Diagnostic performance of anti-β2 glycoprotein I and anticardiolipin assays for clinical manifestations of the antiphospholipid syndrome

Leptospirosis-associated disturbances of blood vessels, lungs and hemostasis

The frequency of massive pulmonary hemorrhages seems to be increasing in different geographic areas; however, there is no clear explanation for this trend. Although data on the pathogenesis of such complications are scarce, recent research indicates a potential role of autoimmunity and/or multifactorial mechanisms. However, much information is already available on the disturbance of hemostasis and blood vessels in leptospirosis-related literature, even if some contradictory concepts coexist. The purpose of this review is to integrate both new and classical information from human and animal studies on severe pulmonary forms of leptospirosis and disorders of hemostasis and blood vessels. We propose that the involvement of blood vessels in leptospirosis must be understood as a sepsis-like, diffuse process of endothelial activation/damage rather than as a classical systemic vasculitis. Pulmonary hemorrhages are most likely multifactorial and there has recently been evidence against the role of autoimmunity; however, further investigation of strain variations, exposure to hydrocarbons and association with renal dysfunction is required. Thrombocytopenia is a consistent feature of leptospirosis but it is not clear whether it is attributable to sepsis-related mechanisms. In addition, further investigation is required to define whether platelet function is activated or inhibited during severe leptospirosis.

Leptospirosis pulmonary haemorrhage syndrome is associated with linear deposition of immunoglobulin and complement on the alveolar surface

Leptospirosis is a zoonotic infection associated with severe diseases such as leptospirosis pulmonary haemorrhage syndrome (LPHS). The cause of pulmonary haemorrhage is unclear. Understanding which mechanisms and processes are involved in LPHS will be important in treatment regimens under development for this life-threatening syndrome. In the present study, we evaluated 30 lung specimens from LPHS patients and seven controls using histology and immunohistochemistry (detection of IgM, IgG, IgA and C3) in order to describe the pathological features associated with this syndrome. Immunoglobulin deposits were detected on the alveolar surface in 18/30 LPHS patients. Three staining patterns were observed for the immunoglobulins and C3 in the lung tissues of LPHS patients: AS, delicate linear staining adjacent to the alveolar surface, which was indicative of a membrane covering the luminal surface of type I and II pneumocyte cells; S, heterogeneous staining which was sporadically distributed along the alveolar septum; and IA, weak, focal intra-alveolar granular staining. Human LPHS is associated with individual and unique histological patterns that differ from those of other causes of pulmonary haemorrhage. In the present study, it was found that the linear deposition of immunoglobulins (IgA, IgG and IgM) and complement on the alveolar surface may play a role in the pathogenesis of pulmonary haemorrhage in human leptospirosis.

Biosensor analyses of serum autoantibodies: application to antiphospholipid syndrome and systemic lupus erythematosus

Autoimmune disorders are rare human diseases characterized by the presence of circulating autoantibodies that bind the body's own structural compounds as target antigens. The detection of autoantibodies is important for the diagnostic process. Immunofluorescence and immunoassay methods do not allow a reliable characterization of binding characteristics. Therefore, novel analytical techniques should be considered. This review describes the application of surface plasmon resonance biosensor systems for the diagnosis of autoimmune disorders. The covalent attachment of native antigens to the sensor chip is a suitable method for obtaining highly reproducible analyses of autoantibodies, allowing the evaluation of kinetic rate and affinity constants, and it may enable the identification of disease-relevant autoantibodies linked to disease progression. The autoantibody microarray is another future-oriented technique. Patterns of differential antigen recognition should allow early diagnosis. This is due to the fact that a broad range of autoreactive B cell responses in autoimmune disorders can only be mirrored by including a sufficient number of antigens in a microarray format.

Antiphospholipid antibodies in HIV-positive patients

Antiphospholipid (aPL) antibodies classically have been associated with thrombotic phenomena and abortion in patients with autoimmune diseases. The objective of the present work was to evaluate the frequency of such antibodies in patients infected with HIV and study its association with the presence of clinical manifestations of antiphospholipid syndrome (APS). Using a transversal study, a population of patients diagnosed with HIV, identified through an enzyme-linked immunosorbent assay (ELISA) test and confirmed by Western blotting, aged above 17 years old, was investigated. Through a standard questionnaire, the presence of APS manifestations was investigated, as well as the frequency of rheumatic manifestations. Antibodies against beta2 glycoprotein I (anti-beta2 GPI) and anticardiolipin (aCL) IgA, IgG, and IgM were investigated by the ELISA method using commercial kits (QUANTA Lite, INOVA Diagnostics). Ninety patients were studied, 47 (52.2%) male and 43 (47.8%) female. Clinical manifestations of APS were detected in 12 patients (13.3%) of the studied population, whereas arthralgia was the most common rheumatic manifestation (38.9%). Of the 90 patients, 40 (44.4%) were reactive for at least one type of aPL antibody (aCL and/or anti-beta2 GPI). The frequency of aCL was 17.8%, from which 15 (16.7%) had aCL IgG, 3 (3.3%) IgM, and 1 (1.1%) IgA. The frequency of the anti-beta2 GPI antibody was 33.3%, from which 29 (32.2%) were positive for isotype IgA, 4 (4.4%) isotype IgM, and 1 (1.1%) isotype IgG. No association was observed between immunoreactivity for aPL antibodies in general or each isotype in particular and the presence of APS manifestation. In the present study, it was possible to observe a relatively high frequency of aPL antibodies, particularly for isotype IgA anti-beta2 GPI in HIV. However, there was no association to APS manifestations, suggesting that such antibodies had no etiopathogenic role in these complications in patients with such retroviral infection.

Anti-cardiolipin antibodies and overall survival in a large cohort: preliminary report

BACKGROUND

Anti-cardiolipin antibodies have been associated with both arterial and venous thrombosis, but their overall impact on all-cause or vascular mortality is unknown. In this study, we evaluated the influence of anti-cardiolipin antibodies on all-cause and vascular mortality.

METHODS

All individuals who fulfilled the inclusion criteria (completeness of data, no admission from an intensive care unit, unique identification with name and date of birth) and whose anti-cardiolipin antibodies were measured between October 2002 and February 2004 were included in this study (n = 4756; 64% female; median age, 46 years). Death/survival and cause of death were obtained from the Austrian Death Registry. The median observation period was 1.5 years, and the study comprised 7189 person-years.

RESULTS

During the study period, 184 patients (3.9%) died. There were no associations between either anti-cardiolipin IgM or IgG antibodies and both vascular death and noncancer mortality as outcome variables in a Cox regression analysis adjusted for age and sex. In contrast, the risk of cancer-related mortality was increased 2.6-fold.

CONCLUSIONS

Anti-cardiolipin antibodies are associated with cancer mortality, likely as an epiphenomenon of malignancy, but they are not predictive of vascular mortality or noncancer mortality. Hence, although a clear association between anti-cardiolipin antibodies and (mostly nonfatal) vascular events has been described in the literature, our data indicate that this finding is not necessarily associated with an increase in vascular mortality.