Adenosine deaminase activity in rheumatoid pleural effusion

The activity of adenosine deaminase was studied in nine cases of rheumatoid pleural effusion, showing an increase in enzyme activity in all. Rheumatoid arthritis seems unique, however, as it cannot be differentiated from pleural tuberculosis on the basis of this test. Selective increase of adenosine deaminase in both conditions is attributed to stimulation of T lymphocytes in the pleural fluid.

High level of interferon gamma in tuberculous pleural effusion

It has been observed that T-lymphocytes of patients with tuberculosis produce interferon gamma (IFN gamma) in vitro. Based on this idea, we studied IFN gamma in pleural fluid and serum. We studied 80 patients with pleural effusion; 30 patients with tuberculous pleurisy had high IFN gamma concentrations in pleural fluid. Patients with malignant pleural effusions, nonspecific pleural effusion, parapneumonic effusions and pleural transudates had low levels. The IFN gamma levels were higher in those with massive tuberculous effusion and apparent pulmonary lesion on x-ray film. We found that the T4/T8 lymphocyte ratio was higher in pleural fluid than in peripheral blood. Numbers of T3 and T4 lymphocytes were higher in tuberculous pleural effusions compared with those in other patients. There is no correlation between IFN gamma levels and lymphocyte subsets in pleural effusion. Perhaps pleural T-lymphocytes produce IFN gamma after stimulation by mycobacterial antigens and this lymphokine activates macrophages, increasing their bactericidal activity against Mycobacterium tuberculosis.

Intrahepatic, nucleocapsid antigen-specific T cells in chronic active hepatitis B

Hepatitis B core antigen (HBcAg)-specific T cell lines were established from hepatic lymphomononuclear cells derived from five patients with chronic active hepatitis B. No hepatitis B virus envelope antigen-specific cell lines were established. Proliferation in response to recombinant and native HBcAg, but not to native hepatitis B surface antigen containing the pre-S(2) region, confirmed the specificity of the five T cell lines. All cell lines represented mixed populations of CD4+ and CD8+ T cells. The CD4+ subset provided antigen-specific help to autologous B cells with respect to anti-HBc production and to CD8+ cells with regard to HBcAg-induced proliferation and suppressor activity. The CD8+ subset contained suppressor cells that selectively inhibited the proliferative response of autologous HBcAg-specific CD4+ cells without inhibiting CD4+ cells of unrelated specificity (tetanus toxoid). Moreover, the CD8+ cells were also capable of suppressing HBcAg-stimulated antibody to HBcAg production without showing inhibition of total immunoglobulin production stimulated by pokeweed mitogen. The cytotoxic potential of the T cell lines was established in a lectin-dependent cytotoxicity system; natural killer cytotoxicity was completely absent. Our data suggest that the lesional T cells present at the site of hepatocellular injury in chronic active hepatitis B are primarily HBcAg-specific lymphocytes of the helper and suppressor/cytotoxic phenotypes and that both are functionally competent.

Intrahepatic, nucleocapsid antigen-specific T cells in chronic active hepatitis B

Hepatitis B core antigen (HBcAg)-specific T cell lines were established from hepatic lymphomononuclear cells derived from five patients with chronic active hepatitis B. No hepatitis B virus envelope antigen-specific cell lines were established. Proliferation in response to recombinant and native HBcAg, but not to native hepatitis B surface antigen containing the pre-S(2) region, confirmed the specificity of the five T cell lines. All cell lines represented mixed populations of CD4+ and CD8+ T cells. The CD4+ subset provided antigen-specific help to autologous B cells with respect to anti-HBc production and to CD8+ cells with regard to HBcAg-induced proliferation and suppressor activity. The CD8+ subset contained suppressor cells that selectively inhibited the proliferative response of autologous HBcAg-specific CD4+ cells without inhibiting CD4+ cells of unrelated specificity (tetanus toxoid). Moreover, the CD8+ cells were also capable of suppressing HBcAg-stimulated antibody to HBcAg production without showing inhibition of total immunoglobulin production stimulated by pokeweed mitogen. The cytotoxic potential of the T cell lines was established in a lectin-dependent cytotoxicity system; natural killer cytotoxicity was completely absent. Our data suggest that the lesional T cells present at the site of hepatocellular injury in chronic active hepatitis B are primarily HBcAg-specific lymphocytes of the helper and suppressor/cytotoxic phenotypes and that both are functionally competent.

Activity of adenosine deaminase in cerebrospinal fluid for the diagnosis and follow-up of tuberculous meningitis in adults

We studied the activity of adenosine deaminase in the cerebrospinal fluid of 40 normal controls and 205 patients who were grouped according to disease (tuberculous, viral, and purulent meningitis; neoplasms; stroke; and miscellaneous). The mean enzyme value was clearly higher for the patients with tuberculous meningitis (15.7 +/- 4.3 U/liter) than for the other patients (1.4 +/- 1.5 U/liter). The sensitivity of the test for diagnosing tuberculous meningitis was 1 and specificity, 0.99. The enzyme activity, as well as progression of the disease, was studied in 32 patients with tuberculous meningitis. A significant rise in levels of enzyme was observed during the first 10 days of therapy, was followed by a gradual decline, and reached normal values after three to four months of treatment. Two patients showed substantial increases that coincided with the development of complications. The test proved to be a simple and reliable method for early diagnosis and follow-up of tuberculous meningitis.

Adenosine deaminase activity in the diagnosis of tuberculous peritonitis

We studied the activity of adenosine deaminase in the peritoneal fluid of 66 patients who were divided into five groups according to causes of ascites as follows: tuberculous peritonitis (group I), septic peritonitis (group II), secondary to malignant tumours (group III), miscellaneous conditions (group IV), and control subjects of transudates (group V). In patients with tuberculous peritonitis the enzyme activity was significantly higher than for the rest of the groups (p less than 0.001), and enzyme concentrations in all patients were well above the upper non-tuberculous value. Adenosine deaminase activity in the peritoneal fluid has proved to be a simple and reliable method for early diagnosis of tuberculous peritonitis.

Adenosine deaminase activity in the diagnosis of lymphocytic pleural effusions of tuberculous, neoplastic and lymphomatous origin

We studied the activity of adenosine deaminase in 74 lymphocytic pleural effusions which were divided into four groups according to the aetiology: tuberculous (38 cases), neoplastic (17), lymphomatous (7) and miscellaneous (12). The mean enzyme value was significantly higher in the tuberculous cases (93.81 +/- 29.56 U/I) than for the other three groups and significantly higher in pleural effusions of lymphomatous origin than in the neoplastic and miscellaneous groups. Based on the lowest value of enzyme activity found in the tuberculous group (50 U/I), the test had a sensitivity of 1 and a specificity of 0.97.