[Anti-ribosomal antibodies in systemic lupus erythematosus]

To compare indirect immunofluorescence (IIF) with immunoblotting (IB) in the detection of antiribosomal antibodies (anti-P Ab) in patients with systemic lupus erythematosus (SLE) and to investigate the possible association between anti-P Ab with serological and clinical findings in SLE, particularly with neurological manifestations.

Serum specimens from 44 SLE patients and 10 healthy subjects were investigated for anti-P Ab using IB and IIF in rat triple substrate and HEp-2 cells. In SLE patients measurements were made of antinuclear Ab, anti-DNA ds Ab, anti-Sm Ab, anti-U1RNP Ab, anti-Ro Ab, and anti-La Ab. Clinical manifestations of SLE were collected retrospectively when the serological investigation was made.

Of the 44 serum specimens tested, 9 showed a ribosomal pattern with triple rat substrate; 8 of them were IB positive (sensitivity 88%; specificity 97%); 12 serum specimens showed a ribosomal pattern with HEp-2 cells by the IIF technique, 9 were positive by IB (sensitivity 100%; specificity 91%). All ten healthy subjects were negative both with IIF and with IB. The nine patients with anti-P Ab in IB (20.45%) had anti-Ro Ab (55% vs. 37%), Anti-Sm Ab (33% vs. 22%, and U1RNP Ab (33% vs. 20%) more frequently than the 35 negative cases. Central nervous system disease (33 vs. 14%), and particularly seizures (33% vs. 5%) and psychosis (22% vs. 8%) were more common in cases with anti-P Ab, but as with serological associations, none of them reached a statistical signification.

IIF with both rat triple substrate and HEp-2 cells is useful for the presumptive diagnosis of anti-P Ab in patients diagnosed with SLE. No significant serological or clinical association was found in patients with anti-P Ab, although neurological disease was more common in these cases.