent.