Human cytomegalovirus and acute rejection after heart transplantation are not directly associated

Early detection of cytomegalovirus (CMV) infection in bone marrow transplant patients by reverse transcription-PCR for CMV spliced late gene UL21.5: a two site evaluation

BACKGROUND

Bone marrow transplant (BMT) patients at risk of developing cytomegalovirus (CMV) pneumonitis are identified routinely by the early detection of virus in blood. For early diagnosis of CMV infection, the RNA-based approach demonstrates advantages when compared with the current CMV antigen and DNA detection methods.

OBJECTIVES

We have evaluated our previously developed reverse transcription-polymerase chain reaction (RT-PCR) to a spliced late CMV gene (SLG; J. Virol. Methods 56 (1996), 139) to monitor CMV infection in BMT patients at two clinical sites. The diagnostic value of the SLG RT-PCR was compared with the routine CMV antigen and DNA detection methods.

STUDY DESIGN

Weekly blood samples from BMT patients were tested for CMV during the first 3 months post-transplant. The qualitative SLG RT-PCR, semiquantitative DNA PCR, and viral antigen tests were compared. The RNA and DNA PCR results were analysed in terms of their temporal relationship and consistency of CMV detection and compared with CMV infection diagnosed by viral antigen tests.

RESULTS

Of the 101 BMT recipients studied, 25 developed CMV antigenemia and/or DNAemia resulting in symptomatic infection in two patients. All CMV PCR-positive patients were either CMV seropositive pretransplant or received marrow from seropositive donor. The highest incidence of CMV infection was seen in seropositive recipients (R+) irrespective of the donor's status. Detection of CMV infection by SLG RNA preceded CMV DNA detection by 0-2 weeks (median 1 week) and CMV antigen detection by 0-8 weeks (median 3 weeks). Once detected, the SLG RNA remained consistently positive before antiviral treatment was commenced. Both the SLG RNA and CMV DNA detection methods had the same clinical sensitivity, specificity, positive and negative predictive values of 100, 94, 80 and 100%, respectively.

CONCLUSIONS

The RT-PCR for SLG RNA proved to be the earliest indicator of CMV infection in BMT patients demonstrating a sustained pattern of CMV detection during the 3 months post-transplant period. Although very similar in its diagnostic performance to CMV DNA PCR the SLG RNA RT-PCR does not require quantitation and provides an efficient and ongoing indication of active CMV infection.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

Human cytomegalovirus genome sequences in lymph nodes

Human cytomegalovirus (CMV) is a major cause of morbidity in heart and lung transplant patients, resulting from immunosuppression-mediated reactivation of latent CMV originating either from the transplanted tissue, or the recipient. We showed that out of eight donor/recipient pairs, the lymph nodes (LNs) of three donors and four recipients, all CMV seropositive, harboured CMV DNA at exceeding levels compared with those of matched blood samples, as well as CMV RNA otherwise undetectable in patients' blood. On follow-up, patients positive for CMV DNA and RNA in LNs developed viraemia 4 to 5 weeks earlier than those initially polymerase chain reaction-negative for CMV. Our results indicate that LN are a significant site for sequestration and persistence of CMV and that LN may be important in seeding of CMV-infected cells into the circulation.

Viral loads in dual infection with HIV-1 and cytomegalovirus

OBJECTIVE

A one year study of the relation between cytomegalovirus (CMV) and human immunodeficiency virus (HIV) viral loads in a cohort of children with vertically acquired HIV-1 infection.

DESIGN

Comparative analysis of viral load measurements for CMV and HIV-1 in peripheral blood leucocytes (PBLs) of individual children in relation to age and clinical staging.

METHODS

Nested polymerase chain reaction (PCR) was used to measure HIV-1 proviral DNA and CMV genomic DNA in PBLs of 56 children.

RESULTS

The CMV load was highest in 0-2 year old HIV positive children with stage C disease (range, 1-7143 copies/100 ng DNA; median, 125) and was significantly lower in older children. Although higher in young children, HIV-1 viral load did not show the same marked reduction with age that is seen with CMV. Over a one year period, testing of serial samples for both viruses in a subgroup of children revealed a discordant relation between viral loads for CMV and HIV-1.

CONCLUSIONS

CMV viral load falls much faster than HIV viral load in dually infected children. Screening for clinical CMV disease is most likely to be of benefit in children under 2 years of age with stage C disease. In the few children studied, levels of CMV and HIV replication appear to be independent.