Rheumatoid factors in leprosy and parasitic diseases

High-throughput autoantibody profiling of different stages of Schistosomiasis japonica

Infection by the Schistosoma japonicum can result in acute, chronic and late-stage manifestations. The latter often presents with severe organ failures and premature death. Importantly, infection can also produce autoimmune phenomena reflected by the development of autoantibodies. We wished to explore and profile the presence of autoantibodies in sera of patients with different stages of S. japonicum infection with the added aim of providing a reference assisting diagnosis. Blood samples from 55 patients with chronic and 20 patients with late-stage schistosomiasis japonica together, with a control group of 50 healthy people were randomly investigated against a microarray of 121 different autoantigens. In addition, the frequency of antibodies against Schistosoma egg antigen (SEA) was examined. In the sera from patients with chronic schistosomiasis japonica, 14 different highly expressed autoantibodies were detected, while patients with late-stage schistosomiasis were found to express as many as 43 autoantibody specificities together with a significantly higher frequency of antibodies against SEA compared to the control group. The findings presented suggest that autoantibody-based classification of schistosomiasis japonica represents a promising approach for the elucidation of subtypes of the disease. This approach may reflect differential disease mechanisms, which could ultimately lead to better treatment.

Rheumatoid Factor: A Novel Determiner in Cancer History

Simple Summary

Rheumatoid factors are autoantibodies that characterize different autoimmune diseases, in particular rheumatoid arthritis, but that can also be found in the sera of the general healthy population. They have been mainly studied in the context of autoimmune diseases, but some evidence have suggested an association between their presence and the predisposition to develop cancer as well as a facilitation of cancer growth and progression in oncologic patients. In this review, for the first time we thus analyze and discuss the possible roles that these autoantibodies can assume in tumor history, from determiners of a heightened susceptibility of developing cancer to drivers of a reduced response to immunotherapies.

Abstract

The possible interplay between autoimmunity and cancer is a topic that still needs to be deeply explored. Rheumatoid factors are autoantibodies that are able to bind the constant regions (Fc) of immunoglobulins class G (IgGs). In physiological conditions, their production is a transient event aimed at contributing to the elimination of pathogens as well as limiting a redundant immune response by facilitating the clearance of antibodies and immune complexes. Their production can become persistent in case of different chronic infections or diseases, being for instance a fundamental marker for the diagnosis and prognosis of rheumatoid arthritis. Their presence is also associated with aging. Some studies highlighted how elevated levels of rheumatoid factors (RFs) in the blood of patients are correlated with an increased cancer risk, tumor recurrence, and load and with a reduced response to anti-tumor immunotherapies. In line with their physiological roles, RFs showed in different works the ability to impair in vitro anti-cancer immune responses and effector functions, suggesting their potential immunosuppressive activity in the context of tumor immunity. Thus, the aim of this review is to investigate the emerging role of RFs as determiners of cancer faith.

Proteomics analysis reveals differential pattern of widespread protein expression and novel role of histidine-rich glycoprotein and lipopolysaccharide-binding protein in rheumatoid arthritis

Rheumatoid factor (RF) is an auto-antibody against antigen-antibody immune complexes. RF is valuable as a biomarker for the screening of autoimmune and infectious diseases. However, it is suggested that RF would be a more powerful biomarker when used complementarily with RF-correlated proteins. In this study, we utilized a proteomic approach to analyze global protein expression in RF-low and RF-high subjects using high-performance liquid chromatography tandem mass spectrometry. Histidine-rich glycoprotein (HRG) and lipopolysaccharide-binding protein (LBP) were found to be differentially expressed between RF-low and RF-high subjects (cut-off > 2-fold, p < 0.05), which was validated by enzyme-linked immunosorbent assay. To evaluate whether both proteins allow discriminating rheumatoid arthritis patients from healthy controls, receiver-operating characteristic (ROC) curves were analyzed. Areas under the ROC curves of HRG and LBP were 0.861 and 0.888, respectively. The correlation between RF and HRG was statistically significant (p = 0.003), and LBP was also correlated with RF (p = 0.044), as indicated by correlation analysis. HRG and LBP are reportedly involved in RF-producing and RF-correlated diseases. Thus, we propose that HRG and LBP could be useful screening markers for RF-correlated diseases.

Case of lepromatous leprosy misdiagnosed as systemic sclerosis

Hansen's disease (HD) is a chronic granulomatous infectious disease caused by Mycobacterium leprae. The worldwide prevalence rate of HD has decreased gradually over the years. The clinical manifestations of HD are extensive, with involvement of the skin and various organs, and these can resemble those of many rheumatic diseases. Our patient initially presented with gradual sclerotic skin change and slight sclerodactyly with Raynaud's phenomenon, which is frequently observed in systemic sclerosis. However, a skin biopsy with acid-fast stain later confirmed lepromatous leprosy. We report this case to emphasize the role of dermatologists for applying a systematic approach to the skin lesions of HD, which has become difficult to detect because of its rapidly declining prevalence rate.

Glomerulonephritis in schistosomiasis mansoni: a time to reappraise

INTRODUCTION

The current prevalence of glomerulonephritis in patients with hepatosplenic schistosomiasis mansoni in Brazil was evaluated.

METHODS

Sixty three patients (mean age 45.5 ± 11 years) attending the outpatient infectious disease clinic of a University Hospital in Belo Horizonte, Brazil, from 2007 to 2009, were consecutively examined and enrolled in the present investigation. Diagnosis of hepatosplenic schistosomiasis was based on epidemiological, clinical and parasitological data and imaging techniques. Eight patients, who presented >30 mg/day albuminuria, were submitted to percutaneous ultrasound guided renal biopsy. Kidney tissue fragments were examined under light, direct immunofluorescence and electron microscopy.

RESULTS

All patients showed mesangial enlargement. In five, mesangial hypercellularity was observed and four presented duplication of the glomerular basement membrane. Areas of glomerular sclerosis were diagnosed in four. Deposits of immunoglobulin M and C3 were present in six samples; deposits of IgG in four, IgA in three and C1q in two samples. In all patients, immunoglobulin A was reported in the lumen of renal tubules. Deposits of kappa and lambda were observed in six samples. Electron microscopy revealed dense deposits in the glomerular tissue of three patients. Arterial hypertension, small esophageal varices, slight increases in serum creatinine and decreases in serum albumin were associated with glomerular disease.

CONCLUSIONS

Renal disease associated with hepatosplenic schistosomiasis was verified in 12.7% of patients and type I membranoproliferative glomerulonephritis was observed in 50% of them. Schistosomal glomerulopathy still is an important problem in patients with hepatosplenic schistosomiasis in Brazil.

Interactions between HIV infection and leprosy: a paradox

Early in the HIV epidemic it was feared that the disease would undermine leprosy control, as has occurred with tuberculosis. It was predicted that patients with leprosy and HIV coinfection would have an increased risk of lepromatous disease and a faster clinical evolution, and that the leprosy would be more difficult to treat. None of these concerns have materialised and the interaction between HIV and Mycobacterium leprae seems to be far more subtle than that between HIV and tuberculosis. We review the epidemiological, clinical, and pathological data relating to leprosy/HIV coinfection. The published epidemiological data are limited in quality but show neither an increased HIV prevalence among leprosy cases nor an alteration in clinical spectrum of leprosy among coinfected patients. Some data suggest that immune-mediated reactions that complicate leprosy occur at a higher frequency in coinfected patients. Leprosy has now been reported presenting as immune reconstitution disease among patients commencing highly active antiretroviral treatment. Histopathological observations reveal a normal spectrum of appearances in biopsies of leprosy lesions from coinfected patients, even among those with advanced immunodeficiency. These observations suggest that cell-mediated immune responses to M leprae are preserved at the site of disease despite evidence that these responses are abrogated systemically, by contrast with tuberculosis, in which the host granulomatous response is impaired by HIV coinfection. We speculate that this paradox may relate to differences between the activation state and rates of cell turnover within leprosy and tuberculosis granulomas that differentially affect the susceptibility of the granulomas to HIV. The interactions between leprosy and HIV have been little studied and further research on the clinical, pathological, and management aspects of this coinfection is warranted.

First report of leprosy presenting as acute polyarthritis in the setting of type I downgrading lepra reaction

Leprosy is a rare cause of acute polyarthritis. We describe the occurrence of oedema of the hands and feet and acute polyarthritis in the setting of type I (downgrading) lepra reaction in an untreated patient with borderline leprosy. This case report further expands the range of articular manifestations that can occur in leprosy.

Differential requirements for induction of total immunoglobulin and physiological rheumatoid factor production by human peripheral blood B cells

Rheumatoid factors (RFs) are autoantibodies directed against the Fc part of IgG. Considerable evidence exists that there are two classes of RFs, pathological and physiological. Whereas pathological RFs are associated with disease, physiological RFs are considered to be a normal component of the immune response. RF(+) precursor B cells present as part of the B cell repertoire of healthy individuals are held responsible for the production of physiological RFs, which is a transient phenomenon with a clear correlation with an initiating stimulus such as immunization or exposure to an infection. Here we demonstrate a difference in the regulatory control of total Ig and RF production by peripheral blood (PB) B cells of both healthy controls (HC) and patients with rheumatoid arthritis (RA). Highly purified B cells from HC and patients with RA were cocultured with T cells stimulated with immobilized anti-CD3 mAb. Similar to IgM production, IgM-RF production was shown to be dependent on CD40 cross-linking. However, activation of PB B cells in the CD40 system in the presence of IL-2, IL-4, IL-10, combinations of these cytokines or supernatant of anti-CD3-stimulated T cells failed to induce detectable IgM-RF, whereas total IgM production was considerable. From these results we conclude that conditions to activate physiological RF(+) B cells require additional contact besides CD40--CD40L interactions between T and B cells. Since the requirements for RF production were similar using PB B cells from HC and patients with RA it is suggested that the regulatory properties of RF(+) precursors in the PB B cell compartment is equal among these groups. Together, these results indicate that conditions for the induction of total Ig and physiological RFs are different.

Autoimmune mechanisms involved in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) was one of the first systemic disorders to be considered an autoimmune disease. Two major aspects of RA suggest a fundamental immune-mediated derangement in the disease: (1) presence of often massive lymphocytic infiltrates and activated CD4(+) T cells within the inflamed hypertrophied synovium, and (2) production of large amounts of rheumatoid factor (RF) by B-cells and plasma cells in the involved synovium itself. The actual tissue damage to joints and extra-articular structures affected by the disease comes from the rheumatoid inflammatory pannus or granulomatous collections of cells called rheumatoid nodules. RF production has long been studied as a prime example of apparent autoantibody production in association with the basic underlying disease process. RA patients who belong to subtype HLA DR4, Dw4 (DR B1 or 0401, Dw14 (0404/0408), or Dw15 (0405/0410) are most likely to be seropositive for RF and to have severe progressive disease. RFs are felt to represent an autoantibody associated with RA, since they show principal specificity for structures on the C gamma 3 and C gamma 2 (Fc) domains of IgG. Recent work by our group has defined a number of solvent-exposed linear RF-reactive epitopes on C gamma 3 and C gamma 2 using a strategy of overlapping 7-mers of primary sequence. RFs also have been demonstrated to react with two different regions, SKDWSFY and LSQPKIVKWDR, on beta 2-microglobulin (beta 2m). Many of the RF-reactive sites on C gamma 2 and C gamma 3 as well as on beta 2m show common immunodominant valines, leucines, tryptophanes, arginines, lysines, and glutamines, thus comprising common reactive residues. In the future, this approach may provide more direct insight into the specificities of other autoantibodies.

Humoral immunity in Hansen's disease

For many years immune response in leprosy has been studied. Since 1960 several reports dealing with humoral immunity have been described in the literature. Different autoantibody rates occur in leprosy. There is an increase in the prevalence of autoantibodies in elderly patients with long standing disease, in lepromatous leprosy and in those with reactional states. The differences in rates among various studies are attributed to different methods and variations among patient samples concerning age, gender, polar forms, therapy and other elements. The prevalence of numerous antibodies, immune complexes, cryoglobulins and complement levels have been studied by many authors. This also highlights the importance of the more recent reviews of anti-Mycobacterium leprae glycolipid antibodies such as the anti-phenolic glycolipid-I antibodies in which titers are variable and depend on genetic factors.

Tropical rheumatology. Immunological aspects

The presence of auto-antibodies in infectious diseases continues to puzzle and provoke. It is hoped that sequencing studies in particular will yield further clues as to the role and mechanism of production of autoantibodies in infectious diseases. This, in turn, may also provide further insights into the role of auto-antibodies in auto-immune diseases. From a practical clinical viewpoint, the search for improved auto-antibody tests and new diagnostic markers with improved sensitivity and specificity must continue in the tropics. Until this is achieved, the results of auto-antibody tests in persons living in the tropics, persons from the tropics or patients with tropical infections, must be interpreted with caution.