Ribosomal P autoantibodies in systemic lupus erythematosus. Frequencies in different ethnic groups and clinical and immunogenetic associations.
OBJECTIVE
To determine the frequencies and clinical associations of antiribosomal P antibodies (anti-P) in a large multiethnic cohort of patients with systemic lupus erythematosus (SLE), and to assess whether anti-P was associated with any major histocompatibility complex (MHC) class II alleles or shared amino acid sequences.


METHODS
Sera from 394 SLE patients were studied for anti-P using an enzyme-linked immunosorbent assay, and MHC class II alleles (HLA-DRB1, DQA1, and DQB1) were determined by DNA oligotyping.


RESULTS
Anti-P antibodies were found in 13-20% of patients in the majority of ethnic groups, but were perhaps more frequent in Chinese patients (36%) and less common in Bulgarian patients (6%). Neuropsychiatric lupus (psychosis and/or depression) was significantly associated with anti-P. The HLA-DR2, DQ6 haplotypes DRB1*1501 or *1503, DQA1*0102, and DQB1*0602 were increased in anti-P-positive whites, blacks, and Mexican Americans. The HLA-DQB1*0602 allele showed the strongest association with anti-P when these 3 ethnic groups were combined and compared with both race-matched anti-P-negative SLE patients and normal controls. The HLA-DQ8 specificity (DQB1*0302) was increased both in whites and in Mexican-Americans with anti-P who were negative for HLA-DQB1*0602, and perhaps also increased in Greeks, but not in blacks, in whom HLA-DQB1*0301 was increased. A shared amino acid sequence in HLA-DQB1 (at position 26 of leucine and position 30 of tyrosine) was strongly associated with anti-P positivity (70%) versus anti-P negativity (42%) across ethnic lines.


CONCLUSIONS
The anti-P response in SLE patients, occurring in approximately 15% of patients, was strongly influenced by certain MHC class II alleles and was correlated with diffuse neuropsychiatric dysfunction.
Arnett
F C
FC
University of Texas-Houston Health Science Center, USA.
Reveille
J D
JD
Moutsopoulos
H M
HM
Georgescu
L
L
Elkon
K B
KB
D001741:Black or African American; D001323:Autoantibodies; D006684:HLA-DR Antigens / Q000235:genetics; D006239:Haplotypes; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology / Q000208:ethnology / Q000276:immunology*; D017058:Mexican Americans; D011110:Polymorphism, Genetic; D015995:Prevalence; D015800:Protozoan Proteins; D012269:Ribosomal Proteins / Q000276:immunology*; D044465:White People
D001323:Autoantibodies; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; C064601:L12E protein, Trypanosoma cruzi; D015800:Protozoan Proteins; D012269:Ribosomal Proteins