Detection of anti-IFI16 antibodies by ELISA: clinical and serological associations in systemic sclerosis.

OBJECTIVES: To validate the clinical significance of anti-IFI16 autoantibodies in SSc and assess their associations with serological markers of SSc. METHODS: A semi-quantitative ELISA was used to detect anti-IFI16 autoantibodies in the sera of 344 SSc patients from seven Italian hospitals and 144 healthy controls. SSc-associated autoantibodies [anti-RNA polymerase III (anti-RNAP III) antibodies, anti-centromere, anti-topo I] and IF patterns were evaluated using commercial assays. Statistical analyses were performed to test clinical and serological associations. RESULTS: The results of this study confirm a significant prevalence (29%) of anti-IFI16 antibodies in the SSc population (n = 344). Anti-IFI16 antibodies were also detected in 30% of the SSc patients who tested negative for both ACAs and anti-topo I (anti-Scl70) antibodies. In this subgroup of patients, anti-IFI16 antibodies were significantly associated with the limited cutaneous form of SSc with a sensitivity of 40% and a specificity of 81%. Moreover, analysis of the distribution of anti-RNAP III antibodies vs anti-IFI16 in the same SSc population showed that they were mutually exclusive. IIF revealed no association between anti-IFI16 and fluoroscopic patterns, due to a lack of IFI16 autoantigen in HEp-2 cells. Anti-IFI16 antibody levels were also significantly associated with heart involvement. CONCLUSIONS: Anti-IFI16 autoantibodies are frequently detected in SSc, displaying clinical and laboratory associations, and being particularly useful for diagnosis and disease classification in patients who are negative for other SSc serological markers.

Characterization for anti-cytoplasmic antibodies specificity by morphological and molecular techniques.

PURPOSE: The aim of our study was the characterization of anti-cytoplasmic antibodies by home-made morphological and biochemical techniques. Indeed, indirect immunofluorescence (IIF) on HEp-2 cell line is not always exhaustive in relation to the complexity of the antigens involved. METHODS: Nine serum samples with anti-cytoplasmic antibodies (2 anti-Golgi apparatus, 3 with diffuse pattern and 4 with lysosome/endosome-like pattern) were tested with fluorescent confocal microscopy, Western blot analysis and, when necessary, with electron microscopy technique. RESULTS: Confirmation of the IIF staining pattern was performed in confocal microscopy by comparison with the respective antibody marker. The anti-endoplasmatic reticulum positivity was also confirmed by electron microscopy evaluation. Both anti-lysosome/endosome and anti-endoplasmatic reticulum positivity have been definitely identified by Western blot through clear reactivity with calreticulin and LC3B, respectively. CONCLUSIONS: These results do not aim at representing a standard routine laboratory procedure. Electron microscopy evaluation cannot be proposed as a routine approach, but confocal microscopy technique may be offered in centralized reference laboratories. Newer technologies, especially multiplex immunoassay, can also lead to an easier identification of these autoantibodies, without recurring to a home-made immunoblotting. Only with a complete characterization we will be able to define the clinical relevance of anti-cytoplasmic antibodies, which are still considered as "esoteric" and not as "diagnostic" antibodies.

Diagnostic value of anti-mutated citrullinated vimentin in comparison to anti-cyclic citrullinated peptide and anti-viral citrullinated peptide 2 antibodies in rheumatoid arthritis: an Italian multicentric study and review of the literature.

In the last years, the detection of antibodies (Abs) against citrullinated peptides (ACPA) has largely replaced rheumatoid factor (RF) as the most helpful biomarker in the diagnosis of rheumatoid arthritis (RA). Current assays detect ACPA reactivity with epitopes on various different citrullinated proteins. Among these, anti-cyclic citrullinated peptide (CCP) Abs have been widely demonstrated to be an important diagnostic and prognostic tool because of their high specificity. Recently, citrullinated vimentin, a protein highly released in synovial microenvironment, has been identified as potential autoantigen in the pathophysiology of RA and an enzyme-linked immunosorbent assay (ELISA) for the detection of Abs directed against a mutated citrullinated vimentin (anti-MCV) was developed. Several recent studies evaluating the characteristics of anti-MCV in comparison to anti-CCP Abs, have given conflicting results. Anti-MCV have been demonstrated to perform better than anti-CCP as predictor of radiographic damage. Conversely, its additional diagnostic and prognostic role in comparison to anti-CCP in both early and established RA is controversial. Aim of this study was to evaluate the diagnostic performance of anti-MCV in RA and to compare it to anti-CCP and the recently developed assay targeting viral citrullinated peptide 2 (VCP2) in a large cohort of RA patients (n=285), healthy subjects and other disease controls (n=227). Anti-MCV resulted to have a sensitivity of 59% and a specificity of 92%. In comparison, anti-CCP and anti-VCP2 displayed a sensitivity of 77% and 61% and a specificity of 96% and 95%, respectively. Of interest, at the manufacturer recommended cutoff value of 20U/mL, a high percentage of healthy subjects as well as Epstein Barr (EBV) and hepatitis C (HCV) virus infected patients resulted anti-MCV positive. In our large cohort of RA patients, anti-MCV demonstrated lower sensitivity than anti-CCP and VCP2 test, thus not allowing to confirm previously published data. Moreover, the high rate of detection in infectious diseases limits its diagnostic value in undifferentiated arthritis.

NT pro-B-type natriuretic peptide levels are related to microvascular reperfusion in patients undergoing direct percutaneous transluminal coronary angioplasty for anterior ST-segment elevation myocardial infarction.

OBJECTIVES: The aim of this study was to describe the time course of NT pro-B-type natriuretic peptide (NT pro-BNP) levels in patients with large anterior ST-segment elevation myocardial infarction (STEMI) treated with primary angioplasty (PPCI) and to investigate the relationship between these values and both microvascular reperfusion and left ventricular (LV) function. BACKGROUND: The clinical efficacy of PPCI is largely dependent on the achievement of microvascular reperfusion. Myocardial blush is an angiographic method to evaluate the presence of effective reperfusion after PPCI. NT pro-BNP is a biomarker of LV stress whose levels are also related to clinical outcome in STEMI. METHODS: We studied 84 patients with large anterior STEMI treated with PPCI. NT pro-BNP was measured at baseline, after 2 days (day 2) and 7 days (day 7). Echocardiographic LV ejection fraction (LVEF) was measured at baseline, day 7 and after 6 months. Myocardial blush was graded immediately after PPCI. RESULTS: NT pro-BNP increased from admission to day 2 and decreased from day 2 to day 7 in patients with significant myocardial blush (grade 2-3) as well as in patients with 0-1 myocardial blush. However, in the latter group median NT pro-BNP levels globally increased from admission to day 7, whereas they decreased in patients with significant myocardial blush. Moreover, in such patients LVEF was higher at all time points than in patients with a grade 0-1 myocardial blush. CONCLUSION: This study shows that the time course of NT pro-BNP in the first week after an anterior STEMI is dependent on the effectiveness of microvascular reperfusion assessed after PPCI and reflects the evolution of LVEF over time.

Fecal calprotectin levels in patients with colonic polyposis.

CONTEXT: The usefulness of stool calprotectin determination in diagnosis of inflammatory disease of the colon has been reported; information about its usefulness for patients with polyposis are scarce, however. OBJECTIVE: To evaluate the significance of stool calprotectin concentrations for patients affected by colonic polyposis. PATIENTS: Sixty-three consecutive patients (35 males, 28 females, mean age 60.3 years, range 39-78 years) were enrolled: 26 patients (41.3%) with polyps, 17 patients (27.0%) with asymptomatic diverticular disease, and 20 subjects (31.7%) with normal endoscopic appearance of the colon. RESULTS: Stool calprotectin concentrations were 17.4 +/- 24.5 microg g(-1) for patients with colonic polyposis, significantly higher than concentrations for patients with diverticulosis (7.1 +/- 5.7 microg g(-1); P = 0.026) or for patients with normal appearance of the colon (calprotectin 6.0 +/- 5.8 microg g(-1); P = 0.003). For patients with a single polyp, stool calprotectin concentrations were similar to those for patients with multiple polyps. Calprotectin fecal concentrations for patients with sessile polyps and those with flat polyps were not significantly different. Calprotectin concentrations were not significantly related to the size of the polyps. CONCLUSION: Our data show that colonic polyposis may cause an increase in stool calprotectin values and that these colonic lesions should be suspected when elevated stool calprotectin concentrations are found.

Prevalence of undiagnosed celiac disease in the parents of preterm and/or small for gestational age infants.

OBJECTIVES: The aim of this study was to estimate the prevalence of undiagnosed celiac disease (CD) in the parents of preterm and/or small for gestational age (SGA) infants. METHODS: A sample of 1,714 parents (868 women, 846 men) of 905 preterm (<37 wk of gestational age) and/or SGA (<10th percentile of birthweight) infants consecutively born in Lombardy, Northern Italy, and not diagnosed with CD prior to pregnancy, were tested for CD. Diagnosis was based on antitissue transglutaminase and anti-endomysial antibodies and confirmed by duodenal biopsy. RESULTS: The overall prevalence of undiagnosed CD was 0.64% (95% confidence interval [CI] 0.32-1.15%), 0.92% (0.40-1.81%) in women and 0.35% (0.07-1.03%) in men. In the mothers of preterm infants prevalence of CD was 0.39% (0.05-1.39%). In the mothers of SGA infants prevalence of CD was 1.60% (0.64-3.27%), and the observed number of mothers with CD was 2.25 times higher than the expected one in the Italian female population (P = 0.039). Undiagnosed CD in mothers was associated with an increased risk of SGA birth (odds ratio 6.97, 95% CI 1.11-43.55%). CONCLUSIONS: While additional powered studies are needed, the present results suggest that the prevalence of undiagnosed CD in the mothers of SGA infants is higher than in the general female population.