Cytomegalovirus: the taming of the beast?

Clinical significance of cytomegalovirus infection in patients with inflammatory bowel disease

Cytomegalovirus (CMV) infection is common in humans. The virus then enters a “latency phase” and can reactivate to different stimuli such as immunosuppression. The clinical significance of CMV infection in inflammatory bowel disease is different in Crohn’s disease (CD) and ulcerative colitis (UC). CMV does not interfere in the clinical course of CD. However, CMV reactivation is frequent in severe or steroid-resistant UC. It is not known whether the virus exacerbates the disease or simply appears as a bystander of a severe disease. Different methods are used to diagnose CMV colitis. Diagnosis is classically based on histopathological identification of viral-infected cells or CMV antigens in biopsied tissues using haematoxylin-eosin or immunohistochemistry, other tests on blood or tissue samples are currently being investigated. Polymerase chain reaction performed in colonic mucosa has a high sensitivity and a positive result could be associated with a worse prognosis disease; further studies are needed to determine the most appropriate strategy with positive CMV-DNA in colonic mucosa. Specific endoscopic features have not been described in active UC and CMV infection. CMV colitis is usually treated with ganciclovir for several weeks, there are different opinions about whether or not to stop immunosuppressive therapy. Other antiviral drugs may be used. Multicenter controlled studies would needed to determine which subgroup of UC patients would benefit from early antiviral treatment.

Cytomegalovirus and inflammatory bowel disease: is there a link?

The objective of this report is to give an overall view of the epidemiological, clinical, diagnostic and therapeutic features of Cytomegalovirus (CMV) infection in inflammatory bowel disease (IBD). A review of published reports on this topic was carried out, with particular attention paid to the selection of patients included in studies and the diagnostic methods employed. CMV is frequently associated with IBD. In some cases, CMV infection is associated with a poor outcome but it is not clear which patients are more likely to be affected and in which stage of the disease. The use of anti-viral therapy in IBD is controversial and an empirical study with controls is needed. The natural history of CMV infection related to the development and treatment of IBD has not been clarified but it is important to take it in consideration because of the possibility of viral persistence in the immunocompromised host and viral interaction with the immune system.

Prevention of Epstein-Barr virus-lymphoproliferative disease by molecular monitoring and preemptive rituximab in high-risk patients after allogeneic stem cell transplantation

Recipients of a partially T-cell-depleted (TCD) allogeneic stem cell transplantation (allo-SCT) developing reactivation of Epstein-Barr virus (EBV) with quantified viral DNA levels exceeding 1000 genome equivalents/milliliter (geq/mL) are at high risk for EBV-lymphoproliferative disease (EBV-LPD). We studied whether preemptive therapy with rituximab prevents EBV-LPD, LPD-mortality, and abrogates viral reactivation in high-risk patients. We monitored 49 recipients of a TCD allo-SCT weekly for EBV reactivation by quantitative real-time polymerase chain reaction (PCR). Preemptive therapy by a single infusion of rituximab was given to patients with viral reactivation more than or equal to 1000 geq/mL. Results were compared with an historical control group of patients retrospectively monitored for EBV reactivation at similar intervals. There were 17 prospectively monitored patients who showed EBV reactivation more than or equal to 1000 geq/mL and 15 received preemptive therapy. Median time to preemptive therapy was 113 days (range, 41-202 days) after SCT. There were 14 patients who showed complete response (CR) as characterized by prevention of EBV-LPD and complete clearance of EBV-DNA from plasma, which was achieved after a median number of 8 days (range, 1-46 days). One patient progressed to EBV-LPD despite preemptive therapy, but obtained CR after 2 infusions of rituximab and donor lymphocyte infusion. There were 2 patients who had already developed EBV-LPD prior to preemptive rituximab, but obtained CR following 2 rituximab infusions. Comparison of this prospectively followed series to our historical cohort with the same high-risk profile showed a reduction of EBV-LPD incidence (18% +/- 9% versus 49% +/- 11%, respectively) and a complete abrogation of LPD-mortality (0% versus 26% +/- 10%, respectively) (P =.04) at 6 months from EBV-DNA more than or equal to 1000 geq/mL. Frequent quantitative monitoring of EBV reactivation and preemptive therapy by rituximab improves outcome in patients at high risk of EBV-LPD. (Blood. 2002;99:4364-4369)

Assessment of cytomegalovirus infections using neopterin and a new immunoblot

Human cytomegalovirus (HCMV) infections are a major cause of morbidity and mortality in immunocompromised patients despite advances in diagnostic tests and antiviral therapies. The underlying study investigates the diagnostic value of the immune marker neopterin and a recently developed HCMV-specific western blot to detect HCMV infections and to differentiate them into either syndromes or diseases. The mean period of observation was 1428 days. Thirteen HCMV diseases and nine syndromes were diagnosed retrospectively. The first appearance of clinical signs or symptoms was always associated with a marked increase of serum and urine neopterin. The HCMV-specific IgM response followed in the mean 9 days later. Median values and the course of the neopterin levels were significantly higher during the HCMV diseases. In addition, the strength of the humoral immune response was related to the severity of the HCMV infection. Patients with HCMV diseases developed antibodies against a higher number of epitopes. The anti-HCMV IgM response persisted in more than 80% of the patients for longer than 3 years. In conclusion, combining the HCMV-specific western blot and neopterin permit detection of the immune response against HCMV, reflect the severity of the infection and might guide the anti-viral therapy.

Renal Doppler sonographic and histologic findings in post-transplant primary cytomegalovirus disease

Cytomegalovirus (CMV) infections frequently develop in renal transplant patients. The transplanted kidney may be not only the source of infection but also the target for it. We report a case of primary CMV infection in a seronegative patient who received a graft from a seropositive cadaveric donor. The onset of CMV was clinically apparent on post-transplant day 22. Interestingly, soon after transplantation, the patient developed a long-lasting graft dysfunction episode for which diffuse endothelial-cell swelling was the most relevant finding at biopsy. On sonography, renal graft vascular impedance deteriorated and improved repeatedly during the follow-up period. We postulate that the patient had CMV-induced immunogenic-mediated endothelial-cell injury.

Emergence of ganciclovir-resistant cytomegalovirus disease among recipients of solid-organ transplants

BACKGROUND

Concerns have been raised about emergence of ganciclovir resistance as a result of the advent of both routine oral ganciclovir prophylaxis and highly potent immunosuppression. We retrospectively assessed the occurrence of ganciclovir-resistant cytomegalovirus disease among transplant recipients who had received oral ganciclovir prophylaxis and highly potent immunosuppression.

METHODS

We studied 240 recipients of liver, kidney, or pancreas transplants. Antiviral susceptibility testing of blood cytomegaloviral isolates was done when patients failed to respond to intravenous ganciclovir treatment for symptomatic cytomegalovirus infection. Portions of the UL97 gene associated with ganciclovir resistance were sequenced in cytomegalovirus isolates with phenotypic resistance to ganciclovir.

FINDINGS

Ganciclovir-resistant cytomegalovirus disease developed in five (7%) of 67 seronegative recipients of cytomegalovirus-seropositive organs (D+/R-) compared with none of 173 seropositive recipients (p=0.002). Among the 25 (10.4%) patients who developed cytomegalovirus disease within 1 year after transplantation, five had ganciclovir-resistant cytomegalovirus disease. Among D+/R-transplant recipients, ganciclovir-resistant cytomegalovirus disease was more common among the group receiving the most potent immunosuppression--ie, recipients of kidney and pancreas or pancreas alone (four of 19) compared with all other transplant recipients (one of 48, p=0.02). Ganciclovir-resistant cytomegalovirus disease was diagnosed at a median of 10 months after transplantation (range 7-12) after lengthened exposure to ganciclovir, was associated with previously described mutations of the UL97 gene, and led to serious clinical complications.

INTERPRETATION

Ganciclovir-resistant cytomegalovirus is an important cause of late morbidity among D+/R- transplant recipients who have had lengthened exposure to ganciclovir and have received highly potent immunosuppression. Strategies to reduce this complication, especially among D+/R- patients, are warranted.