Segregation of autoantibodies with disease in monozygotic twin pairs discordant for systemic sclerosis. Three further cases.
OBJECTIVE
To study the serologic status of 3 previously unreported monozygotic twin pairs discordant for systemic sclerosis (SSc).


METHODS
Autoantibodies were measured by indirect immunofluorescence, immunodiffusion, and immunoprecipitation of 35S-labeled cell lines. Major histocompatibility complex (MHC) class II allele typing and DNA fingerprinting were used to confirm monozygosity.


RESULTS
Anti-PM-Scl, anti-threonyl transfer RNA synthetase, and anti-topoisomerase I antibodies, respectively, were found in each of the twins with SSc. None of the unaffected twin siblings had an identifiable autoantibody, although serum from 1 unaffected twin precipitated several unknown proteins. The MHC class II genotype in each twin was the genotype expected for the autoantibody that was present.


CONCLUSIONS
Autoantibodies of certain defined specificities are intimately linked with the development of SSc, because they segregate with SSc in individuals who start life with identical germline genes.
McHugh
N J
NJ
Bath Institute for Rheumatic Diseases, Trimbridge, England.
Harvey
G R
GR
Whyte
J
J
Dorsey
J K
JK
D001323:Autoantibodies / Q000378:metabolism*; D001324:Autoantigens / Q000276:immunology; D004264:DNA Topoisomerases, Type I / Q000276:immunology; D004200:Diseases in Twins; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005802:Genes, MHC Class II; D006650:Histocompatibility Testing; D006801:Humans; D005779:Immunodiffusion; D008297:Male; D008875:Middle Aged; D015531:Radioimmunoprecipitation Assay; D012595:Scleroderma, Systemic / Q000235:genetics / Q000276:immunology*; D013914:Threonine-tRNA Ligase / Q000276:immunology; D014430:Twins, Monozygotic
D001323:Autoantibodies; D001324:Autoantigens; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; C077044:EXOSC10 protein, human; D004264:DNA Topoisomerases, Type I; D013914:Threonine-tRNA Ligase