SOCS and Herpesviruses, With Emphasis on Cytomegalovirus Retinitis.

Suppressor of cytokine signaling (SOCS) proteins provide selective negative feedback to prevent pathogeneses caused by overstimulation of the immune system. Of the eight known SOCS proteins, SOCS1 and SOCS3 are the best studied, and systemic deletion of either gene causes early lethality in mice. Many viruses, including herpesviruses such as herpes simplex virus and cytomegalovirus, can manipulate expression of these host proteins, with overstimulation of SOCS1 and/or SOCS3 putatively facilitating viral evasion of immune surveillance, and SOCS suppression generally exacerbating immunopathogenesis. This is particularly poignant within the eye, which contains a diverse assortment of specialized cell types working together in a tightly controlled microenvironment of immune privilege. When the immune privilege of the ocular compartment fails, inflammation causing severe immunopathogenesis and permanent, sight-threatening damage may occur, as in the case of AIDS-related human cytomegalovirus (HCMV) retinitis. Herein we review how SOCS1 and SOCS3 impact the virologic, immunologic, and/or pathologic outcomes of herpesvirus infection with particular emphasis on retinitis caused by HCMV or its mouse model experimental counterpart, murine cytomegalovirus (MCMV). The accumulated data suggests that SOCS1 and/or SOCS3 can differentially affect the severity of viral diseases in a highly cell-type-specific manner, reflecting the diversity and complexity of herpesvirus infection and the ocular compartment.

Cytomegalovirus retinitis: decreased risk of bilaterality with increased use of systemic treatment. Swiss HIV Cohort Study Group.

Cytomegalovirus (CMV) retinitis may be treated systemically or intravitreally. We reviewed retrospectively patients with CMV retinitis, in order to determine whether systemic treatment was associated with less spread of CMV retinitis from one eye to the other. Of 222 cases, 92 patients had bilateral disease at onset of CMV retinitis, leaving 130 for analysis. Bilaterality occurred in 10 patients during 12,687 days of systemic treatment and in 34 during 14,791 days without systemic treatment (odds ratio [OR] = 2.92; confidence interval [CI], 1.44-5.90). Patients who had received systemic treatment for <50% of the follow-up period had a greater risk of bilaterality (OR = 3.7; CI, 2.79-4.54) than did the more intensively treated patients. CD4 cell levels also contributed to increased risk, but multivariate analysis showed that CD4 cell counts and treatment intensity were independent risk factors. CMV retinitis was more likely to become bilateral in patients who received less intravenous therapy. Local treatment can complete but does not replace systemically administered therapy.

Successful treatment of severe cytomegalovirus retinitis with foscarnet and intraocular injection of ganciclovir in a myelosuppressed unrelated bone marrow transplant patient.

A female patient with ALL received a bone marrow transplant (BMT) from an unrelated donor with a one locus HLA mismatch. The donor was heterozygous at the HLA-A locus, while the patient was homozygous at this locus. The patient had cytomegalovirus (CMV) antigenemia on day 42 following an intensive preparative regimen that included anti-thymocyte globulin and BU+CY+TBI to prevent graft rejection. Ganciclovir was given initially for the treatment of CMV antigenemia, although the patient soon developed severe myelosuppression. The patient's hematopoietic recovery was poor, and CMV and human herpesvirus-6 (HHV-6) were detectable in the peripheral blood. Severe CMV retinitis was treated with foscarnet and the intraocular injection of ganciclovir. The CMV retinitis improved and the marrow gradually recovered. CMV and HHV-6 were no longer detectable in the peripheral blood. Foscarnet and intraocular injection of ganciclovir appeared to be an effective treatment for CMV retinitis in this myelosuppressed BMT patient.