Anti-chromatin and anti-histone antibodies in Egyptian patients with systemic lupus erythematosus

Clinical use of anti-histone antibodies in idiopathic and drug-induced lupus

Anti-histone antibodies (AHAs) make their appearance in a number of systemic autoimmune diseases including systemic lupus erythematosus (SLE) and drug-induced lupus erythematosus (DILE). Although being known for over 50 years, they are poorly studied and understood. There is emerging evidence for their use in predicting clinical features of SLE, diversifying their clinical use. AHAs, however, are probably less prevalent in DILE than once thought owing to a move away from older DILE drugs to modern biological agents which do not appear to elicit AHAs. This review examines the historical studies that have defined AHAs and looks at some of the recent work with these autoantibodies.

Anti-nucleosome antibodies increase the risk of renal relapse in a prospective cohort of patients with clinically inactive systemic lupus erythematosus

An important goal in the management of systemic lupus erythematosus (SLE) is the prediction of relapses. This study assesses whether anti-nucleosome antibodies (anti-NCS) increase the risk of renal relapse in inactive SLE. A prospective cohort of 115 patients with inactive SLE (M-SLEDAI ≤ 2) were followed for 12 months to assess the development of relapse (increase of M-SLEDAI ≥ 4) and specific renal flare (renal SLEDAI ≥ 4). At baseline, we identified potential risk factors for relapse, including anti-NCS. At baseline, 18 (16%) of the 115 patients with inactive SLE were anti-NCS positive. At the 12-month follow-up, anti-NCS-positive patients had a higher incidence of renal relapse compared to anti-NCS-negative patients (38.9% vs 13.4%, respectively). In Cox regression analysis, after adjusting for age, disease duration, anti-dsDNA, and immunosuppressive drugs, the presence of anti-NCS positivity at baseline increased the risk of renal relapse (HR: 5.31, 95% CI 2.03–13.92). Nevertheless, there were no differences in the incidence of other relapses in anti-NCS-positive versus anti-NCS-negative. Our results indicate that in inactive SLE, anti-NCS determination can be useful for identifying patients with a higher risk of developing renal relapse. Interestingly, this study identified that continued use of oral immunosuppressive therapy in patients with inactive SLE can reduce the risk of renal relapse.

Infliximab-induced autoantibodies: a multicenter study

The purpose of this study was to assess autoantibody incidence in patients treated with infliximab for various diseases, and the development of autoimmune diseases using a multicenter, longitudinal, open-label, phase IV observational study. All patients received anti-tumor necrosis factor (anti-TNF) according to local treatment guidelines. The autoantibodies assessed before and after infliximab treatment were ANA, anti-Sm, anti-dsDNA, anticardiolipin IgM/IgG, anti-Scl70, anti-centromere B, anti-chromatin, anti-ribosomal P, anti-Sm-RNP, anti-RNP A, anti-RNP 68 kD, anti-La/SSB, anti-Ro/SSA 52 kD and 60 kD, and anti-Jo1. ANA was determined by indirect immunofluorescence on HEp-2 cells (INOVA); the remaining was assessed using BioPlexTM 2200. The Fisher exact test, Wilcoxon test, and the McNemar were used when appropriate.Two hundred eighty-six patients were included (139 with rheumatoid arthritis, 77 with ankylosing spondylitis, 29 with inflammatory bowel disease, 27 with psoriatic arthritis, and 14 with psoriasis), 167 females and 119 males, with mean age of 46.3 years. Subjects received at least five infusions of infliximab (6-month treatment). A significant difference was observed in antinuclear antibody (ANA) detection between samplings (p = 0.001). Among patients that had ANA before treatment (n = 92), six became ANA-negative, 48 had increased titers, 29 maintained, and nine decreased titers after treatment; a total of 186 patients had a positive ANA after treatment. Fine speckled nuclear pattern was most commonly observed (both before and after infliximab treatment). The number of patients with anti-dsDNA had a statistically significant increase (p = 0.003). No significant differences were noted for anticardiolipin and the remaining autoantibodies tested. Among the 286 patients included in the study, only one (0.35 %) showed clinical signs of drug-induced lupus, presenting elevated ANA and anti-dsDNA titers that normalized once treatment was discontinued. Infliximab induced the formation of autoantibodies in the combined population (ANA and anti-dsDNA with no apparent clinical importance).

Co-Positivity for Anti-dsDNA, -Nucleosome and -Histone Antibodies in Lupus Nephritis Is Indicative of High Serum Levels and Severe Nephropathy

OBJECTIVE

To characterize the significance of correlated autoantibodies in systemic lupus erythematosus (SLE) and its complication lupus nephritis (LN) in a large cohort of patients.

METHODS

Clinical data were statistically analyzed in 1699 SLE patients with or without nephritis who were diagnosed and treated during 2002-2013 in the northeast region of China. Reactivity to a list of 16 autoantibodies was detected by the serum test Euroline ANA profile (IgG). Serum titers of the anti-nucleosome autoantibodies were measured by ELISA assays. Kidney biopsies were examined by pathologists. Immune complex deposition was identified by immunohistochemistry stain.

RESULTS

Simultaneous positivity of anti-dsDNA, -nucleosome and -histone antibodies (3-pos) was prevalent in SLE patients with LN compared to Non-renal SLE patients (41% vs 11%, p< 0.001). Significant correlations were found between any two of the above three anti-nucleosome antibodies in LN patients. In comparison to non-3-pos cohorts, 3-pos patients with LN had significantly higher serum levels of the three antibodies and more active disease; was associated with type IV disease; suffered from more severe renal damages; received more intensive treatment and had worse disease outcome. The serum levels of these three autoantibodies in 3-pos LN patients were significantly decreased when they underwent clinical recovery.

CONCLUSIONS

Simultaneous reactivity to anti-dsDNA, -nucleosome and -histone antibodies by Euroline ANA profile (IgG) may indicate severe nephropathy in patients with SLE.

Epidemiology and risk factors for chronic kidney disease in Chinese patients with biopsy-proven lupus nephritis

BACKGROUND

Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE). It is the most common secondary glomerulonephritis leading to end-stage renal disease.

AIM

The purpose of this study is to evaluate the epidemiology and risk factors of chronic kidney disease (CKD) in Chinese patients with LN.

METHODS

Clinical, laboratory, renal histopathology, treatment and outcome data were collected and retrospectively analysed in LN patients with or without CKD.

RESULTS

At the end of the study, 94 (45.63%) patients were identified as having CKD among 206 individuals with renal biopsy-proven LN. Renal function, represented by serum creatinine and estimated glomerular filtration rate, was significantly decreased in the CKD patients (P = 0.008 and P < 0.001, respectively) at the time of the kidney biopsy. Compared with the non-CKD group, significantly increased proportions of hypertension (P < 0.001), serositis (P = 0.042) and anti-histone antibody positivity (P = 0.004) were detected in the CKD patients. Renal pathological activity and chronicity index scores were significantly increased in the CKD group (P < 0.001 for all). Finally, hypertension (hazard ratio (HR) 2.432, 95% confidence interval (CI) 1.575-3.754, P < 0.001), anti-histone antibody (HR 2.907, 95% CI 1.837-4.600, P < 0.001), and tubular atrophy (HR 1.248, 95% CI 1.007-1.547, P = 0.043) were independent risk factors for CKD.

CONCLUSIONS

Hypertension, anti-histone antibody and tubular atrophy are independent risk factors for CKD in Chinese LN patients.

Simultaneous positivity for anti-DNA, anti-nucleosome and anti-histone antibodies is a marker for more severe lupus nephritis

OBJECTIVE

The purpose of this study is to examine autoantibody profile of systemic lupus erythematosus (SLE) patients with lupus nephritis (LN) and to establish the correlation between the antibody reactivity and disease activity of LN.

METHODS

Autoantibodies and serological parameters were measured and analyzed in 589 SLE patients. The associations of the co-positivity of anti-dsDNA, -nucleosome and -histone antibodies (3-pos) with clinical, serological and outcome parameters were analyzed.

RESULTS

At the study entry, the prevalence for anti-dsDNA (61.52 % vs. 34.11 %, P < 0.0001), anti-nucleosome (56.09 % vs. 37.21 %, P = 0.0002) and anti-histone (49.35 % vs. 33.33 %, P = 0.0013) antibodies in patients with LN were significantly higher than that in patients without LN. Patients with 3-pos had a higher proportion of proliferative renal lesions (class III + IV). The incidence of a poor renal outcome (7.14 % vs. 2.52 %, P = 0.0174) in LN patients with 3-pos was significantly higher than those without 3-pos. Moreover, the rate of remission (73.63 % vs. 82.37 %, P = 0.0245) was significantly reduced and recurrence increased (58.90 % vs. 23.44 %, P < 0.0001) in 3-pos patients as compared to that in non 3-pos within the LN group.

CONCLUSION

Our data indicate a strong association between the 3-pos and renal disease activities, especially proliferative glomerulonephritis. The ability of 3-pos to predict renal flares may lead to major additional benefits in the follow-up of these patients.

Are anti-nucleosome antibodies a better diagnostic marker than anti-dsDNA antibodies for systemic lupus erythematosus? A systematic review and a study of metanalysis

BACKGROUND

Methods to detect anti-nucleosome antibodies (ANuA) have been available for more than 10 years and the test has demonstrated its good sensitivity and high specificity in diagnosing systemic lupus erythematosus (SLE). Despite these data produced through clinical and laboratory research, the test is little used.

OBJECTIVE

To verify the diagnostic performance of methods for measuring ANuA and to compare them with those for anti-dsDNA antibodies.

DATA SOURCES

A systematic review of English and non-English articles using MEDLINE and EMBASE with the search terms "nucleosome", "chromatin", "anti-nucleosome antibodies" and "anti-chromatin antibodies". Additional studies were identified checking reference lists in the selected articles.

STUDY SELECTION

We selected studies reporting on anti-nucleosome tests performed by quantitative immunoassays, on patients with SLE as the index disease (sensitivity) and a control group (specificity). A total of 610 titles were initially identified with the search strategy described. 548 publications were subsequently excluded based on abstract and title. Full-text review was undertaken as the next step on 62 publications providing data on anti-nucleosome testing; 25 articles were then excluded because they did not include either SLE patients or a control group, and 37 articles were selected for the metanalysis. Finally, a sub-metanalysis study was conducted on the 26 articles providing data on both ANuA and anti-dsDNA antibody assays in the same series of patients.

DATA EXTRACTION

Extraction of data from selected articles was performed by two authors independently, using predefined criteria: the number of patients with SLE as the index case, and the number of healthy or diseased controls; specification of the analytical method used to detect anti-nucleosome and anti-dsDNA antibodies; the cut-off used in the study; and the sensitivity and specificity of the assay. Demographic and clinical data on the population investigated (adults or children; lupus patients with or without nephritis; patients with active or inactive disease) were also recorded and analyzed in a separate evaluation.

RESULTS

The systematic review and metanalysis showed that the overall sensitivity of the ANuA assay is 61% (confidence interval-CI, 60-62) and the specificity 94% (CI, 94-95). The overall positive likelihood ratio is 13.81 (CI, 9.05-21.09) and the negative likelihood ratio 0.38 (CI, 0.33-0.44). The odds ratio for having SLE in ANuA-positive patients is 40.7. The comparative analysis on anti-dsDNA antibodies conducted on the 26 studies which provided data for both antibodies showed that ANuA have greater diagnostic sensitivity (59.9% vs 52.4%) and a specificity rating only slightly higher (94.9% vs 94.2%). The probability that a subject with positive ANuA have SLE is 41 times greater than a subject with negative ANuA, while for anti-dsDNA the probability is 28 times greater. These figures are even more impressive in children, in whom ANuA have an odds ratio for the diagnosis of SLE of 146, compared to 51 for anti-dsDNA antibodies. In selected studies, ANuA (p<0.0001) but not anti-dsDNA antibodies (p=0.256) were significantly associated with disease activity measured by the international score systems. However, neither antibody appears to correlate with kidney involvement.

CONCLUSIONS

Data from the metanalysis have shown that ANuA have equal specificity but higher sensitivity and prognostic value than anti-dsDNA antibodies in the diagnosis of SLE. Despite a certain heterogeneity among the various studies, the use of ANuA appears more efficacious than anti-dsDNA.

Measurement of autoantibodies in pediatric-onset systemic lupus erythematosus and their relationship with disease-associated manifestations

OBJECTIVE

To evaluate an autoantibody profile in pediatric-onset systemic lupus erythematosus (SLE) patients to determine clinical and statistical associations with disease-associated manifestations.

METHODS

Sera from 53 SLE patients and 22 healthy individuals were collected. Antibodies to C1q, histone, chromatin, ribosomal P, dsDNA, and high-avidity dsDNA were measured by enzyme-linked immunosorbent assays. Patient records were evaluated for clinical and laboratory associations.

RESULTS

The most prevalent autoantibodies found in the SLE cohort were anti-C1q antibodies (n = 32, 60%), which correlated significantly with proteinuria and decreased complement levels (P < 0.05). Anti-C1q and antihistone antibodies were significantly elevated in patients with class III/IV nephritis compared with class I/II/V nephritis (P = 0.041). SLE patients with active nephritis at the time of sample collection demonstrated significantly elevated levels of anti-C1q antibodies compared with those without active nephritis, also exhibiting 100% sensitivity for active nephritis, proteinuria, and urinary casts. Antibodies to C1q, dsDNA, histone, and chromatin were significantly elevated in patients with active disease (P < 0.01). Chart-documented anti-dsDNA antibodies were positive in 28 SLE patients, INOVA anti-dsDNA antibodies in 25 patients, and high-avidity anti-dsDNA antibodies in 8 patients. Antihistone correlated significantly with leukopenia and hemolytic anemia (P < 0.05).

CONCLUSIONS

This study indicates the importance of measuring anti-C1q antibodies in pediatric-onset SLE patients because elevated anti-C1q antibodies may be more indicative of renal disease activity, showing significant correlation with proteinuria, urinary casts, and active nephritis. Antibodies to C1q, histone, chromatin, and dsDNA exhibited the strongest association with clinical features, indicating the importance of measuring all of these antibodies in pediatric-onset SLE patients.