Norovirus causing severe gastrointestinal disease following allogeneic hematopoietic stem cell transplantation: A retrospective analysis.

BACKGROUND: Norovirus (NV) can cause chronic and severe gastroenteritis with possible lethal outcome in immunocompromised patients. The knowledge of NV infections in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is limited. The aim of this study was to clarify the clinical importance of NV in a large cohort of HSCT recipients. METHODS: All patients undergoing HSCT and diagnosed with NV at Karolinska University Hospital from 2006-2012 were included in the study (63 patients). Clinical data were collected from medical records, and statistics were performed using the logistic regression method. RESULTS: The majority of patients (70%) had short-term symptoms (≤14 days). However, 54% of all patients required admission or prolonged hospitalization owing to the infection. In 16% of the patients the symptoms were chronic (>30 days), and in all but one of these patients the clinical picture also was severe, with malnutrition requiring long-term TPN, or serious dehydration. Severe combined immune deficiency (SCID) diagnosis was associated with chronic symptoms of NV infection (OR 30.3, CI 2.5-368). CONCLUSION: NV is an important pathogen in the HSCT setting, although the infection seems to be mild in most patients. Increased knowledge is needed to further identify risk factors for a severe course of NV infection in HSCT patients.

Management of cytomegalovirus infections - Swedish recommendations 2023.

Cytomegalovirus (CMV) infection, which mostly causes a subclinical infection early in life, has important clinical consequences in certain patient groups. CMV is the most common congenital infection and can cause permanent disabilities such as hearing loss and motor- and cognitive deficits in affected infants. In allogeneic haematopoietic stem cell and solid organ transplant recipients, CMV still is an important infectious complication with a risk for life-threatening disease. The previous Swedish recommendations for the management of CMV infections were updated by an expert group under the guidance of The Swedish Reference Group for Antiviral Treatment (RAV) and published at the website of RAV in August 2023 (https://www.sls.se/rav/rekommendationer/cytomegalovirus/). We here provide a translation of the updated recommendations, with minor modifications regarding diagnosis of CMV pneumonia. In the present recommendations, we discuss aspects of old and new CMV antivirals, including dosing for different age groups, and cover the management of congenital infections and CMV in immunocompromised patients. The recommendations are evidence-graded in accordance with the Oxford Centre for Evidence-Based Medicine.

The Importance of Secretor-Status in Norovirus Infection Following Allogeneic Hematopoietic Stem Cell Transplantation.

Background. Human secretor-status is a strong susceptibility factor for norovirus infection in immunocompetent people. The predominant norovirus genotype GII.4 almost exclusively infects secretors and is also associated with more severe symptoms. However, it is not known to what extent this also applies to immunocompromised individuals. Our objective was to determine the importance of secretor-status and norovirus genotype for the susceptibility and/or the clinical course of norovirus infection in allogeneic hematopoietic stem cell transplant (HCT) patients. Methods: This was a retrospective study of 89 HCT patients diagnosed with norovirus infection. Secretor-status and norovirus genotype were determined using stored extracted DNA or blood (n = 89) and fecal samples (n = 22), respectively. Results: Seven of eighty-nine (8%) of the patients were secretor-negative, a small proportion compared to the expected rate of at least 20% non-secretors in the general Swedish population. Among the genotyped samples, norovirus genotype GII.4 was predominant (n = 12) and only detected in secretor-positive individuals. Patients with norovirus GII.4 had a median symptom duration of 36 (3-681) days compared to 15 (1-94) days in patients infected with other norovirus genotypes (n = 10, p = 0.1). Conclusions: The results suggest that secretor-status affects the susceptibility to norovirus infection even when the immune system is severely compromised. The norovirus genotype may also be a risk factor for chronic norovirus symptoms in immunocompromised patients.

Improved survival after allogeneic hematopoietic stem cell transplantation in recent years. A single-center study.

We analyzed the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) over the past 2 decades. Between 1992 and 2009, 953 patients were treated with HSCT, mainly for a hematologic malignancy. They were divided according to 4 different time periods of treatment: 1992 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009. Over the years, many factors have changed considerably regarding patient age, diagnosis, disease stage, type of donor, stem cell source, genomic HLA typing, cell dose, type of conditioning, treatment of infections, use of granulocyte-colony stimulating factor (G-CSF), use of mesenchymal stem cells, use of cytotoxic T cells, and home care. When we compared the last period (2006-2009) with earlier periods, we found slower neutrophil engraftment, a higher incidence of acute graft-versus-host disease (aGVHD) of grades II-IV, and less chronic GVHD (cGHVD). The incidence of relapse was unchanged over the 4 periods (22%-25%). Overall survival (OS) and transplant-related mortality (TRM) improved significantly in the more recent periods, with the best results during the last period (2006-2009) and a 100-day TRM of 5.5%. This improvement was also apparent in a multivariate analysis. When correcting for differences between the 4 groups, the hazard ratio for mortality in the last period was 0.59 (95% confidence interval [CI]: 0.44-0.79; P < .001) and for TRM it was 0.63 (CI: 0.43-0.92; P = .02). This study shows that the combined efforts to improve outcome after HSCT have been very effective. Even though we now treat older patients with more advanced disease and use more alternative HLA nonidentical donors, OS and TRM have improved. The problem of relapse still has to be remedied. Thus, several different developments together have resulted in significantly lower TRM and improved survival after HSCT over the last few years.

Hepatitis E virus is an infrequent but potentially serious infection in allogeneic hematopoietic stem cell transplant recipients.

Hepatitis E virus (HEV) can cause chronic infection and liver cirrhosis in immunocompromised individuals. The frequency and clinical importance of HEV was studied retrospectively in a cohort of 236 Swedish allogeneic hematopoietic stem cell transplantation (HSCT) recipients. In blood samples collected at 6 months after HSCT, HEV RNA was identified in 8/236 (3.4%) patients, and 11/236 (4.7%) patients had detectable anti-HEV IgG and/or IgM, eight of whom were HEV RNA negative. Two of the patients with positive HEV RNA died with ongoing signs of hepatitis: one of acute liver and multiple organ failure, the other of unrelated causes. The remaining six patients with HEV RNA had cleared the infection at 7-24 (median 8.5) months after HSCT. HEV infection was associated with elevated alanine aminotransferase at 6 months after HSCT (OR 15, 1.3-174, p = 0.03). Active graft-versus-host disease of the liver at 6 months after HSCT was present in 3/8 (38%) patients with HEV RNA, but was not significantly associated with HEV infection. In conclusion, HEV infection is an important differential diagnosis in patients with elevated liver enzymes after HSCT. Although spontaneous clearance was common, the clinical course may be severe.

Management of BK-virus infection - Swedish recommendations.

BK-virus (BKV) associated nephropathy (BKVAN) and BKV associated haemorrhagic cystitis (HC) are complications of BKV infection/reactivation in renal and allogeneic haematopoietic stem cell transplantation (HSCT) patients, respectively. The task of how to manage these diseases was given to the chair by the Swedish Reference Group for Antiviral Therapy (RAV). After individual contributions by members of the working group, consensus discussions were held in a meeting on 23 January 2018 arranged by RAV. Thereafter, the recommendations were published in Swedish on November 2018. The current translation to English has been approved by all co-authors. High BKV serum levels suggest an increased risk for BKVAN and potential graft failure. For detection of BKVAN, careful monitoring of BKV DNA levels in serum or plasma is recommended the first year after renal transplantation and when increased creatinine serum levels of unknown cause are observed. Notably, a renal biopsy is mandatory for diagnosis. To reduce the risk for progression of BKVAN, there is no specific treatment, and tailored individual decrease of immunosuppression is recommended. For BKV-HC, BKV monitoring is not recommended, since BK-viruria frequently occurs in HSCT patients and the predictive value of BKV in plasma/serum has not been determined. However, the risk for BKV-HC is higher for patients undergoing myeloablative conditioning, having an unrelated, HLA-mismatched, or a cord blood donor, and awareness of the increased risk and early intervention may benefit the patients. Also for BKV-HC, no specific therapy is available. Symptomatic treatment, e.g. forced diuresis and analgesics could be of use.