Increased titres of anti‐nuclear antibodies do not predict the development of associated disease in the absence of initial suggestive signs and symptoms

Identifying antinuclear antibody positive individuals at risk for developing systemic autoimmune disease: development and validation of a real-time risk model

Objective

Positive antinuclear antibodies (ANAs) cause diagnostic dilemmas for clinicians. Currently, no tools exist to help clinicians interpret the significance of a positive ANA in individuals without diagnosed autoimmune diseases. We developed and validated a risk model to predict risk of developing autoimmune disease in positive ANA individuals.

Methods

Using a de-identified electronic health record (EHR), we randomly chart reviewed 2,000 positive ANA individuals to determine if a systemic autoimmune disease was diagnosed by a rheumatologist. A priori, we considered demographics, billing codes for autoimmune disease-related symptoms, and laboratory values as variables for the risk model. We performed logistic regression and machine learning models using training and validation samples.

Results

We assembled training (n = 1030) and validation (n = 449) sets. Positive ANA individuals who were younger, female, had a higher titer ANA, higher platelet count, disease-specific autoantibodies, and more billing codes related to symptoms of autoimmune diseases were all more likely to develop autoimmune diseases. The most important variables included having a disease-specific autoantibody, number of billing codes for autoimmune disease-related symptoms, and platelet count. In the logistic regression model, AUC was 0.83 (95% CI 0.79-0.86) in the training set and 0.75 (95% CI 0.68-0.81) in the validation set.

Conclusion

We developed and validated a risk model that predicts risk for developing systemic autoimmune diseases and can be deployed easily within the EHR. The model can risk stratify positive ANA individuals to ensure high-risk individuals receive urgent rheumatology referrals while reassuring low-risk individuals and reducing unnecessary referrals.

Antinuclear Antibodies Are Associated with an Increased Risk of Diffuse Large B-Cell Lymphoma

Immune dysregulation is thought to increase the risk of non-Hodgkin lymphoma (NHL), but the evidence varies by subtype. We evaluated whether antinuclear antibodies (ANA), double-stranded DNA antibodies (anti-dsDNA), and extractable nuclear antigen antibodies (anti-ENA) were associated with the risk of common NHL subtypes in a nested case-control study. The autoantibodies were tested in serum collected years prior to NHL diagnosis in 832 cases and 809 controls from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Logistic regression was used to determine odds ratios (ORs) and 95% confidence intervals (95% CI) for the association with NHL risk. No association was observed between ANA positivity and NHL risk overall (OR: 1.18, 95% CI: 0.88-1.58); however, ANA positivity was associated with an increased risk of diffuse large B-cell lymphoma (DLBCL) (OR: 1.83, 95% CI: 1.15-2.91), with 19.7% of cases and 12.2% of controls testing positive. The presence of either anti-ENA or anti-dsDNA was associated with an increased risk of NHL (OR: 2.93, 95% CI: 1.18-7.28), particularly DLBCL (OR: 3.51, 95% CI: 1.02-12.0) and marginal zone lymphoma (OR: 8.86, 95% CI: 1.26-62.0). Our study demonstrates that autoantibodies are associated with an elevated risk of DLBCL, providing support for autoimmunity as a risk factor.

The influence of demography and referral medical specialty on the detection of autoantibodies to HEP-2 cells in a large sample of patients

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.

[Antinuclear antibodies : Practical diagnostic recommendations for dermatologists]

Antinuclear antibodies (ANA) are a common diagnostic finding in patients with systemic autoimmune diseases. In patients with typical clinical symptoms, the determination of ANA is of both diagnostic and prognostic importance. However, if ANA were determined due to unspecific symptoms, the interpretation of ANA findings can be problematic. In these cases, misjudgements with severe consequences for the patients are possible. Many systemic autoimmune diseases have prominent early skin involvement and the dermatologist can be the first physician that such a patient sees. Therefore, knowledge of ANA diagnostics is important for dermatologists. Basic principles of autoantibody diagnostics, guidance for the interpretation of laboratory results and new developments are discussed in this overview.

Dry Eye Indexes Estimated by Keratograph 5M of Systemic Lupus Erythematosus Patients without Secondary Sjögren's Syndrome Correlate with Lupus Activity

Purpose

To investigate the incidence, severity, and influencing factors of dry eye in systemic lupus erythematosus (SLE) patients without secondary Sjögren's syndrome (sSS).

Methods

A total of 78 patients who were diagnosed with systemic lupus erythematosus and met inclusion criteria were selected as the study subjects in this cross-sectional study. Tear meniscus height (TMH) and noninvasive Keratograph tear breakup time (NIKBUT) including NIKBUT-first and NIKBUT-average of the subjects were measured using a noninvasive ocular analyzer, the Keratograph 5M (Oculus, Wetzlar, Germany). Symptoms related to dry eye were assessed using the Ocular Surface Disease Index (OSDI). The severity of SLE was evaluated by Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). Results of the levels of 4 serum antibodies were collected from the patients' medical records. Correlations between SLEDAI and various ocular surface parameters were analyzed, and multiple-factor binary logistic regression analysis was conducted.

Results

In the study subjects, mean TMH was 0.22 mm, mean NIKBUT-first was 9.12 s, and mean OSDI was 13.14. The subjects (19 eyes) whose NIKBUT-average was < 10 s and OSDI was ≥ 13 accounted for 24.36% of all the included patients. SLEDAI showed a statistically significant correlation with TMH (r = −0.233, p=0.040), NIKBUT-first (r = −0.254, p=0.025), NIKBUT-average (r = −0.343, p=0.002), and OSDI (r = 0.256, p=0.024). According to multiple-factor binary logistic regression analysis, SLEDAI could be considered as a risk factor of the incidence of dry eye in SLE patients without sSS.

Conclusions

One-fourth of the SLE patients without sSS suffered from dry eye, and the severity of dry eye correlated with the activity of SLE.

ANA testing in the presence of acute and chronic infections

Autoantibody testing is performed to help diagnose patients who have clinical symptoms suggestive of possible autoimmune diseases. Antinuclear antibodies (ANA) are present in many systemic autoimmune conditions such as systemic lupus erythematosus (SLE). However, a positive ANA test may also be seen with non-autoimmune inflammatory diseases, including both acute and chronic infections. When the ANA test is used as an initial screen in patients with non-specific clinical symptoms, such as fever, joint pain, myalgias, fatigue, rash, or anemia, the likelihood of a positive result due to infection will increase, especially in children. This article identifies acute and chronic infectious diseases that are likely to produce a positive ANA result and summarizes recent literature addressing both the causes and consequences of these findings.

Severity of dry eye syndrome is related to anti-dsDNA autoantibody in systemic lupus erythematosus patients without secondary Sjogren syndrome: A cross-sectional analysis

There are as many as one-third of the systemic lupus erythematosus (SLE) patients who suffer from dry eye syndrome. To this date, dry eye syndrome in SLE patients is believed to be caused by secondary Sjogren syndrome (sSS). However, there is increasing evidence for possible independency of dry eye syndrome and sSS in patients suffering from autoimmune diseases. The purpose of this retrospective observational case series was to identify SLE patients without sSS who had dry eye syndrome, examine the correlation of different autoantibodies and dry eye severity, and determine the cause of dry eye in these patients.We included 49 consecutive SLE patients with dry eye who visited our dry eye clinic. In order to rule out sSS, these patients were all negative for anti-Sjogren's-syndrome-related antigen A and B (anti-SSA/SSB) and had no oral symptoms. Each patient's lupus activity was determined by serological tests including antidouble-stranded DNA antibody (anti-dsDNA), complement levels (C3, C4), erythrocyte sedimentation rate (ESR), and antinuclear antibody (ANA). Severity of dry eye syndrome was determined by corneal sensation (KSen), superficial punctuate keratopathy (SPK), Schirmer-I test (Schirmer), and tear film break-up time (TBUT). The autoantibodies and the dry eye parameters in each group were tested using the χ test or the Mann-Whitney U test for normally distributed or skewed data, respectively.The anti-dsDNA showed significant correlations with KSen (P < 0.001), SPK (P < 0.001), and Schirmer (P = 0.042) but not TBUT. The C3 showed significant correlations with KSen (P < 0.001), SPK (P < 0.001), and Schirmer (P = 0.014) but not TBUT. No correlations of dry eye parameters were observed between C4, ESR, and ANA.The major finding of this study was that the severity of dry eye syndrome in SLE patients without sSS was strongly correlated with anti-dsDNA and C3 but not with C4, ESR, and ANA.

Anti-idiotypic monobodies for immune response profiling

A major goal in the study of autoimmune disease is the identification of biomarkers of disease to allow early diagnosis and initiation of treatment. The production of autoantibodies is the key feature of most autoimmune disease, so much effort has focused on characterizing the antigens reactive with these antibodies. However, even for the most well understood autoimmune diseases like rheumatoid arthritis and systemic lupus erythematosus, identification of antigens that detect autoantibodies in all patients have yet to be discovered. We describe a novel strategy for deriving mimotopes to disease-specific serum antibodies by selecting anti-idiotypic monobodies from a large molecular diversity library. Monobodies are derived by partial randomization of two surface exposed loops of a fibronectin domain scaffold in a phage display vector. The phage library is selected for binding to serum antibodies using a subtractive panning strategy. We evaluated this strategy by selecting the monobody library on a pool of serum immunoglobulin derived from a group of rheumatoid arthritis patients and evaluated selected clones for multi-patient reactivity and specificity for rheumatoid arthritis. The use of the fibronectin scaffold to derive stable, easy to produce molecular probes for diagnosis of autoimmune disease could be of significant value in improving diagnostic assays for virtually any disease that exhibits a characteristic immune response.

The initial manifestations and final diagnosis of patients with high and low titers of antinuclear antibodies after 6 months of follow-up

BACKGROUND

The antinuclear antibody (ANA) test is the most commonly used test to screen for autoimmune diseases. However, only a limited numbers of studies have addressed the characteristics of patients positive for ANA. In this study, we aimed to clarify the relationship between initial presentations, ANA titer, and final diagnoses.

METHODS

Patients who visited National Taiwan University Hospital and received a first ANA test were enrolled and then followed for a further 6 months. The symptoms and signs at the time of ANA testing, ANA titers, and the final diagnoses were recorded and analyzed.

RESULTS

A total of 355 patients were positive for ANA. Joint pain was the most common initial presentation at the time of ANA testing. Compared with the patients with low ANA titers (<1:640), those with high ANA titers (≥ 1:640) were more susceptible to autoimmune diseases. More importantly, of the patients with initial presentations of joint pain, fever, abnormal urinalysis, or skin rash/skin tightness, autoimmune diseases were more frequently diagnosed in those with high ANA titers than with low ANA titers (p<0.05). In addition, both anti-double strand DNA antibodies and anti-extractable nuclear antibodies were more commonly detected in patients with high ANA titers.

CONCLUSIONS

A high ANA titer seems to be a useful biomarker for the diagnosis of autoimmune diseases, especially for patients presenting with joint pain, fever, abnormal urinalysis, or skin rash/skin tightness.

Evaluation of anti-ribosomal P protein immunoassay in Japanese patients with connective tissue diseases: comparison with an indirect immunofluorescence assay

OBJECTIVES

To investigate the prevalence of anti-ribosomal P protein (anti-P) antibodies in Japanese patients with connective tissue diseases (CTDs) using enzyme-linked immunosorbent assays (ELISAs) and western blotting (WB) and to evaluate the indirect immunofluorescence (IIF) staining patterns of anti-P-positive sera.

METHODS

Anti-P antibodies were measured by two different commercially available ELISA kits and WB in 239 outpatients, 99 with systemic sclerosis (SSc), 73 with systemic lupus erythematosus (SLE), 45 with dermatomyositis (DM), and 22 with Sjögren's syndrome (SjS). Sera positive for anti-P antibodies by WB were analysed by IIF.

RESULTS

The frequency of positive WB findings in SLE (18/73, 25%) was higher than in other diseases. ELISA kits A and B for anti-P antibodies showed 21% and 43% sensitivity, and 93% and 88% specificity, respectively, for diagnosing SLE, based on the manufacturer's cut-off values. Receiver operating characteristic (ROC) curve analysis, based on positive WB findings, determined a new cut-off threshold but revealed that both ELISA kits still had good diagnostic characteristics. In IIF assays on anti-P antibody positive sera, typical anti-P antibody cytoplasmic staining patterns (n=8) were seen less frequently than other staining patterns (n=17).

CONCLUSIONS

Routine screening for anti-P antibodies by IIF has low sensitivity. ELISAs using cut-off values established by individual facilities are suitable for detecting anti-P antibodies and provide a tool with good diagnostic characteristics, on a parity with WB.