Liver autoantibodies in patients with scleroderma

Systemic sclerosis and primary biliary cholangitis: Longitudinal data to determine the outcomes

Background

Several studies described the cross-sectional characteristics of systemic sclerosis patients and coexisting primary biliary cholangitis, but longitudinal prognostic data are lacking.

Aims

To describe the systemic sclerosis-primary biliary cholangitis phenotype, including baseline characteristics and outcomes.

Methods

We performed a multicentre the European Scleroderma Trials and Research Group study of systemic sclerosis patients with primary biliary cholangitis or with primary biliary cholangitis-specific antibodies, matched with systemic sclerosis controls free from hepatobiliary involvement matched for disease duration and cutaneous subset. Data were recorded at baseline and at the last available visit.

Results

A total of 261 patients were enrolled (115 primary biliary cholangitis-systemic sclerosis, 161 systemic sclerosis). At baseline, systemic sclerosis-primary biliary cholangitis patients had a higher prevalence of anti-centromere antibodies (p = 0.0023) and a lower prevalence of complete absence of digital ulcers. The milder vascular involvement was confirmed at follow-up when crucial differences emerged in the percentage of patients experiencing digital ulcers; a significantly higher number of patients who never experienced digital ulcers were observed among primary biliary cholangitis-systemic sclerosis patients (p = 0.0015). Moreover, a greater incidence of pulmonary arterial hypertension (p < 0.001) and of conduction blocks (p = 0.0256) was observed in systemic sclerosis patients without primary biliary cholangitis. Patients with primary biliary cholangitis had higher levels of liver enzymes at baseline than systemic sclerosis patients; a significant decrease in liver enzymes was observed at follow-up. Out of 18 patients with cholangitis, one received a liver transplant at follow-up.

Conclusion

Our data show that systemic sclerosis-primary biliary cholangitis exhibit a mild systemic sclerosis and primary biliary cholangitis phenotype with outcomes being in general favourable.

Clinical Relevance of Liver Involvement in the Clinical Course of Systemic Sclerosis

Liver involvement in systemic sclerosis (SSc) is rare. We evaluated the prevalence of liver fibrosis and hepatic autoimmunity in SSc patients in a retrospective observational cohort (97 SSc or mixed connective tissue disease with sclerodermic manifestations patients undergoing transient elastography, evaluating liver stiffness (LS) and controlled attenuation parameter (CAP), due to clinical indications along with biochemistry assessments and major antibodies associated to liver autoimmunity). Among them, 11 had LS ≥ 7.5 kPa and 5 showed an LS compatible with cirrhosis (LS ≥ 12.5 kPa). Predictors of LS ≥ 7.5 fibrosis were alcohol consumption (>14 or >7 alcoholic units/week for men and women, respectively), waist circumference (>102 or >88 cm for men and women, respectively), elevated alkaline phosphatase, and anti-La and anti-mitochondrial antibody (AMA) positivity. Six patients had CAP values compatible with severe steatosis (≥280 dB/m). Waist circumference, body mass index and diabetes mellitus were significant predictors of steatosis. Out of 97 patients, 19 were positive for AMA, 4 for anti-Sp100, 1 for anti-Gp210 and 7 were diagnosed with primary biliary cholangitis. Among SSc patients, hepatic fibrosis biomarkers and AMA prevalence are relatively high, suggesting the opportunity of performing a transient elastography and a screening for hepatic autoimmunity at diagnosis and/or during disease progression.

Detection of anti-kelch-like 12 and anti-hexokinase 1 antibodies in primary biliary cholangitis patients in China

OBJECTIVES

primary biliary cholangitis (PBC) is a chronic cholestatic disease, characterized by positive anti-mitochondrial autoantibodies (AMA) in 90-95 % patients. Anti-kelch-like 12 (anti-KLHL12) and anti-hexokinase1 (anti-HK1) antibodies have been identified as the two new serum markers in recent years, which are used in the diagnosis of AMA-negative PBC patients. The objective of the study was to examine the performance of these two new biomarkers in China.

METHODS

a total of 192 patients were enrolled and screened for anti-KLHL12 and anti-HK1 antibodies and AMA by ELISA. Receiver operating characteristic (ROC curve) analysis was applied to examine the diagnostic importance of AMA, anti-KLHL12 and anti-HK1 antibodies. Furthermore, correlation analysis between some important biochemical indexes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], bilirubin, gamma-glutamil transferasa [γ-GT]), staging of pathological changes of the liver and the expression of novel antibodies in PBC patients were also examined.

RESULTS

the positivity of the anti-HK1 antibody in AMA-positive PBC patients and AMA-negative patients was 44.7 % and 33.3 %, respectively. The specificity, proportion of positive patients (PPV) and proportion of negative patients (NPV) were 93 %, 89 % and 53 %, respectively. In contrast, the positivity to the anti-KLHL12 antibody in AMA-positive and negative PBC patients was 41.2 % and 22.2 %, respectively. Specificity, PPV and NPV were 98 %, 95 % and 52 %, respectively. The area under the curve (AUC) with anti-HK1 and anti-KLHL12 antibodies were 0.720 and 0.703. With the combination with anti-HK1 and anti-KLHL12 antibodies, the AUC of AMA increased from 0.889 to 0.891, increasing the sensitivity from 0.764 to 0.836. Anti-KLHL12 and anti-HK1-positive patients had higher serum levels of ALP, γ-GT and bilirubin, with statistically significant differences (p < 0.01) compared with anti-KLHL12 or anti-HK1-negative patients. Notably, correlation analysis showed a significant positive correlation between antibody expression and ALP, γ-GT and bilirubin serum levels (r = 0.735, 0.491, 0.466; p < 0.01).

CONCLUSIONS

anti-HK1 and anti-KLHL12 antibodies have been identified as two significant biomarkers in PBC patients. Furthermore, the presence of these antibodies is likely to correlate with the severity of PBC.

Clinical relevance of HEp-2 indirect immunofluorescent patterns: the International Consensus on ANA patterns (ICAP) perspective

The indirect immunofluorescence assay (IIFA) on HEp-2 cells is widely used for detection of antinuclear antibodies (ANA). The dichotomous outcome, negative or positive, is integrated in diagnostic and classification criteria for several systemic autoimmune diseases. However, the HEp-2 IIFA test has much more to offer: besides the titre or fluorescence intensity, it also provides fluorescence pattern(s). The latter include the nucleus and the cytoplasm of interphase cells as well as patterns associated with mitotic cells. The International Consensus on ANA Patterns (ICAP) initiative has previously reached consensus on the nomenclature and definitions of HEp-2 IIFA patterns. In the current paper, the ICAP consensus is presented on the clinical relevance of the 29 distinct HEp-2 IIFA patterns. This clinical relevance is primarily defined within the context of the suspected disease and includes recommendations for follow-up testing. The discussion includes how this information may benefit the clinicians in daily practice and how the knowledge can be used to further improve diagnostic and classification criteria.

Systemic sclerosis and primary biliary cholangitis: An overlapping entity?

Systemic sclerosis (SSc) is a complex autoimmune disease that may lead to skin and internal organ fibrosis. Based on skin involvement, two subsets of the disease are recognized (limited cutaneous SSc and diffuse cutaneous SSc). The new 2013 American College of Rheumatology/European League against Rheumatism classification criteria allow to identify SSc patients at the early stage of the disease that allows new research avenues. The aetiology of the disease is still unknown, but it has an important autoimmune basis and its association with other autoimmune diseases has been reproducibly reported. Among them, primary biliary cholangitis is considered the most common liver disease in SSc. The aim of this review is to provide an overview on recent findings about SSc associated to primary biliary cholangitis. Although the aetiology of the two diseases is still unknown, data suggest that these two disorders share the expression of fibrogenic cytokines, involved both in generation and function of T lymphocytes subpopulation (Th17 cells) and regulatory T lymphocytes. In addition, the relationships between SSc and primary biliary cholangitis may be closer as suggested by the presence of primary biliary cholangitis-specific antibodies in SSc patients and vice versa. Recent findings confirm a prevalence of overt primary biliary cholangitis in about 2% of SSc population, in particular in patients with limited cutaneous SSc and positive anticentromere antibodies. The prevalence increases if also patients with only primary biliary cholangitis-specific antibodies are considered. Data regarding SSc prevalence in primary biliary cholangitis patients have also been recently clarified. Altogether, stimulating results are moving the field forward regarding the relationships of these two autoimmune and fibrotic disorders that may belong to an overlapping entity.

Gastrointestinal and Hepatic Disease in Systemic Sclerosis

Although classification criteria for systemic sclerosis (SSc) do not incorporate gastrointestinal tract (GIT) manifestations often present in this disease, the GIT is the most common internal organ involved. Pathophysiology of GIT involvement is thought to be similar to other organs in SSc with fibroproliferative vascular lesions of small arteries and arterioles, increased production of profibrotic growth factors, and alterations of innate, humoral, and cellular immunity. These processes result in neuropathy progressing to myopathy with eventual fibrosis. Proper diagnostics and therapeutics for SSc-GIT involvement require the treating physician to have an understanding of an integrated approach and potential medication adverse effects.

Selective deletion of PPARβ/δ in fibroblasts causes dermal fibrosis by attenuated LRG1 expression

Connective tissue diseases of the skin are characterized by excessive collagen deposition in the skin and internal organs. Fibroblasts play a pivotal role in the clinical presentation of these conditions. Nuclear receptor peroxisome-proliferator activated receptors (PPARs) are therapeutic targets for dermal fibrosis, but the contribution of the different PPAR subtypes are poorly understood. Particularly, the role of fibroblast PPARβ/δ in dermal fibrosis has not been elucidated. Thus, we generated a mouse strain with selective deletion of PPARβ/δ in the fibroblast (FSPCre-Pparb/d-/-) and interrogated its epidermal and dermal transcriptome profiles. We uncovered a downregulated gene, leucine-rich alpha-2-glycoprotein-1 (Lrg1), of previously unknown function in skin development and architecture. Our findings suggest that the regulation of Lrg1 by PPARβ/δ in fibroblasts is an important signaling conduit integrating PPARβ/δ and TGFβ1-signaling networks in skin health and disease. Thus, the FSPCre-Pparb/d-/- mouse model could serve as a novel tool in the current gunnery of animal models to better understand dermal fibrosis.

Review article: pathogenesis and clinical manifestations of gastrointestinal involvement in systemic sclerosis

BACKGROUND

Gastrointestinal tract (GIT) involvement is a common cause of debilitating symptoms in patients with systemic sclerosis (SSc). There are no disease modifying therapies for this condition and the treatment remains symptomatic, largely owing to the lack of a clear understanding of its pathogenesis.

AIMS

To investigate novel aspects of the pathogenesis of gastrointestinal involvement in SSc. To summarise existing knowledge regarding the cardinal clinical gastrointestinal manifestations of SSc and its pathogenesis, emphasising recent investigations that may be valuable in identifying potentially novel therapeutic targets.

METHODS

Electronic (PubMed/Medline) and manual Google search.

RESULTS

The GIT is the most common internal organ involved in SSc. Any part of the GIT from the mouth to the anus can be affected. There is substantial variability in clinical manifestations and disease course and symptoms are nonspecific and overlapping for a particular anatomical site. Gastrointestinal involvement can occur in the absence of cutaneous disease. Up to 8% of SSc patients develop severe GIT symptoms. This subset of patients display increased mortality with only 15% survival at 9 years. Dysmotiity of the GIT causes the majority of symptoms. Recent investigations have identified a novel mechanism in the pathogenesis of GIT dysmotility mediated by functional anti-muscarinic receptor autoantibodies.

CONCLUSIONS

Despite extensive investigation, the pathogenesis of gastrointestinal involvement in systemic sclerosis remains elusive. Although treatment currently remains symptomatic, an improved understanding of novel pathogenic mechanisms may allow the development of potentially highly effective approaches including intravenous immunoglobulin and microRNA based therapeutic interventions.

Anti-kelch-like 12 and anti-hexokinase 1: novel autoantibodies in primary biliary cirrhosis

BACKGROUND & AIMS

Using high-density human recombinant protein microarrays, we identified two potential biomarkers, kelch-like 12 (KLHL12) and hexokinase-1 (HK1), in primary biliary cirrhosis (PBC). The objective of this study was to determine the diagnostic value of anti-KLHL12/HK1 autoantibodies in PBC. Initial discovery used sera from 22 patients with PBC and 62 non-PBC controls. KLHL12 and HK1 proteins were then analysed for immunoglobulin reactivity by immunoblot and enzyme-linked immunosorbent assay (ELISA) in two independent cohorts of PBC and disease/healthy control patients.

METHODS

Serum samples from 100 patients with PBC and 165 non-PBC disease controls were analysed by immunoblot and samples from 366 patients with PBC, 174 disease controls, and 80 healthy donors were tested by ELISA.

RESULTS

Anti-KLHL12 and anti-HK1 antibodies were each detected more frequently in PBC compared with non-PBC disease controls (P < 0.001). Not only are both markers highly specific for PBC (≥95%) but they also yielded higher sensitivity than anti-gp210 and anti-sp100 antibodies. Combining anti-HK1 and anti-KLHL12 with available markers (MIT3, gp210 and sp100), increased the diagnostic sensitivity for PBC. Most importantly, anti-KLHL12 and anti-HK1 antibodies were present in 10-35% of anti-mitochondrial antibody (AMA)-negative PBC patients and adding these two biomarkers to conventional PBC assays dramatically improved the serological sensitivity in AMA-negative PBC from 55% to 75% in immunoblot and 48.3% to 68.5% in ELISA.

CONCLUSIONS

The addition of tests for highly specific anti-KLHL12 and anti-HK1 antibodies to AMA and ANA serological assays significantly improves efficacy in the clinical detection and diagnosis of PBC, especially for AMA-negative subjects.