Tehran University Medical Journal

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Background: Human Cytomegalovirus (HCMV) infections are a significant challenge in patients with Hematopoietic Cell Transplant (HCT). Acute Graft vs. Host (GVHD) is recognized as a predisposing factor for increased incidence of HCMV reactivation. Availability of rapid and accurate tests for HCMV detection in HCT recipients is of foremost importance in developing countries, such as Iran.
Methods: A total of 201 peripheral blood leukocyte (PBL) and plasma specimens from 26 allogeneic HCT recipients were examined for HCMV DNA by polymerase chain reaction (PCR) assay. Densitometric analysis of 257bp PCR products from clinical samples and 101-106 "cloned plasmid" per µg DNA containing a HCMV specific fragment were analyzed using LabWorks software (v3.0.02). Optical density of amplicons was plotted, and calculated HCMV viral loads were compared with the patients' antigenemia results.
Results: HCMV viral loads ranged between <102 to 1.35×102 copies per µg DNA among 7 HCT patients. In addition, 14 episodes of positive antigenemia assay in 7 patients in which peak HCMV load were compared with GVHD grade II-IV patients. Significant correlation was also detected between HCMV DNA load in PBL and plasma samples, as well as HCMV DNA load in PBL samples and antigenemia results. Receiver–Operating Characteristic analysis determined that 2,200 HCMV copies in PBL samples as the threshold value for initiation of Ganciclovir therapy.
Conclusion: This report shows that rapid and sensitive assays, like quantitative PCR, are extremely valuable for detection of active HCMV infection, and life-threatening HCMV disease in HCT recipients during the post transplant period. Furthermore, high HCMV DNA load among GVHD grade II-IV patients confirms the high risk of HCMV reactivation among these HCT recipients. Tests such as quantitative PCR also helps physicians initiate timely preemptive therapy and for a shorter period, which may lead to better clinical outcome in HCMV-infected transplant patients.

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Background: Tuberculosis is still one of the most important causes of mortality and morbidity in many countries and is the second only to human immunodeficiency virus as a cause of death worldwide resulting from a single infectious agent. In 1993, the World Health Organization declared tuberculosis a global public health emergency. Conven-tional methods for the diagnosis of Mycobacterium tuberculosis (MTB) infections are time consuming, as MTB culture requires 3-8 weeks for growth. To determine the sensitivity of polymerase chain reaction (PCR) in peripheral blood mononuclear cells (PBMC), we have evaluated Mycobacterium tuberculosis DNA in peripheral blood samples with PCR technique in adults with new cases of pulmonary and extra-pulmonary tuberculosis. Setting: Department of Infectious disease of Imam Khomeini Hospital, 2004- 2005, Tehran, Iran.

Methods: In this cross-sectional study, we evaluated MTB DNA extracted from 3ml citrated peripheral blood samples from 95 adults with new cases of pulmonary and extra-pulmonary tuberculosis. DNA extraction was performed using a commercial PCR kit with IS1081 primers. For prevention of cross contamination and reduction of false positives, all steps were performed under laminar hood.

Results: The 95 patients, 59 of whom were male, had a mean age 44.44 years (SD±20.26) 69 cases had pulmonary and 26 had extra-pulmonary tuberculosis. PCR was positive in 32 (33.7%) patients and negative in 63 (66.3%) cases. The overall sensitivity and accuracy of the PCR assay was 44.1% for pulmonary, 19.2% for extra-pulmonary and 10% for disseminated tuberculosis, respectively.

Conclusion: The low sensitivity of the IS1081 primer MTB-PCR assay on PBMC may pose problems for the rapid diagnosis of tuberculosis. However, further studies are needed to confirm this technique as an alternative test for the diagnosis of tuberculosis.