Autoantibodies to survival of motor neuron complex in @entity1 with XXXX : immunoprecipitation of D, E, F, and G proteins without other components of small nuclear ribonucleoproteins.

@entity1 @entity627 @entity6017 @entity4508 @entity575 @entity65219 @entity1252 @entity12922 @entity2631 @entity29203 @entity58556 @entity2057 @entity792 @entity6558
OBJECTIVE: Autoantibodies in the systemic @entity627 are clinically useful biomarkers of the diagnosis or of certain clinical characteristics. An unusual pattern of immunoprecipitation, in which the D, E, F, and G proteins of small nuclear RNPs ( @entity12922 ) but without other components of the @entity12922 , was noticed at the autoantibody screening. The purpose of this study was to examine the target antigens and clinical manifestations associated with this specificity. METHODS: Autoantibodies in sera from 1,966 American @entity1 (including 434 with @entity1252 , 121 with @entity2631 , 86 with @entity6558 / @entity6017 [PM/DM]) and 248 Italian @entity1 with @entity792 were screened by immunoprecipitation of (35) @entity4508 -labeled cell extracts. Sera with which D, E, F, and G proteins of @entity12922 was immunoprecipitated, but without the other @entity12922 proteins, were further examined by analysis of RNA components by immunoprecipitation ( @entity575 staining), Western blotting using survival of motor neuron (SMN) complex, and immunofluorescence. RESULTS: Three sera that immunoprecipitated D, E, F, and G proteins without other components (U1-70K, A, B'/B, C) of the @entity12922 were found. Four additional proteins (130 kd, 120 kd, 38 kd, and 33 kd) were also commonly immunoprecipitated. The target antigen was identified as SMN complex ( @entity29203 , @entity58556 , SMN, and @entity65219 , respectively), which plays a critical role in the assembly of @entity12922 . In immunofluorescence analyses, all 3 sera showed nuclear dots (Cajal bodies) and cytoplasmic staining. Only 1 serum was weakly positive on Western blotting of SMN, suggesting that these sera mainly recognize native molecule or quaternary structure. All 3 @entity1 were white @entity1 with PM, an interesting finding, since deletion or mutation of SMN is known to cause @entity2057 . CONCLUSION: SMN complex was identified as a new Cajal body autoantigen recognized by sera from white @entity1 with PM. The biologic and clinical significance of anti-SMN autoantibodies will need to be clarified.
