Efficiency of IgM Anti-Cardiolipin Serum Level Screening for Monitoring Response to Anti-Tuberculosis Treatment in Comparison with Sputum Smear Conversion Test

Background: Two original methods for evaluation of response to tuberculosis treatment are sputum smear and culture. Sputum smear test has a low sensitivity and sputum culture is not available in many countries with endemic tuberculosis. There are some biomarkers diseases such as IgM anti-cardiolipin antibody which could be assessed for this purpose. Objectives: Therefore, we decided to measure the reduction rate of IgM anti-cardiolipin antibody during treatment of smear positive pulmonary tuberculosis (PTB) patients for monitoring response to treatment and then compare efficiency of this test with sputum smear conversion. Methods: In this research study 30 sputum smear positive PTB patients were included by convenient sampling method and then their serum samples were taken before and after the first 3 months of anti-TB treatment for measurement of IgM anti-cardiolipin antibody serum level by Elisa method. Their serum level changes during treatment were analyzed by paired t test with SPSS software (ver.18). Results: The mean IgM anti-cardiolipin serum level during treatment showed significant reduction relative to its level at baseline in 27 (90%) of total patients (P < 0.0001). Also, this result was confirmed in both cavitary (P < 0.0001) and non-cavitary (P = 0.005) groups. The sensitivity of test (90%) was equal with sputum smear conversion rate in our study (90%) and was associated with clinical improvement in all of 30 cases (100%). Conclusions: The reduction of IgM anti cardiolipin serum level during treatment, could be a reliable indicator of effective treatment and specially it may be applicable in PTB patients who have negative sputum smear test or cannot deliver sufficient sputum for evaluation of response to anti-TB treatment.