Adenosine deaminase in the diagnosis of tuberculous pleural effusions. A report of 218 patients and review of the literature.

The activity of adenosine deaminase in the pleural fluid of 218 consecutive patients was studied. According to the etiology of exudative pleural effusions, the patients were divided into the following five groups: (1) tuberculosis; (2) lung cancer; (3) pneumonias; (4) miscellaneous; and (5) idiopathic. Patients with pleural tuberculosis presented significantly higher ADA activity than patients with nontuberculous pleural effusions (p less than 0.0001). The results indicated that in a population with a relatively high prevalence of tuberculosis, the analysis of ADA levels in pleural effusions constitutes a useful marker for the diagnosis which, in addition, can be made quickly and cheaply. Additionally, a comprehensive review of the literature on the role of ADA in the diagnosis of tuberculous pleural effusions is presented.

On the correct determination of reference values for serum antibodies against pigeon serum antigen using a group of healthy blood donors.

An enzymatic immunoassay was developed in order to evaluate the statistical distribution of IgG serum antibodies against pooled pigeon sera antigen in 102 healthy blood donors (HBD). A non-normal distribution was obtained as demonstrated by abnormal values of skewness (2.02) and kurtosis (6.50). A cut-off point (0.120) was determined from the mean plus 2 standard deviations of the optical density values obtained in the HBD group. This value was able to segregate 94% of subjects. However, when calculation of the mean less 2 SD was performed to delimit 95% of the samples, an aberrant negative value was obtained. In contrast, when the nonparametric method of percentile calculation was applied, an optical density value of 0.130 discriminated 97.5% of samples. In addition, the interval between p97.5 and p2.5 delimited 95% of samples. We conclude that when reference values and cut-off point are determined from an enzymatic immunoassay, careful analysis of the statistical distribution of reference values is necessary in order to avoid the inappropriate application of parametric procedures as demonstrated in this study for antibodies against pigeon serum antigens.

Evaluation of adenosine deaminase activity in the Mycobacterium tuberculosis culture supernatants.

BACKGROUND: Adenosine deaminase (ADA) catalyzes hydrolytic and irreversible deamination of deoxyadenosine into deoxyinosine and of adenosine into inosine, and is related to lymphocytic proliferation and differentiation. The measurement of ADA activity in body fluids is a useful tool in the evaluation of mycobacterial infections. Elevated ADA activity has been found in pleural effusions of patients with pleural tuberculosis relative to those from patients with nontuberculous pleural diseases, and is mainly associated with cellular host factors such as monocyte-macrophages or lymphocytes. In contrast, there is little information about ADA activity measurement in mycobacteria culture supernatants. METHODS: We evaluated ADA activity as described by Giusti in the culture supernatants of eight Mycobacterium tuberculosis isolates. RESULTS: Mycobacteria culture supernatants did not display any ADA activity. CONCLUSIONS: This result supports the notion that Mycobacterium tuberculosis is not the source of ADA activity. However, increased ADA activity in biological fluids from tuberculosis patients might be due to the interaction of the mycobacterium with host factors.

Absence of antiphospholipid/co-factor antibodies in Takayasu arteritis.

UNLABELLED: There are anecdotal reports and small series describing the presence of anticardiolipin antibodies in patients with Takayasu Arteritis. This communication describes a systematic study searching for non-organ specific autoantibodies which includes antinuclear antibodies, anticardiolipin and anti-beta(2) GP(1) antibodies in a cohort of 28 Mexicans with angiographic definitive diagnostic of Takayasu Arteritis. MATERIAL AND METHODS: Twenty-eight consecutive patients, who fulfilled classification and diagnostic criteria for Takayasu Arteritis and had a diagnostic panaortogram, were bled to study the presence of circulating autoantibodies in a cross-sectional design. RESULTS: There were no antinuclear antibodies, although a few sera had faint cytoplasm fluorescent deposit and reacted with cell extract. We did not recognize a distinct pattern. Also, there was no IgG nor IgM anticardiolipin antibodies nor anticofactor antibodies of clinical interest. DISCUSSION AND CONCLUSIONS: The presence of circulating non-organ specific autoantibodies is not a characteristic feature in Takayasu Arteritis when strict diagnostic criteria are applied. The occasional presence of such immune markers could be due to technical differences in sample management, less strict diagnosis or biological variability in certain cases, but has no diagnostic value.

[Takayasu arteritis; IV. Absence of autoantibodies and coagulation/fibrinolysis abnormalities]. / Arteritis de Takayasu; IV. Ausencia de autoanticuerpos y anomalías de la coagulación/fibrinolisis.

The etiopathogenesis of the non-specific arteritis known as Takayasu's arteritis, an inflammatory occlusive disease of the aorta and its main branches, is unknown. We searched for abnormalities in clotting and fibrinolytic systems, as well as the presence of non-organ specific autoantibodies, including those potentially reactive with vascular endothelium, in 21 untreated patients. There were only minor abnormalities in coagulation and fibrinolysis in a few patients, and the occasional presence of non-organ specific antibodies, including antiphospholipid antibodies. The findings had no clinical relevance. This study suggests that there is no support for a significative role of humoral immunity, coagulation and fibrinolysis in the pathogenesis of Takayasu's arteritis.

Heat inactivation of bovine serum used for blockade in immunoenzymatic assay is associated with spurious fall on the titers of anticardiolipin antibodies in primary antiphospholipid syndrome sera.

Anticardiolipin antibodies (ACA) were evaluated using enzyme-linked immunosorbent assay (ELISA) with and without heat inactivation of bovine serum used for plastic surface blockade. Untreated sera samples from primary antiphospholipid syndrome patients (PAS) and healthy blood donors (HBD) were tested. A significant decrease of ACA titers of PAS sera occurred with inactivated bovine serum blockade ELISA when compared with basal ELISA. In HBD sera there was no significant change. Probably, as happens with normal human serum, heating for normal bovine serum produces an increase in ACA titers. This bovine ACA may react with cardiolipin, and when human samples are added, they find antigen sites occupied, resulting in a spurious decrease of ACA titers.

Effect of heat inactivation and sheep erythrocyte adsorption on the titer of anticardiolipin antibodies in primary antiphospholipid syndrome and healthy blood donors' sera.

The standard enzyme linked immunosorbent assay (ELISA) currently in use for detection of anticardiolipin antibodies (ACA) was used to evaluate the influence of heat inactivation and sheep erythrocyte adsorption on individual optical density (OD) of sera from healthy blood donors or patients with primary antiphospholipid syndrome. Each sample was tested after single or combined maneuvers as follows: adsorbed, adsorbed and inactivated, only inactivated, and compared to basal readings. A significant increase of ACA titers did occur after inactivation of normal sera, but adsorption had no effect. In contrast, neither inactivation nor adsorption changed ACA titer in primary antiphospholipid syndrome sera as a group, although in certain sera there were changes. This observation may suggest the presence in normal serum of a thermolabile factor which modulates ACA binding to its antigen and the reactivity of the anticardiolipin antibodies of the primary antiphospholipid syndrome with sheep erythrocyte membrane phospholipids.

Ocular vaso-occlusive disease in primary antiphospholipid syndrome.

PURPOSE: To evaluate the ocular involvement in patients with the primary antiphospholipid syndrome. METHODS: The authors performed a cross-sectional ophthalmologic study of 17 patients with the primary antiphospholipid syndrome. Retinal fluorangiography was performed in 13 patients. RESULTS: Visual symptoms were described by ten patients. Visual acuity was markedly decreased in five eyes. Conjunctival telangiectases and microaneurysms, in addition to single instances of bilateral episcleritis and limbal keratitis, were the anterior segment findings. Fundus abnormalities were present in 15 patients. Venous tortuosity was the most common finding but there were instances of optic disc edema, vitreous hemorrhages, cotton-wool spots, vitreous bands, serous detachment of the macula, and retinal capillary abnormalities. Fluorangiography showed vaso-occlusive retinopathy in six eyes (5 patients, 29%). Choriocapillary vessel occlusion was observed in two eyes (1 patient) and binocular reticular degeneration of pigmentary epithelium was present in another case. CONCLUSION: The eye is frequently involved in the primary antiphospholipid syndrome, and serious ocular damage may occur. Detailed ophthalmologic evaluation is warranted in these patients.

[The prevalence of IgG anticardiolipin antibody at the anticoagulant clinic of the Ignacio ChavezNational Institute of Cardiology. I. Unselected population]. / La prevalencia de anticuerpo IgG anticardiolipina en la clínica de anticoagulantes del Instituto Nacional de Cardiología "Ignacio Chávez". I. Población no seleccionada.

The recently described antiphospholipid antibodies syndrome (APA) is recognized because recurrent abortion, thrombocytopenia and repeated arterial and/or, venous thrombosis plus the demonstration of serum antibodies reactive with anionic phospholipids. We studied 51 patients who attend the anticoagulation clinic at our Institute. In a representative sample, we search for serum IgG specific for cardiolipin using an standard assay. We did not pick up unrecognized APA cases. The low frequency of this condition could be an explanation for our negative results in non-selected cases. Besides, this study denies a relationship between the chronic use of coumarin anticoagulants and development of peculiar antibodies.

[Anticardiolipin antibodies. Clinical significance and limits of the method]. / Anticuerpos anticardiolipina. Significado clínico y límites del método.

Recently we have available immunologic techniques with high sensitivity (nanogram 10(-9) g) useful for recognizing antibodies, including the antiphospholipid antibodies. As a consequence, a clinical syndrome termed precisely antiphospholipid or anticardiolipin syndrome was described in 1983. This clinical entity has manifestations pertaining to several medical fields such as cardiology, angiology, neurology, obstetrics and rheumatology. It is necessary to set limits for the information provided by such tests in each laboratory. In our hands the positive predictive value is very low for establishing a diagnosis of autoimmune disease. It is better as a negative predictive value to exclude that possibility. However, as is the case in almost all data generated through biological assays, a result of anticardiolipin antibody detection by ELISA is meaningful only in a clinical context. This fact is emphasized, making the point of the necessity of prospective controlled studies.

Increase of unidentified HLA antigens in pulmonary tuberculosis.

We studied the HLA-A, B,C and DR antigens in 50 patients with advanced pulmonary tuberculosis in an effort to detect some genetic factors which may predispose to the development of this disease. We found a decrease in HLA-A3, A9, B5, B8, B13, B17 and B27. The incidence of "double blank" antigens in the locus A was 18% (2.5% in controls, p less than 0.0005) in the locus B 16% (1.5% in controls, p less than 0.0005) and 28% in the DR locus (7% in controls, p less than 0.0005). Our results suggest that the cells responsible for the immune response in patients with tuberculosis appear to have a diminished number of HLA antigens serologically determined. That phenomenon could be explained by several hypothesis like poor expression of these proteins or masking for another substance. In spite of the mechanism, this abnormal membrane expression of HLA antigens could be important for the development of the disease since the cell-cell interactions critical for the mounting of an adequate immune response might not be appropriate.

Cellular immune response to fractionated avian antigens by peripheral blood mononuclear cells from patients with pigeon breeder's disease.

Pigeon breeder's disease (PBD), a form of hypersensitivity pneumonitis caused by repeated inhalation of antigens of pigeon origin, is characterized by a diffuse inflammation of the lower respiratory tract. Although a variety of immunologic and nonimmunologic mechanisms have been described in the development of the disease, the pathogenesis is still far from clear. In this study we analyzed the T-lymphocyte proliferative response to a variety of avian antigens with use of peripheral blood mononuclear cells from 11 patients who had PBD and 10 healthy volunteers. We used a new method based on avian antigen-bearing nitrocellulose particles derived from Western blots to study the T-cell proliferative response to 15 antigenic fractions obtained from pigeon serum. With this technique, complex mixtures of antigens can be fractionated by polyacrylamide gel electrophoresis, transferred to nitrocellulose membranes, and used for T-cell proliferation assays with selected antigenic determinants. A wide variety of responses were observed, and there were no reproducible patterns of reaction within either group. Nine of 10 healthy subjects responded to some soluble fractions. However, patients with PBD displayed the strongest response and responded to a significantly greater number of antigenic fractions. Fraction 2, representing a 220 kd molecular weight protein, was the only immunodominant antigen when both groups were compared; it was recognized by 73% of the patients with PBD and by only 20% of control subjects (p < 0.03). These findings show that T lymphocytes of patients with PBD recognize a wide range of bird proteins, which induce marked T-cell proliferation.

Detection of salivary and seric IgG and IgA antipooled pigeon sera activities in patients with pigeon breeder's disease.

Pigeon breeder's disease (PBD) is an interstitial lung disease induced by exposure to pigeon antigens. Search of antipigeon antigen antibodies (APSA) in serum or bronchoalveolar lavage is generally used for auxiliary diagnostic purposes. However, APSA can be present in a number of exposed but asymptomatic individuals as well as in patients with other interstitial lung diseases who live in areas where keeping pigeons is a common domestic habit. In this study, saliva was evaluated as an alternative means to serum for APSA detection by ELISA using pooled pigeon sera as antigen. Serum and saliva samples obtained from 17 patients with PBD, 14 with idiopathic pulmonary fibrosis (IPF), 19 asymptomatic relatives (AR) exposed to pigeon antigens, and 27 clinical healthy voluntary subjects (CHVS) were tested for IgG and IgA APSA. Our results showed that both fluids obtained from PBD patients exhibited a significantly higher specific IgG antibody activity compared to the other groups. Serum optical density (O.D.) values for PBD were 1.187 +/- 0.738 vs. 0.024 +/- 0.033, 0.255 +/- 0.471, and 0.204 +/- 0.346 for CHVS, AR and IPF, respectively (P < 0.05). Salivary O.D. for PBD were 0.801 +/- 0.447 vs 0.010 +/- 0.011, 0.104 +/- 0.151, and 0.22 +/- 0.447 (P < 0.05). In contrast, serum specific IgA did not discriminate between PBD and IPF patients. In addition, although the PBD group exhibited the highest values of IgA salivary APSA, high levels were also observed in saliva specimens from CHVS, a group of normal individuals who deny pigeon exposure. These findings suggest that measurement of IgG salivary APSA can play a role in the evaluation process of patients with pigeon breeder's disease.

Detection of antibodies against avian antigens in bronchoalveolar lavage from patients with pigeon breeder's disease: usefulness of enzyme-linked immunosorbent assay and enzyme immunotransfer blotting.

The study reported here evaluated the usefulness of the enzyme-linked immunosorbent assay (ELISA) in the detection of antibodies against pigeon antigens in the serum and bronchoalveolar lavage (BAL) of patients with clinical, radiological, and functional evidence of interstitial lung disease (ILD) with and without pigeon breeder's disease (PBD). The results were compared with those obtained by the simultaneous use of counterimmunoelectrophoresis (CIE) in the same patients. In PBD, ELISA detected antibodies against pigeon's sera in both serum and BAL in 100% of patients, while CIE failed to detect the antibodies in the serum of one patient and in most of the samples of BAL. In addition, we used enzyme immunotransfer blotting to determine the number of epitopes in pigeon serum recognized by antibodies present in serum and BAL. There was a heterogeneous response in both fluids, but the reaction pattern demonstrated that patient's sera recognize to-25 different pigeon epitopes. We conclude that ELISA is a highly sensitive and specific method for the detection of antibodies against pigeon antigens in the serum and BAL of patients with PBD and that the host response involves a great number of avian antigens.

Human amniotic fluid modulation of collagenase production in cultured fibroblasts. A model of fetal membrane rupture.

The participation of a mechanical factor as the only cause of rupture of fetal membranes during normal labor or premature rupture has been criticized, and the involvement of an enzymatic mechanism has been proposed. In this study we analyzed the effect of human amniotic fluids at different gestational ages on the collagenase synthesis of cultured fibroblasts. Our results show that term amniotic fluids are capable of inducing the synthesis of collagenase and other proteases in fibroblasts, as revealed by selective increases in collagenase activity and in immunoreactive collagenase. Nonterm amniotic fluids failed to do the same. This phenomenon is proposed as a model for studying the collagen degradation of fetal membranes during term gestation.

Anticardiolipin antibodies are not associated with rheumatic heart disease.

The aim of this study was to examine the prevalence of anticardiolipin antibodies in rheumatic valve heart disease. Serum samples of 31 consecutive patients with rheumatic heart disease and documented valve involvement, as well as six patients with acute rheumatic fever were tested for IgG anticardiolipin antibodies by a validated ELISA. No anticardiolipin antibodies were found when a cut-off point set at mean +/- 5 s.d. was applied. We can conclude that anticardiolipin antibodies are not present in rheumatic heart disease patients and, as suggested by several observations, these antibodies do not appear to have a pathogenic role in this particular disease.