Antiribonucleoprotein antibodies in children with human immunodeficiency virus infection: comparative study with childhood-onset systemic lupus erythematosus.

A number of clinical and laboratory features of human immunodeficiency virus (HIV) infection are found in systemic lupus erythematosus (SLE).

Objective: To analyze the presence of circulating antibodies to small nuclear ribonucleoproteins (snRNP) in both diseases.

Methods: We studied sera from 44 HIV-infected children, from 22 patients with childhood-onset SLE, and from 50 healthy children. Anti-snRNP antibodies were detected by (ELISA) using recombinant and affinity-purified nuclear antigens, by counterimmunoelectrophoresis (CIE), and by immunoblotting using extractable nuclear antigens.

Results: Anti-snRNP antibodies were detected by ELISA in 30 HIV-infected patients (68.1%) and 19 SLE patients (86.3%). These antibodies were directed against U1-RNP (61.3% and 77.2%), Sm (29.5% and 54.5%), 60kD-Ro/SS-A (47.7% and 50%), and La/SS-B proteins (18.1% and 9%), respectively. None of the HIV-infected children and 11 SLE patients (50%) showed anti-snRNP antibodies by CIE. None of the HIV-infected patients showed anti-70 kD U1-RNP or anti-D-Sm antibodies by immunoblotting. No differences between the two groups were noted relative to the presence of nonprecipitating anti-snRNP antibodies. No such reactivities were observed among the normal sera tested.

Conclusions: Nonprecipitating anti-snRNP antibodies in HIV-infected children are as frequent as in childhood-onset SLE. The significance of these antibodies is not clear at present. Perhaps they are polyreactive and low-affinity antibodies and a mechanism of molecular mimicry may explain these results; however, we cannot exclude a specific stimulation of B-cells by nuclear antigens.