Asialoglycoprotein receptor (ASGPR) as target autoantigen in liver autoimmunity: lost and found

Asialoglycoprotein receptor (ASGPR) has attracted the attention of liver immunologists for many years. This liver-specific lectin was found to be a major B and T cell autoantigenic target in patients with autoimmune liver diseases, and in particular in autoimmune hepatitis (AIH). This review discusses the biological significance of ASGPR and its relevance to the pathogenesis of autoimmune and virus-triggered liver diseases. We also discuss emerging data on the diagnostic and clinical relevance of anti-ASGPR antibodies in light of recent reports based on commercially available anti-ASGPR enzyme-linked immunosorbent assays. Finally, we critically revisit the data reporting on disease-specific cellular immune responses against ASGPR and their relevance in relation to the pathogenesis of AIH.

Reactivation of resolved hepatitis B virus infection after immunosuppression: is it time to adopt pre-emptive therapy?

New therapeutic options like monoclonal antibodies (anti-CD20/rituximab) and hematopoietic stem cell transplantation (HSCT) have increased both the effectiveness of therapies and the risk for reactivation of Hepatitis B virus (HBV). We describe two cases with serological evidence of resolved HBV infection (hepatitis B surface antigen (HBsAg) negative/antibody to hepatitis B core antigen (anti-HBc) and antibody to hepatitis B surface antigen (anti-HBs) positive), who developed reverse seroconversion (clearance of HBsAb/appearance of HBsAg) with active HBV infection after treatment with combination of conventional chemotherapy, rituximab and autologous HSCT for hematological malignancies. Review of the literature highlights the increasing incidence of HBV reactivation in patients with resolved infection and raises concerns as to whether current guidelines for pre-chemotherapy screening with sensitive HBV-DNA assays and serial monitoring for anti-HBs titres should be implemented also for patients with resolved infection. Future studies should aim at clarifying the cost-benefit from administration of nucleoside analogues in these patients.

Efficient management of secondary haemophagocytic lymphohistiocytosis with intravenous steroids and γ-immunoglobulin infusions

BACKGROUND

Secondary haemophagocytic lymphohistiocytosis (sHLH) is a rare life-threatening condition mainly associated with underlying infections, malignancies, and autoimmune or immune-mediated diseases.

AIM

To analyse all sHLH cases that were diagnosed and managed under real-world circumstances in our department focusing on the treatment schedule and the outcome.

METHODS

Prospectively collected data from all adult patients fulfilling the criteria of sHLH who diagnosed and managed from January 1, 2010 to June 1, 2018, in our department of the tertiary care university hospital of Larissa, Greece, were analysed retrospectively (n = 80; 52% male; median age: 55 years). The electronic records and/or written charts of the patients were reviewed for the demographic characteristics, clinical manifestations, underlying causes of sHLH, laboratory parameters, treatment schedule and 30-d-mortality rate. Most of patients had received after consent intravenous γ-immunoglobulin (IVIG) for 5 d (total dose 2 g/kg) in combination with intravenous steroid pulses followed by gradual tapering of prednisolone.

RESULTS

Seventy-five patients (94%) reported fever > 38.5 °C, 47 (59%) had liver or spleen enlargement and 76 (95%) had ferritin > 500 ng/mL including 20 (25%) having considerably high levels (> 10000 ng/mL). Anaemia and thrombocytopenia occurred in 72% and leucopoenia in 47% of them. Underlying infections were diagnosed in 59 patients (74%) as follows: leishmaniasis alone in 15/80 (18.9%), leishmaniasis concurrently with Coxiella Burnetti or non-Hodgkin lymphoma in 2/80 (2.5%), bacterial infections in 14/80 (17.5%) including one case with concurrent non-Hodgkin lymphoma, viral infections in 13/80 (16.3%), fungal infections in 2/80 (2.5%), infections by mycobacteria in 1/80 (1.3%) and unidentified pathogens in 12/80 (15%). Seventy-two patients (90%) had received combination treatment with IVIG and intravenous steroids. Overall, sHLH resolved in 76% of patients, 15% died within the first month but 82.5% of patients were still alive 6 mo after diagnosis. Univariate analysis showed older age, anaemia, thrombocytopenia, low fibrinogen, disseminated intravascular coagulation (DIC), and delay of diagnosis as factors that negatively affected remission. However, multivariate analysis showed low platelets and DIC as the only independent predictors of adverse outcome.

CONCLUSION

sHLH still carries a remarkable morbidity and mortality. Underlying infections were the major cause and therefore, they should be thoroughly investigated in patients with sHLH. Early recognition and combination treatment with IVIG and corticosteroids seem an efficient treatment option with successful outcome in this life-threatening condition.

Salmonella enteritidis Infection Complicated by Acute Myocarditis: A Case Report and Review of the Literature

Salmonella spp. is the cause of commonly encountered infections, with seasonal pattern of occurrence and worldwide distribution. Some of the clinical manifestations such as gastroenteritis and bacteremia are common, whereas others like mycotic aneurysms and osteomyelitis are infrequent especially in immunocompetent patients. Salmonella has been rarely described as a cause of myocarditis in the literature. We describe a case of an 18-year-old previously healthy male patient with myocarditis after Salmonella enteritidis infection. Clinical manifestations and diagnostic approach of this severe complication are discussed with a review of the literature.

Role of autoantibodies in the clinical management of primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease characterized by immune-driven destruction of small intrahepatic bile ducts leading a proportion of patients to hepatic failure over the years. Diagnosis at early stages in concert with ursodeoxycholic acid treatment has been linked with prevention of disease progression in the majority of cases. Diagnosis of PBC in a patient with cholestasis relies on the detection of disease-specific autoantibodies, including anti-mitochondrial antibodies, and disease-specific anti-nuclear antibodies targeting sp100 and gp210. These autoantibodies assist the diagnosis of the disease, and are amongst few autoantibodies the presence of which is included in the diagnostic criteria of the disease. They have also become important tools evaluating disease prognosis. Herein, we summarize existing data on detection of PBC-related autoantibodies and their clinical significance. Moreover, we provide insight on novel autoantibodies and their possible prognostic role in PBC patients.

Diagnostic and clinical significance of antigen-specific pancreatic antibodies in inflammatory bowel diseases: A meta-analysis

BACKGROUND

Non-invasive criteria are needed for Crohn's disease (CD) diagnosis, with several biomarkers being tested. Results of individual diagnostic test accuracy studies assessing the diagnostic value of pancreatic autoantibodies-to-glycoprotein-2 (anti-GP2) tests for the diagnosis of CD appear promising.

AIM

To systematically review and meta-analyze evidence on the diagnostic accuracy of anti-GP2 tests in patients with suspected/confirmed CD.

METHODS

An electronic search was conducted on PubMed, Cochrane-CENTRAL and grey literature (CRD42019125947). The structured research question in PICPTR format was "Population" including patients with symptoms akin to CD, the "Index test" being anti-GP2 testing, the "Comparator" involved standard CD diagnosis, the "Purpose of test" being diagnostic, "Target disorder" was CD, and the "Reference standard" included standard clinical, radiological, endoscopical, and histological CD diagnostic criteria. Quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies-2 tool and hierarchical models were employed to synthesize the data.

RESULTS

Out of 722 studies retrieved, 15 were meta-analyzed. Thirteen studies had industry-related conflicts-of-interest, and most included healthy donors as controls (spectrum bias). For the combination of IgA and/or IgG anti-GP2 test, the summary sensitivity was 20% (95% confidence interval: 10%-29%) at a median specificity of 97%. If the test was applied in 10000 suspected patients, 9669 would be true negatives and in 26, the diagnosis would be missed. In this hypothetical cohort, the anti-GP2 would fail to produce a diagnosis for 81.3% of the positive cases. Low summary points of sensitivity and high specificity were estimated for the IgG or IgA anti-GP2 test. Analogous results were observed when the analyses were restricted using specific cut-offs, or when ulcerative colitis patients were used as comparators.

CONCLUSION

Anti-GP2 tests demonstrate low sensitivity and high specificity. These results indicate that caution is required before relying on its diagnostic value. Additionally, the need for improving the methodology of diagnostic test accuracy studies is evident.

Flow cytometric detection of p38 MAPK phosphorylation and intracellular cytokine expression in peripheral blood subpopulations from patients with autoimmune rheumatic diseases

Flow cytometric analysis of p38 mitogen-activated protein kinase (p38 MAPK) signaling cascade is optimally achieved by methanol permeabilization protocols. Such protocols suffer from the difficulties to accurately detect intracellular cytokines and surface epitopes of infrequent cell subpopulations, which are removed by methanol. To overcome these limitations, we have modified methanol-based phosphoflow protocols using several commercially available antibody clones suitable for surface antigens, intracellular cytokines, and p38 MAPK. These included markers of B cells (CD19, CD20, and CD22), T cells (CD3, CD4, and CD8), NK (CD56 and CD7), and dendritic cells (CD11c). We have also tested surface markers of costimulatory molecules, such as CD27. We have successfully determined simultaneous expression of IFN- γ , as well as IL-10, and phosphorylated p38 in cell subsets. The optimized phosphoflow protocol has also been successfully applied in peripheral blood mononuclear cells or purified cell subpopulations from patients with various autoimmune diseases. In conclusion, our refined phosphoflow cytometric approach allows simultaneous detection of p38 MAPK activity and intracellular cytokine expression and could be used as an important tool to study signaling cascades in autoimmunity.

Crohn's disease-specific anti-CUZD1 pancreatic antibodies are absent in ruminants with paratuberculosis

BACKGROUND

Pancreatic autoantibodies (PABs) specifically recognizing GP2 and/or CUZD1 are present in more than 35% of patients with Crohn's disease (CrD). We have recently provided evidence of the presence of GP2-specific PABs in ruminants with paratuberculosis (ptb), a Mycobacterium avium paratuberculosis (MAP)-induced disease resembling CrD.

OBJECTIVE

To assess whether anti-CUZD1 antibodies are also present in ruminants with ptb.

METHODS

A total of 110 samples (73 cattle/37 sheep) were studied including 40 with ptb (24 cattle/16 sheep; 20 anti-GP2 antibody pos) and 70 without ptb (49 cattle/21 sheep; 10 anti-GP2 antibody pos). The samples were pre-characterized for anti-MAP and anti-GP2 antibodies by ELISA. Evidence of MAP was confirmed by PCR. Anti-CUZD1 antibody testing was performed by indirect immunofluorescence (IIF) based on transfected HEK293 cells expressing CUZD1. Anti-sheep or anti-cattle specific antisera were used as revealing antibodies.

RESULTS

None of the ruminant sera had anti-CUZD1 antibodies by IIF testing at dilutions varying from 1/10 to 1/160. Methodological flaws were prevented by a series of tests. Control sera from anti-CUZD1 positive CrD samples have shown anti-CUZD1 antibody reactivity at various concentrations. Antibody reactivity to GP2-expressing HEK293 cells has confirmed the reactivity to GP2 in ruminant sera found positive for anti-GP2 antibodies by ELISA.

CONCLUSION

The present study has found no evidence of anti-CUZD1 PABs in MAP-induced ptb. Our findings indicate that the induction of CUZD1-specific PABs is unrelated to MAP infection and that the mechanisms responsible for the loss of tolerance to GP2 and CUZD1 are probably quite distinct.

Popular and unpopular infectious agents linked to primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a progressive cholestatic liver disease characterized by the autoimmune destruction of the biliary epithelial cells of the small and medium-size bile ducts. The disease affects middle aged women and usually affects more than one member within a family. The pathognomonic serological hallmark of the disease is the presence of circulating anti-mitochondrial antibodies, and disease-specific anti-nuclear antibodies. Susceptibility genes and environmental risk factors such as infections and smoking have been reported as important for the development of the disease. Among the environmental agents, infectious triggers are the best studied. Most of the work published so far has investigated the role of infections caused by Novosphingobium aromaticivorans and Escherichia coli. This review will discuss the popular and unpopular infectious agents causatively linked to PBC. It will also examine reports investigating the epidemiological aspects of the disease and their direct or indirect implications to bacterial-induced PBC.

p38 mitogen-activated protein kinase impairment of innate immune cells is a characteristic feature of HBeAg-negative chronic hepatitis B

The mitogen-activated protein kinase p38 (MAPK) is implicated in the induction of immune responses by regulating the differentiation of T lymphocytes and production of cytokines. Our aim was to investigate p38MAPK phosphorylation in different stages of the natural history of hepatitis B virus (HBV) infection. Peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll-Hypaque density-based centrifugation from 10 patients with HBeAg-negative chronic hepatitis B [HBeAg(-) CHB;HBV-DNA>2000IU/mL], eight patients with HBeAg-negative chronic HBV infection [HBeAg(-) CI;undetectable HBV-DNA] and 8 healthy controls (HCs). p38MAPK phosphorylation was assessed by phospho-specific flow cytometry in PBMCs and cell subsets (CD3+,CD3-,CD56+,CD56-) after stimulation with cytokines (IL-12+IL-2 and IL-12+IL-18) or nonspecific stimuli [arsenite, phorbol 12-myristate 13-acetate (PMA) and ionomycin] at 0,30,60,120 and 240 minutes using p38 phospho-specific conjugated antibodies. ΙFN-γ was determined by ELISA in PBMCs culture supernatants after stimulation with rhIL-2, rhIL-12 and rhIL-18, with and without pre-treatment with the p38 MAPK inhibitor, SB203580. HBeAg(-) CI patients showed the highest expression of phosphor-p38 MAPK in total PBMCs and subpopulations compared to HBeAg(-) CHB and HCs. A striking impairment in p38 phosphorylation was noted in CD56+ cells and in especially in NK cells (CD3-CD56+). SB203580-induced inhibition of p38MAPK phosphorylation was associated with suppression of IFN-γ production in all groups. The universal lack of p38 MAPK activation in CD56+ and in particular in NK cells from HBeAg(-) CHB patients during viremia suggests a potential cell-dependent implication of this pathway in the natural history of HBV infection.