Mucormycosis in Liver Allograft Following Transplant for Secondary Biliary Cirrhosis.

Mucormycosis, a group of opportunistic mycoses caused by Mucorales, present a significant threat to immunocompromised patients. In this report, we present the case of a 57-year-old male patient who underwent liver transplant for secondary biliary cirrhosis following inadvertent bile duct injury. Despite initial satisfactory postoperative evolution, the patient developed fever, and imaging revealed a suspicious lesion. Preliminary culture growth suggested a filamentous fungus, leading to initiation of liposomal amphotericin B. However, the lesion progressed, and a surgical debridement was necessary. During surgery, involvement of the liver dome and diaphragm was observed, and a nonanatomical hepatectomy was performed. Despite efforts, the patient's condition deteriorated, ultimately resulting in multiple organ failure and mortality. This case emphasizes the challenging nature of mucormycosis in livertransplant recipients.

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.

A Novel Homozygous RHOH Variant Associated with T Cell Dysfunction and Recurrent Opportunistic Infections.

RHOH, an atypical small GTPase predominantly expressed in hematopoietic cells, plays a vital role in immune function. A deficiency in RHOH has been linked to epidermodysplasia verruciformis, lung disease, Burkitt lymphoma and T cell defects. Here, we report a novel germline homozygous RHOH c.245G > A (p.Cys82Tyr) variant in a 21-year-old male suffering from recurrent, invasive, opportunistic infections affecting the lungs, eyes, and brain. His sister also succumbed to a lung infection during early adulthood. The patient exhibited a persistent decrease in CD4+ T, B, and NK cell counts, and hypoimmunoglobulinemia. The patient's T cell showed impaired activation upon in vitro TCR stimulation. In Jurkat T cells transduced with RHOHC82Y, a similar reduction in activation marker CD69 up-regulation was observed. Furthermore, the C82Y variant showed reduced RHOH protein expression and impaired interaction with the TCR signaling molecule ZAP70. Together, these data suggest that the newly identified autosomal-recessive RHOH variant is associated with T cell dysfunction and recurrent opportunistic infections, functioning as a hypomorph by disrupting ZAP70-mediated TCR signaling.

Nocardiosis in kidney transplant recipients: A tertiary care center experience.

INTRODUCTION: Kidney transplant recipients are at increased risk of opportunistic infections, including Nocardia. The incidence of nocardiosis in kidney transplant recipients is 0.4-1.3%. The data regarding its epidemiology and outcomes is limited. METHODS: This was a 10-year retrospective observational study from January 2012 to December 2021 at a tertiary care center in northern India, in which all kidney transplant recipients with Nocardia infection were included and followed. RESULTS: 12 (1.1%) patients had a Nocardia infection among the 1108 kidney transplant recipients. All were living donor kidney transplant recipients, and the mean age at diagnosis was 48.67 ± 12.60 years. Nocardia infection occurred at a median of 26 months (range 4-235) post-transplantation, with 4 (33.1%) of the cases occurring within a year of transplant. Breakthrough infection occurred in 7 (58.3%) patients on cotrimoxazole prophylaxis. 41.7% (n = 5) cases had an episode of rejection in the preceding year of Nocardia diagnosis. Concurrent cytomegalovirus (CMV) infection was present in one (8.3%) case. The lung was the most frequently involved organ. Microscopy was positive in all the cases; while culture was positive in 10 cases, and antimicrobial susceptibility testing (AST) were performed for these isolates. The majority (60%) of isolates were resistant to cotrimoxazole. All tested isolates remained susceptible to Amikacin, Imipenem, and Linezolid. No patients experienced Nocardia recurrence after completion of antibiotic therapy. The mortality at 12 months was 66.7% (n = 4), and only one death was Nocardia-related. CONCLUSION: Nocardia may cause a late-manifesting infection beyond the traditional window. The cotrimoxazole prophylaxis may not be sufficient for Nocardia prevention.

Good girl goes bad: Understanding how gut commensals cause disease.

This review examines the complex connection between commensal microbiota and the development of opportunistic infections. Several underlying conditions, such as metabolic diseases and weakened immune systems, increase the vulnerability of patients to opportunistic infections. The increasing antibiotic resistance adds significant complexity to the management of infectious diseases. Although commensals have long been considered beneficial, recent research contradicts this notion by uncovering chronic illnesses linked to atypical pathogens or commensal bacteria. This review examines conditions in which commensal bacteria, which are usually beneficial, contribute to developing diseases. Commensals' support for opportunistic infections can be categorized based on factors such as colonization fitness, pathoadaptive mutation, and evasion of host immune response. Individuals with weakened immune systems are especially susceptible, highlighting the importance of mucosal host-microbiota interaction in promoting infection when conditions are inappropriate. Dysregulation of gut microbial homeostasis, immunological modulation, and microbial interactions are caused by several factors that contribute to the development of chronic illnesses. Knowledge about these mechanisms is essential for developing preventive measures, particularly for susceptible populations, and emphasizes the importance of maintaining a balanced gut microbiota in reducing the impact of opportunistic infections.

Anti-Interleukin-23 Autoantibodies in Adult-Onset Immunodeficiency.

BACKGROUND: Autoantibodies against interleukin-12 (anti-interleukin-12) are often identified in patients with thymoma, but opportunistic infections develop in only some of these patients. Interleukin-12 (with subunits p40 and p35) shares a common subunit with interleukin-23 (subunits p40 and p19). In a patient with disseminated Burkholderia gladioli infection, the identification of both anti-interleukin-23 and anti-interleukin-12 prompted further investigation. METHODS: Among the patients (most of whom had thymoma) who were known to have anti-interleukin-12, we screened for autoantibodies against interleukin-23 (anti-interleukin-23). To validate the potential role of anti-interleukin-23 with respect to opportunistic infection, we tested a second cohort of patients with thymoma as well as patients without either thymoma or known anti-interleukin-12 who had unusual infections. RESULTS: Among 30 patients with anti-interleukin-12 who had severe mycobacterial, bacterial, or fungal infections, 15 (50%) also had autoantibodies that neutralized interleukin-23. The potency of such neutralization was correlated with the severity of these infections. The neutralizing activity of anti-interleukin-12 alone was not associated with infection. In the validation cohort of 91 patients with thymoma, the presence of anti-interleukin-23 was associated with infection status in 74 patients (81%). Overall, neutralizing anti-interleukin-23 was detected in 30 of 116 patients (26%) with thymoma and in 30 of 36 patients (83%) with disseminated, cerebral, or pulmonary infections. Anti-interleukin-23 was present in 6 of 32 patients (19%) with severe intracellular infections and in 2 of 16 patients (12%) with unusual intracranial infections, including Cladophialophora bantiana and Mycobacterium avium complex. CONCLUSIONS: Among patients with a variety of mycobacterial, bacterial, or fungal infections, the presence of neutralizing anti-interleukin-23 was associated with severe, persistent opportunistic infections. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

Immunosuppression by opioids: Mechanisms of action on innate and adaptive immunity.

Opioids are excellent analgesics for the clinical treatment of various types of acute and chronic pain, particularly cancer-related pain. Nevertheless, it is well known that opioids have some nasty side effects, including immunosuppression, which is commonly overlooked. As a result, the incidence of opportunistic bacterial and viral infections increases in patients with long-term opioid use. Nowadays, there are no effective medications to alleviate opioid-induced immunosuppression. Understanding the underlying molecular mechanism of opioids in immunosuppression can enable researchers to devise effective therapeutic interventions. This review comprehensively summarized the exogenous opioids-induced immunosuppressive effects and their underlying mechanisms, the regulatory roles of endogenous opioids on the immune system, the potential link between opioid immunosuppressive effect and the function of the central nervous system (CNS), and the future perspectives in this field.

NLRP3 Inflammasome Contributes to Host Defense Against Talaromyces marneffei Infection.

Talaromyce marneffei is an important thermally dimorphic pathogen causing disseminated mycoses in immunocompromised individuals in southeast Asia. Previous studies have suggested that NLRP3 inflammasome plays a critical role in antifungal immunity. However, the mechanism underlying the role of NLRP3 inflammasome activation in host defense against T. marneffei remains unclear. We show that T. marneffei yeasts but not conidia induce potent IL-1ß production. The IL-1ß response to T. marneffei yeasts is differently regulated in different cell types; T. marneffei yeasts alone are able to induce IL-1ß production in human PBMCs and monocytes, whereas LPS priming is essential for IL-1ß response to yeasts. We also find that Dectin-1/Syk signaling pathway mediates pro-IL-1ß production, and NLRP3-ASC-caspase-1 inflammasome is assembled to trigger the processing of pro-IL-1ß into IL-1ß. In vivo, mice deficient in NLRP3 or caspase-1 exhibit higher mortality rate and fungal load compared to wild-type mice after systemic T. marneffei infection, which correlates with the diminished recruitment of CD4 T cells into granulomas in knockout mice. Thus, our study first demonstrates that NLRP3 inflammasome contributes to host defense against T. marneffei infection.

Secondary Immunodeficiency in Hematological Malignancies: Focus on Multiple Myeloma and Chronic Lymphocytic Leukemia.

Secondary immunodeficiency is reported in most patients with hematological malignancies such as chronic lymphocytic leukemia and multiple myeloma. The aim of our review was to evaluate the existing literature data on patients with hematological malignancies, with regard to the effect of immunodeficiency on the outcome, the clinical and therapeutic approach, and on the onset of noninfectious complications, including thrombosis, pleural effusion, and orofacial complications. Immunodeficiency in these patients has an intense impact on their risk of infection, in turn increasing morbidity and mortality even years after treatment completion. However, these patients with increased risk of severe infectious diseases could be treated with adequate vaccination coverage, but the vaccines' administration can be associated with a decreased immune response and an augmented risk of adverse reactions. Probably, immunogenicity of the inactivated is analogous to that of healthy subjects at the moment of vaccination, but it undertakes a gradual weakening over time. However, the dispensation of live attenuated viral vaccines is controversial because of the risk of the activation of vaccine viruses. A particular immunization schedule should be employed according to the clinical and immunological condition of each of these patients to guarantee a constant immune response without any risks to the patients' health.

COVID-19: Overview of rheumatology fellows.

SARS-COV-2 infection has spread worldwide since it originated in December 2019, in Wuhan, China. The pandemic has largely demonstrated the resilience of the world's health systems and is the greatest health emergency since World War II. There is no single therapeutic approach to the treatment of COVID-19 and the associated immune disorder. The lack of randomised clinical trials (RCTs) has led different countries to tackle the disease based on case series, or from results of observational studies with off-label drugs. We as rheumatologists in general, and specifically rheumatology fellows, have been on the front line of the pandemic, modifying our activities and altering our training itinerary. We have attended patients, we have learned about the management of the disease and from our previous experience with drugs for arthritis and giant cell arteritis, we have used these drugs to treat COVID-19.

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.

Epidemiology, mortality and effectiveness of prophylaxis for Pneumocystis jiroveci pneumonia among rheumatic patients: a territory-wide study.

BACKGROUND: Pneumocystis jiroveci pneumonia (PJP) is an opportunistic infection affecting immunocompromised individuals. However, evidence regarding the burden and effectiveness of prophylaxis among rheumatic patients remains limited. Delineating the epidemiology and efficacy of prophylaxis among rheumatic patients is urgently needed. METHODS: We performed a territory-wide cohort study of rheumatic patients in Hong Kong. All patients with a diagnosis of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV), immune-mediated myositis (IMM), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), or spondyloarthritis (SpA) between 2015 and 2019 were included. Prevalence, frequency of prophylaxis and mortality of PJP were calculated. Number needed to treat (NNT) analysis was also performed. RESULTS: Out of 21,587 patients (54% RA, 25% SLE, 13% SpA, 5% IMM, 2% AAV and 1% SSc), 1141 (5.3%) patients were prescribed PJP prophylaxis. 48/21,587 (0.2%) developed PJP. No patients who developed PJP received prophylaxis prior to infection. The incidence of PJP was highest among SSc, AAV, and IMM patients. Among these diseases, the majority of PJP occurred while patients were on glucocorticoids at daily prednisolone-equivalent doses of 15 mg/day (P15) or above. PJP prophylaxis was effective with NNT for SSc, AAV and IIM being 36, 48 and 114 respectively. There were 19 PJP-related mortalities and the mortality rate was 39.6%. CONCLUSION: PJP is an uncommon but important infection among rheumatic patients, PJP prophylaxis is effective and should be considered in patients with SSc, AAV and IMM, especially those receiving glucocorticoid doses above P15.

Low-dose IL-2 therapy invigorates CD8+ T cells for viral control in systemic lupus erythematosus.

Autoimmune diseases are often treated by glucocorticoids and immunosuppressive drugs that could increase the risk for infection, which in turn deteriorate disease and cause mortality. Low-dose IL-2 (Ld-IL2) therapy emerges as a new treatment for a wide range of autoimmune diseases. To examine its influence on infection, we retrospectively studied 665 patients with systemic lupus erythematosus (SLE) including about one third receiving Ld-IL2 therapy, where Ld-IL2 therapy was found beneficial in reducing the incidence of infections. In line with this clinical observation, IL-2 treatment accelerated viral clearance in mice infected with influenza A virus or lymphocytic choriomeningitis virus (LCMV). Noticeably, despite enhancing anti-viral immunity in LCMV infection, IL-2 treatment exacerbated CD8+ T cell-mediated immunopathology. In summary, Ld-IL2 therapy reduced the risk of infections in SLE patients and enhanced the control of viral infection, but caution should be taken to avoid potential CD8+ T cell-mediated immunopathology.

Cryptococcus gattii Species Complex as an Opportunistic Pathogen: Underlying Medical Conditions Associated with the Infection.

The Cryptococcus gattii species complex has often been referred to as a primary pathogen due to its high infection frequency among apparently immunocompetent patients. In order to scrutinize the immune status of patients and the lineages of etiologic agents, we analyzed patient histories and the molecular types of etiologic agents from 135 global C. gattii cases. Eighty-six of 135 patients had been diagnosed as immunocompetent, although some of them had underlying medical issues, and 49 were diagnosed as immunocompromised with risk factors similar to those seen in Cryptococcus neoformans infection. We focused on the 86 apparently immunocompetent patients and were able to obtain plasma from 32 (37%) to analyze for the presence of autoantibodies against the granulocyte-macrophage colony-stimulating factor (GM-CSF) since these antibodies have been reported as a hidden risk factor for C. gattii infection. Among the 32 patients, 25 were free from any known other health issues, and 7 had various medical conditions at the time of diagnosis for cryptococcosis. Importantly, plasma from 19 (76%) of 25 patients with no recognized underlying medical condition showed the presence of GM-CSF autoantibodies, supporting this antibody as a major hidden risk factor for C. gattii infection. These data indicate that seemingly immunocompetent people with C. gattii infection warrant detailed evaluation for unrecognized immunologic risks. There was no relationship between molecular type and underlying conditions of patients. Frequency of each molecular type was related to its geographic origin exemplified by the overrepresentation of VGIV in HIV-positive (HIV+) patients due to its prevalence in Africa. IMPORTANCE The C. neoformans and C. gattii species complex causes cryptococcosis. The C. neoformans species complex is known as an opportunistic pathogen since it primarily infects immunocompromised patients. C. gattii species complex has been referred to as a primary pathogen due to its high infection frequency in apparently immunocompetent people. We analyzed 135 global cases of C. gattii infection with documented patient history. Eighty-six of 135 patients were originally diagnosed as immunocompetent and 49 as immunosuppressed with similar underlying conditions reported for C. neoformans infection. A significant number of C. gattii patients without known underlying conditions possessed autoantibodies against granulocytes-macrophage colony-stimulating factor (GM-CSF) in their plasma, supporting the presence of GM-CSF antibodies as a hidden risk factor for C. gattii infection. No relationship was found between C. gattii lineages and the underlying conditions except for overrepresentation of the molecular type VGIV among HIV+ patients due to the prevalence of VGIV in Africa.

Clinical Application of Metagenomic Next-Generation Sequencing for Suspected Infections in Patients With Primary Immunodeficiency Disease.

Background: Infections are the major cause of morbidity and mortality in patients with primary immunodeficiency disease (PID). Timely and accurate microbiological diagnosis is particularly important in these patients. Metagenomic next-generation sequencing (mNGS) has been used for pathogen detection recently. However, few reports describe the use of mNGS for pathogen identification in patients with PID. Objective: To evaluate the utility of mNGS for detecting pathogens in patients with PID, and to compare it with conventional microbiological tests (CMT). Methods: This single center retrospective study investigated the diagnostic performance of mNGS for pathogens detection in PID patients and compared it with CMT. Sixteen PID patients with suspected infection were enrolled, and medical records were analyzed to extract detailed clinical characteristics such as gene variation, immune status, microbial distribution, time-consuming of mNGS and CMT, treatment, and outcomes. Results: mNGS identified pathogenic microbe in 93.75% samples, compared to 31.25% for culture and 68.75% for conventional methods, and detected an extra 18 pathogenic microorganisms including rare opportunistic pathogens and Mycobacterium tuberculosis. Pathogen identification by mNGS required 48 hours, compared with bacterial culture for 3-7 days and even longer for fungus and Mycobacterium tuberculosis culture. Conclusions: mNGS has marked advantages over conventional methods for pathogenic diagnosis, particularly opportunistic pathogens and mixed infections, in patients with PID. This method might enable clinicians to make more timely and targeted therapeutic decisions, thereby improving the prognosis of these patients.

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.

Canadian Association of Gastroenterology Clinical Practice Guideline for Immunizations in Patients With Inflammatory Bowel Disease (IBD)-Part 2: Inactivated Vaccines.

BACKGROUND AND AIMS: The effectiveness and safety of vaccinations can be altered by immunosuppressive therapies, and perhaps by inflammatory bowel disease (IBD) itself. These recommendations developed by the Canadian Association of Gastroenterology and endorsed by the American Gastroenterological Association, aim to provide guidance on immunizations in adult and pediatric patients with IBD. This publication focused on inactivated vaccines. METHODS: Systematic reviews evaluating the efficacy, effectiveness, and safety of vaccines in patients with IBD, other immune-mediated inflammatory diseases, and the general population were performed. Critical outcomes included mortality, vaccine-preventable diseases, and serious adverse events. Immunogenicity was considered a surrogate outcome for vaccine efficacy. Certainty of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. Key questions were developed through an iterative online platform, and voted on by a multidisciplinary group. Recommendations were formulated using the Evidence-to-Decision framework. Strong recommendation means that most patients should receive the recommended course of action, whereas a conditional recommendation means that different choices will be appropriate for different patients. RESULTS: Consensus was reached on 15 of 20 questions. Recommendations address the following vaccines: Haemophilus influenzae type b, recombinant zoster, hepatitis B, influenza, pneumococcus, meningococcus, tetanus-diphtheria-pertussis, and human papillomavirus. Most of the recommendations for patients with IBD are congruent with the current Centers for Disease Control and Prevention and Canada's National Advisory Committee on Immunization recommendations for the general population, with the following exceptions. In patients with IBD, the panel suggested Haemophilus influenzae type b vaccine for patients older than 5 years of age, recombinant zoster vaccine for adults younger than 50 year of age, and hepatitis B vaccine for adults without a risk factor. Consensus was not reached, and recommendations were not made for 5 statements, due largely to lack of evidence, including double-dose hepatitis B vaccine, timing of influenza immunization in patients on biologics, pneumococcal and meningococcal vaccines in adult patients without risk factors, and human papillomavirus vaccine in patients aged 27-45 years. CONCLUSIONS: Patients with IBD may be at increased risk of some vaccine-preventable diseases. Therefore, maintaining appropriate vaccination status in these patients is critical to optimize patient outcomes. In general, IBD is not a contraindication to the use of inactivated vaccines, but immunosuppressive therapy may reduce vaccine responses.

Case Report: Acquired Disseminated BCG in the Context of a Delayed Immune Reconstitution After Hematological Malignancy.

Context: Disseminated infections due to Mycobacterium bovis Bacillus Calmette-Guérin (BCG) are unusual and occur mostly in patients with inborn error of immunity (IEI) or acquired immunodeficiency. However, cases of secondary BCGosis due to intravesical BCG instillation have been described. Herein, we present a case of severe BCGosis occurring in an unusual situation. Case Description: We report one case of severe disseminated BCG disease occurring after hematological malignancy in a 48-year-old man without BCG instillation and previously vaccinated in infancy with no complication. Laboratory investigations demonstrated that he was not affected by any known or candidate gene of IEI or intrinsic cellular defect involving IFNγ pathway. Whole genome sequencing of the BCG strain showed that it was most closely related to the M. bovis BCG Tice strain, suggesting an unexpected relationship between the secondary immunodeficiency of the patient and the acquired BCG infection. Conclusion: This case highlights the fact that, in addition to the IEI, physicians, as well as microbiologists and pharmacists should be aware of possible acquired disseminated BCG disease in secondary immunocompromised patients treated in centers that administrate BCG for bladder cancers.