IIFA nuclear/cytoplasmic patterns detected on HEp-2 substrates and related antigens/diagnosis
| Most commonly recognised patterns | ||
|---|---|---|
| Nuclear patterns | Related antigens | Related diagnosis |
| Homogeneous | dsDNA, histones, chromatin/nucleosomes, HMG | SLE, drug induced SLE/vasculitis, JIA |
| Coarse speckled | U1-SnRNP, U2–6 snRNP (Sm), nuclear matrix | MCTD, SLE, Raynaud, SSc, SS, UCTD |
| Fine speckled | SSA/Ro, SSB/La, Topo-1, common to many antigens | SLE, SS, SSc, IM, MCTD |
| Centromere | Kinetochore: CENP-A, B, C, F | SSc (limited), Raynaud's |
| Nucleolar | PM/Scl, RNA-polymerase, URNP, U3-RNP, To/Th, B23 phosphoprotein/numatrin | SSc, Raynaud's, IM, overlap |
| Cytoplasmic patterns | Related antigens | Related diagnosis |
| Diffuse | RibP, Jo-1, other tRNA synthetases, SRP | SLE, IM |
| Fine speckled | Jo-1, SRP, PDH (mitochondria) | IM, DM, PBC, interstitial lung disease |
| Less commonly recognised patterns | ||
| Nuclear patterns | Related antigens | Related diagnosis |
| Peripheral/rim or nuclear envelope | Lamins, LAP1/2 gp210, nucleoporin p62; nuclear envelope and nuclear pore complex antigens | SLE, RA, PBC, IM autoimmune liver diseases |
| Dense fine speckled | DFS70/LEDGF-P75 | Healthy subjects and other inflammatory conditions |
| Pleomorphic cell cycle speckled (PCNA) | Auxiliary protein proliferating cell nuclear antigen: elongation factor of DNA polymerase delta | SLE, lymphoproliferative diseases, SS |
| Nucleolar (clumpy) | U3-SnRNP (fibrillarin) | SSc |
| Multiple/few nuclear dots | Sp100, PML bodies, p80-coilin | PBC, CAH, SS |
| Centrosome/centriole (formerly:spindle apparatus) | Enolase, ninein, pericentrin | SSc, Raynaud's, inflammatory disease |
| MSA (mitotic spindle) | NuMA/centrophilin | RA, inflammatory conditions; pneumonia (mycoplasma) |
| Cytoplasmic patterns | Related antigens | Related diagnosis |
| Discrete speckled | Endosome (early endosome antigen 1), GW/Processing bodies, multivesicular bodies/lysosomes | Neurological conditions, SS, SLE, RA, PBC, UCTD |
| Golgi complex | Golgi proteins/golgins: giantin, golgin 245, golgin 110, golgin 97, golgin 95, others | SLE, SS, RA, overlap syndromes, cerebellar ataxia |
| Cytoplasmic fibres | Actin, cytokeratin, tropomyosin, vimentin | CAH, 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.