Association between Previous Tuberculous Infection and Cerebal Glioma

An increased incidence of previous infection with tuberculosis has been found in a series of patients with cerebral gliomas, and it is suggested that such an association may be due to defective immunity acting as a common aetiological factor.     

Trend in Annual Risk of Tuberculous Infection in North India

Setting

Six selected districts in Northern India.

Objectives

To find out the trend in Annual risk of tuberculous infection (ARTI) in north India.

Study Design

Two rounds of community level surveys were conducted during 2000–2001 and 2009–10 respectively. Representative samples of children 1–9 years of age were tuberculin tested and maximum transverse diameter of induration was recorded in mm at about 72 hours. ARTI was computed from the estimated Prevalence of infection using mirror-image technique and anti-mode method.

Results

ARTI was found to decline from 1.9% (confidence interval: 1.7–2.1) at round I to 1.1% (confidence interval: 0.8–1.3) at round II at the rate of 8% per year during the intervening period.

Conclusion

A significant reduction in the risk of tuberculous infection among children was observed between two rounds of surveys carried out at an interval of about 9 years.     

Circulating Antibody Response in BCG Vaccination,Tuberculous Infection and Sarcoidosis

The bentonite flocculation test was used to differentiate antibodies formed by BCG vaccination from those produced by infections with virulent tubercle bacilli. Of 116 BCG-vaccinated nurses, only two (1.7%) showed antibody titres higher (1:128) than the threshold titre of 1:64 established for tuberculous patients.The bentonite test was also used to follow the course of infection in 54 patients with tuberculosis. A good correlation was found between the clinical course of the disease and O.T.-bentonite titres on repeated serological testing.Tuberculosis-like antibodies were demonstrated in sarcoidosis patients. These antibodies, however, are globulins (7S), in contrast to the macroglobulins (19S) found in tuberculous patients.     

In Vitro Studies on the Mechanism of Acquired Resistance to Tuberculous Infection

The relationship between lymphocytes and macrophages in cellular immunity against tuberculous infection was studied by means of an in vitro cell culture system without addition of streptomycin. The peritoneal macrophages were obtained from normal mice or mice immunized with heat-killed tubercle bacilli in paraffin oil, boosted with live BCG and infected with H37Rv cells in vitro. The infected monolayers of macrophages were cultivated for 48 hr with immune lymphoid cells obtained from immunized mice. The intracellular growth of H37Rv cells 3,5 and 7 days after infection was examined by counting tubercle bacilli within infected macrophages under a microscope. 1) The increase of bacilli within macrophages derived from immunized mice was slightly smaller than that in normal macrophages. 2) The addition of immune lymph node cells to the macrophage monolayers resulted in a marked decrease in the number of bacilli within both normal and “immune” macrophages. Conversely, normal lymph node cells exhibited an enhancing effect on the intracellular bacillary growth. 3) Immune lymph node cells showed a higher capacity to cause macrophages to suppress intracellular growth of bacilli than that of splenic lymphoid cells or thymocytes after addition to macrophage monolayers. 4) The treatment of lymphoid cells with inhibitors of protein synthesis, cycloheximide or streptovitacin A, resulted in a remarkable reduction of the ability of sensitized lymphocytes to cause macrophages to suppress multiplication of intracellular bacilli.     

In Vitro Studies on the Mechanism of Acquired Resistance to Tuberculous Infection

Immune lymph node cells were obtained from mice immunized with bovine gamma globulin (BGG) in complete Freund's adjuvant or allogeneic MH134 tumor cells. They showed the capacity of conferring bactericidal activity on macrophages infected with Mycobacterium tuberculosis, H37Rv, when they were incubated on macrophage monolayers together with the corresponding antigen, i.e., BGG or solubilized cellular antigen of the tumor cells. However, such capacity was lower than that of tubercle bacilli-immune lymph node cells. Culture supernatants were harvested after incubation of tubercle bacilli-immune, BGG-immune or allogeneic tumor-immune lymph node cells with the corresponding antigen for 24 hr. Macrophages were altered so as to suppress intracellular bacillary growth when macrophage monolayers were exposed to the supernatants for more than 2 days. When normal lymph node cells were incubated on normal macrophage monolayers together with a mitogen such as PHA or concanavalin A, growth of tubercle bacilli within the macrophages was slightly but difinitely suppressed. The mechanism of elicitation of cellular immunity to the infection with tubercle bacilli is discussed on the basis of results presented in this and the preceding paper.     

Immunizing Capacity of Viable and Killed Attenuated Mycobacterial Cells Against Experimental Tuberculous Infection

The relationship of the dose of vaccine to the immune response was determined in CF-1 mice vaccinated intraperitoneally with viable cells of the attenuated H37Ra strain of Mycobacterium tuberculosis and in mice vaccinated with cells of the same strain killed by autoclaving at 121 C for 15 min. The results showed, in terms of increased resistance to tuberculous infection, that the immune response with both living and killed cells was dependent upon the dose of vaccine, whereas only the living cells were dependent upon the time of challenge after vaccination. The dose response curves show dramatically that viable cells, which do not multiply in vivo, are several hundred times more effective immunizing agents against tuberculous infection than are autoclaved cells. Viable 2-week-old H37Ra cells were far more immunogenic than viable 4-week-old cells. Autoclaved 2-week-old cells, however, were no more immunogenic than autoclaved 4-week-old cells. H37Ra cells killed by boiling (98 C), exposure to 65 C for 30 min, treating with 2% phenol, or by being dried with acetone also lost most of their capacity to immunize mice. The effect of adjuvant on the immune response of mice to tuberculous infection was tested by incorporating both viable and autoclaved cells in Freund's incomplete adjuvant. We found that this vehicle had little or no effect on the immunizing capacity of either viable or heat-killed mycobacterial cells. The relationship of all the findings to the specificity of the immune response to tuberculosis is discussed.     

Tuberculous Enteritis

Tuberculous enteritis occurs in about 2 percent of patients with pulmonary tuberculosis. Although it is uncommon in the United States, tuberculous enteritis should be considered in any patient with active pulmonary tuberculosis and abdominal complaints.Eight cases of T. enteritis have been treated at Harbor General Hospital in the last 25 years. Associated pulmonary disease was shown radiologically to be present in seven of eight patients. Findings on contrast studies of the gastrointestinal tract showed disease in six of six patients examined.In five patients, surgical operation was required for diagnosis or complications. Resection of diseased bowel with primary anastomosis was done in five patients. Although medical therapy is the mainstay in the treatment of both pulmonary and intestinal tuberculosis, one staged resection of diseased bowel with primary anastomosis is the procedure of choice for complications such as obstruction, hemorrhage or perforation.