Tuberculin reactivity in tuberculous meningitis
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《美国医学杂志》
1 Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
2 Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
Abstract
OBJECTIVE: To study tuberculin reactivity in childhood tuberculous meningitis both in clinical and histopathological (HP) context. METHODOLOGY: Children with tuberculous meningitis (TBM) were given tuberculin test by Mantoux technique, which was read at the end of 72 hours after the placement of skin test. Histopathological examination of the punch biopsy specimen of the tuberculin test site was performed and histopathological grading of the tuberculin reaction was compared with clinical reaction and clinical parameters. RESULTS: Of the 50 children studied, 68% of them were malnourished and 42% had BCG scar. Tuberculin test was positive in 22 (44%) cases. Spearman analysis showed negative correlation between stage of TBM and the size of tuberculin reaction. BCG status did not affect the size of tuberculin reaction. Histopathological grade of the tuberculin reaction was found to be directly proportional to the size of the tuberculin reaction and it was not affected by the stage of TBM. CONCLUSION: Tuberculin positivity is low in TBM irrespective of the nutritional status. At least some degree of inflammatory reaction can be seen at the site of tuberculin administration. In tuberculin negative cases, varying grades of cellular response in the absence of clinical induration can be seen in histopathology.
Keywords: Tuberculin skin test; Histopathology; Tuberculous meningitis; Children
Tuberculin test still remains the standard method of determining hypersensitivity to mycobacterial antigen in children in developing countries both in community and hospital setting. It detects the cellular immune response elicited by crude mycobacterial antigens. Its operating characteristics are superior to many other tests commonly used in the diagnosis of tuberculosis, despite the fact that this test is performed with a multiple antigenic mixture (PPD) and its result is dependent on the variability in immunologic reactivity. In spite of the above-mentioned fact, an important problem with the tuberculin test is its lack of sensitivity, particularly in severe forms of tuberculosis like tuberculous meningitis (TBM). The prevalence of negative tuberculin test is 10 - 20% in all forms of tuberculosis and up to 70% in TBM[1],[2]. However, Beck et al has shown that morphological absence of response to tuberculin does not necessarily mean an absence of cellular response at the site of tuberculin administration in adults with pulmonary tuberculosis.[3] The present work was undertaken to study response to tuberculin in childhood tuberculous meningitis in clinical and histopathological (HP) context.
Materials and methods
This descriptive study was carried out in the Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India, between May 1999 and April 2000. All consecutive children under 12 years of age with TBM were recruited in this study, which had prior approval of the institute ethical and research committee. The diagnosis of TBM was based on the modified criteria of Ahuja et al[4]. It consists of clinical features suggestive of tuberculous meningitis, supported by Cerebrospinal fluid (CSF) analysis, computerised tomography (CT) of the head, and any evidence of an active extraneural tuberculous focus if any. The criteria are:
A. Clinical: Fever with or without change in the temperament over a period of 2 weeks with/without any cause (mandatory). Loss of appetite, irritability, headache, vomiting, meningeal signs, convulsions and focal neurological deficit. Known contact with sputum positive adult tuberculosis (optional).
B. Cerebrospinal fluid: Pleocytosis with more than 20 cells/mm3, lymphocytes more than 60%, protein more than 100 mg% and sugar less than 60% of corresponding blood sugar.
C. Radiological: CT studies of the head showing 2 or more of the following :
Exudates in basal cisterns or in Sylvian fissures
Hydrocephalus
Infarcts
D. Extra neural tuberculosis: Active tuberculosis of lungs, gastrointestinal tract, lymphnodes, skeletal system as evidenced by appropriate radiological or microbiological or by presence of caseation necrosis on histopathological examination.
TB meningitis is classified into 4 groups based on the above clinical and laboratory criteria.
1. Definite tuberculous meningitis
i. Clinical criteria (A)
ii. Bacterial isolation from CSF or diagnosis at autopsy
2. Highly probable tuberculous meningitis
i. Clinical criteria (A)
ii. All 3 of (B) and (C) and (D)
3. Probable tuberculous meningitis
i. Clinical criteria (A)
ii. Any 2 of (B),(C) and (D)
4. Possible tuberculous meningitis
i. Clinical criteria (A)
ii. Any one of (B),(C) and (D)
After an informed consent from the parents/ caretakers, the children were examined for the presence of BCG scar and malnutrition (assessed by Quetlet index). The clinical stage of tuberculous meningitis was graded as per the 'Medical Research Council' classification.[5] Routine cytological and microbiological examination of CSF was performed in all children. Tuberculin test was administered by Mantoux technique on the volar surface of left forearm with one TU PPD RT23 Tween 80 (BCG laboratory, Guindy, Chennai). Seventy-two hours after the placement of skin test, the maximum transverse diameter of the induration was measured with a transparent plastic ruler using the pen method.[6] The tuberculin reaction was considered to be positive if the induration was 10 mm at the end of 72 hours.[7] Biopsy of the tuberculin test site was performed under local anesthesia with 2% lignocaine using a 4 mm disposable punch biopsy needle (Stiefel Laboratories, Slough, England) after 72 hours of administration of the tuberculin test. The biopsy specimen was fixed in 4% neutral buffered formaldehyde for routine histological study.[8] Histopathologicaly, the tuberculin reaction was classified as follows,
Grade 0 No inflammatory response
Grade I Inflammatory reaction (tissue edema and cellular response) seen in the epidermis and the papillary layer of the dermis.
Grade II Grade I reaction with involvement of reticular layer of dermis.
Grade III Grade II reaction with involvement of subcutaneous tissue and/or presence of tissue necrosis.
Children who were infected with human immunodeficiency virus were excluded from the present study. All of the present study cases were treated with standard antituberculous therapy and other supportive measures. Analysis of the results was done using the analysis of variance and correlation coefficient estimation by Spearman rank analysis.
Results
Fifty children with tuberculous meningitis constituted the study population. The median and mean ages were 3 years and 45.6 months respectively with sixty eight percent being less than 5 years. The number of boys (n=28) was more than the number of girls (n=22). The overall tuberculin positivity in the present study was 44 percent. Certain salient observations in the present study population are presented in table1. Of the 50 cases studied, 12 (24%) had highly probable TBM, 34 (68%) had probable TBM and only 4 (8%) cases had possible TBM. All the four cases of possible TBM showed good response to antituberculous therapy and were followed up for varying periods of 9-18 months. No acid fast bacillus (AFB) was isolated from any of the CSF samples. In four of our cases, AFB was cultured from gastric aspirate and it was considered as an evidence of intrathoracic tuberculosis. At admission, five children (10%) had stage I disease, 29 (58%) had stage II disease and 16 (32%) had stage III disease. The occurrence of tuberculin reactivity in the individual stages is given in Figure1. Correlation analysis showed that the size of the tuberculin reaction was smaller in advanced stage and larger in early stage of TBM (r = -0.37; P = 0.001). Among the twenty-two tuberculin positive children, 12 had BCG scar. In the remaining twenty-eight who were tuberculin negative, 17 had BCG scar. Spearman rank analysis showed that BCG status did not affect the size of tuberculin reaction (r = 0.07; P > 0.05). It was also found that age, sex and nutritional status did not influence the size of tuberculin induration (P > 0.05). Also there was no association between CSF quantitative cellular response and the size of the tuberculin reaction (P > 0.05).
Histopathological (HP) examination revealed that at least grade I reaction to tuberculin was seen in all cases. When the HP grading and the size of the tuberculin reaction were compared, it was noted that grade III reaction was present mainly among the positive tuberculin reactors (6 out of 7). More than three-fourth of children (22 out of 28) with negative tuberculin reaction had only grade 1 reaction Figure1. The mean size of tuberculin reactions in HP grade I, II and III were 4.5, 10.4 and 15.8 mm respectively. HP grade of the tuberculin reaction was found to be directly proportional to the size of the tuberculin reaction (F = 6.9, P = 0.02). An important point to note is that the grade of the tuberculin reaction was not affected by the stage of TBM (F = 1.6, P > 0.05). It was also found that there was no association between age, sex, nutritional status, CSF cellular response and the grade of tuberculin reaction (P > 0.05).
Discussion
The reported tuberculin positivity has varied between 25 - 51%.[9],[10] In the present study, tuberculin positivity was noted in 44% cases and this is comparable to the previously reported observations. Reported tuberculin reaction positivity in children with malnutrition was between 18 - 50%.[11],[12] However in the present study, there was no significant difference in the tuberculin reactivity among children with normal nutrition and malnutrition.
In their study on tuberculin reaction, Beck et al[3] have discussed about the individual components of the inflammatory reaction rather than the reaction in its entirety. This study reported a poor correlation between the cellular infiltration and size of the induration and concluded that the amount of cellular infiltrate and the induration are distinct phenomena and clinical induration is the result of tissue edema.
The present study has shown the degree of inflammatory reaction is directly proportional to size of induration. But there was no definite relationship between the severity of inflammatory reaction and the stage of TBM. This is probably due to the occurrence of cellular response without tissue edema in some tuberculin negative cases. This possibly indicates that there may be accumulation of certain inhibitory inflammatory cells at the site of tuberculin testing,[13] which inhibit the development of clinical induration, or there may be cytokine-mediated modulation of inhibition of release of mediators after an adequate recruitment of cells.[14], [15]
Studies[3],,[8] on histopathology of tuberculin skin reaction have shown that the localization of inflammatory cells are mainly confined to the perivascular and periappendicular foci in the dermis and are most marked in the papillary dermis. The intensity of the cellular infiltrate has been noted to progressively lessen in the deeper layers of the skin. These observations formed the basis of our HP grading of tuberculin reaction into four grades.
It is observed from our study that tuberculin positivity is low in childhood TBM and it is not affected by the nutritional status. At least some degree of inflammatory reaction can be seen at the site of tuberculin administration. In tuberculin negative cases, varying grades of cellular response in the absence of clinical induration can be seen in histopathology. Further studies on the specific cellular kinetics/ local inflammatory mediators in negative tuberculin reactors will help to understand the immunopathogenesis of tuberculous meningitis.
References
1. Holden M, Dubin MR, Diamond PH. Frequency of negative intermediate-strength tuberculin sensitivity in patients with active tuberculosis. N Engl J Med 1971; 285 : 1506-1059.
2. Nash DR, Douglass JE. Anergy in active pulmonary tuberculosis: a comparison between positive and negative reactors and an evaluation of 5 TU and 250 TU skin test doses. Chest 1980; 77: 32-37.
3. Beck JS, Morley SM, Gibbs JH et al. The cellular responses of tuberculosis and leprosy patients and of healthy controls in skin tests to 'New Tuberculin' and Leprosin A. Clin Exp Immunol 1986; 64 : 484-494.
4. Ahuja GK, Mohan KK, Prasad K, Behari M. Diagnostic criteria for tuberculous meningitis and their validation. Tuber Lung Dis 1994; 75: 149-152.
5. Streptomycin in Tuberculosis Trials Committee, Medical Research Council. Streptomycin Treatment of Tuberculous Meningitis. Lancet 1948; 1: 582-596.
6. Sokal JE. Measurement of delayed skin-test responses. New Eng J Med 1975; 293: 501-502.
7. Serane TV, Nalini P. Tuberculin reactivity in healthy school children in Pondicherry. Indian J Pediatr 2001; 68: 729-732.
8. Gibbs JH, Ferguson J, Brown RA et al. Histometric study of the localization of lymphocyte subsets and accessory cells in human Mantoux reactions. J Clin Pathol 1984; 37 : 1227-1234.
9. Seth R, Sharma U. Diagnostic criteria for Tuberculous Meningitis. Indian J Pediatr 2002; 69 : 299-303.
10. Farinha NJ, Razali KA, Holzel H, Morgan G, Novelli VM. Tuberculosis of the central nervous system in children: a 20-year survey. J Infect 2000; 41 : 61-68.
11. Gocmen A, Kiper N, Ertan U, Kalayci O, Ozcelik U. Is the BCG test of diagnostic value in tuberculosis. Tuber Lung Dis 1994;75 : 54-57.
12. Seth V, Kukreja N, Sundaram KR, Malaviya AN. Delayed hypersensitivity after BCG in preschool children in relation to their nutritional status. Indian J Med Res 1981; 74 : 392-398.
13. Elliner JJ. Pleural fluid and peripheral blood lymphocyte function in tuberculosis. Ann Intern Med 1978; 89 : 932-933.
14. Rubin LA, Kurman CC, Fritz ME et al. Soluble interleukin 2 receptors are released from activated human lymphoid cells in vitro. J Imrnunol 1985; 135 : 3172 3177.
15. Barral Netto M, Barral A, Santos SB et al. Soluble IL 2 receptor as an agent of serum mediated suppression in human visceral leishmaniasis. J Immunol 1991; 147 : 281-284.(Mahadevan B, Mahadevan S,)
2 Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
Abstract
OBJECTIVE: To study tuberculin reactivity in childhood tuberculous meningitis both in clinical and histopathological (HP) context. METHODOLOGY: Children with tuberculous meningitis (TBM) were given tuberculin test by Mantoux technique, which was read at the end of 72 hours after the placement of skin test. Histopathological examination of the punch biopsy specimen of the tuberculin test site was performed and histopathological grading of the tuberculin reaction was compared with clinical reaction and clinical parameters. RESULTS: Of the 50 children studied, 68% of them were malnourished and 42% had BCG scar. Tuberculin test was positive in 22 (44%) cases. Spearman analysis showed negative correlation between stage of TBM and the size of tuberculin reaction. BCG status did not affect the size of tuberculin reaction. Histopathological grade of the tuberculin reaction was found to be directly proportional to the size of the tuberculin reaction and it was not affected by the stage of TBM. CONCLUSION: Tuberculin positivity is low in TBM irrespective of the nutritional status. At least some degree of inflammatory reaction can be seen at the site of tuberculin administration. In tuberculin negative cases, varying grades of cellular response in the absence of clinical induration can be seen in histopathology.
Keywords: Tuberculin skin test; Histopathology; Tuberculous meningitis; Children
Tuberculin test still remains the standard method of determining hypersensitivity to mycobacterial antigen in children in developing countries both in community and hospital setting. It detects the cellular immune response elicited by crude mycobacterial antigens. Its operating characteristics are superior to many other tests commonly used in the diagnosis of tuberculosis, despite the fact that this test is performed with a multiple antigenic mixture (PPD) and its result is dependent on the variability in immunologic reactivity. In spite of the above-mentioned fact, an important problem with the tuberculin test is its lack of sensitivity, particularly in severe forms of tuberculosis like tuberculous meningitis (TBM). The prevalence of negative tuberculin test is 10 - 20% in all forms of tuberculosis and up to 70% in TBM[1],[2]. However, Beck et al has shown that morphological absence of response to tuberculin does not necessarily mean an absence of cellular response at the site of tuberculin administration in adults with pulmonary tuberculosis.[3] The present work was undertaken to study response to tuberculin in childhood tuberculous meningitis in clinical and histopathological (HP) context.
Materials and methods
This descriptive study was carried out in the Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India, between May 1999 and April 2000. All consecutive children under 12 years of age with TBM were recruited in this study, which had prior approval of the institute ethical and research committee. The diagnosis of TBM was based on the modified criteria of Ahuja et al[4]. It consists of clinical features suggestive of tuberculous meningitis, supported by Cerebrospinal fluid (CSF) analysis, computerised tomography (CT) of the head, and any evidence of an active extraneural tuberculous focus if any. The criteria are:
A. Clinical: Fever with or without change in the temperament over a period of 2 weeks with/without any cause (mandatory). Loss of appetite, irritability, headache, vomiting, meningeal signs, convulsions and focal neurological deficit. Known contact with sputum positive adult tuberculosis (optional).
B. Cerebrospinal fluid: Pleocytosis with more than 20 cells/mm3, lymphocytes more than 60%, protein more than 100 mg% and sugar less than 60% of corresponding blood sugar.
C. Radiological: CT studies of the head showing 2 or more of the following :
Exudates in basal cisterns or in Sylvian fissures
Hydrocephalus
Infarcts
D. Extra neural tuberculosis: Active tuberculosis of lungs, gastrointestinal tract, lymphnodes, skeletal system as evidenced by appropriate radiological or microbiological or by presence of caseation necrosis on histopathological examination.
TB meningitis is classified into 4 groups based on the above clinical and laboratory criteria.
1. Definite tuberculous meningitis
i. Clinical criteria (A)
ii. Bacterial isolation from CSF or diagnosis at autopsy
2. Highly probable tuberculous meningitis
i. Clinical criteria (A)
ii. All 3 of (B) and (C) and (D)
3. Probable tuberculous meningitis
i. Clinical criteria (A)
ii. Any 2 of (B),(C) and (D)
4. Possible tuberculous meningitis
i. Clinical criteria (A)
ii. Any one of (B),(C) and (D)
After an informed consent from the parents/ caretakers, the children were examined for the presence of BCG scar and malnutrition (assessed by Quetlet index). The clinical stage of tuberculous meningitis was graded as per the 'Medical Research Council' classification.[5] Routine cytological and microbiological examination of CSF was performed in all children. Tuberculin test was administered by Mantoux technique on the volar surface of left forearm with one TU PPD RT23 Tween 80 (BCG laboratory, Guindy, Chennai). Seventy-two hours after the placement of skin test, the maximum transverse diameter of the induration was measured with a transparent plastic ruler using the pen method.[6] The tuberculin reaction was considered to be positive if the induration was 10 mm at the end of 72 hours.[7] Biopsy of the tuberculin test site was performed under local anesthesia with 2% lignocaine using a 4 mm disposable punch biopsy needle (Stiefel Laboratories, Slough, England) after 72 hours of administration of the tuberculin test. The biopsy specimen was fixed in 4% neutral buffered formaldehyde for routine histological study.[8] Histopathologicaly, the tuberculin reaction was classified as follows,
Grade 0 No inflammatory response
Grade I Inflammatory reaction (tissue edema and cellular response) seen in the epidermis and the papillary layer of the dermis.
Grade II Grade I reaction with involvement of reticular layer of dermis.
Grade III Grade II reaction with involvement of subcutaneous tissue and/or presence of tissue necrosis.
Children who were infected with human immunodeficiency virus were excluded from the present study. All of the present study cases were treated with standard antituberculous therapy and other supportive measures. Analysis of the results was done using the analysis of variance and correlation coefficient estimation by Spearman rank analysis.
Results
Fifty children with tuberculous meningitis constituted the study population. The median and mean ages were 3 years and 45.6 months respectively with sixty eight percent being less than 5 years. The number of boys (n=28) was more than the number of girls (n=22). The overall tuberculin positivity in the present study was 44 percent. Certain salient observations in the present study population are presented in table1. Of the 50 cases studied, 12 (24%) had highly probable TBM, 34 (68%) had probable TBM and only 4 (8%) cases had possible TBM. All the four cases of possible TBM showed good response to antituberculous therapy and were followed up for varying periods of 9-18 months. No acid fast bacillus (AFB) was isolated from any of the CSF samples. In four of our cases, AFB was cultured from gastric aspirate and it was considered as an evidence of intrathoracic tuberculosis. At admission, five children (10%) had stage I disease, 29 (58%) had stage II disease and 16 (32%) had stage III disease. The occurrence of tuberculin reactivity in the individual stages is given in Figure1. Correlation analysis showed that the size of the tuberculin reaction was smaller in advanced stage and larger in early stage of TBM (r = -0.37; P = 0.001). Among the twenty-two tuberculin positive children, 12 had BCG scar. In the remaining twenty-eight who were tuberculin negative, 17 had BCG scar. Spearman rank analysis showed that BCG status did not affect the size of tuberculin reaction (r = 0.07; P > 0.05). It was also found that age, sex and nutritional status did not influence the size of tuberculin induration (P > 0.05). Also there was no association between CSF quantitative cellular response and the size of the tuberculin reaction (P > 0.05).
Histopathological (HP) examination revealed that at least grade I reaction to tuberculin was seen in all cases. When the HP grading and the size of the tuberculin reaction were compared, it was noted that grade III reaction was present mainly among the positive tuberculin reactors (6 out of 7). More than three-fourth of children (22 out of 28) with negative tuberculin reaction had only grade 1 reaction Figure1. The mean size of tuberculin reactions in HP grade I, II and III were 4.5, 10.4 and 15.8 mm respectively. HP grade of the tuberculin reaction was found to be directly proportional to the size of the tuberculin reaction (F = 6.9, P = 0.02). An important point to note is that the grade of the tuberculin reaction was not affected by the stage of TBM (F = 1.6, P > 0.05). It was also found that there was no association between age, sex, nutritional status, CSF cellular response and the grade of tuberculin reaction (P > 0.05).
Discussion
The reported tuberculin positivity has varied between 25 - 51%.[9],[10] In the present study, tuberculin positivity was noted in 44% cases and this is comparable to the previously reported observations. Reported tuberculin reaction positivity in children with malnutrition was between 18 - 50%.[11],[12] However in the present study, there was no significant difference in the tuberculin reactivity among children with normal nutrition and malnutrition.
In their study on tuberculin reaction, Beck et al[3] have discussed about the individual components of the inflammatory reaction rather than the reaction in its entirety. This study reported a poor correlation between the cellular infiltration and size of the induration and concluded that the amount of cellular infiltrate and the induration are distinct phenomena and clinical induration is the result of tissue edema.
The present study has shown the degree of inflammatory reaction is directly proportional to size of induration. But there was no definite relationship between the severity of inflammatory reaction and the stage of TBM. This is probably due to the occurrence of cellular response without tissue edema in some tuberculin negative cases. This possibly indicates that there may be accumulation of certain inhibitory inflammatory cells at the site of tuberculin testing,[13] which inhibit the development of clinical induration, or there may be cytokine-mediated modulation of inhibition of release of mediators after an adequate recruitment of cells.[14], [15]
Studies[3],,[8] on histopathology of tuberculin skin reaction have shown that the localization of inflammatory cells are mainly confined to the perivascular and periappendicular foci in the dermis and are most marked in the papillary dermis. The intensity of the cellular infiltrate has been noted to progressively lessen in the deeper layers of the skin. These observations formed the basis of our HP grading of tuberculin reaction into four grades.
It is observed from our study that tuberculin positivity is low in childhood TBM and it is not affected by the nutritional status. At least some degree of inflammatory reaction can be seen at the site of tuberculin administration. In tuberculin negative cases, varying grades of cellular response in the absence of clinical induration can be seen in histopathology. Further studies on the specific cellular kinetics/ local inflammatory mediators in negative tuberculin reactors will help to understand the immunopathogenesis of tuberculous meningitis.
References
1. Holden M, Dubin MR, Diamond PH. Frequency of negative intermediate-strength tuberculin sensitivity in patients with active tuberculosis. N Engl J Med 1971; 285 : 1506-1059.
2. Nash DR, Douglass JE. Anergy in active pulmonary tuberculosis: a comparison between positive and negative reactors and an evaluation of 5 TU and 250 TU skin test doses. Chest 1980; 77: 32-37.
3. Beck JS, Morley SM, Gibbs JH et al. The cellular responses of tuberculosis and leprosy patients and of healthy controls in skin tests to 'New Tuberculin' and Leprosin A. Clin Exp Immunol 1986; 64 : 484-494.
4. Ahuja GK, Mohan KK, Prasad K, Behari M. Diagnostic criteria for tuberculous meningitis and their validation. Tuber Lung Dis 1994; 75: 149-152.
5. Streptomycin in Tuberculosis Trials Committee, Medical Research Council. Streptomycin Treatment of Tuberculous Meningitis. Lancet 1948; 1: 582-596.
6. Sokal JE. Measurement of delayed skin-test responses. New Eng J Med 1975; 293: 501-502.
7. Serane TV, Nalini P. Tuberculin reactivity in healthy school children in Pondicherry. Indian J Pediatr 2001; 68: 729-732.
8. Gibbs JH, Ferguson J, Brown RA et al. Histometric study of the localization of lymphocyte subsets and accessory cells in human Mantoux reactions. J Clin Pathol 1984; 37 : 1227-1234.
9. Seth R, Sharma U. Diagnostic criteria for Tuberculous Meningitis. Indian J Pediatr 2002; 69 : 299-303.
10. Farinha NJ, Razali KA, Holzel H, Morgan G, Novelli VM. Tuberculosis of the central nervous system in children: a 20-year survey. J Infect 2000; 41 : 61-68.
11. Gocmen A, Kiper N, Ertan U, Kalayci O, Ozcelik U. Is the BCG test of diagnostic value in tuberculosis. Tuber Lung Dis 1994;75 : 54-57.
12. Seth V, Kukreja N, Sundaram KR, Malaviya AN. Delayed hypersensitivity after BCG in preschool children in relation to their nutritional status. Indian J Med Res 1981; 74 : 392-398.
13. Elliner JJ. Pleural fluid and peripheral blood lymphocyte function in tuberculosis. Ann Intern Med 1978; 89 : 932-933.
14. Rubin LA, Kurman CC, Fritz ME et al. Soluble interleukin 2 receptors are released from activated human lymphoid cells in vitro. J Imrnunol 1985; 135 : 3172 3177.
15. Barral Netto M, Barral A, Santos SB et al. Soluble IL 2 receptor as an agent of serum mediated suppression in human visceral leishmaniasis. J Immunol 1991; 147 : 281-284.(Mahadevan B, Mahadevan S,)