Background Since more common patterns of antinuclear antibodies (ANAs) such as homogeneous or nucleolar patterns are well recognized, the prevalence of uncommon or atypical pattern is not well described
Objectives Our aim was to describe the prevalence of atypical ANAs patterns in a big cohort of ANA measurements in general Colombian population.
Methods We included all ANAS determinations done during 2 consecutive years (2013 and 2014) from Dinamica IPS in 8 different cities in Colombia. We defined such as uncommon patters the following: anti MSA-2 (mitotic spindle apparatus), cytoplasmatic fibers, lysosomal, Golgi, multiple dots, NuMA1 (MSA-1), anti MSA-3, PCNA, centrosome and nuclear envelope. All patient sera submitted for ANAs testing were tested by conventional indirect immunofluorescence using Hep-2 cells (AESKU.DIAGNOSTICS, Wendelsheim, Germany). We use 3 images for sample and in some cases several dilutions were needed. Parametric test were used for comparison among groups.
Results The overall sample included 113,491 consecutive samples for ANAs, being positive in 62,501 (55%) cases. 912 (1.45%) samples in 838 patients were classified as atypical pattern. Mean age for atypical positive pattern patients was 47±16.8 years and 80% of patients were female. The most common atypical patterns are summarized in Table. We did not find any difference among sex according atypical patterns. In subgroup analysis, centrosome pattern was more common in younger patients (<18 years) than in older than 18 years (27.84% vs 11.5%; Chi2, p=0.001), anti MSA-2 pattern was significantly more common in patients >18 years than in ≤18 years (23.6% vs 11.3%; Chi2, p=0.038), and cytoplasmic fibers was more prevalent in patients older than 55 years (14.7 vs 9%, p=0.013).
Conclusions In this large cohort of almost 130.000 samples of ANAs from a Colombian general population, the prevalence of atypical ANAs was around 1.5%. That prevalence is in concordance with some other series (1). Anti NuMa and MSA-2 patterns were the most common atypical ANAS. Anti centrosome were more common in young people, anti MSA in middle age patients and anti cytoplasmic fibers in elderly population.
Vermeersch P et al. Autoimmunity Rev 2013;12:998–1003
Disclosure of Interest None declared