Immune reconstitution inflammatory syndrome associated with pulmonary pathogens

Tuberculosis and its associated risk factors among HIV-positive pregnant women in northwest Ethiopia: A retrospective follow-up study

Background

People living with the human immunodeficiency virus have a higher risk of developing active tuberculosis disease. Human immunodeficiency virus infected pregnant women are at a much higher risk of getting active tuberculosis infection, partly due to immune modulation. However, very little is known about the epidemiology of tuberculosis among pregnant women infected with the virus, particularly in resource-limited settings where the burdens of these infections are substantial. Hence, this study aimed to estimate tuberculosis incidence and identify its risk factors among human immunodeficiency virus infected pregnant women in northwest Ethiopia.

Methods

An institutional-based retrospective follow-up study was conducted among pregnant women who were enrolled in option B+ prevention of mother to child transmission service between June 2013 and April 2021 in Pawe district. The Kaplan-Meier survival curve and Weibull regression model were used to estimate survival probability and identify risk factors of tuberculosis, respectively. The best model between the Cox and parametric models was chosen using the Akaike and Bayesian information criteria.

Result

Out of 289 human immunodeficiency virus infected pregnant women included in the final analysis, 29 (10.03 %) developed active tuberculosis. The overall incidence of tuberculosis was 17.4 per 1000 person-months of observation (95 % CI: 12.1, 25.1). Lack of isoniazid preventive therapy (AHR: 6.68, 95 % CI: 2.67, 16.7), new enrollment to care (AHR: 2.62, 95 % CI: 1.14, 6.03), under-nutrition (AHR: 5.09, 95 % CI: 2.02, 12.83), low CD4 count (AHR: 2.61, 95 % CI: 1.01, 6.78), and suboptimal antiretroviral therapy adherence (AHR: 3.17, 95 % CI: 1.46, 6.86) were predictors of tuberculosis among HIV-positive pregnant women.

Conclusion

This study found a high incidence of tuberculosis among human immunodeficiency virus infected pregnant women. Thus, strengthening the provision of tuberculosis preventive therapy, reinforcing adherence support, and controlling under-nutrition should be considered to decrease the risk of tuberculosis.

IFN-γ Limits Immunopathogenesis but Delays Fungal Clearance during Pneumocystis Pneumonia

High levels of IFN-γ are produced in the lung during an adaptive immune response to Pneumocystis, but the effects of this prototypical Th1 cytokine on fungal clearance and immunopathogenesis have not been fully defined. Therefore, Pneumocystis-infected immunodeficient mice were immune reconstituted and administered control or anti-IFN-γ neutralizing Ab to determine how IFN-γ regulates the balance between host defense and immune-mediated lung injury. Mice treated with anti-IFN-γ demonstrated an initial worsening of Pneumocystis pneumonia-related immunopathogenesis, with greater weight loss, heightened lung inflammation, and more severe pulmonary function deficits than control mice. However, IFN-γ neutralization also enhanced macrophage phagocytosis of Pneumocystis and accelerated fungal clearance. When anti-IFN-γ-treated mice were also given IL-4 and IL-13 to promote a Th2-biased lung environment, the accelerated fungal clearance was preserved, but the severity of immunopathogenesis was reduced, and a more rapid recovery was observed. A direct suppressive effect of IFN-γ on macrophages was required but was not solely responsible for delayed fungal clearance, suggesting that IFN-γ acts through multiple mechanisms that likely include modulation of both macrophage and Th polarization. Enhanced Pneumocystis clearance in anti-IFN-γ-treated and IFN-γR-deficient mice was associated with significantly elevated IL-17+ CD4+ T cells and IL-17 protein in the lungs. Furthermore, neutralization of IL-17, but not IL-4, signaling blocked the accelerated fungal clearance observed in anti-IFN-γ-treated mice. Together, these data demonstrate that although IFN-γ delays fungal clearance by suppressing the lung Th17 response, it also serves an important regulatory role that limits immunopathogenesis and preserves pulmonary function.

Hypercalcemia during initiation of antiretroviral therapy in human immunodeficiency virus and Leishmania coinfection: A case report

RATIONALE

Hypercalcemia is a common complication of many granulomatous diseases but is not typically associated with leishmaniasis. Here we report an unusual case of hypercalcemia during the initiation of antiviral therapy in a patient with acquired immunodeficiency syndrome coinfected with visceral leishmaniasis.

PATIENT CONCERNS

Our patient presented with malaise and altered mental status following antiretroviral therapy initiation. He was found to have de novo hypercalcemia complicated by acute kidney injury.

DIAGNOSIS, INTERVENTIONS, AND OUTCOMES

An extensive workup for other etiologies of hypercalcemia was negative. The patient was ultimately thought to have hypercalcemia secondary to visceral leishmaniasis in the setting of immune reconstitution inflammatory syndrome. He was treated with intravenous volume expansion, bisphosphonates, and oral corticosteroid therapy with complete resolution.

LESSONS

This case highlights an unusual presentation of immune reconstitution inflammatory syndrome, in which proinflammatory cytokine signaling during the restoration of cellular immunity may have led to increased ectopic calcitriol production by granuloma macrophages, thereby altering bone-mineral metabolism and driving hypercalcemia.

Advances in immunomodulatory strategies for host-directed therapies in combating tuberculosis

Tuberculosis (TB) maintains its infamous status regarding its detrimental effect on global health, causing the highest mortality by a single infectious agent. The presence of resistance and immune compromising disease favours the disease in maintaining its footing in the health care burden despite various anti-TB drugs used to fight it. Main factors contributing to resistance and difficulty in treating disease include prolonged treatment duration (at least 6 months) and severe toxicity, which further leads to patient non-compliance, and thus a ripple effect leading to therapeutic non-efficacy. The efficacy of new regimens demonstrates that targeting host factors concomitantly with the Mycobacterium tuberculosis (M.tb) strain is urgently required. Due to the huge expenses and time required of up to 20 years for new drug research and development, drug repurposing may be the most economical, circumspective, and conveniently faster journey to embark on. Host-directed therapy (HDT) will dampen the burden of the disease by acting as an immunomodulator, allowing it to defend the body against antibiotic-resistant pathogens whilst minimizing the possibility of developing new resistance to susceptible drugs. Repurposed drugs in TB act as host-directed therapies, acclimatizing the host immune cell to the presence of TB, improving its antimicrobial activity and time taken to get rid of the disease, whilst minimizing inflammation and tissue damage. In this review, we, therefore, explore possible immunomodulatory targets, HDT immunomodulatory agents, and their ability to improve clinical outcomes whilst minimizing the risk of drug resistance, through various pathway targeting and treatment duration reduction.

Favorable Outcome Following Sotrovimab Monoclonal Antibody in a Patient with Prolonged SARS-CoV-2 Omicron Infection with HIV/AIDS

Persistent viral shedding or prolonged coronavirus disease 2019 (COVID-19) symptom is one of unresolved problem in immunocompromised individuals. We herein report an HIV/AIDS patient with Pneumocystis jirovecii pneumonia and prolonged COVID-19, possibly due to immune reconstitution inflammatory syndrome. His viral shedding and COVID-19 symptoms persisted for 39 days but were promptly resolved following sotrovimab monoclonal antibody therapy. This case suggests that prolonged COVID-19 and persistent viral shedding due to severe cellular immunodeficiency can occur in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron infection and that sotrovimab is effective in the treatment of prolonged COVID-19 caused by omicron/BA.1.

Pneumocystis jirovecii-associated immune reconstitution inflammatory syndrome-like phenomenon in a child with leukaemia: a case report and literature review

BACKGROUND

Immune reconstitution inflammatory syndrome (IRIS) refers to the phenomenon of intense immune responses against pathogens in patients with AIDS undergoing antiretroviral therapy to reconstitute immune function, resulting in functional impairment of multiple organs. Non-AIDS immunosuppressed hosts may also develop similar manifestations to IRIS during immune recovery.

CASE PRESENTATION

An 8-year-old girl presented with acute lymphoblastic leukaemia was admitted for scheduled chemotherapy treatment. During chemotherapy, she experienced pancytopenia and Pneumocystis jirovecii pneumonia, which was diagnosed based on the abnormal shadows observed on chest computed tomography, the elevation of serum β-D-glucan, and the positive mNGS results of Pneumocystis jirovecii in both sputum and blood. After treatment with Granulocyte Colony-Stimulating Factor, sulfamethoxazole, and caspofungin, aggravation of lung lesions was discovered and severe interstitial lung disease developed in a short period along with a rapidly increasing leukocyte count. Intravenous methylprednisolone pulse therapy was given, but lung function did not improve, and she finally died after the withdrawal of medical care.

CONCLUSIONS

For patients with acute lymphocytic leukaemia infected with Pneumocystis jirovecii, the rapid aggravation of pulmonary lesions in the process of blood recovery and immune reconstitution should raise vigilance against the possibility of IRIS-like reactions. The use of granulocyte stimulating factors may aggravate the inflammatory response in the lungs. The timing, dosage, and duration of treatment of glucocorticoids and the impact of high-dose methylprednisolone pulse therapy on the prognosis of patients should be explored in further research.

Immune Reconstitution Inflammatory Syndrome Associated with Pneumocystis jirovecii Pneumonia and Cytomegalovirus Colitis in a Patient with Rheumatoid Arthritis

A 68-year-old woman presenting with rheumatoid arthritis was admitted due to pancytopenia caused by methotrexate. Pneumocystis jirovecii pneumonia was diagnosed based on the abnormal shadows observed on chest computed tomography, the presence of serum β-D-glucan, and positive P. jirovecii-DNA results in a sputum analysis. Subsequently, after treatment with leucovorin and trimethoprim-sulfamethoxazole, lung consolidation was found to be aggravated, along with a rapidly increasing leukocyte count. In addition, cytomegalovirus colitis was diagnosed. Both conditions were associated with immune reconstitution inflammatory syndrome caused by recovery from leukopenia. The patient was successfully treated with intravenous methylprednisolone pulse therapy and ganciclovir.

Dynamics of Plasmatic Levels of Pro- and Anti-Inflammatory Cytokines in HIV-Infected Individuals with M. tuberculosis Co-Infection

Tuberculosis (TB) and HIV have profound effects on the immune system, which can lead to the activation of viral replication and negatively regulate the activation of T cells. Dysregulation in the production of cytokines necessary to fight HIV and M. tuberculosis may ultimately affect the results of the treatment and be important in the pathogenesis of HIV infection and TB. This work presents the results of a study of the expression of pro- and anti-inflammatory cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, IL-1RA) in drug-naïve patients with dual infection of HIV/TB at the late stages of HIV-infection, with newly diagnosed HIV and TB, and previously untreated HIV in the process of receiving antiretroviral (ART) and TB treatment vs. a cohort of patients with HIV monoinfection and TB monoinfection. The study revealed that during a double HIV/TB infection, both Th1 and Th2 immune responses are suppressed, and a prolonged dysregulation of the immune response and an increased severity of the disease in pulmonary/extrapulmonary tuberculosis is observed in HIV/TB co-infection. Moreover, it was revealed that a double HIV/TB infection is characterized by delayed and incomplete recovery of immune activity. High levels of IL-6 were detected in patients with HIV/TB co-infection before initiation of dual therapy (2.1-fold increase vs. HIV), which persisted even after 6 months of treatment (8.96-fold increase vs. HIV), unlike other cytokines. The persistent enhanced expression of IL-6 in patients with dual HIV/TB co-infection allows the consideration of it as a potential marker of early detection of M. tuberculosis infection in HIV-infected individuals. The results of multivariate regression analysis showed a statistical trend towards an increase in the incidence of IRIS in patients with high IL-1Ra levels (in the range of 1550–2500 pg/mL): OR = 4.3 (95%CI 3.7–14.12, p = 0.53), which also allows IL-1Ra to be considered as a potential predictive biomarker of the development of TB-IRIS and treatment outcomes.

Immune Reconstitution Inflammatory Syndrome-like Condition Associated with Pneumocystis jirovecii Pneumonia During Folinic Acid Treatment in a Rheumatoid Arthritis Patient

A 94-year-old woman with rheumatoid arthritis who had been treated with low-dose methotrexate was referred to our hospital because of a 3-day history of a fever and pancytopenia. With a diagnosis of febrile neutropenia of unknown origin, empirical antibiotic treatment and folinic acid therapy were initiated. Despite a recovery from pancytopenia, the high fever remained, and dyspnea developed. She was clinically diagnosed with Pneumocystis jirovecii pneumonia (PCP) and successfully treated with trimethoprim/sulfamethoxazole and adjunctive corticosteroid therapy. Folinic acid treatment effectively brought about rapid immune recovery but might have led to a clinical manifestation of PCP resembling immune reconstruction inflammatory syndrome.

Heterothermy and antifungal responses in bats

Hibernation, a period where bats have suppressed immunity and low body temperatures, provides the psychrophilic fungus Pseudogymnoascus destructans the opportunity to colonise bat skin, leading to severe disease in susceptible species. Innate immunity, which requires less energy and may remain more active during torpor, can control infections with local inflammation in some bat species that are resistant to infection. If infection is not controlled before emergence from hibernation, ineffective adaptive immune mechanisms are activated, including incomplete Th1, ineffective Th2, and variable Th17 responses. The Th17 and neutrophil responses, normally beneficial antifungal mechanisms, appear to be sources of immunopathology for susceptible bat species, because they are hyperactivated after return to homeothermy. Non-susceptible species show both well-balanced and suppressed immune responses both during and after hibernation.

Cryptococcal Immune Reconstitution Inflammatory Syndrome: From Blood and Cerebrospinal Fluid Biomarkers to Treatment Approaches

Immune reconstitution inflammatory syndrome (IRIS) presents as an exaggerated immune reaction that occurs during dysregulated immune restoration in immunocompromised patients in late-stage human immunodeficiency virus (HIV) infection who have commenced antiretroviral treatments (ART). Virtually any opportunistic pathogen can provoke this type of immune restoration disorder. In this review, we focus on recent developments in the identification of risk factors for Cryptococcal IRIS and on advancements in our understanding of C-IRIS immunopathogenesis. We overview new findings in blood and cerebrospinal fluid which can potentially be useful in the prediction and diagnosis of cryptococcal meningitis IRIS (CM-IRIS). We assess current therapeutic regimens and novel treatment approaches to combat CM-IRIS. We discuss the utility of biomarkers for clinical monitoring and adjusting treatment modalities in acquired immunodeficiency syndrome (AIDS) patients co-infected with Cryptococcus who have initiated ART.

Systemic Inflammation Associated with Immune Reconstitution Inflammatory Syndrome in Persons Living with HIV

Antiretroviral therapy (ART) has represented a major advancement in the care of people living with HIV (PLWHH), resulting in significant reductions in morbidity and mortality through immune reconstitution and attenuation of homeostatic disruption. Importantly, restoration of immune function in PLWH with opportunistic infections occasionally leads to an intense and uncontrolled cytokine storm following ART initiation known as immune reconstitution inflammatory syndrome (IRIS). IRIS occurrence is associated with the severe and rapid clinical deterioration that results in significant morbidity and mortality. Here, we detail the determinants underlying IRIS development in PLWH, compiling the available knowledge in the field to highlight details of the inflammatory responses in IRIS associated with the most commonly reported opportunistic pathogens. This review also highlights gaps in the understanding of IRIS pathogenesis and summarizes therapeutic strategies that have been used for IRIS.

A Fatal Case of Kaposi Sarcoma Immune Reconstitution Syndrome (KS-IRIS) Complicated by Kaposi Sarcoma Inflammatory Cytokine Syndrome (KICS) or Multicentric Castleman Disease (MCD): A Case Report and Review

Patient: Male, 28-year-old

Final Diagnosis: Kaposi sarcoma inflammatory cytokine syndrome (KICS)

Symptoms: Abdominal pain • anemia • dyspnea • fever • shock • thrombocytopenia

Medication: —

Clinical Procedure: Skin biopsy

Specialty: Infectious Diseases

Autophagy markers as mediators of lung injury-implication for therapeutic intervention

Lung injury is characterized by inflammatory processes demonstrated as loss of function of the pulmonary capillary endothelial and alveolar epithelial cells. Autophagy is an intracellular digestion system that work as an inducible adaptive response to lung injury which is a resultant of exposure to various stress agents like hypoxia, ischemia-reperfusion and xenobiotics which may be manifested as acute lung injury (ALI), acute respiratory distress syndrome (ARDS), chronic lung injury (CLI), bronchopulmonary dysplasia (BPD), chronic obstructive pulmonary disease (COPD), asthma, ventilator-induced lung injury (VILI), ventilator-associated lung injury (VALI), pulmonary fibrosis (PF), cystic fibrosis (CF) and radiation-induced lung injury (RILI). Numerous regulators like LC3B-II, Beclin 1, p62, HIF1/BNIP3 and mTOR play pivotal role in autophagy induction during lung injury possibly for progression/inhibition of the disease state. The present review focuses on the critical autophagic mediators and their potential cross talk with the lung injury pathophysiology thereby bringing to limelight the possible therapeutic interventions.

Emerging trends in COVID-19 treatment: learning from inflammatory conditions associated with cellular therapies

Coronavirus disease 2019 (SARS-CoV2) is an active global health threat for which treatments are desperately being sought. Even though most people infected experience mild to moderate respiratory symptoms and recover with supportive care, certain vulnerable hosts develop severe clinical deterioration. While several drugs are currently being investigated in clinical trials, there are currently no approved treatments or vaccines for COVID-19 and hence there is an unmet need to explore additional therapeutic options. At least three inflammatory disorders or syndromes associated with immune dysfunction have been described in the context of cellular therapy. Specifically, Cytokine Release Syndrome (CRS), Immune Reconstitution Inflammatory Syndrome (IRIS), and Secondary Hemophagocytic Lymphohistiocytosis (sHLH) all have clinical and laboratory characteristics in common with COVID19 and associated therapies that could be worth testing in the context of clinical trials. Here we discuss these diseases, their management, and potential applications of these treatment in the context of COVID-19. We also discuss current cellular therapies that are being evaluated for the treatment of COVID-19 and/or its associated symptoms.

Prevalence and risk factors of paradoxical tuberculosis associated immune reconstitution inflammatory syndrome among HIV-infected patients in Beijing, China

Background

In this study, we aimed to describe the prevalence, clinical presentation and risk factors of paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) cases in China.

Methods

We performed a descriptive analysis of demographic and clinical data of HIV/TB coinfected patients receiving ART at Beijing Ditan Hospital between January 2014 and October 2018.

Results

Of 199 patients included, 45 (22.6%) developed paradoxical TB-IRIS, and 19 (9.5%) TB-IRIS cases presented miliary TB. The pre-ART CD4 count lower than 50 cells/mm³ was found to be significantly associated with development of TB-IRIS. Similarly, patients with higher than 4-fold increase in CD4 cell count after antiretroviral therapy (ART) had significantly higher odds of having TB-IRIS. When patients aged 25–44 years were utilized as the control group, youths (< 25 years old) were more likely to have miliary TB. No significant difference was observed in the intervals from initiation of ART to IRIS presentation between miliary and non-miliary group.

Conclusions

In conclusion, our data demonstrate that approximate one quarter of patients coinfected with TB and HIV develop paradoxical TB-IRIS after initial of ART therapy in China. Lower baseline CD4 count and rapid increase in CD4 count are the major risk factors associated with the occurrence of paradoxical TB-IRIS.

JC Polyomavirus, progressive multifocal leukoencephalopathy and immune reconstitution inflammatory syndrome: a review

The human neurotropic virus JC Polyomavirus, a member of the Polyomaviridae family, is the opportunistic infectious agent causing progressive multifocal leukoencephalopathy, typically in immunocompromised individuals. The spectrum of underlying reasons for the systemic immunosuppression that permits JCV infection in the central nervous system has evolved over the past 2 decades, and therapeutic immunosuppression arousing JCV infection in the brain has become increasingly prominent as a trigger for PML. Effective immune restoration subsequent to human immunodeficiency virus-related suppression is now recognized as a cause for unexpected deterioration of symptoms in patients with PML, secondary to a rebound inflammatory phenomenon called immune reconstitution inflammatory syndrome, resulting in significantly increased morbidity and mortality in a disease already infamous for its lethality. This review addresses current knowledge regarding JC Polyomavirus, progressive multifocal leukoencephalopathy, progressive multifocal leukoencephalopathy-related immune reconstitution inflammatory syndrome, and the immunocompromised states that incite JC Polyomavirus central nervous system infection, and discusses prospects for the future management of these conditions.

<p>A Challenge in Diagnosis of Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome (TB-IRIS)</p>

Tuberculosis immune reconstitution inflammatory syndrome (TB-IRIS) in HIV-infected patients is the sign and symptom of exacerbation, or radiological manifestation of Mycobacterium tuberculosis (Mtb) infection, can describe the improvement of the immune system after initiating highly active antiretroviral therapy (HAART). No approved or explicit symptomatic tests for TB-IRIS exist, the diagnosis depends on the clinical manifestations. Here we report a TB-IRIS case with diagnostic challenges.

Clinical and genetic markers associated with tuberculosis, HIV-1 infection, and TB/HIV-immune reconstitution inflammatory syndrome outcomes

BACKGROUND

Tuberculosis (TB) and AIDS are the leading causes of infectious disease death worldwide. In some TB-HIV co-infected individuals treated for both diseases simultaneously, a pathological inflammatory reaction termed immune reconstitution inflammatory syndrome (IRIS) may occur. The risk factors for IRIS are not fully defined. We investigated the association of HLA-B, HLA-C, and KIR genotypes with TB, HIV-1 infection, and IRIS onset.

METHODS

Patients were divided into four groups: Group 1- TB+/HIV+ (n = 88; 11 of them with IRIS), Group 2- HIV+ (n = 24), Group 3- TB+ (n = 24) and Group 4- healthy volunteers (n = 26). Patients were followed up at INI/FIOCRUZ and HGNI (Rio de Janeiro/Brazil) from 2006 to 2016. The HLA-B and HLA-C loci were typed using SBT, NGS, and KIR genes by PCR-SSP. Unconditional logistic regression models were performed for Protection/risk estimation.

RESULTS

Among the individuals with TB as the outcome, KIR2DS2 was associated with increased risk for TB onset (aOR = 2.39, P = 0.04), whereas HLA-B*08 and female gender were associated with protection against TB onset (aOR = 0.23, P = 0.03, and aOR = 0.33, P = 0.01, respectively). Not carrying KIR2DL3 (aOR = 0.18, P = 0.03) and carrying HLA-C*07 (aOR = 0.32, P = 0.04) were associated with protection against TB onset among HIV-infected patients. An increased risk for IRIS onset was associated with having a CD8 count ≤500 cells/mm3 (aOR = 18.23, P = 0.016); carrying the KIR2DS2 gene (aOR = 27.22, P = 0.032), the HLA-B*41 allele (aOR = 68.84, P = 0.033), the KIR2DS1 + HLA-C2 pair (aOR = 28.58, P = 0.024); and not carrying the KIR2DL3 + HLA-C1/C2 pair (aOR = 43.04, P = 0.034), and the KIR2DL1 + HLA-C1/C2 pair (aOR = 43.04, P = 0.034), CONCLUSIONS: These results suggest the participation of these genes in the immunopathogenic mechanisms related to the conditions studied. This is the first study demonstrating an association of HLA-B*41, KIR2DS2, and KIR + HLA-C pairs with IRIS onset among TB-HIV co-infected individuals.

Niflumic Acid Reverses Airway Mucus Excess and Improves Survival in the Rat Model of Steroid-Induced Pneumocystis Pneumonia

Although the role of adaptive immunity in fighting Pneumocystis infection is well known, the role of the innate, airway epithelium, responses remains largely unexplored. The concerted interaction of innate and adaptive responses is essential to successfully eradicate infection. Increased expression of goblet-cell-derived CLCA1 protein plus excess mucus in infant autopsy lungs and in murine models of primary Pneumocystis infection alert of innate immune system immunopathology associated to Pneumocystis infection. Nonetheless, whether blocking mucus-associated innate immune pathways decreases Pneumocystis-related immunopathology is unknown. Furthermore, current treatment of Pneumocystis pneumonia (PcP) relying on anti-Pneumocystis drugs plus steroids is not ideal because removes cellular immune responses against the fungal pathogen. In this study, we used the steroid-induced rat model of PcP to evaluate inflammation and mucus progression, and tested the effect of niflumic acid (NFA), a fenamate-type drug with potent CLCA1 blocker activity, in decreasing Pneumocystis-associated immunopathology. In this model, animals acquire Pneumocystis spontaneously and pneumonia develops owing to the steroids-induced immunodeficiency. Steroids led to decreased animal weight evidencing severe immunosuppression and to significant Pneumocystis-associated pulmonary edema as evidenced by wet-to-dry lung ratios that doubled those of uninfected animals. Inflammatory cuffing infiltrates were noticed first around lung blood vessels followed by bronchi, and both increased progressively. Similarly, airway epithelial and lumen mucus progressively increased. This occurred in parallel to increasing levels of MUC5AC and mCLCA3, the murine homolog of hCLCA1. Administration of NFA caused a significant decrease in total mucus, MUC5AC and mCLCA3 and also, in Pneumocystis-associated inflammation. Most relevant, NFA treatment improved survival at 8 weeks of steroids. Results suggest an important role of innate immune responses in immunopathology of steroid-induced PcP. They warrant evaluation of CLCA1 blockers as adjunctive therapy in this condition and describe a simple model to evaluate therapeutic interventions for steroid resistant mucus, a common condition in patients with chronic lung disease like asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.

Immune Reconstitution Disorders: Spotlight on Interferons

Three decades of research in hematopoietic stem cell transplantation and HIV/AIDS fields have shaped a picture of immune restoration disorders. This manuscript overviews the molecular biology of interferon networks, the molecular pathogenesis of immune reconstitution inflammatory syndrome, and post-hematopoietic stem cell transplantation immune restoration disorders (IRD). It also summarizes the effects of thymic involution on T cell diversity, and the results of the assessment of diagnostic biomarkers of IRD, and tested targeted immunomodulatory treatments.

Radiologic features of pneumonitis associated with nivolumab in non-small-cell lung cancer and malignant melanoma

Aim: To assess the clinical features/imaging characteristics of pneumonitis reported during nationwide nivolumab postmarketing surveillance in Japan. Patients & methods: Clinical and radiological data were collected from pneumonitis cases reported during/after nivolumab treatment for melanoma or non-small-cell lung cancer. The expert central review committee evaluated each case. Results: Among 144 cases analyzed, 91 (63.2%) had radiological patterns considered typical for drug-induced pneumonitis and 53 (36.8%) patients had previously unobserved patterns with one or more atypical features, including 23 cases (16.0%) with ground glass opacity confined to the area around the tumor (peritumoral infiltration). A higher proportion of patients with (vs without) peritumoral infiltration had an antitumor response to nivolumab. Conclusion: Images of nivolumab-induced pneumonitis showed previously unobserved radiological patterns.

Understanding mechanisms underlying the pathology of immune reconstitution inflammatory syndrome (IRIS) by using animal models

Purpose of Review

Despite the increasing number of clinical reports on immune reconstitution inflammatory syndrome (IRIS), mechanistic understanding of IRIS is still largely limited. The main focus of this review is to summarize animal studies, which were performed to better understand the cellular and molecular mechanisms underlying the pathology of IRIS.

Recent Findings

Three IRIS animal models have been reported. They are Mycobacterial IRIS (M-IRIS), cryptococcal IRIS (C-IRIS) and Pneumocystis-IRIS. M-IRIS animal model suggested that, rather than lymphopenia itself, the failure to clear the pathogen by T cells results in excessive priming of the innate immune system. If this happens before T cell reconstitution, hosts likely suffer IRIS upon T cell reconstitution. Interestingly, T cells specific to self-antigens, not only pathogen-specific, could drive IRIS as well.

Summary

The mechanism to develop IRIS is quite complicated, including multiple layers of host immune responses; the innate immune system that detects pathogens and prime host immunity, and the adaptive immune system that is reconstituted but hyper-activated particularly through CD4⁺ T cells. Animal models of IRIS, although there are still small numbers of studies available, have already provided significant insights on the mechanistic understanding of IRIS.

Concomitant Human Herpes Virus 6 and nivolumab-related pneumonitis: Potential pathogenetic insights

The development of immune system modulating agents, such as immune checkpoint inhibitors (ICIs), has revolutionized cancer treatment. Nivolumab, a human monoclonal antibody against PD-1, has emerged as an efficient treatment for various malignancies, including non-small cell lung cancer (NSCLC); however, it is associated with important immune related side-effects, attributed to organ-specific inflammation, such as immune-mediated pneumonitis, a relatively uncommon, albeit potentially fatal adverse event. We herein present the unique case of severe interstitial pneumonitis with concomitant detection of Human Herpes Virus 6 (HHV-6) in a nivolumab treated patient with NSCLC. Potential pathogenetic mechanisms are discussed.

Alveolar T-helper 17 responses to streptococcus pneumoniae are preserved in ART-untreated and treated HIV-infected Malawian adults

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Pneumococcal-specific Th17 responses in HIV-infected adults are preserved.

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The frequency of pneumococcal-specific Th17 cells is increased in ART-treated HIV-infected adults.

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Depletion of pneumococcal-specific Th17 cells is unlikely the reason behind the increased susceptibility to pneumonia in HIV-infected adults.

Objective

We explored if HIV infection is associated with impaired T-Helper 17 responses against Streptococcus pneumoniae in the lung.

Methods

We recruited 30 HIV-uninfected healthy controls, 23 asymptomatic HIV-infected adults not on ART, and 40 asymptomatic HIV-infected adults on ART (Median time 3.5yrs), in whom we collected bronchoalveolar lavage fluid. We measured alveolar CD4⁺ T cell immune responses following stimulation with pneumococcal cell culture supernatant using flow cytometry-based intracellular cytokine staining.

Results

We found that the proportion of alveolar CD4⁺ T cells producing IL-17A following stimulation with pneumococcal cell culture supernatant (CCS) was similar between HIV-uninfected controls and ART-naïve HIV-infected adults (0.10% vs. 0.14%; p = 0.9273). In contrast, the proportion and relative absolute counts of CD4⁺ T cells producing IL-17A in response to pneumococcal CCS were higher in ART-treated HIV-infected adults compared HIV-uninfected controls (0.22% vs. 0.10%, p = 0.0166; 5420 vs. 1902 cells/100 ml BAL fluid; p = 0.0519). The increase in relative absolute numbers of IL-17A-producing alveolar CD4⁺ T cells in ART-treated individuals was not correlated with the peripheral blood CD4⁺ T cell count (r=–0.1876, p = 0.1785).

Conclusion

Alveolar Th17 responses against S. pneumoniae are preserved in HIV-infected adults. This suggests that there are other alternative mechanisms that are altered in HIV-infected individuals that render them more susceptible to pneumococcal pneumonia.