Anti-calreticulin segregates anti-Ro sera in systemic lupus erythematosus:Anti-calreticulin is present in sera with anti-Ro alone but not in anti-Rosera with anti-La or anti-ribonucleoprotein

Objective. To examine a well characterized group of patients with systemic lupus erythematosus (SLE) for anti-calreticulin. Methods. The sera of 77 patients with SLE were studied by immunodiffusion, solid phase immunoassay, and immunoblot for antibodies against ribonucleopr otein (RNP) autoantigens and calreticulin. Results. Thirty-five had anti-calreticulin and 40 had anti-60 kDa Ro. There was no association of anti-60 kDa Ro and anti-calreticulin. However, among anti-60 kDa Ro positive sera that also contained tither anti-La or anti-RN P, none of 18 had anti-calreticulin. All the remaining sera with anti-GO kD a Ro had anti-calreticulin and anti-52 kDa Ro. Conclusion, Anti-60 kDa Ro patients with SLE can be divided into those with anti-60 kDa Ro and either anti-La or anti-RNP or those with anti-60 kDa Ro , anti-52 kDa Ro, and anti-calreticulin.