2002 OPEN FORUM Abstracts
Correlation of Tuberculin Test & CD4 Count in HIV Positive Patients with Pulmonary & extra pulmonary Tuberculosis
Dr. Bhavin Dalal*, Dr. Kamal Goplani*, Dr. Pranav Dalal***, Dr. Shahid Surti**, Dr. Rasik Parmar**; *Assistant Professor of Medicine, Civil Hospital,; **Resident in Medicine, Civil Hospital; ***Resident in Medicine, V. S. Hospital, Ahmedabad, Gujarat, INDIA.
Objectives: This study was conducted to check the correlation of CD4 count with Mantoux test (Tuberculin Test / TT).
Methods: ýne hundred HIV infected patients not on anti-retroviral therapy were taken into the study and clinical data and routine investigations recorded. HIV infection was diagnosed by ELISA, which was performed twice for different antibodies. Apart from routine investigations TT, CD4 count and CD8 count were performed in all patients. TT was done by standard Mantoux method. CD4 count was performed by flow cytometry. Other investigations were performed as and when required to diagnosis tuberculosis & other opportunistic infections.
Results: Out of 100 patients, 55 patients were suffering from some kind of tuberculosis (Group I), while out of 45 patients not suffering from tuberculosis (Group II). Out of 45 patients 76.4 % patients were suffering from Pulmonary Tuberculosis or Mixed Tuberculosis (Pulmonary & Extra Pulmonary). Importance of TT to add diagnostic significance for Tuberculosis was limited for the patients whose CD4 count was low (CD4 < 50), while there was definite difference in mean TT in patients whose CD4 count > 50, who were suffering & not suffering from Tuberculosis. There is also good correlation between TT and CD4 count. In patients with TT < 5 mm, mean CD4 count was 65.10 and 163.59 (Z > 2) in group I (with Tuberculosis) and group II (without Tuberculosis) respectively; while in patients with TT ³ 5 mm, mean CD4 count was 233.73 and 486.50 (Z > 2) in group I (with Tuberculosis) and group II (without Tuberculosis) respectively. Expected CD4 count range for the patients of group I is 2 130 & 130 350 for TT < 5mm & TT ³ 5 mm respectively. Same way expected CD4 count range for the patients of group II is 75 230 & 230 650 for TT < 5 mm & TT ³ 5 mm. According to regression analysis equation for CD4 count was derived, which was Y = 25 X + 55, where Y = Expected CD4 count & X = TT (mm of induration). From this equation CD4 count can be very easily calculated; eg, if patientÕs TT is 7 mm his/her CD4 count is 25(7) + 55 = 230.
Conclusion: TT has some role to play for diagnosis of Tuberculosis in HIV positive patients with higher CD4 count. In developing countries it is difficult to perform CD4 count due to cost & unavailability, TT can be utilized as a good marker to check immunosuppression status in HIV positive patients. Though it is very difficult to start HAART from such expected CD4 count, this can be definitely utilized to start prophylaxis in developing countries.