The Anti-Cytoplasmic and Anti-Mitotic Autoantibodies; Are These Antibodies Associated with Diseases?

Abstract

Examination of antinuclear antibody (ANA) is used in diagnosis of systemic autoimmune diseases, and the indirect immunofluorescence (IIF) assay using HEp-2 cells is the gold standard method. HEp-2 allows the detection of multiple target antigen-directed autoantibodies. The guide “The International Consensus on ANA Patterns (ICAP)”, characterizes the patterns into three groups: nuclear, cytoplasmic, and mitotic. The majority of these are associated with autoimmune diseases, but some are rarely seen in autoimmune diseases or may be associated with conditions other than autoimmune disease. There is no consensus on how to report cytoplasmic and mitotic patterns-negative or positive. We aimed to examine the characteristics of patients that had cytoplasmic or mitotic staining in ANA evaluation by IIF. In our Medical Microbiology Laboratory, 18985 ANA tests of 16940 patients were studied between 01.01.2015-31.12.2019. Cytoplasmic or mitotic pattern was detected in 393 (2.07%) tests belonging to 385 patients. Cytoplasmic patterns suggestive of anti-mitochondrial antibody (AMA), anti-smooth muscle antibody (ASMA), anti-Jo-1 and anti-ribosomal P-protein were not included. The most common patterns were anti-midbody, anti-spindle fibers, and anti-vimentin patterns. There were 66 rheumatology patients that were negative for ANA but had cytoplasmic or mitotic staining. There was no statistically significant difference between the diagnosis and patterns of these patients. We suggest that the ANA should be reported as “negative” in case of cytoplasmic or mitotic pattern unless the term anti-cell antibody is used. It should be noted in the description part of the report in order to distinguish significant cytoplasmic patterns and give an idea for some specific conditions.