Comparison of assay systems for detecting antibodies to nuclear ribonucleoproteins

Cerebrospinal Fluid Anti-SSA Autoantibodies in Primary Sjögren’s Syndrome with Central Nervous System Involvement

BACKGROUND

Central nervous system involvement in primary Sjogren's syndrome is a matter of controversy, and its diagnosis remains difficult.

METHODS

We report 3 patients with primary Sjogren's syndrome and central nervous system involvement in whom we assessed intrathecal immunoglobulin G synthesis and the presence of cerebrospinal fluid anti-SSA and anti-SSB autoantibodies.

RESULTS

We found intrathecal immunoglobulin G synthesis and presence of cerebrospinal fluid anti-SSA autoantibodies in all patients, with demonstration for the first time of specific anti-SSA autoantibody intrathecal synthesis in 2 patients.

CONCLUSION

We suggest that cerebrospinal fluid anti-SSA autoantibodies could serve as a biomarker for Sjogren's-syndrome-related central nervous system involvement.

Drug-induced, Ro/SSA-positive cutaneous lupus erythematosus

OBJECTIVE

To study the clinical and immunopathologic findings of drug-induced, Ro/SSA-positive cutaneous lupus erythematosus (CLE).

DESIGN

Retrospective medical and laboratory record review.

SETTING

Immunodermatology Division of Johns Hopkins Hospital (Baltimore, Md).

PATIENTS

Of 120 patients found to have anti-Ro/SSA antibodies by hemagglutination and/or double immunodiffusion, 70 had clinical and immunopathologic confirmation of CLE. Fifteen of these 70 patients had a history of new drug exposure, defined as less than 6 months, associated with disease development.

RESULTS

The disease-associated drugs included hydrochlorothiazide (5 patients), angiotensin-converting enzyme inhibitors (3 patients), calcium channel blockers (3 patients), interferons (2 patients), and statins (2 patients). The most common presentations were photodistributed diffuse erythema and subacute CLE-type lesions without evidence of significant systemic disease. All specimens revealed interface dermatitis and fine granular IgG deposition along the basement membrane zone and throughout the epidermis. Most patients experienced improvement or resolution of clinical lesions within 8 weeks and decrease of Ro/SSA titers within 8 months after discontinuation of drug treatment.

CONCLUSIONS

Antihypertensive drugs are the most commonly associated with Ro-positive CLE. Clinical and immunopathologic features of this drug-induced variant do not seem to differ from the idiopathic disease. In most cases, the disease improves or resolves on discontinuation of the offending drug treatment. It is not known if these drugs precipitate disease in patients who have subclinical disease. Drug-induced Ro/SSA-positive CLE should be included on the differential diagnosis in patients presenting with photosensitive or subacute CLE-type eruptions.

New methods for detection of anti-nuclear antibodies

Many different autoantibodies which react with a variety of different nuclear and cytoplasmic antigens have been described. Detection of some these antibodies has been shown to be clinically useful in a number of different autoimmune diseases. For many years, the detection of most of the clinically relevant antibodies was done with by immunofluorescence on tissue substrates and human cultured cell lines. Within the past few years, a number of technical advances has now made it possible to convert to enzyme immunoassay. The paper reviews the clinically relevant antibodies and discusses the variety of new methods which are now available for ANA detection in diagnostic laboratories.