ANA negative systemic lupus erythematosus sera revisited serologically

Abstract

Objective: To better define the serology of a panel of sera from patients with a clinical diagnosis of systemic lupus erythematosus (SLE) or subacute cutaneous lupus erythematosus (SCLE) with a negative antinuclear antibody (ANA) test on mouse liver. Methods: Sensitive ELISA methods for anti-Ro/SSA, anti-La/SSB, and anti-U1RNP were applied to a panel of 76 sera with either SLE or SCLE and a negative ANA test on mouse liver. Results: These sera had previously been shown to have a high prevalence of anti-Ro/SSA (68%) and anti-La/SSB (27%) precipitins respectively. None had precipitins to U1RNP or Sm. ELISA methodology revealed that all of the sera 76=76 (100%) had elevated levels (Mean±2SDofa panel of 21 normal sera) of anti-Ro/SSA, 36=76 (46%) had elevated levels of anti-La/SSB, and 27 of 76 (35%) had elevated levels of anti-U1RNP. Conclusion: The subset of patients with SLE and SCLE with a negative ANA test on mouse liver almost uniformly have antibodies to the Ro/SSA antigen by a sensitive ELISA. This adds evidence to the idea that this is a more homogeneous disease subset within the spectrum of SLE.