Immune-Related Urine Biomarkers for the Diagnosis of Lupus Nephritis.

The kidney is one of the main organs affected by the autoimmune disease systemic lupus erythematosus. Lupus nephritis (LN) concerns 30-60% of adult SLE patients and it is significantly associated with an increase in the morbidity and mortality. The definitive diagnosis of LN can only be achieved by histological analysis of renal biopsies, but the invasiveness of this technique is an obstacle for early diagnosis of renal involvement and a proper follow-up of LN patients under treatment. The use of urine for the discovery of non-invasive biomarkers for renal disease in SLE patients is an attractive alternative to repeated renal biopsies, as several studies have described surrogate urinary cells or analytes reflecting the inflammatory state of the kidney, and/or the severity of the disease. Herein, we review the main findings in the field of urine immune-related biomarkers for LN patients, and discuss their prognostic and diagnostic value. This manuscript is focused on the complement system, antibodies and autoantibodies, chemokines, cytokines, and leukocytes, as they are the main effectors of LN pathogenesis.

Characterization of Type-I IFN subtype autoantibodies and activity in SLE serum and urine.

BACKGROUND/OBJECTIVE: Type-I interferons contribute to pathogenesis in systemic lupus erythematosus, including nephritis. Interferons consist of a family of 16 proteins yet are often characterized in patients without knowledge of the specific interferon subtypes involved. Different interferons may function in the kidneys, and other organs, relative to what is often measured in patient blood. Moreover, antibodies to interferons may potentially modulate systemic or organ-specific interferon activity. The aim of this study was to characterize global interferon activity levels and identify autoantibodies to the 12 interferon α subtypes in patient serum and urine. METHODS: Interferon activity levels in serum and urine were measured using an interferon bioassay. Anti-interferon and anti-cytokine autoantibodies were measured by ELISA. Serum and urine samples were also characterized for their ability to neutralize the biological activity of exogenously added interferons. RESULTS: Serum interferon activity was increased in 62% of systemic lupus erythematosus patient samples, relative to healthy donor controls, whereas binding interferon α autoantibodies to at least one interferon α subtype were found in 68% of the samples evaluated. High Systemic Lupus Erythematosus Disease Activity Index scores were significantly (p = 0.001) associated with patient samples containing interferon α autoantibodies to three or more interferon α subtypes in their serum. Interferon α autoantibodies that potently block interferon activity were rare (∼5% of samples), but collectively bound to all 12 interferon α subtypes. Urine interferon activity and interferon α autoantibody profiles did not correlate with their serum counterparts, suggesting immune responses in systemic lupus erythematosus kidneys can be distinct from those measured in serum. Analysis of autoantibodies to 15 additional cytokines in serum identified higher frequencies of granulocyte-macrophage colony-stimulating factor and interleukin 17A autoantibodies, suggesting these signaling pathways may potentially contribute, with interferons, to systemic lupus erythematosus pathogenesis. CONCLUSIONS: The measurement of autoantibodies to multiple interferon subtypes in serum and urine may provide an alternative method for following interferon-mediated systemic lupus erythematosus disease activity. The results suggest autoantibodies might be used for patient monitoring and/or identifying additional cytokine signaling pathways that are functioning in different systemic lupus erythematosus patients.

Serum and urine lipidomic profiles identify biomarkers diagnostic for seropositive and seronegative rheumatoid arthritis.

Objective: Seronegative rheumatoid arthritis (RA) is defined as RA without circulating autoantibodies such as rheumatoid factor and anti-citrullinated protein antibodies; thus, early diagnosis of seronegative RA can be challenging. Here, we aimed to identify diagnostic biomarkers for seronegative RA by performing lipidomic analyses of sera and urine samples from patients with RA. Methods: We performed untargeted lipidomic analysis of sera and urine samples from 111 RA patients, 45 osteoarthritis (OA) patients, and 25 healthy controls (HC). These samples were divided into a discovery cohort (n = 97) and a validation cohort (n = 84). Serum samples from 20 patients with systemic lupus erythematosus (SLE) were also used for validation. Results: The serum lipidome profile of RA was distinguishable from that of OA and HC. We identified a panel of ten serum lipids and three urine lipids in the discovery cohort that showed the most significant differences. These were deemed potential lipid biomarker candidates for RA. The serum lipid panel was tested using a validation cohort; the results revealed an accuracy of 79%, a sensitivity of 71%, and a specificity of 86%. Both seropositive and seronegative RA patients were differentiated from patients with OA, SLE, and HC. Three urinary lipids showing differential expression between RA from HC were identified with an accuracy of 84%, but they failed to differentiate RA from OA. There were five lipid pathways that differed between seronegative and seropositive RA. Conclusion: Here, we identified a panel of ten serum lipids as potential biomarkers that can differentiate RA from OA and SLE, regardless of seropositivity. In addition, three urinary lipids had diagnostic utility for differentiating RA from HC.

Serum and Cerebrospinal Fluid Testing in Optic Neuropathy Patients with Malignant Tumors.

PURPOSE: To evaluate the value of serum and cerebrospinal fluid (CSF) testing in optic neuropathy (ON) patients with malignant tumors. METHODS: Fourteen patients clinically diagnosed as ON with malignant tumors but without intracranial or orbital mass in MRI were included in this study. Detailed medical records including medical history, complete ophthalmic examination, colour fundus photography, visual field test, orbital MRI examination, serum and CSF testing data were collected and analyzed. The diagnosis of paraneoplastic optic neuropathy (PON) based on the 2004 recommended criteria of the paraneoplastic syndrome- Euronetwork consortium for paraneoplastic neurological disorders, and current adaption for neuropathies. All patients underwent serum tests for pathogens and autoantibodies including antinuclear antibodies, anticardiolipin antibodies, antineutrophil cytoplasmic antibodies, AQP4-Ab and MOG-Ab, as well as CSF tests for malignant cells under microscope. Serum paraneoplastic antibodies were detected in PON patients. Monkey cerebellar tissue-based assay was used to detect unknown serum anti-neuron antibodies in PON patients with negative paraneoplastic antibody testing results. RESULTS: Fourteen ON patients were classified as four groups based on their clinical and MRI characteristics, as well as serum and CSF testing results: [1] definite PON, 6 cases (11 eyes); [2] possible PON, 3 case (5 eyes); [3] meningeal carcinomatosis-associated optic neuropathy (MCON), 4 cases (6 eyes); [4] infiltrative optic neuropathy (ION), 2 cases (2 eyes). Malignant cells were found under microscope in CSF samples from MCON and ION patients, contrast to no malignant cells in CSF samples from PON cases. All 14 ON patients with malignant tumors showed negative results in serum tests for pathogens and autoantibodies. Serum paraneoplastic antibodies were tested in PON patients, anti- CV2, anti-Yo, and anti- amphiphysin were detected positive in 2, 1, and 1 case, respectively, in definite PON group, whereas no serum paraneoplastic antibody detected in possible PON group. Two unknown serum antineuronal antibodies (an anti- Purkinje cell antibody and an anti-granular cell antibody) were detected using monkey cerebellar tissue-based assay in 2 of 5 PON patients with negative paraneoplastic antibody test results. CONCLUSIONS: Serum and CSF tests are of great importance in differentiating different subtypes of ON with malignant tumors. Current diagnosis of PON still depends on combination of clinical and MRI manifestations, as well as serum and CSF tests. Tissue-based assay may help to detect new biomarkers for ON etiology and diagnosis.

Rapidly progressive glomerulonephritis after introduction of certolizumab pegol: a case report.

Tumour necrosis factor (TNF) inhibitors are used against a variety of connective tissue diseases, including rheumatoid arthritis. Contrarily, although rare, TNF inhibitors are known to induce autoimmune diseases, such as systemic lupus erythematosus and psoriasis as a paradoxical reaction. We experienced a case of rapidly progressive glomerulonephritis after introduction of certolizumab pegol. The patient was a 30-year-old woman who was previously diagnosed with rheumatoid arthritis in X-8. She received treatment with methotrexate (8 mg/week) and infliximab (3 mg/kg/8 weeks), following which she showed low disease activity and remission. In September X-1, methotrexate and infliximab were discontinued and certolizumab pegol was introduced because she desired to bear children. In March X, the patient experienced renal dysfunction, and urinary protein analysis revealed positivity for myeloperoxidase anti-neutrophil cytoplasmic autoantibody. Renal biopsy showed crescentic glomerulonephritis, and the patient was diagnosed with rapidly progressive glomerulonephritis due to TNF inhibitor-induced microscopic polyangiitis. As she desired to bear children, rituximab was introduced in addition to corticosteroids, which led to remission of the symptoms. TNF inhibitors should be discontinued in patients who develop rapidly progressive glomerulonephritis, and these patients should be treated with immunosuppressive drugs, such as massive corticosteroids and cyclophosphamide. In the present case, rituximab was useful for not only the treatment, but also for the preservation of fertility.

Camptothecin and Topotecan, Inhibitors of Transcription Factor Fli-1 and Topoisomerase, Markedly Ameliorate Lupus Nephritis in (NZB × NZW)F1 Mice and Reduce the Production of Inflammatory Mediators in Human Renal Cells.

OBJECTIVE: To examine the therapeutic effects of camptothecin (CPT) and topotecan (TPT), inhibitors of transcription factor Fli-1 and topoisomerase, on lupus nephritis in (NZB × NZW)F1 (NZBWF1) mice, and to examine the effects of CPT and TPT on inflammatory mediators in human renal cells. METHODS: Female NZBWF1 mice were treated with vehicle, cyclophosphamide (CYC), CPT (1 mg/kg or 2 mg/kg), or TPT (0.03 mg/kg, 0.1 mg/kg, or 0. 3 mg/kg) by intraperitoneal injection twice a week, beginning at the age of 25 weeks (n = 8-10 mice per group). Blood and urine were collected for monitoring autoantibodies and proteinuria. Mice were euthanized at 40 weeks, and renal pathology scores were assessed. Human renal endothelial and mesangial cells were treated with CPT or TPT, and cytokine expression was measured. RESULTS: None of the NZBWF1 mice treated with 1 mg/kg or 2 mg/kg of CPT or 0.3 mg/kg of TPT had proteinuria >100 mg/dl at the age of 40 weeks. One of 8 mice treated with 0.1 mg/kg of TPT and 1 of 10 mice treated with CYC had proteinuria >300 mg/dl, whereas 90% of the mice treated with vehicle had proteinuria >300 mg/dl. Compared to vehicle control, mice treated with 1 mg/kg or 2 mg/kg of CPT, 0.1 mg/kg or 0.3 mg/kg of TPT, or CYC had significantly prolonged survival, attenuated renal injury, diminished splenomegaly, reduced anti-double-stranded DNA autoantibody levels, and reduced IgG and C3 deposits in the glomeruli (all P < 0.05). Human renal cells treated with CPT or TPT had reduced expression of Fli-1 and decreased monocyte chemotactic protein 1 production following stimulation with interferon-α (IFNα) or IFNγ. CONCLUSION: Our findings indicate that low-dose CPT and TPT could be repurposed to treat lupus nephritis.

Quantitative targeted GC-MS-based urinary steroid metabolome analysis for treatment monitoring of adolescents and young adults with autoimmune primary adrenal insufficiency.

PURPOSE: Primary adrenal insufficiency (PAI) is a rare and life-threatening disease. A recent Endocrine Society guideline argued against hormonal monitoring of glucocorticoid replacement. However, about 50% of adolescents and young adults (AYAs) with chronic diseases are non-adherent to their treatment regimens. Therefore, suitable hormonal monitoring of glucocorticoid replacement would be highly desirable in AYAs with PAI. We investigated whether quantitative targeted gas chromatography-mass spectrometry urinary steroid metabolome analysis would be suitable for monitoring glucocorticoid replacement in AYAs with autoimmune PAI. METHOD: Retrospective analysis of 21 urinary steroid profiles of four AYAs aged 15.6 ±â€¯2.0 years with autoimmune PAI on hydrocortisone and fludrocortisone treatment. 24-hr cortisol metabolite excretion rates (CMERs) were calculated using the sum of major seven urinary cortisol metabolites. CMERs were transformed into z-scores according to reference values of healthy age- and sex matched subjects. RESULTS: Three patients showed good treatment adherence (17 of 21 samples). Mean CMER of these samples was 7.4 ±â€¯1.8 mg/m2/d, corresponding to a z-score of 1.8 ±â€¯1.1. CMER reflected 59.7 ±â€¯14.5% of prescribed hydrocortisone dosages. A forth patient displayed clinical symptoms of PAI during treatment. CMER was only 0.3 mg/m2 (-3.4 z), reflecting only 3.1% of prescribed hydrocortisone dosage, compatible with lack of treatment adherence. Thereafter, the parents supervised the intake of tablets and treatment adherence improved. CONCLUSION: Quantitative targeted GCMS steroid metabolome analysis could support monitoring of glucocorticoid replacement treatment in patients with PAI.

The Presence of Some Humoral Immunologic Indicators and Clinical Manifestations in Cryoglobulin Positive Heroin Addicts without Evidence of Hepatitis Virus Infection.

INTRODUCTION: Cryoglobulins are single or mixed immunoglobulins that are subject to reversible precipitation at low temperatures. OBJECTIVE: The aims of this paper were: 1. Comparison of cryoglobulin positive (CP), cryoglobulin negative (CN) heroin addicts and the control group (CG) in terms of serum immunoglobulins IgG, IgA and IgM and complement components C3 and C4; 2. Comparison of CP and CN heroin addicts in terms of rheumatoid factor (RF) and circulating immune complexes (CIC); 3. Assessment of clinical manifestations in CP heroin addicts. METHODS: This is a comparative study of cases (outpatients) treated at the University Clinic of Toxicology in Skopje over 3.5 years, from January 2009 to June 2012. In this study 140 heroin addicts without HbsAg were examined, seronegative for HCV and HIV infections.They were divided into 2 groups: 70 CP and 70 CN heroin addicts. A previously designed self-administered questionnaire was used as a data source on participants. All heroin addicts underwent the following analyses: urea and creatinine in serum; creatinine in urine; proteinuria; 24-hour proteinuria; IgM, IgG, IgA, C3, C4; RF; CIC; creatinine clearance; ECG; toxicological analyses for opioids in a urine sample; cryoglobulins. In addition to these 2 groups, IgG, IgA, IgM, C3 and C4 were also examined in 70 healthy subjects (CG). RESULTS: The study showed that there was no statistically significant difference between CP, CN heroin addicts and CG regarding the concentration of IgA, IgG, IgM, C3 and C4, and between CP and CN regarding the concentration of CIC. There was significant difference between CP and CN regarding the concentration of RF. The following conditions were significantly more frequently manifested in CP than in CN heroin addicts: arthralgia, Raynaud's phenomenon, respiratory difficulties, neurological disorders, manifested skin changes, hematuria, 24-hour proteinuria levels, and decreased renal clearance. CONCLUSION: There were no differences in concentrations of IgG, IgA, IgM, C3, C4 and CIC, while there was a difference in concentration of RF between CP and CN heroin addicts. Clinical manifestations (arthralgias, Raynaud's phenomenon, respiratory, neurologic, renal disorders and skin changes) were more common in CP heroin addicts.

Autoantibodies and autoantigens in the urine of SLE patients.

Autoantibodies against RNA polymerase I (RNAPI), DNA, La and ribosomal P proteins were detected in the urine of systemic lupus erythematosus (SLE) patients, many with normal protein excretion rates. In a number of cases, the antibodies were detectable in the urine but not the serum sample of the same patient. The presence and relative concentrations of the urinary autoantibodies correlated with disease activity. RNAPI antigens were detected in the urine of SLE patients by radioimmunoassay and immunoblotting using rabbit antisera prepared against the purified holoenzyme. Immunoaffinity purification of the rabbit anti-RNAPI with SLE urine proteins resulted in antibodies directed primarily against the largest RNAPI subunit (S1; 194 kDa). Antibodies prepared against recombinant fusion proteins representing the DNA binding regions of human RNAPI(S1) reacted with a 35 kDa SLE urinary protein, a putative fragment of RNAPI(S1). Ribosomal protein P0 was detected in SLE patients' urine by immunoblotting, using rabbit antiserum prepared against recombinant human P1 fusion protein. The relative quantities of urinary P0 correlated with disease status. Analysis of urinary autoantibodies and corresponding antigens in conjunction with analysis of serum autoantibodies may be of value for the purpose of monitoring disease activity.

Urine selenium changes during pregnancy do not correlate with thyroid autoantibodies in a mildly iodine deficient population.

Selenium (Se) is a key component of iodinases; higher Se levels are associated with lower titers of antithyroid peroxidase antibodies (anti-TPO). Pregnancy exerts profound effects on thyroid function and autoimmunity. To assess the relationship of urine Se levels with thyroid function and autoimmunity in pregnant women residing in Athens, Greece, we studied prospectively 47 euthyroid women in uncomplicated singleton pregnancies (mean age + SD: 30 + 5 years) in each trimester, measuring urine Se levels, urine iodine, plasma thyrotropin (TSH), free thyroxine and triiodothyronine (FT4 and FT3), as well as levels of anti-TPO antibodies. Changes of the measured parameters were assessed over each trimester; thyroid parameters were assessed with relation to Se levels. Urine Se dropped by the third trimester, whereas urine iodine did not change appreciably during pregnancy. TSH and anti-TPO did not show appreciable changes; FT4 and FT3 gradually decreased as the pregnancy advanced. No relationship between urine Se levels and anti-TPO was found. During pregnancy, changes in urine Se levels accompany mild changes in thyroid function. However, we did not find some association between these changes and thyroid autoimmune activity over this period, probably because the effect of Se on thyroid autoimmunity may only become apparent in case of excess Se fortification.

Dangerous small B-cell clones.

The detection of a monoclonal immunoglobulin in serum or urine usually raises concerns about the size of the underlying B-cell-derived clone and possible systemic effects caused by its expansion. However, a small clone can synthesize a very toxic protein, producing devastating systemic damage and protean clinical presentations. The resulting "monoclonal component-related diseases," although difficult to diagnose, may be progressive and even fatal. The monoclonal protein can aggregate and deposit systemically as occurs in light-chain amyloidosis, monoclonal immunoglobulin deposition disease, crystal-storing histiocytosis, and monoclonal cryoglobulinemia. Alternatively, some monoclonal proteins possess antibody activity toward autogenous antigens and cause chronic cold agglutinin disease, mixed cryoglobulinemia, and peripheral neuropathies. Other humoral mediators may contribute to neuropathy in variant disorders such as the POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome. The clone synthesizing the noxious monoclonal proteins is often small, and sensitive techniques may be required to detect these immunoglobulins. A delay in diagnosis can allow irreversible organ damage and dramatically shorten survival. Prompt recognition of suggestive signs and symptoms should trigger a thorough diagnostic approach to reach the correct diagnosis quickly, because this is the key to effective therapy. Although the treatment of these conditions is not optimal, significant advances have been made, improving the duration and quality of life.

Urine autoantibodies in interstitial cystitis.

Interstitial cystitis is a chronic bladder disease with certain features that suggest autoimmunity may play a role in initiating or maintaining the disease process. We therefore determined whether immunoglobulin fractions from 14 IC patient and 19 control urine specimens bound in vitro to primary cultures of human bladder epithelial cells, as well as epithelial cells from a variety of other tissues. Urine autoantibodies that bound to normal human bladder epithelial cells were present in 8 of 14 IC specimens (from 6 of 9 IC patients) as compared to 3 of 23 control specimens (from 2 of 17 control patients). These antibodies, which were usually also present at low titers in sera from these persons, bound to at least four nuclear or cytoplasmic antigens, with the specificity of autoantibodies from a given individual varying over time. The autoantibodies were not specific for normal or malignant bladder epithelial cells, but bound to epithelial cells from a variety of tissues. These data show that anti-epithelial cell autoantibodies are present in the urine of IC patients, but suggest that these antibodies are not likely to be a primary cause of this disease.

Urinary autoantibodies against intrinsic factor in pernicious anaemia patients.

In radioimmunoassay seven concentrated urines of penicious anaemia (PA) patients were positive for intrinsic factor (IF). Four were studied by gel filtration. Two contained both binding and blocking antibodies against IF, one had only blocking antibodies and one lacked both types of antibodies. The antibodies were mainly of the IgG-type. No such antibodies were found in the urine of a healthy person. None of the urines studied contained enough protein to be classified as proteinuric. Not until the interferences of the autoantibodies in the IF assay can be eliminated is the assay of value in the diagnosis of PA.

The Sdx antigen and antibody: biochemical studies on the inhibitory property of human urine.

Anti-Sdx is an IgM complement-binding autoantibody that defines a red cell antigen which is independent of I, i, Sp1 (Pr) and Gd. Hemagglutination by the antibody is unusually sensitive to variation in pH, salt, or other charged molecular species. The antibody is inhibited by urine from Sd(a+) persons, but inhibition is a nonspecific effect caused by charged molecules. No specific Sdx substance could be demonstrated, and Sdx antigen does not appear to be directly associated with the Sid blood group. In view of these findings we propose that this antibody should be renamed anti-Rx.

Improved measurement of anti-thyroglobulin IgG in urine of patients with autoimmune thyroid diseases by sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay.

Previously, antithyroglobulin IgG was assayed in dialyzed urine from patients with autoimmune thyroid diseases by a sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay), and most of the assay results were useful as a diagnostic aid for autoimmune thyroid diseases. However, dialysis of urine was laborious and time-consuming, and some results were less reliable due to low levels of anti-thyroglobulin IgG in urine. This paper describes some improvements of the assay. Useful assay results could be obtained for most of urine samples without dialysis, although some interfering substance(s) was suggested to be present in some urine samples before dialysis. Accurate assay results with no interference could be obtained after gel filtration by only two min centrifugation in place of dialysis. More reliable assay results for urine samples containing low levels of antithyroglobulin IgG were obtained after concentration using a molecular sieve.

Clinical significance of serum and urine prolactin levels in lupus glomerulonephritis.

UNLABELLED: Prolactin (PRL) has been involved in the pathogenesis of systemic lupus erythematosus (SLE) and hyperprolactinemia has been connected with systemic activity. However, the clinical significance of PRL has not been investigated in lupus glomerulonephritis (GN). METHODS: We studied SLE patients (ACR criteria) with biopsy-proven renal disease. Renal histology was classified according to World Health Organization (WHO) criteria. Renal function tests, albuminuria, complement levels (nephelometry), anti-DNA antibodies (C. luciliae) and serum and urine PRL concentrations (RIA) were determined at baseline and at 4-month intervals for one year. Renal activity was defined as mild, moderate or severe according to serum creatinine, creatinine clearance, albuminuria, red blood cells (RBC), and casts. RESULTS: There were 26 patients with mean age 28.5 y and mean disease duration 47.9 months. Twenty patients had diffuse proliferative glomerulonephritis (GN), four had focal GN and two had membranous GN with proliferative changes. Renal activity was mild in ten patients, moderate in ten and severe in six. Mean serum (24.7+/-5.3) and urine (0.90+/-0.36) PRL levels were higher in patients with severe renal activity (P < 0.05 compared with mild group). PRL levels decreased after treatment, but this trend was not uniform during the follow-up period. CONCLUSION: Hyperprolactinemia was prevalent in SLE patients and high levels of PRL in the serum and urine could be related to severe renal disease.

Measurement of anti-thyroglobulin IgG in urine of patients with autoimmune thyroid diseases by sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay).

Anti-thyroglobulin IgG in urine of patients with Graves' disease and chronic thyroiditis and healthy subjects was measured by a sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay). Anti-thyroglobulin IgG in dialyzed urine was reacted simultaneously with 2,4-dinitrophenylated thyroglobulin and thyroglobulin-beta-D-galactosidase conjugate. The immune complex formed consisting of the three components was trapped onto polystyrene balls coated with (anti-2,4-dinitrophenyl group) IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine, and transferred onto polystyrene balls coated with (anti-human IgG gamma-chain) IgG. beta-D-Galactosidase activity bound to the last polystyrene balls was assayed by fluorometry. Anti-thyroglobulin IgG was detected in most of the patients, but not in most of the healthy subjects; levels of anti-thyroglobulin IgG in urine of the patients were well correlated to those in serum of the same patients. The measurement of anti-thyroglobulin IgG in urine by the immune complex transfer enzyme immunoassay was suggested to be useful as a diagnostic aid for autoimmune thyroid diseases. The conventional standard ELISA was not sufficiently sensitive for measuring anti-thyroglobulin IgG in urine.