DNA hybridization for detection of human cytomegalovirus in bronchoalveolar lavage and pharynx biopsy

Diagnosis and treatment approaches of CMV infections in adult patients

BACKGROUND

Cytomegalovirus (CMV) infections are very common in the general population. Clinical CMV disease, particularly CMV pneumonitis, greatly impacts the morbidity and mortality of immunosuppressed patients.

OBJECTIVE

To present an overview of the basic aspects of the biology, epidemiology, and clinical features of CMV in relation to the available diagnostic and therapeutic approaches in adult patients.

METHODS

Review of the medical literature on cytomegalovirus infection and disease in adult hosts, with a focus on approaches to diagnosis and treatment of CMV respiratory disease in immunosuppressed hosts.

CONCLUSIONS

Cytomegalovirus infections are likely to remain a significant cause of morbidity and mortality among immunosuppressed patients. Important aspects of the biological events underlying the transition from infection to clinical disease remain unclear. Despite that, considerable progress has been made in the design of improved diagnostic techniques and the development of antiviral agents. Preventive and particularly preemptive therapeutic approaches demand further technical improvements in diagnostic testing. At present, the emphasis in the search for improved diagnostic testing rests on the development of quantitative methods for early detection of the increased viral replicative activity that presumably precedes the onset of CMV disease in infected individuals.

Sensitive non-isotopic DNA hybridisation assay or immediate-early antigen detection for rapid identification of human cytomegalovirus in urine

A sensitive non-radioactive DNA hybridisation assay employing digoxigenin-labelled probes was compared with immediate-early antigen detection and conventional virus isolation for the identification of human cytomegalovirus (HCMV) in 249 urine samples. Of 44 specimens yielding HCMV by virus isolation, more were positive by DNA hybridisation (32; 73%) than by immediate-early antigen detection (25; 52%) (P = 0.05). The specificity of the hybridisation assay in 45 apparently falsely positive specimens was supported by detection of HCMV DNA in 40 of these specimens using the polymerase chain reaction. Many urine specimens may thus contain large amounts of non-viable virus or free viral DNA. Evaluation of various protocols for the extraction and denaturation of virus DNA prior to hybridisation showed that proteinase K digestion with phenol/chloroform extraction was the most sensitive and reliable procedure. We conclude that the non-radioactive DNA hybridisation assay described is a potentially valuable routine diagnostic test.

Detection of human cytomegalovirus DNA in liver biopsies from patients with cytomegalovirus-related liver disease

Infection with human cytomegalovirus (HCMV) has been associated with severe diseases in immunologically impaired patients. Cytomegalovirus hepatitis has been frequently described in this population, but this diagnosis is still difficult. Molecular hybridization with the V EcoRI restriction fragment of human cytomegalovirus strain AD 169 has been tested upon DNA extracted from liver samples to assess the usefulness of this technique for cytomegalovirus hepatitis diagnosis. This probe was shown by the Southern technique not to hybridize with DNA extracted from cells infected with other herpesviruses or with DNA of non-infected normal liver. The sensitivity was estimated to be 2 x 10(5) genomes. Twenty-five renal transplant recipients under immunosuppressive therapy and three patients having the acquired immunodeficiency syndrome were studied. In 9 out of 10 renal transplant recipients with normal liver, previous exposure to cytomegalovirus, as defined by serological tests, was not sufficient to allow positive detection by the probe. Out of 11 patients with abnormal liver, cytomegalovirus DNA sequences were shown in 5. In 2 patients with histological evidence of cytomegalovirus hepatitis, a very strong signal showed the presence of viral genomes. These results show that the Southern technique with the V EcoRI probe can be useful for the diagnosis of HCMV hepatitis and might be proposed for the detection of this viral genome in human tissues.