Cytomegalovirus infection: the point in 2001

Anti-cytomegalovirus preemptive therapy to prevent cytomegalovirus disease in HIV-infected patients: a systematic review

BACKGROUND

HIV patients are at higher risk of contracting and developing into an asymptomatic form of CMV infection. This review aimed to evaluate the efficacy and safety of preemptive therapy for preventing CMV disease in HIV patients.

METHODS

The electronic search was conducted in MEDLINE/PubMed and CENTRAL from inception until 9 September 2022. Studies were included if they assessed the efficacy or safety of anti-CMV preemptive therapy compared to placebo or no therapy. Risk of bias were assessed using the Cochrane Risk of Bias tool for randomized trials version 2 or the Cochrane Collaboration Risk of Bias in Non-randomized Studies of Interventions. The random-effects model was used to calculate effect sizes.

RESULTS

We identified six RCTs (2135 participants) and four observational studies (395 participants), with five RCTs were performed before highly active antiretroviral therapy (HAART) era. Preemptive therapy did not reduce the incidence of CMV disease (RR 0.84, 95% CI: 0.59-1.18), yet reduced the RR of all-cause mortality rate by 26% (RR 0.85, 95% CI: 0.74-0.97) with a low quality of evidence. The incidence of neutropenia as an adverse event increased significantly (RR 2.47, 95% CI: 1.12-5.45) with moderate quality of evidence.

CONCLUSIONS

With the advent of HAART, a limited number of studies have been performed to explore anti-CMV preemptive therapy due to the improved outcomes of HIV patients with CMV viremia. Therefore, optimal HAART should take precedence over anti-CMV preemptive therapy. The protocol for this review was registered in the Prospective Register of Systematic Reviews (CRD42020145765).

Diffusion MRI findings of cytomegalovirus-associated ventriculitis: a case report

Cytomegalovirus (CMV) ventriculoencephalitis is a rare but serious potential complication of CMV infection in immunocompromised patients. Characteristic diffusion-weighted imaging findings can be helpful for the diagnosis of CMV ventriculitis, as in this case report.

Monitoring of human cytomegalovirus infection in immunosuppressed patients using real-time PCR on whole blood

BACKGROUND

Quantitative monitoring of human cytomegalovirus (HCMV) is currently used in the follow-up of immunosuppressed patients.

OBJECTIVE

To investigate whether real-time PCR quantification (QPCR) of HCMV DNA could replace pp65 antigenemia.

STUDY DESIGN

We compared HCMV QPCR on whole blood (WB) and on plasma with a pp65-antigenemia assay on 192 samples. Afterwards, we tested 1310 samples from 308 immunosuppressed patients both by antigenemia assay and QPCR on WB.

RESULTS

The first study comparison showed that QPCR results on WB and plasma were significantly correlated with antigenemia. QPCR on WB was more sensitive than QPCR on plasma or antigenemia, detecting 31 and 49 additional positive samples, respectively. During the second comparison, QPCR on WB and antigenemia were again correlated (r=0.70; p<0.0001), but QPCR detected 244 additional positive samples. HCMV DNA was detected earlier than pp65 antigen (median difference: 14 days; range: 7-30). One, 5, 10, 50 and 100 pp65-positive cells/200,000 leukocytes corresponded to 439, 1531, 2623, 9150 and 15,671 HCMV DNA copies/mL of WB, respectively, but this equivalence differed according to the sub-group of patients considered.

CONCLUSION

QPCR on WB is the most sensitive method for the monitoring of HCMV infection in immunosuppressed patients.

Withdrawal of maintenance therapy for cytomegalovirus retinitis in AIDS patients exhibiting immunological response to HAART

BACKGROUND: Before the introduction of highly active antiretroviral therapy (HAART), CMV retinitis was a common complication in patients with advanced HIV disease and the therapy was well established; it consisted of an induction phase to control the infection with ganciclovir, followed by a lifelong maintenance phase to avoid or delay relapses. METHODS: To determine the safety of CMV maintenance therapy withdrawal in patients with immune recovery after HAART, 35 patients with treated CMV retinitis, on maintenance therapy, with CD4+ cell count greater than 100 cells/mm³ for at least three months, but almost all patients presented these values for more than six months and viral load < 30000 copies/mL, were prospectively evaluated for the recurrence of CMV disease. Maintenance therapy was withdrawal at inclusion, and patients were monitored for at least 48 weeks by clinical and ophthalmologic evaluations, and by determination of CMV viremia markers (antigenemia-pp65), CD4+/CD8+ counts and plasma HIV RNA levels. Lymphoproliferative assays were performed on 26/35 patients. RESULTS: From 35 patients included, only one had confirmed reactivation of CMV retinitis, at day 120 of follow-up. No patient returned positive antigenemia tests. No correlation between lymphoproliferative assays and CD4+ counts was observed. CONCLUSION: CMV retinitis maintenance therapy discontinuation is safe for those patients with quantitative immune recovery after HAART.

Gastrointestinal infections in immunocompromised hosts

PURPOSE OF REVIEW

Patients with immunocompromised states are increasing in the world not only because of HIV infection but also as a result of better therapies in solid organ transplantation, stem cell transplantation, and leukemia. All these patients are at similar risk of gastrointestinal infections, and the subsequent morbidity and mortality from these infections makes it important to recognize the net state of immunosuppression of each person infected.

RECENT FINDINGS

This review evaluates emerging pathogens, new diagnostic tools and guidelines, and the latest therapies published in the last 12 months in HIV and solid organ transplantation. The echinocandins provide a new therapy for Candida esophagitis, whereas Mycobacterium avium complex therapy may be discontinued with immune reconstitution in patients with HIV. The emergence of antimicrobial-resistant bacteria and viruses is a new threat to managing these infections, especially in poorer countries. Also, several community viruses such as adenovirus were shown to cause significant morbidity to immunocompromised patients. Lastly, the interaction among immunosuppressive medications, diarrhea, and rejection makes an important argument for evaluating patients for infection before adjusting medications.

SUMMARY

The immunocompromised host is rapidly increasing in the world, resulting in exposures to new pathogenic organisms that cause gastrointestinal infections. New diagnostic tests and better antimicrobial therapy are improving outcomes in patients with access to health care. Unfortunately, these challenges are increasing daily with the development of multidrug-resistant bacteria and viruses that do not respond to standard therapies. The most important factor in overcoming these infections is restoration of the immune system, either by using antiretroviral therapy or decreasing immunosuppression.

Expression and purification of recombinant Kaposi's sarcoma-associated herpesvirus DNA polymerase using a Baculovirus vector system

The DNA polymerase (POL) of Kaposi's sarcoma-associated herpesvirus (KSHV) is essential for viral DNA replication and, thus, may be considered as a viable target for anti-KSHV therapeutics. To produce large quantities of homogeneous and pure POL required for high-throughput screening (HTS) for inhibitors, we generated a recombinant baculovirus vector encoding a hexahistidine (His6)-tagged POL and infected Spodoptera frugiperda Sf-9 insect cells. High expression of recombinant POL (rPOL) was achieved for up to 72h post-infection. The rPOL was solubilized in lysis buffer containing 0.3% Cymal-5 detergent, purified by metal-chelating and dsDNA-cellulose affinity chromatography, and analyzed by anti-His antibody Western blot and mass spectrometry. The functionality of rPOL was confirmed by its DNA synthesis activity in vitro, which was effectively blocked by the anti-herpetic DNA polymerase inhibitors, foscarnet and cidofovir diphosphate, in a dose-dependent manner. The POL expressed and purified from the recombinant baculovirus-infected insect cells may be useful toward the development of HTS of large chemical libraries to identify novel KSHV DNA polymerase inhibitors.

Potential antiviral therapeutics for smallpox, monkeypox and other orthopoxvirus infections

We assessed the activities of 24 different antiviral compounds against smallpox (two strains of variola major and one of variola minor), monkeypox, vaccinia and cowpox viruses by a neutral red uptake assay. To establish assay parameters, we examined viral replication and its inhibition at various times postinfection and at several multiplicities of infection. Drugs were selected to target a range of functions involved in viral replication. Eight compounds (cidofovir, cyclic HPMPC (cHPMPC), HPMPA, ribavirin, tiazofurin, carbocyclic 3-deazaadenosine, 3-deazaneplanocin A and DFBA (1-(2,4-difluorobenzyloxy)adenosine perchlorate)-a derivative of adenosine N1-oxide) inhibited the replication of all three variola strains and the other orthopoxviruses at drug concentrations within a pharmacologically achievable range. Two others (methisazone and bis-POM-PMEA) showed a lesser degree of antiviral effect, while the remainder were inactive. To examine possible naturally occurring drug resistance among a large number of variola isolates obtained from different geographical regions and at different times, we examined the sensitivity of 35 different strains of variola as well as other orthopoxviruses to a subset of three of the most active compounds: cidofovir, cHPMPC, and ribavirin. Preliminary data indicate that nearly all isolates appear to have similar drug sensitivities. These findings are currently being verified and expanded.

Genetic control of innate immune responses against cytomegalovirus: MCMV meets its match

Cytomegalovirus (CMV) is a widespread pathogen that is responsible for severe disease in immunocompromised individuals and probably, associated with vascular disease in the general population. There is increasing evidence that cells of the innate immune system play a key role in controlling this important pathogen. This is particularly evident in the experimental murine CMV (MCMV) model of infection which has revealed an important role for natural killer (NK) cells in controlling early viral replication after infection with MCMV. In this model, different strains of inbred mice exhibit striking differences in their level of susceptibility to MCMV infection. Genetic studies, performed almost 10 years ago, revealed that this pattern of susceptibility/resistance can be attributed to a single genetic locus termed Cmv1 and recently several groups that have been working on the mapping and identification of Cmv1 have met with success. Interestingly, Cmv1 is allelic to a member of the Ly49 gene family, which encode activating or inhibitory transmembrane receptors present on the surface of NK cells. All Ly49 receptors characterized to date interact with MHC class I molecules on potential target cells, resulting in the accumulation of signals to the NK to either 'kill' or 'ignore' the cell based upon the repertoire of MHC class I molecules expressed. The identification of Cmv1 as Ly49H, a stimulatory member of the Ly49 family, adds an interesting twist to the Ly49 story. Although the ligand of Ly49H is not yet known, there is already compelling evidence that the ligand is upregulated on virally infected cells, resulting in specific activation of Ly49H-expressing NK cells. This review provides an historical perspective of the MCMV infection model from its inception to the discovery of the gene responsible for the phenotype and provides a basis for further experiments aimed at understanding the role of NK cells, in general, and Ly49H, in particular, in mediating resistance to cytomegalovirus.