[Value of determining the activity of adenosine deaminase (ADA) in the differential diagnosis of pleural effusions]. / Valor da determinação da atividade de adenosina desaminase (ADA) no diagnóstico diferencial dos derrames pleurais.

BACKGROUND: Pleural effusion (PE) is a common problem in medical practice. Transudative effusions usually do not present difficulty in diagnosis, in most populations. Exudative PE however, require careful differential diagnosis that include necessarily tuberculosis and metastatic cancer. METHODS: We have conducted a cross-sectional study of 221 patients with persistent PE, in order to evaluate accuracy of determining adenosine deaminase activity (ADA) for diagnosis of tuberculosis pleuritis. This group of patients, taken mostly from the State Hospital for pulmonary diseases, consecutively, was constituted as follows: 1) Tuberculosis (confirmed, n = 150; likely, n = 9); 2) Cancer (confirmed, n = 21; likely, n = 16; Lymphoma = 3); and 3) Miscellaneous (n = 22). All individuals were submitted to clinical examination, chest X-ray, blood tests, and underwent thoracocentesis with pleural biopsy. Pleural fluids were analyzed by routine tests plus determination of ADA activity using Giusti's Method. RESULTS: In agreement with previous reports we have found 40 U/L to be the best cutoff point according to a Receiver Operating Curve (ROC) analysis of our data. Sensitivity of ADA activity < or = 40 U/L was 93.3% and specificity 93.5%, resulting in a positive predictive value of 97.2% and a negative predictive value of 85.3%, in this specific population of patients, when taking into account only the individuals with confirmed tuberculosis by histopathology or culture. Three out of the 4 patients with elevated ADA without tuberculosis had lymphoma. CONCLUSION: ADA determination in pleural fluids, a quick and inexpensive technique, is shown to be an accurate method for identifying tuberculosis pleuritis. Our findings are comparable to reports from other series, and stress how useful it is to incorporate this test to the routine evaluation of pleural effusions in areas of high incidence of tuberculosis.

Pathology of the central nervous system in patients infected with the human immunodeficiency virus (HIV): a report of 252 autopsy cases from Brazil.

The central nervous system (CNS) was studied in 252 HIV-infected patients from the States of Rio de Janeiro and São Paulo in Brazil, the regions with the highest incidence of AIDS in the country. We compared the frequency and morphology of opportunistic infections and CNS changes caused by the HIV, with those described in other series and briefly analysed the risk factors involved in our cases. There were CNS lesions in 230 cases (91.3%), 30 (11.9%) with multiple infections and/or tumours. Most infections were opportunistic (65.4%), including 15.4% viral and 50% bacterial, fungal or protozoal infections. The most frequent was toxoplasmosis (34.1%), followed by cryptococcosis (13.5%), cytomegalovirus (CMV) infection (7.9%) and nodular encephalitis (6.7%). Primary lymphomas were observed in 4% of the cases and HIV encephalitis or leukoencephalopathy in 10.7%. Other opportunistic and HIV associated lesions were present in a limited number of cases and there were also vascular and non-specific lesions. Our study confirms the high frequency of CNS lesions in HIV infected patients. They are morphologically similar to those previously described. However, the higher incidence of toxoplasmosis and cryptococcosis, a lower incidence of viral opportunistic and HIV-associated lesions, and the presence of rarer lesions such as histoplasmosis and chagasic encephalitis, differ from other series, and may reflect geographical and/or socio-economic factors.

Diminished in vitro production of interleukin-1 and tumor necrosis factor-alpha during acute visceral leishmaniasis and recovery after therapy.

Disturbance of T cell-mediated immunity has been reported in acute visceral leishmaniasis (AVL). In a study of 16 patients with AVL, defective production of interleukin-1 (IL-1) by peripheral blood mononuclear cells was demonstrated in response to leishmania antigens, heat-killed Listeria organisms, and lipopolysaccharide when compared to posttherapy values or controls. This global defect in IL-1 production was corrected after successful therapy. Twelve of 16 patients responded with a greater than or equal to 2.5-fold increase in IL-1 production that correlated with clinical cure, P less than .01. Depressed production of tumor necrosis factor (TNF) was leishmania antigen-specific and similarly recovered after therapy. In vitro TNF production during the follow-up period did not correlate with clinical status but high serum levels were associated with AVL. Since T cells are activated by processed antigens presented on class II major histocompatibility molecules and by newly synthesized IL-1, defective IL-1 production may contribute to the immunosuppression observed in AVL.

Dengue: neuropathological findings in 5 fatal cases from Brazil.

Neuropathological examination of 5 patients with dengue who died of shock in Rio de Janeiro during an outbreak in summer 1987, showed nonspecific lesions (edema, vascular congestion, hemorrhagic foci and perivascular lymphocytic infiltrates). In one case with delayed marked neurological symptoms, several foci of perivenous demyelination were observed. Neurological manifestations are various and not uncommon in dengue, but their anatomical substratum is not known. An immunopathological mechanism has been postulated in some cases but has never been demonstrated morphologically. The perivenous leukoencephalitis observed in one of our cases could represent the morphological substratum of such an immunological mechanism.

Immunological response of Swiss mice to infection with three different strains of Trypanosoma cruzi.

The immunological response of Swiss mice to infection with three strains of Trypanosoma cruzi which differ in their morphobiological, antigenic and isoenzymic characters [Peruvian, 12 SF (São Felipe) and Colombian strains] was investigated. The three strains stimulated an elevation of the immunoglobulin fractions IgG2a, IgG2b and IgM during acute infection, as measured by radial immunodiffusion, and an early drop of IgG1 levels. There were low levels of specific antibodies and a negative cutaneous delayed hypersensitivity test to T. cruzi antigens. Cellular reaction of the spleen was evident, with proliferation of lymphocytes and the presence of blastic lymphoid cells in the red and white pulp, and hyperplasia of germinal centres of the lymphoid follicles. Those aspects were consistent with a depletion of the T-cell zone (periarteriolar lymphocyte sheath). Despite these common features, there were clear differences in the onset, intensity and evolution of the splenic cellular reaction and IgG serum levels and in the relationship between these levels and parasitaemia in the mice infected with the three strains of T. cruzi. A positive correlation was seen between high IgG levels and mortality, corresponding to intense exudative tissue lesions, showing that a raised immunoglobulin level was not associated with protection. It is worth observing that the 12 SF strain, which showed the lowest parasitaemic profile and mortality rate, stimulated the greatest elevation of IgG2b during acute infection; and also that IgG2a and IgG2b were the immunoglobulins which showed the greatest increases following infection by all three strains of T. cruzi.

[Cerebral hemorrhage as the initial manifestation of systemic lupus erythematosus: clinical and histopathological study of 2 cases]. / Hemorragia cerebral como primeira manifestacão do lupus eritematoso sistêmico: estudo clínico e histopatológico de dois casos.

Two patients with cerebral hemorrhage as the first manifestation of systemic lupus erythematosus (SLE) are reported. The first one showed in the CT scan blood within the brain. Laboratory findings gave the diagnosis of lupus. She was treated with corticosteroids and plasmapheresis with good results. The second patient died within few days and the anatomopathologic study showed a large area of hemorrhage within the brain. The microscopic study of the kidney and other organs made the diagnosis of lupus erythematosus. The authors regard the intracranial bleeding as a rare complication of lupus. They consider that the CT scan must be done in all patients with central nervous system complications of SLE. They consider that the cerebral hemorrhage must be related to the autoimmune disorders that occur in SLE.

[Necrotizing myelopathy and neoplasms: clinico-pathological report of 2 cases]. / Mielopatia necrotizante e neoplasias: registro clínico-patológico de dois casos.

Two clinico-pathological cases of necrotic myelopathies with a distant malignancy are presented. The first patient had histiocytic medullary reticulosis and the second one had a renal cell carcinoma. The authors referred to other similar cases found in the literature. In both patients the pathological features in the spinal cord were similar to the other cases reported, but in their first case they found an intense inflammatory reaction and hyperplasia of astrocytes into bizarre giant forms. The cause of necrotizing myelopathy associated with neoplasms remain unknown. The authors think that the presence of inflammatory reaction and the changes in the astrocytes in their first case are consistent with the effects of a virus.