Evaluation of a machine learning tool for the early identification of patients with undiagnosed psoriatic arthritis - A retrospective population-based study.

Background: Psoriatic arthritis (PsA), an immune-mediated chronic inflammatory skin and joint disease, affects approximately 0.27% of the adult population, and 20% of patients with psoriasis. Up to 10% of psoriasis patients are estimated for having undiagnosed PsA. Early diagnosis and treatment can prevent irreversible joint damage, disability and deformity. Questionnaires for screening to identify undiagnosed PsA patients require patient and physician involvement. Objective: To evaluate a proprietary machine learning tool (PredictAI™) developed for identification of undiagnosed PsA patients 1-4 years prior to the first time that they were suspected of having PsA (reference event). Methods: This retrospective study analyzed data of the adult population from Maccabi Healthcare Service between 2008 and 2020. We created 2 cohorts: The general adult population ("GP Cohort") including patients with and without psoriasis and the Psoriasis cohort ("PsO Cohort") including psoriasis patients only. Each cohort was divided into two non-overlapping train and test sets. The PredictAI™ model was trained and evaluated with 3 years of data predating the reference event by at least one year. Receiver operating characteristic (ROC) analysis was used to investigate the performance of the model, built using gradient boosted trees, at different specificity levels. Results: Overall, 2096 patients met the criteria for PsA. Undiagnosed PsA patients in the PsO cohort were identified with a specificity of 90% one and four years before the reference event, with a sensitivity of 51% and 38%, and a PPV of 36.1% and 29.6%, respectively. In the GP cohort and with a specificity of 99% and for the same time windows, the model achieved a sensitivity of 43% and 32% and a PPV of 10.6% and 8.1%, respectively. Conclusions: The presented machine learning tool may aid in the early identification of undiagnosed PsA patients, and thereby promote earlier intervention and improve patient outcomes.

Silicone prosthetics and anti-thyroid autoimmunity.

INTRODUCTION: In esthetic surgery, the use of silicone implants is a topic of hot discussion. MATERIAL AND METHODS: An analysis of 119 esthetic surgical interventions on the mammary gland was performed. A study of the immune and endocrine parameters after mammoplasty was carried out. RESULTS: The phenomenon of an increase in the levels of autoantibodies to the TSH receptor was revealed. The phenomenon of pre-operative growth of prolactin and TSH levels has been confirmed. An increase in thyroid autoimmunity after silicone mammoplasty is interpreted as a result of a silicone adjuvant action. An increase in the incidence of ASIA syndrome in patients who underwent breast surgery was registered. However, it was observed in both patients with silicone and non-silicone breast surgeries and therefore could not be solely explained by the use of silicone. Within 12 months following silicone mammoplasty, the patients with an increase of anti-TSH receptor autoimmunity nevertheless did not show any clinical and laboratory signs of overt thyroid disease, thus staying in a pre-nosological state. PRACTICAL RECOMMENDATIONS: Based on these results, we recommend the following for esthetic surgery: (a) all patients planned for silicone implant surgery should be examined for autoantibodies to the TSH receptor and (b) patients who have undergone breast endoprosthesis, starting 6 months after the operation, need long-term follow-up for thyroid status with mandatory testing for the level of these autoantibodies.

Autoimmune autonomic nervous system imbalance and conditions: Chronic fatigue syndrome, fibromyalgia, silicone breast implants, COVID and post-COVID syndrome, sick building syndrome, post-orthostatic tachycardia syndrome, autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants.

Chronic fatigue syndrome (CFS), fibromyalgia, silicone breast implants syndrome (SBIs), COVID and post-COVID syndrome (PCS), sick building syndrome (SBS), post-orthostatic tachycardia syndrome (POTS), autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants (ASIA) are frequently accompanied by clinical symptoms characteristic for dysautonomia: severe fatigue, dizziness, fogginess, memory loss, dry mouth and eyes, hearing dysfunction, tachycardia etc. The recent discovery of an imbalance of autoantibodies against G protein-coupled receptors (GPCR) in some autoimmune diseases, post-COVID syndrome, SBIs allowed researchers to assume the novel mechanism in these conditions - autoimmune autonomic nervous system imbalance. In this review, all data published on an imbalance of autoantibodies against GPCR, clinical symptoms and pathogenic mechanisms in CFS, Fibromyalgia, SBIs, COVID and PCS, SBS, POTS, and some autoimmune diseases were analyzed. Possible criteria to diagnose the autoimmune autonomic nervous system imbalance were created.

WITHDRAWN: Autoimmune autonomic nervous system imbalance and conditions: Chronic fatigue syndrome, fibromyalgia, silicone breast implants, COVID and post-COVID syndrome, sick building syndrome, post-orthostatic tachycardia syndrome, autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants.

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.autrev.2022.103230. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Intravenouse immunoglobuline in dysautonomia.

Nowadays intravenous immunoglobulin (IVIg) treatment is considered to play a promising role in the autoimmune disease therapy. Despite its significant beneficial effects, the precise mechanism of action needs further studies, as well as recommended dosage in the treatment of autoimmune dysautonomia. In some diseases, like Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating neuropathy (CIDP), IVIg has a strong evidence that allows to recommend and prescribe the medication, while in other diseases only single case studies are available that requires further research. The review summarizes the currently available information on the effectiveness of IVIg in primary autoimmune neuropathies and neurological complications of systemic diseases, as well as side effects, features of clinical use with an emphasis on doses and treatment protocols in dysautonomia. Being safe and effective therapy, immunologic treatment is one of the most promising tools to achieve clinical remission of dysautonomia and good quality of life in autoimmune patients.

The Novel Diagnostic Index Based on HLA-DRB1 Genotype and PD-L1 Expression can Predict Severe irAEs in Patients with Metastatic Melanoma Taking Immune Checkpoint Inhibitors. The Results of the Pilot Study.

Immune-related adverse events (irAEs) occur in up to 50% of patients treated with an anti-CTLA-4 antibody and 30% of patients treated with PD-1/PD-L1 antibodies. Severe forms of toxicity are observed in 3% of patients and require systemic steroid therapy and constant monitoring. One of the considered predictor biomarkers of irAEs development is HLA-genotypes. This research aims to evaluate the diagnostic significance of HLA-DRB1 genotypes and other clinical and laboratory parameters to predict the development of irAEs. The study involved 28 patients with metastatic melanoma taking checkpoint inhibitors therapy [nivo 53.6%, Ipi+nivo 32.1%, other (pembro, prolgo) 14.3%]. The PD-L1 expression and HLA-DRB1 genotype were evaluated. After 2-3 months the development of irAES was assessed. The complications of 3-4 grade or multi-organ damage were termed as severe irAEs. Various IrAEs developed in 57.1% (16/28) of patients, while severe irAEs occurred in 35.7% (10/28). Among all patients, HLA-DRB1 genotypes associated with the risk of autoimmune diseases were found in 78.5% (22/28). The PD-L1 expression was detected in 60.7% (17/28) of individuals. Combination treatment increases the risk of toxicity, p = 0.0028, with a diagnostic sensitivity of 56% and a diagnostic specificity of 100% (RR = 2.71, OR = 31.67). An index based on the parameters studied (HLA-DRB1, absence of PD-L1 expression, and type of treatment) was created. It allows assuming the risk of developing severe irAES (p = 0.0126). When comparing this indicator between irAEs 1-2 and irAEs 3-4, the presence of an index value of more than 2 gives a sensitivity for predicting severe toxicity of 40.00% and a specificity of 83.33%.

New laboratory criteria of the autoimmune inflammation in pulmonary sarcoidosis and tuberculosis.

Sarcoidosis and tuberculosis have many clinical and laboratory similarities, which allowed researchers to assume the presence of common pathogenetic mechanisms in the development of both diseases. Recently, much attention has been paid to investigate the autoimmune origins in these pathologies. The aim of this study is to find out the characteristics of the autoinflammatory immune response in sarcoidosis and tuberculosis. In patients with sarcoidosis (n = 93), tuberculosis (n = 28), and in healthy donors (n = 40), the serum anti-MCV concentration was measured by ELISA, and B cell subpopulations were analyzed by flow cytometry. Based on the results obtained, the formula ([B-naïve%]\[B-memory%]) * ([B-CD38%] + [B-CD5%]) / [anti-MCV] was described. The increase in the calculated index by more than 5 units with a sensitivity of 80.00% and a specificity of 93.10% (AUC = 0.926) suggest the presence of the autoimmune component, which is more typical for sarcoidosis, rather than tuberculosis patients and may serve as a diagnostic criterion.

Relapsing polychondritis associated with heart block.

OBJECTIVE: The present article aims at describing a rare case of an RP patient who evolved with heart block and was successfully treated with corticoid pulse therapy, without the need for pacemaker insertion. PATIENTS AND METHODS: A systematic research on relapsing polychondritis (RP) and heart block (HB) published in PubMed/MEDLINE, Web of Sciences, LILACS, and Scielo from 1966 to August 2020 was performed. RESULTS: It was found 10 studies on RP associated with HB, and we added a case. Most were male (7/10) with ages 30 to 66 years old. RP disease duration was 1 week-6 years. In most cases (7/10), the RP was active when the HB occurred. A complete HB was observed in 4/7, followed by type II degree block in 3/7, and one patient had a sinus node dysfunction. Most patients received glucocorticoids. A pacemaker was inserted in 4/9 cases. Good outcome was observed in 3/9 patients and mortality in 2/10. CONCLUSIONS: We report the first case of an RP patient who had a heart block and was successfully treated with methylprednisolone pulse therapy. The authors suggest that in these RP cases, an attempt with a glucocorticoid pulse therapy may be offered to treat the heart block and prevent the insertion of a pacemaker.

The tellurium-based immunomodulator, AS101 ameliorates adjuvant-induced arthritis in rats.

Despite undeniable improvement in the management of rheumatoid arthritis (RA), the discovery of more effective, less toxic and, ideally, less immune suppressive drugs are much needed. In the current study, we set to explore the potential anti-rheumatic activity of the non-toxic, tellurium-based immunomodulator, AS101 in an experimental animal model of RA. The effect of AS101 was assessed on adjuvant-induced arthritis (AIA) rats. Clinical signs of arthritis were assessed. Histopathological examination was used to assess inflammation, synovial changes and tissue lesions. Very late antigen-4 (VLA-4)+ cellular infiltration was detected using immunohistochemical staining. Enzyme-linked immunosorbent assay (ELISA) was used to measure circulating anti-cyclic citrullinated-peptide autoantibody (ACPA) and real-time polymerase chain reaction (PCR) was used to measure the in-vitro effect of AS101 on interleukin (IL)-6 and IL-1ß expression in activated primary human fibroblasts. Prophylactic treatment with intraperitoneal AS101 reduced clinical arthritis scores in AIA rats (P < 0·01). AS101 abrogated the migration of active chronic inflammatory immune cells, particularly VLA-4+ cells, into joint cartilage and synovium, reduced the extent of joint damage and preserved joint architecture. Compared to phosphate-buffered saline (PBS)-treated AIA rats, histopathological inflammatory scores were significantly reduced (P < 0·05). Furthermore, AS101 resulted in a marked reduction of circulating ACPA in comparison to PBS-treated rats (P < 0·05). Importantly, AS101 significantly reduced mRNA levels of proinflammatory mediators such as IL-6 (P < 0·05) and IL-1ß (P < 0·01) in activated primary human fibroblasts. Taken together, we report the first demonstration of the anti-rheumatic/inflammatory activity of AS101 in experimental RA model, thereby supporting an alternative early therapeutic intervention and identifying a promising agent for therapeutic intervention.

Inhibition of metalloproteinases in therapy for severe lung injury due to COVID-19.

Since its first appearance in December 2019 in the Chinese province of Wuhan, COVID-19 has spread rapidly throughout the world and poses a serious threat to public health. Acute respiratory failure due to widespread lung inflammation progress to acute respiratory distress syndrome (ARDS) with an altered pulmonary and alveolar function that can lead to disability, prolong hospitalizations, and adverse outcomes. While there is no specific treatment for severe acute lung injury (ALI) and ARDS due to the COVID-19 and the management is mostly supportive, it is very important to better understand the pathophysiological processes activated by the inflammatory mediators such as cytokines and metalloproteinases with the aim of their subsequent inhibition in the course of the complex treatment. Herein, we will discuss the pathophysiological mechanisms of ALI/ARDS, with a focus on the pivotal role played by matrix metalloproteinases (MMP) and the kinin-kallikrein system (KKS), and the effects of the possible pharmacological interventions. Aprotinin is a nonspecific protease inhibitor especially of trypsin, chymotrypsin, plasmin, and kallikrein, and it is many years in clinical use. Aprotinin inhibits the release of pro-inflammatory cytokines and involved in the process of glycoprotein homeostasis. Experimental data support that the use of aprotinin to inhibit MMPs and KKS may be a new potential approach to the treatment of ALI / ARDS.

Immunoglobulin A antibodies to oxidized collagen type II as a potential biomarker for the stratification of spondyloarthritis from rheumatoid arthritis.

OBJECTIVES: The discovery of diseased tissue-specific neoantigens offers the opportunity to develop important disease tissue-specific biomarkers that can help in the prediction, diagnosis, and stratification of diseases. This opportunity is specifically significant for autoimmune diseases where diagnostic biomarkers are not available. Inflammatory autoimmune diseases are commonly associated with local generation of large amounts of reactive oxidants. We have previously identified oxidative post-translationally modified (oxPTM) tissue-specific neoantigens in rheumatoid arthritis (RA) and type 1 diabetes that elicit an immune response. In the current study, we studied the presence and clinical significance of antibodies to oxPTM collagen type II (CII) in patients with spondyloarthritis (SpA). METHOD: Levels of antibodies specific to native CII and oxPTM-CII were assessed by enzyme-linked immunosorbent assay. RESULTS: Immunoglobulin G (IgG) binding to oxPTM-CII was observed in 52%, 83%, and 28% of serum samples from patients with axial spondyloarthritis (axSpA), RA, and psoriatic arthritis (PsA), respectively. Importantly, while strong IgA anti-oxPTM-CII responses were detected in axSpA and PsA patients, with 47% and 84% respective binders, no IgA anti-oxPTM-CII was detected in RA patients. IgA anti-oxPTM-CII reactivity in axSpA patients treated with biologics was higher and more frequent, with 85% binders compared to 9% binders in patients treated with synthetic disease-modifying anti-rheumatic drugs. CONCLUSION: Our data imply that SpA and PsA are associated with the presence of antibodies to oxPTM-CII, suggesting that there may be a humoral component that may distinguish patients with SpA from RA. Our approach could be adapted to other diseases, particularly to inflammatory autoimmune diseases.

Imbalance in B cell and T Follicular Helper Cell Subsets in Pulmonary Sarcoidosis.

Sarcoidosis is a systemic granulomatous disease that develops due to the Th1, Th17 and Treg lymphocytes disturbance. There is an assumption, that B cells and follicular T-helper (Tfh) cells may play an important role in this disorder, as well as in several other autoimmune diseases. The aim of this study was to determine CD19+ B cells subset distribution in the peripheral blood and to define disturbance in the circulating Tfh cells subsets in patients with sarcoidosis. The prospective comparative study was performed in 2016-2018, where peripheral blood B cell subsets and circulating Tfh cell subsets were analyzed in 37 patients with primarily diagnosed sarcoidosis and 35 healthy donors using multicolor flow cytometry. In the results of our study we found the altered distribution of peripheral B cell subsets with a predominance of "naïve" (IgD + CD27-) and activated B cell (Bm2 and Bm2') subsets and a decreased frequency of memory cell (IgD+ CD27+ and IgD- CD27+) in peripheral blood of sarcoidosis patients was demonstrated. Moreover, we found that in sarcoidosis patients there are increased levels of B cell subsets, which were previously shown to display regulatory capacities (CD24+++ CD38+++ and CD5 + CD27-). Next, a significantly higher proportion of CXCR5-expressing CD45RA - CCR7+ Th cells in patients with sarcoidosis in comparison to the healthy controls was revealed, that represents the expansion of this memory Th cell subset in the disease. This is the first study to demonstrate the association between the development of sarcoidosis and imbalance of circulating Tfh cells, especially CCR4- and CXCR3-expressing Tfh subsets. Finally, based on our data we can assume that B cells and Tfh2- and Tfh17-like cells - most effective cell type in supporting B-cell activity, particularly in antibody production - may be involved in the occurrence and development of sarcoidosis and in several other autoimmune conditions. Therefore, we can consider these results as a new evidence of the autoimmune mechanisms in the sarcoidosis development.

Improved accuracy in DFS pattern interpretation using a novel HEp-2 ELITE system.

INTRODUCTION/OBJECTIVES: Accurate interpretation of DFS70 (dense fine speckled 70) and mixed antinuclear antibodies (ANAs) patterns can be challenging using conventional HEp-2 immunofluorescence (IIF) method. We evaluated a novel HEp-2 IIF substrate (HEp-2 ELITE/DFS70-KO) composed of a mixture of engineered HEp-2 devoid of the DFS70 autoantigen and conventional HEp-2 cells. The study assessed the utility of the new substrate in ANA screening and its advantages. METHOD: One thousand and five consecutive routine samples sent for ANA screening were tested on both standard HEp-2 and the HEp-2 ELITE DFS70 KO substrates (ImmuGlo ANA HEp-2 and HEp-2 ELITE/DFS70-KO, Trinity Biotech, Buffalo, NY). Anti-DFS70 antibody specificity was additionally determined by immunoblot (IB). Clinical and serological data were included in the analysis of the overall impact of the novel HEp-2 substrate on DFS pattern interpretation. RESULTS: Of the 22 cases suspected as positive for DFS pattern alone or in combination with homogeneous or speckled patterns on conventional HEp-2 cells, 17 were interpreted with a higher accuracy using the new HEp-2 ELITE method as positive for DFS70 (monospecific DFS70 (10), mixed DFS70 (7)), speckled (3), and DFS (2) patterns. CONCLUSIONS: The new substrate was not only useful in deciphering unclear mixed ANA patterns but also highly sensitive in detecting DFS70 pattern in comparison to the DFS70 positivity obtained using IB.

The microbiome in autoimmune diseases.

The microbiome is represented by microorganisms which live in a symbiotic way with the mammalian. Microorganisms have the ability to influence different physiological aspects such as the immune system, metabolism and behaviour. In recent years, several studies have highlighted the role of the microbiome in the pathogenesis of autoimmune diseases. Notably, in systemic lupus erythematosus an alteration of the intestinal flora (lower Firmicutes/Bacteroidetes ratio) has been described. Conversely, changes to the gut commensal and periodontal disease have been proposed as important factors in the pathogenesis of rheumatoid arthritis. At the same time, other autoimmune diseases (i.e. systemic sclerosis, Sjögren's syndrome and anti-phospholipid syndrome) also share modifications of the microbiome in the intestinal tract and oral flora. Herein, we describe the role of the microbiome in the maintenance homeostasis of the immune system and then the alterations of the microorganisms that occur in systemic autoimmune diseases. Finally, we will consider the use of probiotics and faecal transplantation as novel therapeutic targets.

Decrease in 14-3-3η protein levels is correlated with improvement in disease activity in patients with rheumatoid arthritis treated with Tofacitinib.

14-3-3η protein is a proinflammatory mediator that may represent a novel diagnostic and prognostic biomarker for rheumatoid arthritis (RA). We assessed the correlation between changes in serum 14-3-3η levels and changes in clinical disease activity measures in RA patients treated with Tofacitinib (TOF). Paired serum samples from 35 patients with RA were obtained at baseline and 5 months after the initiation of treatment with TOF. The levels of 14-3-3η were measured by JOINT stat 14-3-3η ELISA test kits (Augurex Life Sciences Corp.). The cut-off was defined as 0.19 ng/ml. 14-3-3η positivity was found in 57% of the patients at baseline and in 37% of the patients after 5 months of treatment. Mean ± SD baseline 14-3-3η levels [4.92 ± 8.86 ng/ml] were significantly higher (p < 0.005) than 14-3-3η levels following treatment [1.97 ± 4.59 ng/ml]. A statistically significant improvement (p < 0.001) of CDAI, SDAI, DAS4ESR and DAS4CRP was achieved after 5 month of treatment. Decrease in 14-3-3η protein levels was highly correlated with improvement in DAS4ESR (r = 0.50, p < 0.01), DAS4CRP (r = 0.46, p < 0.01) and ESR (r = 0.36, p = 0.03) and moderately correlated with improvement in CDAI (r = 0.32, p = 0.065) and SDAI (r = 0.33, p = 0.051). The correlation between decrease in 14-3-3η levels and improvement in DAS4ESR remained significant in a partial correlation analysis controlling for ESR (r = 0.39, p = 0.02). This study demonstrates that in RA patients who were treated with TOF, decrease in 14-3-3η levels is correlated with improvement in clinical disease activity parameters. The 14-3-3η protein may serve as an objective biomarker for monitoring of TOF therapy response.

Porphyromonas gingivalis in the tongue biofilm is associated with clinical outcome in rheumatoid arthritis patients.

Several studies have suggested a link between human microbiome and rheumatoid arthritis (RA) development. Porphyromonas gingivalis seems involved in RA initiation and progression, as supported by the high occurrence of periodontitis. In this case-control study, we analysed tongue P. gingivalis presence and quantification in a large healthy and RA cohort. We enrolled 143 RA patients [male/female (M/F) 32/111, mean ± standard deviation (s.d.), age 57·5 ± 19·8 years, mean ± s.d. disease duration 155·9 ± 114·7 months); 36 periodontitis patients (M/F 11/25, mean ± s.d., age 56 ± 9·9 years, mean ± s.d. disease duration 25·5 ± 20·9 months); and 57 patients (M/F 12/45, mean ± s.d., age 61·4 ± 10·9 years, mean ± s.d. disease duration 62·3 ± 66·9 months) with knee osteoarthritis or fibromyalgia. All subjects underwent a standard cytological swab to identify the rate of P. gingivalis/total bacteria by using quantitative real-time polymerase chain reaction. The prevalence of P. gingivalis resulted similarly in RA and periodontitis patients (48·9 versus 52·7%, P = not significant). Moreover, the prevalence of this pathogen was significantly higher in RA and periodontitis patients in comparison with control subjects (P = 0·01 and P = 0·003, respectively). We found a significant correlation between P. gingivalis rate in total bacteria genomes and disease activity score in 28 joints (DAS28) (erythrocyte sedimentation rate) (r = 0·4, P = 0·01). RA patients in remission showed a significantly lower prevalence of P. gingivalis in comparison with non-remission (P = 0·02). We demonstrated a significant association between the percentage of P. gingivalis on the total tongue biofilm and RA disease activity (DAS28), suggesting that the oral cavity microbiological status could play a role in the pathogenic mechanisms of inflammation, leading to more active disease.

A better definition of the anti-DFS70 antibody screening by IIF methods.

BACKGROUND: Anti-DFS70 antibodies have been recently included in a new testing algorithm for patients with suspicion of connective tissue diseases (CTDs). This algorithm enables to assess the probability of having a CTD in patients with a positive antinuclear antibodies (ANA) result. The aim of the study was to analyze the the inter-method agreement between three different HEp-2 cell substrates for anti-DFS70 detection, focusing on two novel IIF methods that assess the presence of monospecific anti-DFS70 antibodies. METHODS: Immunological and clinical records of 29 patients who were double positive for anti-DFS70 autoantibodies using chemiluminescence assay (CIA) and Immunoblot (IB) were studied. The IIF on HEp-2 cells were determined using slides from Inova Diagnostics, Euroimmun and Immco. The capability to detect isolated anti-DFS70 antibodies was compared using immunoadsorption on NOVA Lite HEp-2 Select (Inova Diagnostics) and the HEp-2 ELITE/DFS70 knockout test (Immco). RESULTS: The three substrates had very good sensitivity for detecting patients with anti-DFS staining pattern (93.1%, 79.3% and 72.4% for Euroimmun, Immco and Inova respectively). Most of the patients had full inhibition of DFS pattern (65.5%) by immunoabsorption test. Also, the 55.2% of the subjects were positive for monospecific DFS pattern using HEp-2 ELITE/DFS70 knockout test. However, the correlation between the full inhibition by immunoadsorption and the monospecific DFS pattern in knockout cells was very low (kappa: 0.22). CONCLUSION: The evaluation of monospecific anti-DFS70 antibodies is clinically fundamental and challenging using traditional HEp-2 IIF. Results obtained in this study support the hypothesis that the lack of standardization across IIF kits along with the subjectivity of user interpretation among other factors contribute to the overall reduction in the agreement.