Confirmation of antiphospholipid antibody positivity: a year's results in a cohort of 113 patients

Objective: To evaluate the confirmation rate of antiphospholipid antibodies (aPL), to analyze their behaviour at confirmation time, and to study the clinical value of their confirmation. Methods: Blood samples from 380 subjects, enrolled in this study from June 1, 2007 to May 31, 2008, were tested for anti-cardiolipin (aCL) and anti-beta2glycoprotein (aβ2GPI) antibodies using an ELISA method and for Lupus anticoagulant (LA) using a series of clotting tests. The samples of the 113 subjects resulting positive at the first testing time were assayed again to confirm antiphospholipid positivity. Results: aPL positivity was confirmed in 67 out of the 113 subjects (59.3%). Medium-high antibody levels of all, except IgM aCL, aPL/ELISA had a significantly higher confirmation rate with respect to that in subjects with low levels. The confirmation rate in the category I antibody patients (multiple positivity) was higher than that in the category II antibody subjects (single positivity). LA positivity was confirmed only when it was associated to other aPL. The cut-off of 40 GPL produced a confirmation rate equal to that resulting from a 99th percentile cut-off. Confirmation of aPL positivity made it possible for us to confirm the diagnosis of antiphospholipid syndrome (APS) in 8 out of the 113 subjects originally resulting positive (7,1%). APS clinical features were vascular thrombosis in 4 of these and pregnancy morbidity in the other 4. Conclusions: Our data emphasize aPL positivity confirmation selectivity, and medium-high antibody levels and category I antibodies (multiple positivity) had the best confirmation rates

Clinical significance of fluoroscopic patterns specific for the mitotic spindle in patients with reumatic diseases

Objective: we proposed to determine the clinical significance of anti-NuMA and anti-HsEg5 antibodies in a group of patients affected with rheumatic diseases. Materials and methods: indirect immunofluorescence on HEp-2000 cells at serum dilution of 1:40 was used to examin 26 sera which had previously showed a "mitotic spindle" fluoroscopic pattern type during laboratory routine. Results: 21 sera (80,7%) were identified with NuMA and 5 (19,3%) with HsEg5 patterns alone or associated with other ANA patterns. However only patients with isolated positiveness and that is 15 with NuMA and 4 with HsEg5 stainings were included in this study. Of the NuMA positive patients 5 were affected with arthropathies associated to different forms of thyroiditis, 2 with seronegative arthritis, 2 with antiphospholipid syndrome, 1 with systemic lupus erythematosus (SLE), 1 with rheumatoid arthritis, 1 with sicca syndrome, 1 with undifferentiated connective tissue disease, 1 with Mycoplasma pneumaniae infection and 1 with retinal thrombosis. Of the HsEg5 positive patients 3 were affected with SLE and 1 with seronegative arthritis. Conclusions: NuMA does not prevail in any defined rheumatic disease, while HsEg5 staining were more frequent (75%) in patients affected with SLE all of whom showing high antibody titres

Complement activation in the plasma and placentas of women with different subsets of antiphospholipid syndrome

Problem: As antiphospholipid antibody\u2010positive women with adverse pregnancy outcomes have higher plasma complement activation product levels, and the placentas of women with antiphospholipid syndrome (APS) exhibit C4d complement component deposition, complement activation involvement has been hypothesized in APS pregnancy complications. Method of study: Plasma levels of C5a and C5b\u20109 complement components of 43 APS non\u2010pregnant patients and 17 pregnant APS women were measured using enzyme\u2010 linked immunosorbent assay. The results were compared with those of 16 healthy non\u2010pregnant women and eight healthy pregnant women, respectively. Placenta samples of five APS patients at high risk of pregnancy complications and of five healthy controls were subjected to immunoblotting analysis with specific antibodies to C5b\u20109 and CD46, CD55, CD59 complement regulators. Results: The mean plasma C5a and C5b\u20109 levels were significantly higher in the nonpregnant APS patients with previous thrombosis \ub1 pregnancy morbidity (P = .0001 and P = .0034, respectively) and in the pregnant APS women with adverse outcomes (P = .0093 for both). Similarly, C5b\u20109 amounts were significantly higher in the adverse pregnancy outcome placenta (P = .0115) than in those associated to a favorable outcome. The mean CD46, CD55 and CD59 amounts were, instead, lower, although not always significantly, in the placentas of all the high\u2010risk APS women with respect to the control placentas. Conclusion: Data analysis demonstrated that there was significant complement activation in the more severe subset of APS patients and in only the adverse pregnancy outcome APS women. Further studies will clarify whether the lower CD46, CD55, and CD59 expressions in the APS placentas are limited to only high\u2010risk APS patients

Prevalence and clinical significance of cathepsin G antibodies in systemic sclerosis

Objectives: To evaluate the prevalence and clinical significance of cathepsin G antibodies in patients affected with systemic sclerosis (SSc, scleroderma). Methods: 115 patients affected by SSc, 55 (47,8%) with diffuse scleroderma (dSSc) and 60 (52,2%) with limited scleroderma (lSSc), were tested for cathepsin G antibodies by ELISA method. Moreover these sera were evaluated by indirect immunofluorescence (IIF) on ethanol and formalin fixed human neutrophils. Results: By means of the ELISA method 16 (13,9%) patients were found to be sera positive for anti-cathepsin G, 2 (12.5%) of which showed a perinuclear fluorescence pattern (P-ANCA) and 4 (25%) an atypical ANCA staining, while 10 (62,5%) were negative on IIF. The IIF on scleroderma sera revealed 5 (4,3%) P-ANCA and 18 (15,7%) atypical ANCA patterns. The anti-cathepsin G antibodies significantly prevailed in scleroderma sera (p=0.02) when their frequency was compared with that of healthy controls; while they were not significantly associated to any clinical or serological features of SSc patients. Conclusions: The anti-cathepsin G antibodies were significantly frequent in scleroderma sera; however, no clinical correlations were found. Thus, the significance of their presence in SSc still needs to be clarified

Lupus anticoagulant identifies two distinct groups of patients with different antibody patterns

Background: Whether antibodies directed to β2-Glycoprotein I (aβ2GPI) are responsible for LA activity is not well defined. However, in the absence of such antibodies the molecule responsible for LA phenomenon is unknown. Objective: The aim of this study was the biochemical identification of the target antigen epitope of aPL responsible of LA activity in the absence of aβ2GPI antibodies together with the biological and clinical characteristics of these patients in comparison with classical triple positive patients. Patients/methods: A comparison of patients with LA without (LA+/aβ2GPI−) and those with (LA+/aβ2GPI+) associated aβ2GPI antibodies was performed. Size exclusion chromatography and analytical chromatography were used to identify the molecule with LA activity in patients LA+/aβ2GPI-. Results and conclusions: Analytical size-exclusion chromatography revealed a peak of 996Kd with LA activity perfectly overlapping that of IgM anti phosphatidylserine/prothrombin (aPS/PT) antibodies. Similarly, all the 25 LA+/aβ2GPI− patients were positive for aPS/PT antibodies. LA+/aβ2GPI− compared to 33 LA+/aβ2GPI+ patients turned out to be significantly older, with a lower rate of previous thromboembolic events and a weaker LA activity. Search for aPS/PT and aβ2GPI antibodies in patients with LA is useful to identify two subgroups of LA at different risk of thromboembolic event

Antibodies Against Domain 1 and Domain 4/5 of β2 Glycoprotein I : Clinical Relevance in Obstetric Anti-Phospholipid Syndrome

Background/Purpose: The domain reactivity of antibodies against b2 glycoprotein I (anti-b2GPI) has been investigated in patients with thrombotic anti-phospholipid syndrome (APS), leading to the identification of antibodies targeting domain 1 of the molecule (anti-D1) as the most relevant autoantibody subpopulation. Scarce attention has been paid to the domain profiling of patients with pregnancy morbidity (PM). The aim of this study was to characterize the relevance of the fine epitope reactivity of anti-b2GPI antibodies in anti-phospholipid antibody (aPL)-associated PM. Methods: Women with persistent positivity for anti-b2GPI IgG antibodies at medium-high titers, with at least one pregnancy and without systemic autoimmune disease were included. Anti-D1 and anti-D4/5 antibodies were tested using a chemiluminescent immunoassay and a research ELISA assay, respectively (QUANTA Flash b2GPI IgG and QUANTA Lite, Inova Diagnostics). Statistical analysis was performed using R package. Results: 138 women fulfilling the inclusion criteria were retrospectively recruited at 3 referral centres. 49 patients (35%) had obstetric APS, 18 (13%) thrombotic APS, 37 (27%) thrombotic and obstetric APS while 34 women (25%) were asymptomatic aPL carriers. 81 women (60%) displayed triple aPL positivity, 32 (23%) had two positive aPL test and 23 (17%) carried a single aPL positivity. 110 patients had at least one untreated pregnancy, culminating in a live birth in 31 cases (28%). 89 women underwent a pregnancy course while receiving treatment, with 71 women (80%) having a live birth. A significant difference in the distribution of positive anti-D1 antibodies emerged between women with or without PM and with or without thrombosis (p=0.05, c2=2.710 and p<0.001, c2=12.174, respectively); no significant difference was observed for anti-D4/5 antibodies (Table 1). In a multivariate logistic regression model also encompassing treatment, positive anti-D1 antibodies, but not anti-D4/5, were significantly associated with obstetric complications, conferring an odds ratio (OR) of 2.32 (p=0.040 and p=0.724, respectively). Triple aPL positivity corrected by treatment significantly predicted PM (p=0.015, OR=2.78). Conclusion: Our data suggest that anti-D1 antibodies are significantly associated not only with thrombosis but also with obstetric morbidity while positive anti-D4/5 antibodies are not predictive of PM

Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management

Atrioventricular block is classified as congeni- tal if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental pas- sage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive car- diac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe perma- nent cardiac pacing in almost all patients, including those with structural heart abnormalities