T lymphocytes in pulmonary tuberculosis.

T cells and their sub-populations were evaluated with respect to reactive, intermediate and unreactive forms of tuberculosis as classified by Lenzini. Significant CD4 lymphopenia and a reduction of CD4/CD8 ratios were found in patients with reactive tuberculosis. It was observed that there was a B lymphocytosis, CD8 lymphocytosis and a reduction of CD4/CD8 ratio in patients with intermediate and unreactive forms of tuberculosis. The T lymphocytes and CD4 subset were unchanged. There was no significant difference in the lymphocytes and sub-populations among the intermediate and unreactive groups.

A study of tubercular antigen and antibody in childhood tuberculosis.

A radioimmunoassay for the detection of tubercular (TB) antigen (Ag) and antitubercular antibody (Ab) was evaluated for the serodiagnosis of childhood tuberculosis. Children with primary complex, progressive primary complex, miliary tuberculosis, and calcified lung lesions without clinical evidence of active tuberculosis were studied. Significantly elevated levels of TB Ag and TB Ab isolated from the circulating immune complexes were obtained in primary, progressive primary, and miliary tuberculosis patients as compared to controls (P less than 0.01). The majority of patients with calcified lung lesions and without active tuberculosis demonstrated high levels of antibody. It was observed that elevated levels of TB Ag and/or antibodies were present in 54 per cent of patients with primary complex, 94 per cent of patients with progressive disease and 69 per cent of patients with miliary tuberculosis. It is possible that is suspected patients with the above mentioned diseases, a diagnosis can be established by using these techniques.

A study of Mycobacterium tuberculosis antigen and antibody in cerebrospinal fluid and blood in tuberculous meningitis.

Radioimmunoassay (RIA) techniques have been evaluated to detect specific tubercular antigen (TB Ag) and antitubercular antibody (TB Ab) in CSF and serum of patients with tuberculous meningitis (TBM). A solid-phase RIA using H37RV sonicate antigen of Mycobacterium tuberculosis, anti-BCG antibody, and staphylococcal protein A was standardized. TB Ag and TB Ab levels were noted to be significantly elevated in cerebrospinal fluid (CSF) as well in circulating immune complexes (CIC) isolated from serum samples of TBM patients as compared to control group (P less than 0.01). Detectability of disease by demonstrating elevated TB Ag and/or TB Ab levels in either CSF or CIC or both was 95%. There was no correlation between individual levels of TB Ag and TB Ab in CSF and in circulation. A follow-up study in patient over a period of 4-12 weeks revealed that TB antigen and/or TB Ab persisted in the majority of the cases for several weeks despite chemotherapy.

Circulating immune complexes in pulmonary tuberculosis.

The presence of circulating Immune complexes (CIC) in sera from patients with pulmonary tuberculosis was demonstrated by 3 techniques (a) latex agglutination (b) 3.5% PEG precipitation and determination of optical density (O.D.) at 280 nm and (c) radioimmunoassay (RIA) of CIC using bovine spermatozoa. 40 normal control sera and 100 T.B. patients sera were included in the study. 12% cases were positive for CIC by all the 3 methods mentioned above, 13% were negative by all the 3 methods and the remaining patients were positive by one or more methods of detection. To correlate the levels of CIC as detected by different techniques with the activity of the disease, patients were broadly grouped as (a) sputum positive and (b) sputum negative. Higher levels of CIC were obtained in sputum positive cases than sputum negative by all the 3 methods studied. While IgG, IgA and IgM were elevated in the CIC of T.B. patients, and IgG and IgA were also present in controls, IgM immunoglobulins were detected only in patients and not in controls. The effect of antitubercular treatment on the levels of CIC was also evaluated and it was found that the levels of CIC remained unchanged even after prolonged chemotherapy.

Significance of circulating immune complexes in pulmonary tuberculosis.

In the present study we have tried to demonstrate circulating immune complexes (CIC) in sera from patients with pulmonary tuberculosis (TB) by three techniques; latex agglutination; 3.5% PEG precipitation and determination of optical density at 280 nm and RIA of CIC using bovine spermatozoa. About 40 normal control sera and 100 TB patients sera were investigated for the presence of CIC. Seventeen per cent cases of pulmonary TB were positive by latex agglutination while none of the control was positive. Levels of CIC as detected by PEG precipitation and RIA were significantly elevated in patients as compared to normal controls. While IgG, IgA and IgM were elevated in the CIC of patients, IgM immunoglobulins were detected only in patients and not in controls. Detection of CIC may at times be useful in diagnosis, prognosis and therapeutic monitoring of disease processes, but it is the characterization of immune complexes (IC) and identification of the specific components of these complexes which holds the greatest potential for better understanding of disease mechanisms. CIC were precipitated using 3.5% PEG from sera of patients suffering from TB. The specific anti-TB antibody component of complex was determined using S. aureus protein A as a solid phase, Anti-BCG antibody and 125I-labelled TB antigen. The specific TB antigen component of the IC was dissociated thermally from TB antibody and assayed by a radioimmunoassay technique developed in our laboratory. Patients were classified into two groups. Those those sputum was positive for Mycobacterium tuberculosis by smear and/or culture and those whose sputum was negative. The TB antigen concentrations of CIC was higher 19.1 +/- 2.3 ng/ml (mean +s.e.) in sputum positive cases, and 9.9 +/- 1.9 ng/ml in sputum negative cases as compared to 2.2 +/- 0.3 ng/ml in controls. Patient groups were significantly different from controls as well as from each other (P less than 0.001). Anti-TB antibody ratios were 11.7 +/- 1.48, 5.1 +/- 1.5 and 0.6 +/- 0.1 in sputum positive, sputum negative and controls. The significance of differences between the groups was P less than 0.001. The effect of treatment administered over a period of 12 weeks or more was evaluated. It was observed that in patients with persistent demonstration of M. tuberculosis in the sputum, the TB antigen and TB antibody levels of CIC were consistently high. In patients who responded to anti-tubercular drugs the TB antigen levels decreased progressively while TB antibody levels remained high.(ABSTRACT TRUNCATED AT 400 WORDS)