The presence of masked antiribosomal P autoantibodies in healthy children.
OBJECTIVE
To determine if antiribosomal P (anti-P) autoantibodies are present in healthy children.


METHODS
Sera from healthy children were screened for anti-P by conventional enzyme-linked immunosorbent assay and immunoblot techniques. Sera were also treated with immobilized ribosomal P antigens on nitrocellulose strips; affinity-purified fractions were tested for anti-P by high-sensitivity immunoblot. The relative binding affinities were compared for affinity-purified anti-P antibodies from healthy children and adults, and patients with systemic lupus erythematosus. IgG fractions of anti-P-depleted sera from healthy children were assessed for inhibition of autologous anti-P activity.


RESULTS
Conventional serologic screening showed no IgG nor IgM anti-P in 88 untreated sera. IgG anti-P were unmasked in all 79 sera treated by the membrane batch affinity technique. IgM anti-P were identified in 27 of the treated sera; the percentage of positive sera decreased with increasing age (chi(2) for linear trend P = 0.00081). Affinity-purified anti-P from children had relative binding affinities similar to those of anti-P from other groups. Sera from healthy children contained inhibitory IgG antibodies to anti-P.


CONCLUSIONS
These results show that anti-P autoantibodies are present in all healthy children. The majority of these autoantibodies are masked by IgG antibodies, suggesting concordant development of a regulatory network.
Anderson
C J
CJ
University of Oklahoma Health Sciences Center, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA.
Neas
B R
BR
Pan
Z
Z
Taylor-Albert
E
E
Reichlin
M
M
Stafford
H A
HA
D000293:Adolescent; D000328:Adult; D019138:Antibodies, Blocking / Q000097:blood; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015800:Protozoan Proteins; D012269:Ribosomal Proteins / Q000276:immunology*
D019138:Antibodies, Blocking; D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C064601:L12E protein, Trypanosoma cruzi; D015800:Protozoan Proteins; D012269:Ribosomal Proteins