[show abstract][hide abstract] ABSTRACT: On the basis of the role of immuno-mediated inflammation in atherosclerosis we investigated, (1) the prevalence of anti-endothelial cell antibodies (AECA) in ischaemic heart disease (IHD); (2) if beta2-glycoprotein I (beta2-GPI) was the target antigen of AECA; (3) the relationship between AECA, tissue factor (TF) and tissue factor pathway inhibitor (TFPI). In 93 consecutive IHD patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and 105 controls AECA were detected by ELISA on human umbilical vein endothelial cells (HUVEC). AECA positive sera were evaluated for anti-beta2-GPI antibodies by ELISA. TF and TFPI plasma levels were assessed by ELISA. Twelve of 93 (12.9%) IHD patients and only one of 105 controls (0.95%) were AECA positive. The prevalence of AECA was higher in unstable angina (UA) than in effort angina (EA) (P=0.01). Three of 12 AECA positive sera resulted positive for anti-beta2-GPI and showed a marked decrease in EC-binding when tested on HUVEC cultured in serum-free medium. The binding was restored by the addition of beta2-GPI. TF and TFPI levels were similar in AECA positive and AECA negative patients. The rate of angiographically documented clinical recurrences was 66.7% in the AECA positive and 14.8% in the AECA negative group (P=0.0004) with a significant relationship between restenosis and AECA (P<0.0001), unchanged by the inclusion of cardiovascular risk factors in the regression model. Our results suggest a 'role' for AECA in the immune-mediated inflammation in UA beta2-GPI is not the only AECA target antigen. AECA are not responsible for high TF and TFPI levels. The high rate of clinical recurrences after PTCA, confirmed by angiography, in AECA positive patients is in line with such a role and suggests further large-scale 'ad hoc' studies.
[show abstract][hide abstract] ABSTRACT: Ischemic cardiac manifestations have been reported in a various percentage of patients with anti-phospholipid antibodies. As concerns the relationship between anti-beta2 glycoprotein I antibodies (anti-beta2-GPI) and ischemic heart disease (IHD), it was investigated in only one coronary primary prevention study. We investigated the prevalence of anti-beta2-GPI in a well characterized group of patients with different clinical manifestation of IHD. Sera from 37 patients (mean age 62.7 +/- 9.9) with IHD (20 with unstable angina-UA and 17 with effort angina-EA) and from 40 healthy subjects, matched for age and sex, were tested for the presence of IgG and IgM anti-beta2-GPI using an ELISA technique. Eleven/37 patients (29.7%) resulted positive for anti-beta2-GPI. A positivity for IgG anti-beta2-GPI was found in 10 patients, 1 patient was positive for IgM and 1 for both isotypes. The prevalence of anti-beta2-GPI in the control group resulted significantly lower (2.5%; p < 0.005) than in patients with IHD. Positivity for anti-beta2-GPI was found in 9/20 (45%) patients with UA and only in 2/17 patients (11.8%) with EA (p = 0.0365). IgG anti-beta2-GPI levels (median 7.7U/ml, range 2.6-24.1) were significantly higher in patients with UA compared to patients with EA (median 4.6 U/ml, range 2.3-11.5; p = 0.02) and controls (median 3.15 U/ml, range 2.3-9.0; p < 0.0001); also IgM levels resulted higher in patients with unstable angina. A positivity for anti-beta2-GPI was observed in 4/13 patients (30.8%) with a previous myocardial infarction (MI) and in 7/24 (29.2%) patients without a previous MI. Our findings suggest that anti-beta2-GPI could represent an expression of the T-cell activation detectable in patients with unstable angina. The lack of a significant difference in the prevalence of these antibodies in patients with or without a previous MI suggests that anti-beta2-GPI are not induced by tissue necrosis.
[show abstract][hide abstract] ABSTRACT: Fifty-six sera from patients with autoimmune thyroiditis and 33 sera from patients with MPO-ANCA were examined in order to ascertain whether a cross reactivity between MPO-ANCA and anti-thyroperoxidase (aTPO) was present. Sera from 20 healthy donors aTPO and aMPO negative were used as control. About 95% of heat inactivated sera from patients with autoimmune thyroiditis and from controls gave positive results (atypical pANCA pattern) on ethanol-fixed neutrophils. The prevalence of positive results was significantly lower when unheated aTPO positive sera were used (17.8%). On the other hand, only 9% of sera with MPO-ANCA were positive on cryostatic sections of human thyroid. Indirect immunofluorescence tests (IF) on human neutrophils with MPO defect were negative with sera from patients with MPO-ANCA, but uninactivated sera with aTPO and positive for pANCA on normal neutrophils showed a very high prevalence of positive results (90%). According to our data only few sera positive for aTPO recognize "normal" MPO, but the majority of sera from patients with autoimmune thyroiditis and positive for pANCA on normal neutrophils recognize also an "abnormal" MPO. On the other hand MPO-ANCA usually recognize epitopes presently only on the normal enzyme, a small proportion of these autoantibodies can react with TPO. Heat inactivated sera give false positive results for pANCA on ethanol fixed human neutrophils.
[show abstract][hide abstract] ABSTRACT: Lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) are frequently detected in sera from patients affected by systemic lupus erythematosus (SLE). However, the role of antiphospholipid antibodies (aPL) in thrombus formation has not been defined as yet. Twenty-two patients affected by SLE, all fulfilling the 1982 ARA revised criteria, and twenty healthy subjects were investigated for the presence of LA, aCL and other aPLs. Monocyte procoagulant activity-PCA (Tissue Factor production) was evaluated by one stage plasma recalcification time. In all patients the plasma levels of F1 + 2 and of plasminogen activator inhibitor (PAI) were also determined. Monocyte PCA was significantly higher in SLE patients with LA and/or aCL in comparison to SLE patients without LA and/or aCL (p < 0.01) and to controls (p < 0.05). However, no connection was observed between PCA expression by mononuclear cells and LA or aCL levels. No differences in F1 + 2 and PAI plasma levels were found between SLE patients with or without aPL and controls. In our SLE patients LA and/or aCL positivity appears strictly related to an increased monocyte activation that could play an important role in the occurrence of thrombotic events.