Background The prevalence of anti-cell autoantibodies detected by indirect immunofluorescence assay on HEp-2 cells (HEp-2-IIFA) increases with age and is higher in female sex. The number of medical specialties that use HEp-2-IIFA in the investigation of autoimmune diseases has increased lately. This study aimed to determine the prevalence and patterns of autoantibodies on HEp-2-IIFA according to demographics variables and referring medical specialties. Methods A retrospective analysis of the HEp-2-IIFA carried out between January and June of 2017 was performed. The International Consensus on Antinuclear Antibodies Patterns (ICAP) and the Brazilian Consensus on Autoantibodies were used for patterns definition on visual reading of the slides. Anti-cell (AC) codes from ICAP and Brazilian AC codes (BAC) were used for patterns classification. Results From 54,990 samples referred for HEp-2-IIF testing, 20.9% were positive at titer ≥ 1/80. HEp-2-IIFA positivity in females and males was 24% and 12%, respectively (p < 0.0001). The proportion of positive results in the 4 age groups analyzed: 0–19, 20–39, 40–59, and ≥ 60 years was 23.3, 20.2, 20.1, and 22.8%, respectively (p < 0.0001). Considering all positive sera (n = 11,478), AC-4 nuclear fine speckled (37.7%), AC-2 nuclear dense fine speckled (21.3%), BAC-3 nuclear quasi-homogeneous (10%) and mixed/composite patterns (8.8%) were the most prevalent patterns. The specialties that most requested HEp-2-IIFA were general practitioner (20.1%), dermatology (15%), gynecology (9.9%), rheumatology (8.5%), and cardiology (5.8%). HEp-2-IIFA positivity was higher in patients referred by rheumatologists (35.7% vs. 19.6%) (p < 0.0001). Moderate (46.4%) and high (10.8%) titers were more observed in patients referred by rheumatologists (p < 0.0001). We observed a high proportion of mixed and cytoplasmic patterns in samples referred by oncologists and a high proportion of BAC-3 (nuclear quasi-homogeneous) pattern in samples referred by pneumologists. Conclusions One-fifth of the patients studied were HEp-2-IIFA-positive. The age groups with more positive results were 0–19 and ≥ 60 years. AC-4, AC-2, BAC-3 and mixed/composite patterns were the most frequent patterns observed. Rheumatologists requested only 8.5% of HEp-2-IIFA. Positive results and moderate to high titers of autoantibodies were more frequent in patients referred by rheumatologists.

BACKGROUNDAntinuclear antibody (ANA) test is the most requested exam for the diagnostic evaluation of autoimmune diseases. The number of medical specialties that use ANA in the investigation of organ-specific and non-organ specific autoimmune diseases has increased progressively in recent decades. The objective of this work was to determine the medical specialties that most request ANA and the patterns more frequently associated with the requesting specialties.

BACKGROUNDAutoantibodies to cellular constituents are the hallmark of autoimmunity. Antinuclear antibodies (ANA) are the most frequent autoantibodies seen in autoimmune diseases. Prevalence of ANA increase with age and is higher in women than in men. The objective was to determine the prevalence of ANA and the differences of positivity according to gender and age in a large consecutive serum sample. METHODSWe conducted a retrospective analysis of routine ANA testing, carried out by indirect immunofluorescence on HEp-2 cells, according to manufacturer's instructions. Visual reading of the HEp-2 slides was performed according to the V Brazilian Consensus on Autoantibodies. Titers ≥ 1/80 were referred as positive. Positivity according to gender and age of the patients included were compared. RESULTSBetween January and June of 2017, 54,990 serum samples were referred to the laboratory for autoantibodies testing. From these, 20.9% (11,478) were positive at titer ≥ 1/80 and 79.1% (43,512) were negative. The median age of the patients was 43 years old (mean and SD = 41 ± 17 years). According to age, the patients were separated in four groups: 0-19 (n = 4,800); 20-39 (n = 20,971); 40-59 (n = 19,767) e ≥ 60 (n = 9,452). The proportion of positive results in these groups was 23.3*, 20.2, 20.1 and 22.8*%, respectively. A higher positivity of the test was observed in the ranges of 0-19 and 60 years (p < 0.0001). Out of 40,842 of the 54,990 patients were women (74.3%). ANA positive results were observed in 11,478 of the participants. From these, 85.1% was from the feminine gender. We observed a significant difference in ANA positivity between women (24%) and men (12% (p < 0.0001). The highest positivity of ANA tests in women compared to men was significant in any of the age groups studied. CONCLUSIONANA test positivity on HEp-2 cells was observed in about one fifth of the samples referred to the laboratory for autoantibodies detection. The age groups where ANA tests were more positive were 0-19 and ≥ 60 years. When compared to men, the ANA positivity in women was higher whatever the age group analyzed.

BACKGROUNDThe Brazilian consensus on autoantibodies (BCA) recognizes three types of pattern combinations on antinuclear antibody (ANA) indirect immunofluorescence test using HEp-2 cells: 1) Multiple: combination of patterns clearly identified on visual reading of HEp-2 cells slides (due to the presence of more than one autoantibody); 2) Mixed: mix of different patterns not readily and clearly identified at visual reading; and 3) Composite: combination of patterns due to the presence of a single autoantibody. The aim of this study is to describe the most frequent combinations of patterns depicted on HEp-2 cells using the BCA proposal and the codes of Brazilian (BCA) and the International Consensus on ANA Patterns (ICAP).