Introduction:
Cytomegalovirus (CMV) is a leading cause of morbidity and mortality among the immunosuppressed population, and it is a common cause of opportunistic infections in human immunodeficiency virus (HIV)-positive patients. In this case series study, we describe our experience with nine HIV-positive patients suffering from pneumonia who demonstrated typical cyto-pathologic evidences of CMV pneumonitis.

Material and methods:
Clinical records of all HIV-infected patients with pneumonia who were admitted to National Research Institute of Tuberculosis and Lung Diseases (NRITLD), a tertiary center of tuberculosis and lung diseases in Iran, were prospectively reviewed. Results of micro-biological investigations of bronchoalveolar fluid (BAL) and trans-bronchial lung biopsy (TBLB) specimens were evaluated as well as their histological and cytological findings. All patients with cyto-pathologic evidences of CMV pneumonitis found in TBLB were extracted, characteristic of which was shown as enlarged cells with large pleomorphic nuclei, and intra-nuclear and cytoplasmic inclusions.

Results:
Of these cases, seven patients were diagnosed with concomitant CMV and Pneumocystis jiroveci pneumonitis. Five patients had thrush, two patients tested positive for active tuberculosis, and one patient reported a history of old tuberculosis. Laboratory data analysis revealed LDH ranging from 138 to 1,140, with average amount of 653.22. CD4+ counts ranged from 12 to 156, with average of 56.22. Six patients tested positive for CMV infection with plasma polymerase chain reaction (PCR) method.

Conclusions:
The differential diagnosis for CMV pneumonia in HIV-infected population is extensive and includes diseases, such as bacterial pneumonias, Mycobacterium tuberculosis infections, PCP, and other HIV-associated respiratory infections. Definitive diagnosis is based upon demonstration of CMV in pulmonary secretions or in lung tissue.