S Shobha

Publications (3)12.08 Total impact

• Article: Diagnosis of tuberculous meningitis confirmed by means of an immunoblot method.

  A Mathai, V V Radhakrishnan, S Shobha
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  ABSTRACT: In order to define the mycobacterial antigens that may be specifically associated with human tuberculous infection, the cerebrospinal fluid (CSF) specimens of 30 patients with tuberculous meningitis (TBM) and of an equal number of patients with non-tuberculous meningitis (controls) were compared by means of an immunoblot method for detecting antibody to Mycobacterium tuberculosis. In the CSF of controls, mycobacterial antibody was either absent or, when present, was found to react with 27, 30 and 45 KDa antigens of M. tuberculosis. Among patients with TBM, the numbers as well as intensities of the immunostained bands in the nitrocellulose membranes (NCM) were greater than among controls. Furthermore, a unique disease-associated mycobacterial antigen, 35 KDa of M. tuberculosis, was found to react with a specific antibody in the CSF of patients with TBM but was not detected in the CSF of any of the controls. This 35 KDa antigen could be easily identified in the NCM. The immunoblot method showed 100% sensitivity in all the culture-positive patients with TBM. Because of the high degree of specificity as well as sensitivity of the immunoblot method, we consider that this method is of value for confirming the diagnosis of TBM.
  Journal of Infection 08/1994; 29(1):33-9. · 4.13 Impact Factor
• Article: Correlation between culture of Mycobacterium tuberculosis and IgG antibody to Mycobacterium tuberculosis antigen-5 in the cerebrospinal fluid of patients with tuberculous meningitis.

  V V Radhakrishnan, M Annamma, S Shobha
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  ABSTRACT: A retrospective study was made of the correlation between culture of Mycobacterium tuberculosis and detection of IgG antibody to M. tuberculosis antigen-5 in cerebrospinal fluid (CSF) by means of an enzyme linked immunosorbent assay (ELISA). Mycobacterium tuberculosis was cultured from the CSF in 14 of 70 patients with a clinical diagnosis of tuberculous meningitis (TBM). IgG antibody to M. tuberculosis antigen-5 was demonstrated in significant titres (80-640) in all 14 culture-positive patients. Thus, positive correlation was observed between culture of M. tuberculosis and detection of IgG antibody in the CSF. As a result of this observation, the CSF from 56 culture-negative patients with a clinical diagnosis TBM was specifically investigated for the detection of IgG antibody to M. tuberculosis antigen-5 and the findings were correlated with those of culture-positive patients. The assay was positive in 34 of 56 patients, the antibody titre ranging between 80 and 640. In the CSF of 70 patients with non-tuberculous neurological diseases, the assay was negative at a dilution of 1 in 80. Thus, detection of IgG antibody to M. tuberculosis antigen-5 by indirect ELISA carried 100% specificity and 60.7% sensitivity for a tuberculous aetiology in culture-negative patients with TBM. The results of this study suggest that indirect ELISA for IgG antibody to M. tuberculosis antigen-5 in CSF holds definite promise in diagnosis of TBM, particularly when repeated cultures of CSF are negative for M. tuberculosis.
  Journal of Infection 12/1990; 21(3):271-7. · 4.13 Impact Factor
• Article: Diagnosis of tuberculous meningitis by enzyme-linked immunosorbent assay to detect mycobacterial antigen and antibody in cerebrospinal fluid.

  M Annamma, V V Radhakrishnan, S Shobha
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  ABSTRACT: Enzymed-linked immunosorbent assay (ELISA) was used to detect mycobacterial antigen and antimycobacterial antibody in cerebrospinal fluid (CSF) specimens of 50 patients with tuberculous meningitis (TBM) and 50 patients with non-tuberculous neurological diseases (control group). The assay gave no false negative results in 10 culture-positive patients with TBM. Detection of mycobacterial antigen in CSF is more sensitive and specific for the diagnosis of TBM than detection of antibody, ELISA should be considered as one of the alternative methods in the laboratory diagnosis of TBM, particularly in culture-negative patients with TBM.
  Medical Microbiology and Immunology 02/1990; 179(5):281-8. · 3.83 Impact Factor