Antinuclear antibodies (ANA): immunologic and clinical significance

Urinalysis in patients with neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Increasing evidence has demonstrated that aquaporin-4 (AQP4) immunoglobulin G causes damage to the kidney in neuromyelitis optica spectrum disorder (NMOSD). However, changes in urinalysis in NMOSD have not been investigated thus far. Our objective was to evaluate the changes in urinalysis in NMOSD patients.

METHODS

Case data were collected from 44 patients with AQP4 antibody-positive NMOSD, 53 patients with multiple sclerosis (MS) and 79 age- and sex-matched healthy controls. Analyses of early morning urine and 24-h urine samples comparing NMOSD with MS patients were conducted.

RESULTS

In the acute phase, urine pH levels (P < 0.001) and urine specific gravity levels (P < 0.001) from NMOSD patients were significantly higher and lower, respectively, than for MS patients. 24-h urine sodium and 24-h urine volume from NMOSD patients were significantly higher than for MS patients (both P = 0.001). A 24-h urine volume higher than 2500 ml (odds ratio 11.7, 95% confidence interval 1.863-73.066) and a 24-h urine sodium higher than 200 mmol (odds ratio 16.0, 95% confidence interval 2.122-120.648) are more likely to occur in NMOSD patients in the acute phase than in MS patients.

CONCLUSIONS

The urinalysis results were significantly different between NMOSD patients and MS patients. The pathophysiological changes in AQP4 antibody-positive NMOSD patients were not limited to the central nervous system.

Oxidized Low-Density Lipoprotein Immune Complex Priming of the Nlrp3 Inflammasome Involves TLR and FcγR Cooperation and Is Dependent on CARD9

Oxidized low-density lipoprotein (oxLDL) is known to activate inflammatory responses in a variety of cells, especially macrophages and dendritic cells. Interestingly, much of the oxLDL in circulation is complexed to Abs, and these resulting immune complexes (ICs) are a prominent feature of chronic inflammatory disease, such as atherosclerosis, type-2 diabetes, systemic lupus erythematosus, and rheumatoid arthritis. Levels of oxLDL ICs often correlate with disease severity, and studies demonstrated that oxLDL ICs elicit potent inflammatory responses in macrophages. In this article, we show that bone marrow-derived dendritic cells (BMDCs) incubated with oxLDL ICs for 24 h secrete significantly more IL-1β compared with BMDCs treated with free oxLDL, whereas there was no difference in levels of TNF-α or IL-6. Treatment of BMDCs with oxLDL ICs increased expression of inflammasome-related genes Il1a, Il1b, and Nlrp3, and pretreatment with a caspase 1 inhibitor decreased IL-1β secretion in response to oxLDL ICs. This inflammasome priming was due to oxLDL IC signaling via multiple receptors, because inhibition of CD36, TLR4, and FcγR significantly decreased IL-1β secretion in response to oxLDL ICs. Signaling through these receptors converged on the adaptor protein CARD9, a component of the CARD9-Bcl10-MALT1 signalosome complex involved in NF-κB translocation. Finally, oxLDL IC-mediated IL-1β production resulted in increased Th17 polarization and cytokine secretion. Collectively, these data demonstrate that oxLDL ICs induce inflammasome activation through a separate and more robust mechanism than oxLDL alone and that these ICs may be immunomodulatory in chronic disease and not just biomarkers of severity.

Utility of immunologic testing in suspected rheumatologic disease

The use of diagnostic testing in the clinical practice of medicine has been a shifting landscape from the time that the first blood test was utilized. This is no different in the field of immunology and in particular rheumatology. As the field of immunology is relatively young, the clinical tests are not well established and therefore guidelines for use are still under debate. In this review, we seek to look at some of the key autoantibodies, as well as other tests that are available to diagnose suspected rheumatologic disease, and examine how to best use these tests in the clinic. In particular, we will focus on the anti-nuclear antibodies, anti-neutrophil cytoplasmic antibodies, complement, cryoglobulins, rheumatoid factor, and anti-citrullinated protein antibodies.

Cutaneous manifestations of mixed connective tissue disease: study from a tertiary care hospital in eastern India

Context:

Mixed connective tissue disorder is an uncommon disease. Some scientists are reluctant to recognize it as a separate entity. Some others have defined this ailment. Cutaneous features of this condition are unique. Researchers from India have described these features to relate to those described in the studies from other parts of the globe.

Aims:

This study aims to delineate the skin manifestations of clearly defined mixed connective tissue disease (MCTD) patients, to compare them with those established as overlap syndrome, and to relate them with studies from other parts of the globe.

Settings and Design:

Successive patients who fulfilled the specific criteria for MCTD presenting in the skin outpatient department of a tertiary care hospital in eastern India were clinically examined from 2009 for 3 years.

Materials and Methods:

The number of participants was 23 and the dermatological features of these were compared with 22 patients with overlap syndrome. The antibody to uridine-rich U1 ribonucleoprotein was measured for all patients.

Statistical Analysis Used:

SPSS (Version 17) and MedCalc (Version 11.6).

Results:

The Male: Female ratio among the MCTD patients was 1:6.67 and that of the overlap syndrome was 1:10. Twenty patients of the MCTD group presented with synovitis as against only seven in the overlap group. Raynaud's phenomenon was present in some of the subjects. Puffy fingers were rare in our study. Facial numbness was reported by four of those suffering from MCTD. Antinuclear antibody (ANA) was essentially of a speckled pattern in this disease

Conclusions:

Cutaneous indicators of MCTD are distinct from overlap syndrome. Knowledge of these manifestations prevalent in a region may lead to early diagnosis of the disease.

Predictive value of antinuclear antibodies in autoimmune diseases classified by clinical criteria: Analytical study in a specialized health institute, one year follow-up

Introduction: Determination of antinuclear antibodies (ANA) by indirect immunofluorescence (IIF) is usually the initial test for the diagnosis of systemic rheumatic diseases (SRD). Assigning predictive values to positive and negative results of the test is vital because lack of knowledge about ANAs and their usefulness in classification criteria of SRD leads to inappropriate use. Methods: Retrospective study, ANA tests requested by different specialties, correlation to patients' final diagnosis. Results: The prevalence of autoimmune disease was relatively low in our population yielding a low PPV and a high NPV for the ANA test. 40% of the patients had no clinical criteria applied prior to test. Coexistence of two or more autoimmune disorders affects prevalence and predictive values. Conclusion: Application of the test after careful evaluation for clinical criteria remarkably improves the positive likelihood ratio for the diagnosis.

Clearance deficiency and systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is a fairly heterogeneous autoimmune disease. Impaired clearance functions for dying cells may explain accumulation of nuclear autoantigens in various tissues of SLE patients. Our data show that in a subgroup of patients with SLE, apoptotic cells accumulated in the germinal centres of the lymph nodes. Apoptotic material was attached to the surfaces of follicular dendritic cells. Furthermore, we found an accumulation of apoptotic cells in the skin of patients with cutaneous lupus after UV exposure. Granulocytes and monocytes in whole blood of SLE patients showed a reduced uptake of albumin- and polyglobin-coated beads. Furthermore, we analysed sera from SLE patients in migration assays and observed that the attraction signals for macrophages were reduced by sera of approximately 25% of the SLE patients. Analyses of high-affinity DNA binding IgG autoantibodies of SLE patients revealed that those antibodies had gained their DNA reactivity in a germinal centre reaction. We suggest a stepwise maturation from a non-anti-DNA reactive B cell to an anti-dsDNA autoreactive B cell. We conclude that impaired clearance in early phases of apoptosis leads to a secondary necrotic status of the cells. Danger signals are released; modified autoantigens are accessible, favouring an autoimmune reaction.

Genetic control of anti-Sm autoantibody production in NOD congenic mice narrowed to the Idd9.3 region

Anti-Smith (anti-Sm) autoantibodies are directed to proteins in the small-nuclear ribonucleoprotein (snRNP) family and are considered specific for systemic lupus erythematosus (SLE) in both humans and mice. We previously established that NOD.c3c4 mice, carrying B6 and B10 congenic segments from chromosomes 3 to 4 on an nonobese diabetic (NOD) background, and NOD.Idd9R28 mice, carrying a B10 segment on c4 alone, developed significant penetrance of anti-Sm antibody production. Here we determine autoantibody incidence in additional NOD.Idd9 congenic strains and use a congenic mapping approach to narrow the interval necessary for enhanced autoantibody production to a approximately 5.6-Mb region containing insulin-dependent diabetes (Idd)9.3. The Idd9.3 interval contains the candidate molecule cluster of differentiation (CD)137, which is a member of the tumor necrosis factor (TNF) receptor superfamily, functions as an inducible costimulator of T cells, and controls T-B interactions. The NOD and B10 CD137 alleles have sequence polymorphisms and different functional effects on T cells; the NOD CD137 allele mediates weaker T cell proliferative responses and decreased interleukin (IL)-2 production after CD137-mediated costimulation. Our work establishes CD137 as a candidate gene for control of autoantibody production in NOD.Idd9.3 congenic mice.

Acute lymphocytic leukemia presenting as lupus-like syndrome

Lupus-like syndrome has been described in association with various malignancies. Acute lymphocytic leukemia presenting as lupus-like syndrome has been reported in children. We report a 22-year-old male patient who developed joint and muscle ache, pleurisy, leukopenia, thrombocytopenia, fever, weight loss and was found to have positive antinuclear antibodies. Repeated peripheral smear twice did not show any abnormal cells. Six months later, bone marrow biopsy showed acute lymphocytic leukemia.

Are Isolated Antinucleolar Antibodies a Marker of Scleroderma?

This study was designed to determine the prevalence and positive predictive value of isolated antinucleolar antibody (ANA) in scleroderma patients. We identified 73 rheumatology clinic patients with isolated ANAs. ANA titers greater than 1:160 were considered positive. The overall prevalence of isolated ANAs was 2.9%. The prevalence of isolated ANAs in scleroderma, systemic lupus erythematosus (SLE), and rheumatoid arthritis were 20.3%, 2.68%, and 3.3%, respectively. Scleroderma and SLE were present in 12 patients (16.4%) each. Other rheumatologic disorders identified in these patients were RA (12.3%), undifferentiated connective tissue disease (8.2%), mixed connective tissue disease (4.1%), vasculitis (6.8%), fibromyalgia (8.2%), osteoarthritis (5.4%), crystal-related arthropathy (6.8%), seronegative arthritis (2.7%), sarcoidosis (4.1%), and others (8.2%). There were no statistically significant differences in the median ANA titers in scleroderma versus systemic lupus (P = 0.16) or undifferentiated connective tissue disease (P = 0.18). The median titers were higher in scleroderma in comparison with rheumatoid arthritis (P = 0.01), osteoarthritis (P = 0.007), fibromyalgia (P = 0.001), and crystal-related arthropathy (P = 0.009). Isolated ANAs have poor sensitivity (20.3%) and the positive predictive value for this test is only 16.4% for scleroderma.

Anti-Sm: its predictive value in systemic lupus erythematosus

The clinical manifestations of 131 rheumatic disease patients with anti-Sm antibody were studied. A variety of standard tests was utilized in the study, namely, the FANA test with mouse kidney as substrate for the assay of ANA, the Crithidia test for anti-double stranded DNA (anti-dsDNA) and double immunodiffusion for detecting antibodies to extractable nuclear antigens. The patients were grouped according to the presence of anti-Sm alone, or anti-Sm with some other antibodies. There were 17 with anti-Sm alone; 55 with anti-Sm+anti-RNP; 15 with anti-Sm+anti-dsDNA; and 44 with anti-Sm+anti-RNP. The result of our study showed that although anti-Sm could be found in other diseases, it was exclusively detected in SLE only if anti-dsDNA was also present. Further, the SLE patients with anti-Sm alone had more frequent central nervous system manifestations than other groups of patients. The renal manifestation was observed more frequently in the group of SLE patients with anti-Sm+anti-dsDNA (92.9%). Among other major manifestations, haematologic involvement had a tendency to be less common in the group of patients with anti-Sm alone. The study concludes that the presence of anti-Sm antibody may be of some value to predict the clinical outcome.

Toxoplasma infection and systemic lupus erythematosus: analysis of the serological response by immunoblotting

AIMS

To examine the serological response of patients with systemic lupus erythematosus (SLE) and toxoplasma infection and to compare the blot profiles with those from immunocompetent subjects of similar immune response.

METHODS

Forty serum samples from patients with SLE were tested for toxoplasma antibodies using the dye and indirect haemagglutination tests. Specific IgM was measured by mu-capture enzyme linked immunosorbent assay (ELISA). The sera were immunoblotted using antigen strips prepared from the RH strain of Toxoplasma gondii. For comparison, control blots were prepared from pooled sera from immunocompetent subjects with serological evidence of acute (pool 1), or chronic (pool 2) toxoplasma infection, or with no evidence of infection (pool 3).

RESULTS

Some of the blot profiles from the patients with SLE were compatible with the corresponding serology but others showed considerable variation, particularly among the IgM blots. The blots from sera with low dye test titres suggested that the latter could be false positive results.

CONCLUSIONS

Toxoplasma infection may enhance the production of autoantibodies which, when combined with the high titres characteristic of SLE, might interfere in the dye test and other serological tests. Immunoblotting could prove useful in the immunocompromised for confirming the presence of specific toxoplasma antibodies and for the staging of infection in those with positive serology.

The clearance of a monoclonal anti-DNA antibody following administration of DNA in normal and autoimmune mice

To study the assembly of DNA-anti-DNA complexes in vivo, we have measured the clearance from blood and organ localization of a murine IgG2a monoclonal anti-DNA antibody, called 6/0, following the infusion of DNA intravenously or intraperitoneally. Intraperitoneal DNA caused a profound acceleration of 6/0 anti-DNA clearance that was dose dependent and demonstrable after the infusion of as little as 1.9 microgram per gram of body weight of single-stranded DNA. The antibody was cleared primarily in the liver without increased deposition in the kidney. Intraperitoneal infusions of DNA also accelerated the clearance of 6/0 in autoimmune MRL-lpr/lpr mice. In contrast, intravenous DNA given in comparable doses caused only a slight increase in 6/0 antibody clearance; this accelerated clearance was seen only at low antigen doses and only during the first 10 min following DNA infusion. Using double-radiolabeling techniques, 6/0 and Cl.18, an IgG2ak myeloma protein without anti-DNA activity, were found to disappear from blood at a comparable rate in both B6D2 mice and MRL-lpr/lpr mice. These results suggest that the DNA-anti-DNA immune complexes can form in vivo but that this process is profoundly affected by the manner in which DNA enters the circulation. In addition, the results suggest that DNA-dependent clearance is not a major pathway for anti-DNA metabolism in normal or at least one strain of autoimmune mice.

Rheumatoid factors in the sera of patient with gastrointestinal carcinoma

One hundred and nineteen patients with gastrointestinal (GI) malignancy (80 colorectal, 25 gastric and 14 pancreatic carcinoma) were studied for rheumatoid factors (RF), antinuclear antibodies (ANA) and immunoglobulin levels and the findings correlated with size of tumor, stage of disease and survival. Twenty three (19.3%) of the patients were RF seropositive compared to 5.7% of 70 matched controls (P = 0.02). In two thirds of the seropositive patients RF were detected prior to the initiation of treatment. The proportion of RF seropositivity increased significantly in patients with tumors larger than 4 cm and in patients with Stage D disease. The authors found a high incidence of ANA in the patients: 32.4% compared to 8% in normal subjects (P less than 0.01), but the proportion of RF in this group was not significantly different. Survival distributions of the RF positive cases were different from that of the other patients (18 versus 25 months median survival); however, this was not statistically significant. These findings indicate that RF in GI cancer patients sera is not rare and can be related mainly to "tumor load," although not considerably affecting survival.

Z-DNA-specific antibodies in human systemic lupus erythematosus

Naturally occurring antibodies to left-handed Z-DNA have been shown to be present in the sera of human patients with systemic lupus erythematosus (SLE). These antibodies are of two types. One type reacts with both denatured DNA and Z-DNA. The other type is specific for Z-DNA and remained in the serum after removal of the cross-reactive antibody by extensive absorption on a denatured DNA affinity column. The antibodies appear to be specific for SLE and do not appear frequently in other rheumatic diseases. The presence of the antibody in SLE is correlated with the clinical manifestations of the disease, in parallel with antibodies to native and denatured DNA.

Antinuclear factors in murine alloantisera

We have demonstrated that anti-Thy 1.1 and certain of H-2 alloantisera contain an antinuclear factor (ANF) detected by fluorescent antimouse IgG. The incidence of ANF positive antisera that we report may actually be an underestimate. ANF is present in sera not only from our laboratory but also from other sources; thus ANF is not an artifact of our laboratory. ANF is not identical to alloantibody, and the ANF appears to be of an autoimmune nature. A variety of environmental and genetic factors may influence the appearance of ANF in anti-H-2 sera, but we believe that the consistent detection of ANF in sera directed against H-2.31,34 or against H-2.4 suggest that some specific aspect of immune stimulation by these H-2 antigens, and likely by other H-2 antigenic specifications, induces the appearance of ANF. It is not known whether it is these K and D antigens or other determinants associated with the H-2 complex that may actually provide the immune stimulation for ANF induction. The particular mechanisms that may be operating to induce ANF cannot be determined at present. We are continuing with experiments to define what parameters influence the appearance of ANF in alloantisera.

Laboratory investigation of systemic lupus erythematosus

Diagnosis of systemic lupus erythematosus (SLE) requires documentation of multisystem involvement and the presence of antinuclear antibodies. In almost all cases of SLE, these autoantibodies are detected at significant titer with a sensitive screening test such as the fluorescent antinuclear antibody test. After other diagnostic possibilities, such as rheumatoid arthritis, have been excluded, several laboratory tests (hematocrit determination, complement tests, anti-native DNA assays) are available to monitor the response to therapy.

Laser therapy of rheumatoid arthritis

Thirty people with classical or definite rheumatoid arthritis received laser exposure to a Q-switch neodymium laser that operated at 1.06 micrometer with an output of 15 joules/cm2 for 30 nsec. One hand was lased at the proximal interphalangeal (PIP) and metacarpal phalangeal (MCP) joints, whereas the other hand was sham lased. The patient, physician, and occupational therapy evaluators did not know which hand was being lased. Twenty-one patients noted improvement of both their MCP and PIP joints of both hands during laser therapy. Twenty-seven noted improvement of their PIP joints and 26 noted improvement of the MCP joints during therapy. Heat, erythema, pain, swelling, and tenderness all improved with time in both hands, but the lased hand had more significant improvement in erythema and pain. There was also significant improvement in grasp and tip pressure on the lased side. The level of circulating immune complexes as measured by platelet aggregation decreased during lasing. The improvement may be related to laser exposure. The exact role that laser radiation has upon rheumatoid arthritis and its mechanism of action remain to be elucidated.

Serum-serum interactions in autoimmune mice

Sera from a majority of old, sick mice of the MRL/l strain interact with other MRL/l sera to form visible immunoprecipitates and fix complement. The mouse sera can be divided into two sets such that interset interactions are far more common than intraset ones. The reactive principle in each mouse serum is IgG in the form of an intermediate-sized complex. Reactivity between sera is dependent on IgG anti-IgG specificities.

Transverse myelitis in mixed connective tissue disease

Neurologic disease is reported to occur in just 10% of patients with mixed connective tissue disease (MCTD). Most commonly, this is manifested by mild trigeminal neuralgia. This report details the clinical and neuropathologic findings of transverse myelitis in a patient with MCTD. Neurologic features include progressive areflexic paraplegia with loss of bowel and bladder function. Neuropathologically there was thinning of the thoracic cord, widespread loss of axons and myelin sheaths, reactive astrocytosis, macrophage formation, vascular thickening with perivascular chronic inflammatory cell infiltration, and calcium deposits. This case demonstrates that severe neurologic disease unresponsive to therapy can occur in MCTD.

Clinico-laboratory aspects of anti-nuclear and anti-native DNA antibody tests

Available techniques for detection of anti-nuclear antibodies are here briefly reviewed. The relatively insensitive LE cell test has been largely supplanted by the indirect immunofluorescent ANA test which should be reported in terms of titre and pattern. Specific measurement of nDNA antibodies is now a regular technique in SLE diagnosis and management.

Circulating immune complexes in the idiopathic interstitial pneumonias

We determined circulating immune complex levels and their correlation with pulmonary histopathology, immunofluorescence and steroid responsiveness in 24 patients with idiopathic interstitial pneumonias. Levels were elevated in all but three of 16 patients with cellular disease, but in none of eight with diffuse fibrosis (P less than 0.001). Granular deposition of IgG, usually with elevated levels, but in only 11 per cent of those with normal levels (P less than 0.001). The radiographic and physiologic response to corticosteroid therapy was better in patients with initially elevated levels than in those with normal levels (P less than 0.03). Circulating immune complexex are present in patients with cellular idiopathic interstitial pneumonias, have a pathogentic role in this disease and may identify a patient population that is potentially steroid responsive.