Cytomegalovirus and gastric cancer after renal transplantation: a possible interplay

Frontiers and Controversies in De Novo Gastrointestinal Tumors After Organ Transplantation: Current Progress and Future Directions

The increasing success of organ transplantation has significantly improved survival for patients with end-stage diseases, yet it introduces a complex dilemma: the elevated risk for the development of de novo gastrointestinal (GI) tumors. The sustained immunosuppression required to maintain graft function paradoxically undermines the body's natural defenses against cancer, leading to a higher incidence, aggressive progression, and atypical presentations of GI tumors among transplant recipients compared with the general population. This presents a pressing challenge: balancing the dual imperatives of preventing graft rejection and effectively managing malignancies. Current treatment paradigms, including surgical approaches, chemotherapy, radiation therapy, and the emerging role of immunotherapy, are fraught with complexities due to the altered immune landscape in these patients. This review underscores the critical need to understand the multifaceted relationship between post-transplantation immunosuppression and tumorigenesis, providing a comprehensive exploration of epidemiologic shifts, pathophysiologic insights, and the intricacies of the tumor microenvironment in this unique patient population. Understanding and managing GI tumors in transplant recipients is not only a clinical challenge, but also a necessary frontier in transplant oncology, promising to refine therapeutic strategies and improve the longevity and quality of life for this growing patient cohort.

Human cytomegalovirus-related gastrointestinal disease after kidney transplantation: A systematic review

BACKGROUND

Human-cytomegalovirus (hCMV) infection involving the gastrointestinal tract represents a leading cause of morbidity and mortality among kidney transplant (KT) recipients (KTRs). Signs and symptoms of the disease are extremely variable. Prompt anti-viral therapy administration and immunosuppression modification are key factors for optimizing management. However, complex work-up strategies are generally required to confirm the preliminary diagnosis. Unfortunately, solid evidence and guidelines on this specific topic are not available. We consequently aimed to summarize current knowledge on post-KT hCMV-related gastrointestinal disease (hCMV-GID).

METHODS

We conducted a systematic review (PROSPERO ID: CRD42023399363) about hCMV-GID in KTRs.

RESULTS

Our systematic review includes 52 case-reports and ten case-series, published between 1985 and 2022, collectively reporting 311 cases. The most frequently reported signs and symptoms of hCMV-GID were abdominal pain, diarrhea, epigastric pain, vomiting, fever, and GI bleeding. Esophagogastroduodenoscopy and colonoscopy were the primary diagnostic techniques. In most cases, the preliminary diagnosis was confirmed by histology. Information on anti-viral prophylaxis were extremely limited as much as data on induction or maintenance immunosuppression. Treatment included ganciclovir and/or valganciclovir administration. Immunosuppression modification mainly consisted of mycophenolate mofetil or calcineurin inhibitor minimization and withdrawal. In total, 21 deaths were recorded. Renal allograft-related outcomes were described for 26 patients only. Specifically, reported events were acute kidney injury (n = 17), transplant failure (n = 5), allograft rejection (n = 4), and irreversible allograft dysfunction (n = 3).

CONCLUSIONS

The development of local and national registries is strongly recommended to improve our understanding of hCMV-GID. Future clinical guidelines should consider the implementation of dedicated diagnostic and treatment strategies.

Multiple infections by EBV, HCMV and Helicobacter pylori are highly frequent in patients with chronic gastritis and gastric cancer from Southwest Mexico: An observational study

The chronic inflammation and damage to the gastric epithelium induced by Helicobacter pylori (H. pylori) are the main risk factors for gastric cancer development. Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) induce chronic inflammation and have been found in gastric tumors. The objectives this observational study were to determine the frequency of multiple infections by Helicobacter pylori, Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) and to relate the infection by EBV and HCMV with H. pylori vacA/cagA genotypes in patients with chronic gastritis or gastric cancer. DNA from H. pylori, EBV and HCMV was detected by PCR in biopsies from 106 Mexican patients with chronic gastritis and 32 from gastric cancer. The cagA status and the vacA genotypes of H. pylori were determined by PCR. In chronic gastritis and gastric cancer EBV was found in 69.8% and 87.5%, HCMV in 52.8% and 53.1%, and H. pylori in 48.1% and 40.6%, respectively. In chronic gastritis, 53% of H. pylori patients were EBV and 33% were both EBV/HCMV; in gastric cancer, 92.3% of H. pylori-infected individuals were EBV and 46.1% were EVB/HCMV. All the intestinal- and mixed-type tumors and the 83.3% of diffuse-type tumors were EBV. No significant differences were found between single infections or coinfections with the diagnosis or the cancer type. The H. pylori genotypes were not related to EBV or HCMV infection. The frequency of dual infections by H. pylori, EBV and HCMV is higher in patients from southwest Mexico than other populations. It is likely that these pathogens act synergistically to induce inflammation and gastric cancer.

Gastric Stump Cancer Following Gastrectomy After Renal Transplantation: A Case Report

A patient who had previously undergone a gastrectomy due to gastric ulcer perforation was admitted to our hospital. He presented with epigastric pain and poor oral intake accompanied with gastrointestinal bleeding, and was diagnosed with gastric stump cancer. He had a history of renal transplantation and was administered immunosuppressive agents. To alleviate the obstructive symptom and cure the gastrointestinal bleeding, the patient underwent surgical resection of the malignant tumor, with stable kidney function during the perioperative period. To the best of our knowledge, this is the first case reported in the English literature concerning gastric stump cancer that developed after renal transplantation. We speculate that the long-term use of immunosuppressants concomitant with gastrointestinal disorders after gastric surgery was an important causative factor in its etiology. We also investigated the possible treatment for it.

Cytomegalovirus infection masquerading as gastric carcinoma in an immune-compromised host

A 63-year-old man post-renal transplantation on immunosuppressants presented with reflux symptoms for one month. Significant medical history included a history of upper gastrointestinal bleeding, insulin-dependent diabetes mellitus and ischemic heart disease. Barium meal showed a large plaque-like lesion along greater curvature suspicious of malignancy. Gastroscopy revealed a large polyploidal gastric mass which was biopsied. Histological result showed numerous cytomegalovirus (CMV) viral inclusions within hyperplastic gastric mucosa without dysplasia or neoplasm. The findings were consistent with CMV gastric polyp. Following treatment with antiviral therapy and reduction in immunosuppressants, the CMV gastric polyp became smaller. This highlights the importance of considering CMV as a differential of gastric mass in an immunosuppressed host as treatment options varied between surgery and antiviral therapy.

Natural Killer Cell Diversity in Viral Infection: Why and How Much?

Natural killer cells are a diverse group of innate lymphocytes that are specialized to rapidly respond to cancerous or virus-infected cells. NK cell function is controlled by the integration of signals from activating and inhibitory receptors expressed at the cell surface. Variegated expression patterns of these activating and inhibitory receptors at the single cell level leads to a highly diverse NK cell repertoire. Here I review the factors that influence NK cell repertoire diversity and its functional consequences for our ability to fight viruses.

Transplantation-induced cancers: Emerging evidence that clonal CMV-specific NK cells are causal immunogenic factors

Solid cancers are a major adverse outcome of liver transplantation. Recent reassessments have revealed insights into causal factors, primarily centering on modulations of the natural killer (NK) cell compartment in liver transplant recipients. In the presence of cytomegalovirus, the clonal expansion of differentiated NK cells could restrict the diversity of the NK repertoire favoring the development of certain tumors.