Immunology & Serology Flashcards

Which autoantibody is most specific for systemic lupus erythematosus (SLE)?

Answer: Anti-dsDNA

Anti-dsDNA (along with anti-Sm) is highly specific for SLE and correlates with lupus nephritis activity.

A discrete speckled ANA pattern on HEp-2 cells, with staining in dividing chromosomes, is associated with which antibody and condition?

Answer: Anti-centromere; limited cutaneous systemic sclerosis (CREST)

Anti-centromere antibodies give a discrete speckled pattern (often 40-60 dots per nucleus) and are associated with CREST syndrome.

Anti-Sm and anti-U1-RNP antibodies typically produce which ANA immunofluorescence pattern?

Answer: Coarse speckled

Antibodies to extractable nuclear antigens such as Sm and RNP produce a speckled pattern.

A nucleolar ANA pattern is most often associated with:

Answer: Systemic sclerosis

Nucleolar staining (for example, anti-PM-Scl or anti-fibrillarin) is characteristic of systemic sclerosis.

Which test has the highest specificity for rheumatoid arthritis?

Answer: Anti-cyclic citrullinated peptide (anti-CCP)

Anti-CCP is about 95% specific for RA and can appear before clinical symptoms.

A patient on procainamide develops a positive ANA with a homogeneous pattern. Which antibody is most likely responsible?

Answer: Anti-histone

Anti-histone antibodies are found in most cases of drug-induced lupus (procainamide, hydralazine, isoniazid).

What is the preferred substrate for indirect immunofluorescence ANA testing?

Answer: HEp-2 cells

HEp-2 human epithelial cells have large nuclei and dividing cells, so many antigens and patterns can be seen.