Clinicopathologic Spectrum and Outcomes of Infections Diagnosed on Graft Biopsies and Nephrectomy in Live Renal Allograft Recipients: An Institutional Experience.

OBJECTIVES: Modern immunosuppressive regimens have reduced rejection episodes in renal allograft recipients but have increased the risk of opportunistic infections. Infections are considered to be the second leading cause of death after cardiovascular complications in renal allograft recipients. Data on opportunistic infections affecting the allograft itself are scarce. The present study describes the spectrum of renal opportunistic infections and their outcomes diagnosed on renal allograft biopsies and nephrectomy specimens. MATERIALS AND METHODS: Our retrospective observational study was conducted from December 2011 to December 2021. We analyzed infectious episodes diagnosed on renal allograft biopsies or graft nephrectomy specimens. We obtained clinical, epidemiological, and laboratory details for analyses from hospital records. RESULTS: BK virus nephropathy was the most common opportunistic infection affecting the allograft, accounting for 47% of cases, followed by bacterial graft pyelonephritis (25%). Mucormycosis was the most common fungal infection. The diagnosis of infection from day of transplant ranged from 14 days to 39 months. Follow-up periods ranged from 1 to 10 years. Mortality was highest among patients with opportunistic fungal infection (62%), followed by viral infections, and graft failure rate was highest in patients with graft pyelonephritis (50%). Among patients with BK polyomavirus nephropathy, 45% had stable graft function compared with just 33% of patients with bacterial graft pyelonephritis. CONCLUSIONS: BK polyoma virus infection was the most common infection affecting the renal allograft in our study. Although fungal infections caused the highest mortality among our patients, bacterial graft pyelonephritis was responsible for maximum graft failure. Correctly identifying infections on histology is important so that graft and patient life can be prolonged.

CMV Infection and CMV-Specific Immune Reconstitution Following Haploidentical Stem Cell Transplantation: An Update.

Haploidentical stem cell transplantation (haploSCT) has advanced to a common procedure for treating patients with hematological malignancies and immunodeficiency diseases. However, cure is seriously hampered by cytomegalovirus (CMV) infections and delayed immune reconstitution for the majority of haploidentical transplant recipients compared to HLA-matched stem cell transplantation. Three major approaches, including in vivo T-cell depletion (TCD) using antithymocyte globulin for haploSCT (in vivo TCD-haploSCT), ex vivo TCD using CD34 + positive selection for haploSCT (ex vivo TCD-haploSCT), and T-cell replete haploSCT using posttransplant cyclophosphamide (PTCy-haploSCT), are currently used worldwide. We provide an update on CMV infection and CMV-specific immune recovery in this fast-evolving field. The progress made in cellular immunotherapy of CMV infection after haploSCT is also addressed. Groundwork has been prepared for the creation of personalized avenues to enhance immune reconstitution and decrease the incidence of CMV infection after haploSCT.

Cytomegalovirus Colitis in Immunocompetent and Immunocompromised Children: A 2-Center Study.

BACKGROUND: Data about cytomegalovirus (CMV) colitis in children are scarce. We aimed to describe the characteristics of childhood CMV colitis in terms of risk factors, clinical symptoms, diagnosis, therapeutic approaches, and outcomes. METHODS: Inflammatory bowel disease (IBD) and non-IBD patients with CMV colitis diagnosed by histology and tissue CMV PCR at 2 tertiary centers between January 2017 and November 2019 were studied. Clinical and laboratory data were retrieved from medical records. Underlying conditions, immune status, response to therapy and outcomes were described and followed up to 6 months after diagnosis. RESULTS: A total of 16 children (8 non-IBD, 7 ulcerative colitis and 1 Crohn's disease) with CMV colitis were included. All patients had persistent diarrhea (bloody in 13 cases). There was a significant age difference between IBD and non-IBD children (P < 0.05). The final diagnosis in 1 patient was immunodeficiency with a mutation in JAK1 gene. Three children were categorized as apparently immunocompromised and 4 children as apparently immunocompetent. Ulcer was not visible in 2 children from the non-IBD group. The mean fecal calprotectin level of IBD children was significantly higher than that of non-IBD children (376.12 ± 231.21 µg/g vs. 160.96 ± 69.94 µg/g, P < 0.05). After follow-up, 1 patient died because of another reason. Ganciclovir was used in 14 of 16 children for 3 weeks and the treatment was continued with valganciclovir in selected 6 children. CONCLUSIONS: CMV colitis is a rare but overlooked cause of prolonged diarrhea in immunocompetent and immunocompromised children. CMV colitis might present without any ulcer formation at colonoscopy in infants.

Viral infection in thymoma and thymic tumors with autoimmune diseases.

A thymoma is a type of thymic tumor which is rarely malignant that is frequently reported in adult patients. A number of thymoma-related immune disorders are observed including autoimmune diseases, which suggests a strong connection between thymoma development and immunological mechanisms. Characterized by association with humoral and cellular immunodeficiency, thymoma patients are susceptible to opportunistic infections by environmental factors. Recent reports have suggested that viral infection may play a role in the etiological mechanisms of thymoma development associated with dysregulated immunity. In this review, we summarize the case reports and studies related to viral infection, such as CMV, EBV and HSV, that probably play a part in the pathogenesis of thymoma and related diseases. Furthermore, we demonstrate the underlying mechanisms by which viruses may induce the occurrence of thymoma with autoimmune diseases. Lastly, we discuss the potential application of antiviral therapy in the treatment of thymic diseases.

Risk of infection according to the gamma globulin level in the 100 days following allogeneic stem cell transplantations.

BACKGROUND: Immunoglobulin replacement therapy is recommended in case of severe hypogammaglobulinemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the supposed increased risk of infection in case of hypogammaglobulinemia has not been confirmed in allo-HSCT. In this study, we assessed the relationship between the gamma globulin level and the risk of infection during the 100 days following the allo-HSCT. METHODS: We gathered the weekly laboratory tests from day 7 to day 100 of 76 allograft patients, giving a total of 1 044 tests. 130 infections were documented clinically, by imaging, or microbiologically. RESULTS: Average gamma globulin levels between D-7 and D100 did not differ between patients with or without infection (642 ± 232 and 671 ± 246 mg/dL, respectively, P = .65). Gamma globulin level <400 mg/dl was not associated with the occurrence of infection between the test studied and the next one (aOR 1.33 [0.84-2.15], P = .24). The gamma globulin level was not predictive of bacterial or fungal infections (AUC 0.54 [95%CI: 0.47-0.61]) nor of viral reactivations (AUC 0.51 [95%CI: 0.43-0.60]). CONCLUSIONS: This confirmed that the humoral deficiency is a minor part of the immune deficiency in the 100 days post-transplant. This questions the relevance of the indications of immunoglobulin substitution during this period.

Concomitant BK virus infection and visceral Leishmaniasis in a pediatric liver transplant recipient.

BACKGROUND: Solid organ transplant recipients are vulnerable to various unusual infections. Visceral Leishmaniasis (VL) is a protozoal opportunistic infection, which may affect the immune-suppressed hosts and solid organ transplant recipients. The BK virus infection is an evolving challenge in kidney transplant recipients. However, there are very few reports of BK virus (BKV) nephropathy involving the native kidney in liver transplant recipients. To the best of our knowledge, this is the first report of the simultaneous occurrence of these rare infections in a liver transplant recipient. CASE REPORT: The patient was a 9-year-old girl, a case of liver transplantation who presented with the incidental finding of proteinuria, azotemia, and cytopenia. Investigations revealed that she had concomitant BKV nephropathy and visceral leishmaniasis. Both infections were successfully treated. CONCLUSION: BK virus should be considered as a cause of nephropathy in liver transplant recipients. The presenting features of fever, cytopenia, and splenomegaly in a post-transplant patient should remind of unusual infections such as VL other than the common post-transplant conditions.

Co-infection of Pneumocystis jirovecii pneumonia and pulmonary CMV in a infant with X-linked severe combined immunodeficiency.

We herein report a rare case of co-infection of Pneumocystis jirovecii pneumonia and pulmonary CMV in a 3-month-old infant with X-linked severe combined immunodeficiency, in which diagnostic clues were obtained from the bronchoalveolar lavage fluid. We focus on the value of cytological diagnosis of P. jirovecii pneumonia and pulmonary CMV in the bronchoalveolar lavage fluid. Recognizing morphological characteristics of these pathogenic microorganisms is important to get timely diagnosis and treatment for the patients. Furthermore, repeated severe infections in infants should remind us to screen for immunosuppressed states.

EBV-positive Mucocutaneous Ulcer With Small Lymphocytic Infiltration Mimicking Nonspecific Ulceration.

Epstein-Barr virus (EBV)-associated lymphoproliferative disorder may resemble nonspecific inflammation. We report 3 cases of immunosuppressed adult patients with small lymphocytic EBV ulcers in the skin and oral mucosa, characterized by a lack of atypical lymphocytic infiltration. All 3 cases were diagnosed in routine practice. For comparisons, cases of conventional Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) were reviewed which were extracted from our pathology archives (n=11). The present patients were 2 females and 1 male, aged above 70 years. The primary disease was rheumatoid arthritis (n=2) and dermatitis herpetiformis (n=1). The main source of immunosuppression was prednisolone (n=2) and methotrexate (n=1). The ulcers were located in the oral cavity, buttock, and/or external genitalia. Histology evaluation revealed nonspecific lymphocytic infiltration. Epstein-Barr virus-encoded small RNA (EBER)-positive cells were small and coexpressed CD20. The number of EBER-positive cells ranged from 52 to 132/HPF, which was within the range of that observed in the reviewed conventional EBVMCUs (range, 48 to 1328; median, 121). All 3 cases regressed spontaneously or by the reduction of immunosuppressants. Although the present cases lacked cytologic atypia, those clinical course and loads of EBER-positive cells (>50/HPF) suggested EBV involvement. Current cases of EBVMCU with small lymphocytic infiltration underscore the need for EBER in situ hybridization when an etiology of ulcer with predominant lymphocytes in an immunosuppressed patient is unclear.

Systemic lupus erythematosus and infections.

Systemic lupus erythematosus (SLE) is an inflammatory and multi-systemic autoimmune disorder, characterized by an uncontrolled auto-reactivity of B and T lymphocytes, leading to the production of autoantibodies against self-directed antigens and tissue damage. The life expectancy in patients with SLE has improved tremendously in the last two decades, but the mortality rates still remain three times greater compared to those of the general population. Despite increased awareness and improved management, infections remain a major source of morbidity, mortality, hospitalization, and death in patients with SLE. The infections in SLE patients widely range from opportunistic to common bacterial and viral infections with typical or atypical presentations. Moreover, SLE patients exhibit an increased susceptibility to hospital-acquired infections. Factors associated with increased risk of infections include high disease activity, specific immune dysregulation, drug-induced immune deficiency, and organ failure with irreversible damage. Furthermore, immunosuppressive agents may make patients more susceptible to opportunistic infections. A big challenge faced by physicians in these patients is to distinguish between infections and flares of SLE, as infections may mimic them, leading to predicament in diagnosis and appropriate management. Immunosuppression used to treat severe flares of lupus can have catastrophic complications in patients with active infections. There is an urgent need for biomarkers to make an accurate differential diagnosis in this situation. In spite of increased understanding of SLE, many questions remain unanswered. Further research is needed to determine specific immune dysregulation underlying the increased susceptibility to specific infections, predictors of infection in SLE such as genetic markers, and biomarkers that discriminate between disease activity and active infections. Also, measures must be evaluated appropriately to prevent infections, and their complications in SLE.

Infection prevention in sarcoidosis: proposal for vaccination and prophylactic therapy.

Sarcoidosis is a systemic inflammatory disease characterized by granuloma formation in affected organs and caused by dysregulated immune response to an unknown antigen. Sarcoidosis patients receiving immunosuppressive medications are at increased risk of infection. Lymphopenia is also commonly seen among patient with sarcoidosis. In this review, risk of infections, including opportunistic infections, will be outlined. Recommendations for vaccinations and prophylactic therapy based on literature review will also be summarized. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (2): 87-98).

Update on the Management of BK Virus Infection.

The BK polyomavirus was isolated in 1971; it has been a significant risk factor for both graft dysfunction and failure in renal transplant recipients. So far, no specific treatment option has been available for effective treatment or prophylaxis for BK virus infections. Although the use of heavy immunosuppression has been the main risk factor for BK virus infection, other risk factors are equally important, including elderly recipients, prior rejection episodes, male sex, human leukocyte antigen mismatching, prolonged cold ischemia time, pretransplant BK virus serostatus, and ureteral stenting. Regular follow-up for BK virus infections according to each institution's policy has been, so far, effective in detecting patients with BK virus viremia and consequently preventing allograft loss. The mainstay of management continues to be reduction of immunosuppression. However, newer options are providing new insights, such as cellular immunotherapy. In this review, we will address the diagnosis, screening, new diagnostic tools, and updated management of BK virus infections.

Optimal Management of Acute Lymphoblastic Leukemia (ALL) in Adult Patients During the Novel Coronavirus Disease 2019 (COVID-19) Pandemic.

The outbreak of coronavirus disease 2019 (COVID-19) has become a public health emergency of major international concern. In December 2019, an outbreak of atypical pneumonia known as COVID-19 was identified in Wuhan, China. The newly identified zoonotic coronavirus, severe acute respiratory syndrome coronavirus-2 (SARSCoV-2), is characterized by rapid human-to-human transmission. Acute lymphoblastic leukemia (ALL) patients are often in need for intensive chemotherapy to induce remission that will be complicated with prolonged period of cytopenias. They are often recalled to the hospital for treatment and disease surveillance. These patients may be immunocompromised due to the underlying malignancy or anti-cancer therapy. ALL patients are at higher risk of developing life-threatening infections. Several factors increase the risk of infection and the presence of multiple risk factors in the same patient is common. Cancer patients had an estimated 2-fold increased risk of contracting SARS-CoV-2 than the general population. With the World Health Organization declaring the novel coronavirus outbreak a pandemic, there is an urgent need to address the impact of such pandemic on ALL patients. This include changes to resource allocation, clinical care, and the consent process during a pandemic. Currently and due to limited data, there are no international guidelines to address the optimal management of ALL patients in any infectious pandemic. In this review, we will address the potential challenges associated with managing ALL patients during the COVID-19 infection pandemic with suggestions of some practical approaches, focusing on screening asymptomatic ALL patients, diagnostic and response evaluation and choice of chemotherapy in different scenarios and setting and use of hematopoietic stem cell transplantation (HSCT).

Pan­cancer analysis of transmembrane protease serine 2 and cathepsin L that mediate cellular SARS­CoV­2 infection leading to COVID-19.

Severe acute respiratory syndrome (SARS) coronavirus­2 (SARS­CoV2) is the cause of a new disease (COVID­19) which has evolved into a pandemic during the first half of 2020. Older age, male sex and certain underlying diseases, including cancer, appear to significantly increase the risk for severe COVID­19. SARS­CoV­2 infection of host cells is facilitated by the angiotensin­converting enzyme 2 (ACE­2), and by transmembrane protease serine 2 (TMPRSS2) and other host cell proteases such as cathepsin L (CTSL). With the exception of ACE­2, a systematic analysis of these two other SARS­CoV2 infection mediators in malignancies is lacking. Here, we analysed genetic alteration, RNA expression, and DNA methylation of TMPRSS2 and CTSL across a wide spectrum of tumors and controls. TMPRSS2 was overexpressed in cervical squamous cell carcinoma and endocervical adenocarcinoma, colon adenocarcinoma, prostate adenocarcinoma (PRAD), rectum adenocarcinoma (READ), uterine corpus endometrial carcinoma and uterine carcinosarcoma, with PRAD and READ exhibiting the highest expression of all cancers. CTSL was upregulated in lymphoid neoplasm diffuse large B­cell lymphoma, oesophageal carcinoma, glioblastoma multiforme, head and neck squamous cell carcinoma, lower grade glioma, pancreatic adenocarcinoma, skin cutaneous melanoma, stomach adenocarcinoma, and thymoma. Hypo­methylation of both genes was evident in most cases where they have been highly upregulated. We have expanded on our observations by including data relating to mutations and copy number alterations at pan­cancer level. The novel hypotheses that are stemming out of these data need to be further investigated and validated in large clinical studies.

Changes in Anti-JCV Antibody Status in a Large Population of Multiple Sclerosis Patients Treated with Natalizumab.

INTRODUCTION: Natalizumab (NTZ) can be associated with an opportunistic infection, progressive multifocal leukoencephalopathy (PML), caused by John Cunningham virus (JCV). High titer of anti-JCV antibody (JCV index) in patients treated with NTZ for over 2 years limit it use, leading to treatment discontinuation. OBJECTIVE: Aim of the study was to investigate the JCV index changes pre, during and post NTZ treatment and describe the trend after a long period of NTZ discontinuation. METHODS: Patients with relapsing-remitting multiple sclerosis (RR-MS) treated with NTZ between 2010 and 2018 were enrolled in this retrospective-prospective observational study. Inclusion criteria were: (1) diagnosis of RR-MS according to the McDonald criteria 2010, (2) at least six NTZ administrations, (3) at least two determinations of JCV Index during the follow-up period, (4) NTZ discontinuation period for more than 6 months. JCV index was determined by STRATIFY II. There were three different timepoints: NTZ initiation (T0), NTZ discontinuation (T1) and time after NTZ suspension (T2). Seroconversion was defined as changing status of serum JCV antibody. Main outcomes were the JCV index changes and the rate of seroconversion. RESULTS: At baseline we enrolled 285 patients (208 JCV negative, 67 JCV positive, and 10 not available). There was a statistically significant increase of JCV index during NTZ treatment period (T0 vs T1, p =0.0009) and during NTZ discontinuation period (T1 vs T2, p =0.04). Patients seroconverted to a positive status more frequently during NTZ treatment than after discontinuation (p =0.008). Moreover, patients who shifted to fingolimod (FTY) as exit strategy after NTZ discontinuation, showed a statistically significant increase of JCV index. CONCLUSION: Our data confirmed that a high percentage of patients shift to or remain in a positive JCV status during NTZ treatment and after discontinuation. NTZ suspension seems not to be able to interfere on JCV status modification over an extended period. The choice of alternative treatment as exit strategy after NTZ discontinuation should be carefully considered because it could negatively influence the PML risk stratification of patients.

Investigation of the Relationship Between BK Virus and Human Leukocyte Antigens in Kidney Transplant Recipients.

OBJECTIVES: The main function of HLA is to present antigens to lymphocytes and to initiate specific immune responses. Autoimmune, viral, allergic, and neurologic diseases have been found to be related to HLA molecules. In renal transplant, the main target of the recipient's immune system is the HLA molecules on the surface of donor cells. HLA also plays a role in the development of an immune response to viral infections. After renal transplant, BK virus infections may occur due to immunosuppression. Here, we investigated the relationship between HLA and BK virus in renal transplant recipients. MATERIALS AND METHODS: This retrospective study investigated HLA-A, HLA-B, and HLA-DR tissue typing before renal transplant. DNA was isolated from whole blood, and tissue typing tests were performed based on polymerase chain reaction. Patients were tested for BK virus posttransplant using DNA isolated from urine and/or plasma samples. RESULTS: We found HLA-B*13 allele to be a protective factor (P < .049; odds ratio: 0.131; 95% confidence interval, 0.017-1.029) and HLA-DRB1*03 allele to be a possible risk factor (P < .029; odds ratio: 2.521; 95% confidence interval, 1.157-5.490) against BK virus. No significant relationships were found between BK virus and age, sex, donor type, and HLA mismatch. CONCLUSIONS: HLA class I molecules are known to be effective against viruses with the help of cytotoxic T cells. HLA-B*13 alleles within the HLA class I molecules were identified as protective factors against BK virus. HLA class II is associated with CD4-positive T cells that help secrete immune system cytokines, playing a role in stimulating and suppressing the immune system. We demonstrated that HLA-DRB1*03 allele could be a risk factor against BK virus. This allele may be associated with immunomodulatory cytokine secretion of the immune system.