AC-2 - Nuclear dense fine speckled
Previous Nomenclature None
Description Speckled pattern distributed throughout the interphase nucleus with characteristic heterogeneity in the size, brightness and distribution of the speckles. Throughout the interphase nucleus, there are some denser and looser areas of speckles (very characteristic feature). The metaphase plate depicts strong speckled pattern with some coarse speckles standing out.
Antigen Association DFS70/LEDGF
Clinical Relevance
First level information
About Clinical Relevance & List of Abbreviations

Commonly found as high titer HEp-2 IIFA-positive in apparently healthy individuals or in patients who do not have a systemic autoimmune rheumatic disease (SARD) (9)

The negative association with SARD is only valid if the autoreactivity is confirmed as being directed to DFS70 (also known as LEDGF/p75) and if no other common ENA is recognized (20, 21)

Both in apparently healthy individuals as well as patients who do not have a SARD the AC-2 pattern may be caused by autoantibodies to other antigens than DFS70 (22)

Note: Confirmatory assays for anti-DFS70 antibodies may be available only in specialty clinical laboratories.
First level information references
Mariz HA, Sato EI, Barbosa SH, et al. Pattern on the antinuclear antibody-HEp-2 test is a critical parameter for discriminating antinuclear antibody-positive healthy individuals and patients with autoimmune rheumatic diseases. Arthritis & Rheumatism 2011;63:191–200.
Watanabe A, Kodera M, Sugiura K, et al. Anti-DFS70 antibodies in 597 healthy hospital workers. Arthritis Rheum 2004;50:892–900.
Mahler M, Parker T, Peebles CL, et al. Anti-DFS70/LEDGF antibodies are more prevalent in healthy individuals compared to patients with systemic autoimmune rheumatic diseases. J Rheumatol 2012;39:2104–10.
Ochs RL, Mahler M, Basu A, et al. The significance of autoantibodies to DFS70/LEDGFp75 in health and disease: integrating basic science with clinical understanding. Clin Exp Med 2016;16:273–93.
Second level information
Second level information references
The pseudo-DFS pattern? Some samples yield a nuclear speckled pattern with similar staining at the mitotic chromatin (metaphase and anaphase), very similar to AC-2 (nuclear dense fine speckled pattern), but do not yield a positive result in immunoassays specific for anti-DFS70 antibodies. How should I report such pattern since it is not exactly the AC-2 pattern and there is no anti-DFS70 reactivity? Is this pattern defined by ICAP?
Online since 19 May 2015