Anti-human skeletal muscle glycolipid antibodies in unstable angina.

BACKGROUND: We studied whether the level of anti-skeletal muscle glycolipid antibodies (AGA), a marker of acute rejection in heart transplantation, may be associated with an adverse prognosis in unstable angina. METHODS AND RESULTS: The in-hospital evolution of 50 patients with unstable angina (Braunwald class III B) was assessed. We determined the incidence of death, myocardial infarction, and refractory angina. Blood was collected at admission and 24 hours later for determination of AGA levels by enzyme-linked immunosorbent assay. Twenty-three patients showed a decrease in the AGA level at 24 hours after admission. Ten in-hospital cardiac events occurred in these patients (43.4%) as compared with 4 (14.8%) in the 27 patients who did not show a decrease (P =.025). In patients with previous myocardial infarction (n = 26), the AGA assay was a powerful predictor of outcome. In this subgroup, 66.6% of patients who had decreased AGA levels (8 of 12) had cardiac events as compared with 14.2% (2 of 14) of those who did not have that decrease (P =.001). CONCLUSIONS: We conclude that a decrease of AGA levels 24 hours after admission is associated with a complicated in-hospital course. This finding may provide new insights in the phenomenon of plaque instability involved in the development of acute coronary syndromes.

Primary pulmonary artery sarcoma resembling chronic thromboembolic pulmonary disease.

Two cases of primary pulmonary artery sarcoma resembling chronic thromboembolic disease features are presented. Tumour identification was achieved after pulmonarv thromboendarterectomy, which was indicated by documentation of a prothrombotic state in both patients. A doubtful history of pulmonary emboli or deep venous thrombosis should alert medical personnel to the possible presence of a primary pulmonary artery sarcoma. Advanced imaging methods such as gadolinium-enhanced magnetic resonance imaging could be useful in considering pulmonary thromboendarterectomy. If a tumour is detected, its surgical resection should be considered with caution, taking into account the poor survival results. Invasion of the adventitia or the right ventricle, as documented in the present cases, is unusual. As far as the present authors know, this is the first report of this kind of tumour and its coexistence with an activated protein C resistance state and type II heparin-induced thrombocytopenia.

[Pathogenesis of human chronic chagasic myocarditis]. / Patogenia de la miocarditis chagásica crónica humana.

Studies carried out during the last decades provided evidence in support of an autoimmune pathogenesis for chronic chagasic myocarditis. This opinion was based on 1) the demonstration of molecular mimicry between parasite and host antigens, 2) the appearance of autoantibodies recognizing heart epitopes during the chronic phase of infection, 3) the induction of myocarditis and electrocardiographic alterations in animals immunized with whole parasites, parasite fragments or with biochemically-defined antigens, 4) the isolation from the heart of inflammatory infiltrates of B cells elaborating antibodies against myocardial antigens and 5) or of T cell clones reacting with heart epitopes and 6) induction of heart and nervous tissue alterations by transfer of lymphocytes from infected animals into naive syngeneic hosts. However, the characteristics of the inflammatory infiltrate in human myocarditis, displaying a wide variety of cells, many of them not involved in autoreactivity, such as the presence of giant cell granulomas and abundant eosinophils, as well as its focality and asynchrony, and the frequent association with pericarditis, casts doubts about the possibility of autoimmunity being responsible for the perpetuation of the myocarditis. This is supported by the recent observation that treatment of asymptomatic patients with trypanocidal drugs prevents the development of cardiopathy and that parasite components, either antigens or genomic fragments, are present at the site of the inflammatory lesions. On the basis of this new evidence, other alternative pathogenetic mechanisms should be sought to explain the appearance of a polymorphic long-lasting myocarditis that needs the presence of tiny fragments of parasites to develop. In addition to the well known immunological pathogenesis, the link between such a small amount of parasite components, below the level of microscopic detection, and the induction of such an extensive inflammatory infiltrate, represents interesting avenues for research in the near future.

Anti-skeletal muscle glycolipid antibodies in human heart transplantation as predictors of acute rejection: comparison with other risk factors.

In forty-five patients who underwent orthotopic heart transplantation, the titer of anti-human skeletal muscle glycolipid antibodies (AGA) present in the sera at the moment of transplantation was correlated with the number of histologically diagnosed cellular grade 3A and humoral acute rejection episodes during the first 120 days after transplantation. Determination of a cutoff value of 0.800 for the AGA level was determined by a receiver operating characteristic curve. Thirteen of 19 patients (68.4%) with an AGA titer above 0.800 developed 24 severe rejection episodes, and of the 26 patients with an AGA titer below 0.800, only 4 (15.3%) presented 6 severe rejection episodes during that time. This was especially evident for the humoral rejection episodes, which were diagnosed in only 1 of the 26 patients with AGA below 0.800 and in 7 of the 19 with AGA above 0.800. Comparison by univariate analysis of other well-known risk factors for a greater number of rejection episodes during the early posttransplant period with the AGA level at the moment of transplantation revealed that the latter distinguished a greater number of patients at risk than the other factors, such as a female donor, the lymphocyte direct cross-match, or the status of the patients at transplantation; the odds ratios were 6.33 for the AGA level, 3.17 for the direct cross-match, and 2.76 for the status at transplantation. By multiple logistic regression analysis, the only relevant risk factors in our group of patients were the AGA level (P=0.0009) and the status at transplantation (P=0.0285). These results indicate that determination of the AGA level at the moment of transplantation could represent a useful method for distinguishing which patients are at risk for a greater number of rejection episodes during the early posttransplant period, with a greater sensitivity than other risk factors.

Anti-skeletal muscle glycolipid antibodies in human heart transplantation as markers of acute rejection. Correlation with endomyocardial biopsy.

In seventeen patients the result of the histological study of 153 endomyocardial biopsies (EMB) was compared with the ELISA titer of anti-human skeletal muscle glycolipid antibodies (AGA) present in serum samples collected simultaneously with the EMB procedure during the first four months following cardiac transplantation. The glycolipids were extracted from the quadriceps femoralis of blood group O patients. In the serum samples corresponding to the histological rejection grades with myocyte necrosis (greater than or equal to 2, International Society for Heart and Lung Transplantation grading) the AGA titer was significantly higher (P<0.005) than in the less severe rejection grades. The follow-up in each patient showed that the AGA titer raised in the serum samples collected immediately after, before, or coincidentally with a histological diagnosis of rejection grade 2 or 3A. In only one rejection grade 3A case was a false-negative result observed. Determination of the cut-off of the AGA level versus rejection grades 2 and 3A was determined by a relative-operating characteristic curve. An optical density (OD) of 0.040 showed maximum efficiency with sensitivity 53% and specificity 79%. Four patients who had AGA with an OD above 0.040 at the time of transplant had a significantly higher number of rejection grade 2 and 3A episodes than eleven patients with low pre-transplant AGA titers (P<0.05). These results indicate that search of anti-skeletal muscle glycolipid antibodies may represent a useful noninvasive method for monitoring heart rejection, and suggest that its investigation prior transplant may be a predictor of the number of grades 2 and 3A rejection episodes.