Table 2

IIFA nuclear/cytoplasmic patterns detected on HEp-2 substrates and related antigens/diagnosis

Most commonly recognised patterns
Nuclear patternsRelated antigensRelated diagnosis
 HomogeneousdsDNA, histones, chromatin/nucleosomes, HMGSLE, drug induced SLE/vasculitis, JIA
 Coarse speckledU1-SnRNP, U2–6 snRNP (Sm), nuclear matrixMCTD, SLE, Raynaud, SSc, SS, UCTD
 Fine speckledSSA/Ro, SSB/La, Topo-1, common to many antigensSLE, SS, SSc, IM, MCTD
 CentromereKinetochore: CENP-A, B, C, FSSc (limited), Raynaud's
 NucleolarPM/Scl, RNA-polymerase, URNP, U3-RNP, To/Th, B23 phosphoprotein/numatrinSSc, Raynaud's, IM, overlap
Cytoplasmic patternsRelated antigensRelated diagnosis
 DiffuseRibP, Jo-1, other tRNA synthetases, SRPSLE, IM
 Fine speckledJo-1, SRP, PDH (mitochondria)IM, DM, PBC, interstitial lung disease
Less commonly recognised patterns
Nuclear patternsRelated antigensRelated diagnosis
 Peripheral/rim or nuclear envelopeLamins, LAP1/2 gp210, nucleoporin p62; nuclear envelope and nuclear pore complex antigensSLE, RA, PBC, IM autoimmune liver diseases
 Dense fine speckledDFS70/LEDGF-P75Healthy subjects and other inflammatory conditions
 Pleomorphic cell cycle speckled (PCNA)Auxiliary protein proliferating cell nuclear antigen: elongation factor of DNA polymerase deltaSLE, lymphoproliferative diseases, SS
 Nucleolar (clumpy)U3-SnRNP (fibrillarin)SSc
 Multiple/few nuclear dotsSp100, PML bodies, p80-coilinPBC, CAH, SS
 Centrosome/centriole (formerly:spindle apparatus)Enolase, ninein, pericentrinSSc, Raynaud's, inflammatory disease
 MSA (mitotic spindle)NuMA/centrophilinRA, inflammatory conditions; pneumonia (mycoplasma)
Cytoplasmic patternsRelated antigensRelated diagnosis
 Discrete speckledEndosome (early endosome antigen 1), GW/Processing bodies, multivesicular bodies/lysosomesNeurological conditions, SS, SLE, RA, PBC, UCTD
 Golgi complexGolgi proteins/golgins: giantin, golgin 245, golgin 110, golgin 97, golgin 95, othersSLE, SS, RA, overlap syndromes, cerebellar ataxia
 Cytoplasmic fibresActin, cytokeratin, tropomyosin, vimentinCAH, DM, infections and other inflammatory diseases
  • Within the many patterns that can be distinguished the ones specified in the upper part of the table are the most commonly recognised. The relationship between pattern and antigen specificity may differ in certain conditions. Similarly, the specific antigens marked in bold are the most commonly detected by reflex testing, although other antigens may be of importance in different clinical conditions. Less common pattern are specified in the lower part of this table.

  • CAH, chronic autoimmune hepatitis; CENP, centromere protein; DFS, dense fine speckled; DM, dermatomyositis; dsDNA, double-stranded DNA; GW, glycine—tryptophan; HMG, high mobility group; IM, inflammatory myopathies; JIA, juvenile idiopathic arthritis; MCTD, mixed connective tissue disease; MSA, mitotic spindle; NuMA, nuclear mitotic apparatus; PBC, primary biliary cirrhosis; PDH, pyruvate dehydrogenase; PM/Scl, polymyositis/scleroderma; RA, rheumatoid arthritis; RibP, ribosomal P protein; RNP, ribonucleoprotein; SLE, systemic lupus erythematosus; SRP, signal recognition particle; SS, Sjögren's syndrome; SSc, systemic sclerosis; Topo-1, topo-isomerase 1; tRNA, transfer RNA; UCTD, undifferentiated connective tissue disease.