Does ANA negative SLE exist?
Prior to the use of the current HEp-2 assay, this occurred more frequently as the test was less sensitive and often missed anti-SS-A/Ro (52 kD and 60 kD) antibodies. The HEp-2 assay captures the vast majority of SLE; however, ANA-negative disease can rarely occur. This has been described in patients who have antibodies only against SS-A/Ro-52kD (TRIM-21) or ribosomal P, which are cytoplasmic (not nuclear) antigens. ANA-negative disease has also been described in the following scenarios:
- • severe proteinuria (no Igs in the serum to bind with HEp-2 cells)
- • usually ANA turns positive after treatment
- • after cytotoxic therapy
- • in disease remission