Unusual Manifestations of Acute Cytomegalovirus Infection in Solid Organ Transplant Hosts: A Report of Two Cases

CD4 T Cell-Mediated Immune Control of Cytomegalovirus Infection in Murine Salivary Glands

CD4 T cells are well known for their supportive role in CD8 T cell and B cell responses during viral infection. However, during murine cytomegalovirus (MCMV) infection in the salivary glands (SGs), CD4 T cells exhibit direct antiviral effector functions to control the infection. In this mucosal organ, opposed to other infected tissues, MCMV establishes a sustained lytic replication that lasts for several weeks. While the protective function of CD4 T cells is exerted through the production of the pro-inflammatory cytokines interferon gamma (IFNγ) and tumor necrosis factor alpha (TNF), the reasons for their markedly delayed control of lytic MCMV infection remain elusive. Here, we review the current knowledge on the dynamics and mechanisms of the CD4 T cell-mediated control of MCMV-infected SGs, including their localization in the SG in relation to MCMV infected cells and other immune cells, their mode of action, and their regulation.

Cytomegalovirus skin disease in a kidney transplant patient

A 44-year-old man with a history of renal transplantation presented with right lower abdominal wall swelling, redness and pain. A bacterial abscess was drained, and he was discharged home with oral antibiotics. After failing to improve, he returned to the hospital, where he was briefly treated with intravenous antibiotics and discharged home again. The patient returned 5 days later, reporting worsening right groin swelling that extended into the ipsilateral scrotum. Imaging revealed a persistent fluid collection in the region, and he was taken for surgical debridement. Tissue immunochemistry and histopathological evaluation identified cytomegalovirus infection. Plasma quantitative PCR for cytomegalovirus demonstrated high viraemia. The patient was successfully treated with intravenous ganciclovir, followed by oral valganciclovir, with resolution of the skin changes. Persistent hydrocele with epididymitis on imaging suggests that this process may have been the source of the cutaneous cytomegalovirus infection.

CMV presenting as a skin growth in renal transplant patient

CMV infection is one of the most common opportunistic infection in kidney transplant patients. If not treated, it is associated with increased mortality and graft loss. It can present as viremia or CMV disease in the form of CMV syndrome or tissue invasive CMV disease. The cutaneous presentation of CMV disease is a rare finding. Its identification is vital as cutaneous CMV infection can signal systemic infection and poor prognosis. In our case, 46-year-old male who was a post renal allograft recipient (RAR) presented as a protuberant growth over the medial side of the left ankle. On skin biopsy, nucleomegaly and inclusion bodies were seen in the epithelial cells. Immunohistochemistry was positive for CMV infection. Patient was treated with Ganciclovir, however, he succumbed to death because of severe sepsis due to secondary bacterial infection. Thus, CMV disease should always be kept in mind in immunocompromised patients like post RAR patients who present with cutaneous features like ulcerative lesions or fungating growth.

Acute esophageal necrosis after kidney transplantation: A case report

RATIONALE

Acute esophageal necrosis (AEN) is a rare syndrome with characteristic endoscopic and pathologic findings. It usually results from a combination of tissue hypoperfusion, impaired local defense barriers, and massive reflux of gastric contents. We report a case of AEN after a kidney transplant.

PATIENT CONCERNS

A 53-year-old man with hypertension and end-stage renal disease presented with abdominal pain and a single episode of hematemesis 14 days after kidney transplantation.

DIAGNOSIS

Upper endoscopy revealed circumferential black coloration in the mid to lower esophageal mucosa. Esophageal biopsy showed ulcer, and immunostains were negative for viral etiology.

INTERVENTIONS

Conservative management was done with total parenteral nutrition and proton pump inhibitor.

OUTCOMES

The patient experienced no further episodes of hematemesis or abdominal pain and follow-up endoscopy showed remarkable changes from the black mucosa to a red friable mucosa with whitish exudates.

LESSONS

In the case, AEN occurred in the setting of normal blood pressure after major surgery despite the absence of preceding factors such as hypotension and infections. The possibility of AEN should be considered in patients with solid organ transplantation who present with abdominal pain, dysphagia, and hematemesis.

A Novel Human Skin Tissue Model To Study Varicella-Zoster Virus and Human Cytomegalovirus

The herpesviruses varicella-zoster virus (VZV) and human cytomegalovirus (HCMV) are endemic to humans. VZV causes varicella (chicken pox) and herpes zoster (shingles), while HCMV causes serious disease in immunocompromised patients and neonates. More effective, less toxic antivirals are needed, necessitating better models to study these viruses and evaluate antivirals. Previously, VZV and HCMV models used fetal tissue; here, we developed an adult human skin model to study VZV and HCMV in culture and in vivo While VZV is known to grow in skin, it was unknown whether skin could support an HCMV infection. We used TB40/E HCMV and POka VZV strains to evaluate virus tropism in skin organ culture (SOC) and skin xenograft mouse models. Adult human skin from reduction mammoplasties was prepared for culture on NetWells or mouse implantation. In SOC, VZV infected the epidermis and HCMV infected the dermis. Specifically, HCMV infected fibroblasts, endothelial cells, and hematopoietic cells, with some infected cells able to transfer infection. VZV and HCMV mouse models were developed by subcutaneous transplantation of skin into SCID/beige or athymic nude mice at 2 independent sites. Viruses were inoculated directly into one xenograft, and widespread infection was observed for VZV and HCMV. Notably, we detected VZV- and HCMV-infected cells in the contralateral, uninoculated xenografts, suggesting dissemination from infected xenografts occurred. For the first time, we showed HCMV successfully grows in adult human skin, as does VZV. Thus, this novel system may provide a much-needed preclinical small-animal model for HCMV and VZV and, potentially, other human-restricted viruses.IMPORTANCE Varicella-zoster virus and human cytomegalovirus infect a majority of the global population. While they often cause mild disease, serious illness and complications can arise. Unfortunately, there are few effective drugs to treat these viruses, and many are toxic. To complicate this, these viruses are restricted to replication in human cells and tissues, making them difficult to study in traditional animal models. Current models rely heavily on fetal tissues, can be prohibitively expensive, and are often complicated to generate. While fetal tissue models provide helpful insights, it is necessary to study human viruses in human tissue systems to fully understand these viruses and adequately evaluate novel antivirals. Adult human skin is an appropriate model for these viruses because many target cells are present, including basal keratinocytes, fibroblasts, dendritic cells, and lymphocytes. Skin models, in culture and xenografts in immunodeficient mice, have potential for research on viral pathogenesis, tissue tropism, dissemination, and therapy.

Diagnosis and management of acute esophageal necrosis

Acute esophageal necrosis is a rare syndrome classically characterized by a striking endoscopic image of diffuse and circumferential black mucosal discoloration of distal esophagus, with an abrupt transition at the gastroesophageal junction and variable proximal extension. The typical patient is an older male with general debilitation and multiple comorbidities presenting with hematemesis or melena. The pathophysiology usually involves a combination of esophageal ischemia, backflow injury from gastric chemical contents and impaired mucosal reparative mechanisms associated with debilitated physical states. It may arise in the setting of hemodynamic compromise, diabetic ketoacidosis, hypothermia, alcoholic intoxication, trauma, inflammatory diseases, esophageal local infection, solid organ transplantation, postoperative status, drugs or acute gastric outlet obstruction, usually in the background of a chronic debilitating process, where the concurrent presence of multiple risk factors, including diabetes mellitus, hypertension, malnutrition, malignancy or alcohol abuse, places a patient at higher risk. The characteristic endoscopic appearance establishes the diagnosis. Biopsy is supportive but not required. Management is mainly supportive and consists of correcting coexisting conditions, fluid therapy, bowel rest, intravenous proton pump inhibitor therapy and red blood cell transfusion as needed. Although this is a serious life-threatening condition, appropriate treatment may result in a favorable outcome in the majority of patients.

The Black Esophagus in the Renal Transplant Patient

Acute esophageal necrosis (AEN) is an uncommon disease characterized by gastrointestinal bleeding and endoscopic findings of circumferential black-colored necrosis of the distal esophagus. Patients at risk include elderly males over the age of 65, who typically have multiple chronic medical issues including vascular disease and diabetes. Mortality is reported to be 32%. Here, we present a case of AEN in a renal transplant patient and describe potential inciting factors such as immunosuppression and opportunistic diseases.