Life-threatening immune reconstitution inflammatory syndrome after Pneumocystis pneumonia: a cautionary case series

Immune reconstitution inflammatory syndrome in splenic Pneumocystis jirovecii infection: A case report

To the best of our knowledge, the present report is the first to describe immune reconstitution inflammatory syndrome (IRIS) in a case of Pneumocystis jirovecii (P. jirovecii) infection of the spleen. A 45-year-old, men who have sex with men patient presented with constipation, abdominal pain, nausea, fever, and weight loss. Human immunodeficiency virus infection and P. jirovecii pneumonia were diagnosed. Abdominal computed tomography revealed multiple, hypodense, cystic lesions in the spleen. Based on the histopathological findings of the lesion obtained from a percutaneous splenic biopsy, extrapulmonary P. jirovecii infection of the spleen was diagnosed. Trimethoprim/sulfamethoxazole was administered for 21 days, and antiretroviral therapy was initiated ten days after the former regimen was begun. Temporary enlargement of the splenic lesions and fever recurrence were observed after the trimethoprim/sulfamethoxazole regimen was completed. However, the clinical course was favorable, with no splenic rupture or splenic bleeding. Our investigation suggested that additional therapy, such as corticosteroid administration, may not be required for IRIS in a splenic P. jirovecii infection, but further research is needed for a definitive conclusion.

Risk factors for IRIS in HIV-associated Pneumocystis-pneumonia following ART initiation

BACKGROUND

HIV-infected patients with Pneumocystis-pneumonia (PCP) may develop paradoxical immune reconstitution inflammatory syndrome (IRIS), when combination antiretroviral therapy (cART) is started early during the course of PCP-treatment (PCPT). The aim of this study was to identify risk factors and predictors for PCP-IRIS and to improve individualized patient care.

METHODS

An ICD-10 code hospital database query identified all Frankfurt HIV Cohort patients being diagnosed with PCP from January 2010 - June 2016. Patient charts were evaluated retrospectively for demographic, clinical and therapeutic (cART/PCPT) characteristics and incidence of paradoxical IRIS according to French's case definitions.

RESULTS

IRIS occurred in 12/97 patients that started cART while on PCPT (12.4%). They had a higher rate of re-hospitalization (41.7vs. 4.7%; odds ratio (OR) 14.46; p = 0.009), intensive care treatment (66.7vs. 30.6%; OR = 4.54; p = 0.018), and longer median hospitalization (48 days vs. 23; p < 0.001). A high HIV-RNA level (> 6Log₁₀/ml) before cART initiation was associated with IRIS development (41.6vs. 15.0%; OR 4.05; p = 0.042). Serum immunoglobulin G-levels (IgG) [mg/dl] were lower (894.0 vs. 1446.5; p = 0.023).

CONCLUSION

Higher hospitalization rate and morbidity parameters underscore the clinical importance of PCP-related paradoxical IRIS. A baseline viral load of > 6Log10/ml and serum IgG may help to assess individual risks for PCP-IRIS.

Immune reconstitution inflammatory syndrome in HIV-infected patients with Pneumocystis jirovecii pneumonia

INTRODUCTION

The incidence of immune reconstitution inflammatory syndrome (IRIS) in HIV-infected patients after an episode of Pneumocystis jirovecii pneumonia (PJP) seems to be lower than with other opportunistic infections. We conducted an observational study in order to determine the incidence, clinical characteristics and outcome of patients diagnosed with PJP-related IRIS.

METHODS

We conducted an observational study of HIV patients diagnosed with PJP-related IRIS from January 2000 to November 2015. We analyzed epidemiological and clinical characteristics as well as laboratory findings. We also carried out a systematic review of published cases.

RESULTS

Six cases of IRIS out of 123 (4.9%) HIV-infected patients with PJP who started ART were diagnosed. All six cases were men with a median age of 34 (IQR: 8) years. The six patients developed paradoxical IRIS. Subjects younger than 40 years old (p=0.084) and with an HIV-RNA viral load >100000 copies/ml (p=0.081) at diagnosis showed a tendency to develop IRIS. Thirty-seven published cases of PJP-related IRIS were identified. Although 51% of cases involved respiratory failure, no deaths were reported.

CONCLUSIONS

PJP-related IRIS is rare condition compared to other opportunistic infections. It can lead to a severe respiratory failure in a significant proportion of cases, although no deaths have been reported.

Treatment of Pneumocystis jirovecii pneumonia in HIV-infected patients: a review

INTRODUCTION

Pneumocystis pneumonia is a potentially life-threatening pulmonary infection that occurs in immunocompromised individuals and HIV-infected patients with a low CD4 cell count. Trimethoprim-sulfamethoxazole has been used as the first-line agent for treatment, but mutations within dihydropteroate synthase gene render potential resistance to sulfamide. Despite advances of combination antiretroviral therapy (cART), Pneumocystis pneumonia continues to occur in HIV-infected patients with late presentation for cART or virological and immunological failure after receiving cART. Areas covered: This review summarizes the diagnosis and first-line and alternative treatment and prophylaxis for Pneumocystis pneumonia in HIV-infected patients. Articles for this review were identified through searching PubMed. Search terms included: 'Pneumocystis pneumonia', 'Pneumocystis jirovecii pneumonia', 'Pneumocystis carinii pneumonia', 'trimethoprim-sulfamethoxazole', 'primaquine', 'trimetrexate', 'dapsone', 'pentamidine', 'atovaquone', 'echinocandins', 'human immunodeficiency virus infection', 'acquired immunodeficiency syndrome', 'resistance to sulfamide' and combinations of these terms. We limited the search to English language papers that were published between 1981 and March 2017. We screened all identified articles and cross-referenced studies from retrieved articles. Expert commentary: Trimethoprim-sulfamethoxazole will continue to be the first-line agent for Pneumocystis pneumonia given its cost, availability of both oral and parenteral formulations, and effectiveness or efficacy in both treatment and prophylaxis. Whether resistance due to mutations within dihydropteroate synthase gene compromises treatment effectiveness remains controversial. Continued search for effective alternatives with better safety profiles for Pneumocystis pneumonia is warranted.

Immune reconstitution inflammatory syndrome associated with pulmonary pathogens

Immune reconstitution inflammatory syndrome (IRIS) is an exaggerated immune response to a variety of pathogens in response to antiretroviral therapy-mediated recovery of the immune system in HIV-infected patients. Although IRIS can occur in many organs, pulmonary IRIS, associated with opportunistic infections such as Mycobacterium tuberculosis and Pneumocystis jirovecii, is particularly associated with high morbidity and mortality. The pathology of IRIS is associated with a variety of innate and adaptive immune factors, including CD4⁺ T-cells, CD8⁺ T-cells, γδ T-cells, natural killer cells, macrophages, the complement system and surfactant proteins, Toll-like receptors and pro-inflammatory cytokines and chemokines. Although there are numerous reports about the immune factors involved in IRIS, the mechanisms involved in the development of pulmonary IRIS are poorly understood. Here, we propose that studies using gene-deficient murine and nonhuman primate models will help to identify the specific molecular targets associated with the development of IRIS. An improved understanding of the mechanisms involved in the pathology of pulmonary IRIS will help to identify potential biomarkers and therapeutic targets in this syndrome.

Mechanisms of pulmonary IRIS in HIV-infected individuals recently initiated on ART are poorly definedhttp://ow.ly/AAOR301Bh36

Complications of invasive mycoses in organ transplant recipients

INTRODUCTION

Opportunistic mycoses remain a significant complication in organ recipients. Areas covered: This review is an evidence-based presentation of current state-of-knowledge and our perspective on recent developments in the field Expert commentary: Invasive fungal infections are associated with reduced allograft and patient survival, increase in healthcare resource utilization, and newly appreciated but largely unrecognized immunologic sequelae, such as immune reconstitution syndrome. Given adverse outcomes associated with established infections, prophylaxis is a widely used strategy for the prevention of these infections. Currently available biomarkers that detect circulating fungal cell wall constituents i.e., galactomannan and 1, 3-β-D-glucan have not proven to be beneficial as screening tools for employing targeted prophylaxis or as diagnostic assays in this patient population. However, subsets of patients at risk for opportunistic fungal infections can be identified based on clinically identifiable characteristics or events. Preventive strategies targeted towards these patients are a rational approach for optimizing outcomes.

Guidelines for antiretroviral therapy in HIV-1 infected adults and adolescents 2014, Thailand

New evidence has emerged regarding when to commence antiretroviral therapy (ART), optimal treatment regimens, management of HIV co-infection with opportunistic infections, and management of ART failure. The 2014 guidelines were developed by the collaborations of the Department of Disease Control, Ministry of Public Health (MOPH) and the Thai AIDS Society (TAS). One of the major changes in the guidelines included recommending to initiating ART irrespective of CD4 cell count. However, it is with an emphasis that commencing HAART at CD4 cell count above 500 cell/mm³ is for public health, in term of preventing HIV transmission and personal benefit. In tuberculosis co-infected patients with CD4 cell counts ≤50 cells/mm³ or with CD4 cell counts >50 cells/mm³ who have severe clinical disease, ART should be initiated within 2 weeks of starting tuberculosis treatment. The preferred initial ART regimen in treatment naïve patients is efavirenz combined with tenofovir and emtricitabine or lamivudine. Plasma HIV viral load assessment should be done twice a year until achieving undetectable results; and will then be monitored once a year. CD4 cell count should be monitored every 6 months until CD4 cell count ≥350 cells/mm³ and with plasma HIV viral load <50 copies/mL; then it should be monitored once a year afterward. HIV drug resistance genotypic test is indicated when plasma HIV viral load >1,000 copies/mL while on ART. Ritonavir-boosted lopinavir or atazanavir in combination with optimized two nucleoside-analogue reverse transcriptase inhibitors is recommended after initial ART regimen failure. Long-term ART-related safety monitoring has also been included in the guidelines.

Pathological and protective immunity to Pneumocystis infection

Pneumocystis jirovecii is a common opportunistic infection in the HIV-positive population and is re-emerging as a growing clinical concern in the HIV-negative immunosuppressed population. Newer targeted immunosuppressive therapies and the discovery of rare genetic mutations have furthered our understanding of the immunity required to clear Pneumocystis infection. The immune system can also mount a pathologic response against Pneumocystis following removal of immunosuppression and result in severe damage to the host lung. The current review will examine the most recent epidemiologic studies about the incidence of Pneumocystis in the HIV-positive and HIV-negative populations in the developing and developed world and will detail methods of diagnosis for Pneumocystis pneumonia. Finally, this review aims to summarize the known mediators of immunity to Pneumocystis and detail the pathologic immune response leading to Pneumocystis-related immune reconstitution inflammatory syndrome.

Pneumocystis

Since its initial misidentification as a trypanosome some 100 years ago, Pneumocystis has remained recalcitrant to study. Although we have learned much, we still do not have definitive answers to such basic questions as, where is the reservoir of infection, how does Pneumocystis reproduce, what is the mechanism of infection, and are there true species of Pneumocystis? The goal of this review is to provide the reader the most up to date information available about the biology of Pneumocystis and the disease it produces.

Invasive diagnostic strategies in immunosuppressed patients with acute respiratory distress syndrome

Immunosuppression predisposes the host to development of pulmonary infections, which can lead to respiratory failure and the development of acute respiratory distress syndrome (ARDS). There are multiple mechanisms by which a host can be immunosuppressed and each is associated with specific infectious pathogens. Early invasive diagnostic modalities such as fiber-optic bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, and open lung biopsy are complementary to serologic and noninvasive studies and assist in rapidly establishing an accurate diagnosis, which allows initiation of appropriate therapy and may improve outcomes with relative safety.

Early development of immune reconstitution inflammatory syndrome related to Pneumocystis pneumonia after antiretroviral therapy

Immune reconstitution inflammatory syndrome is a recognized complication after the initiation of combination antiretroviral therapy (cART). We report a patient who developed life-threatening pulmonary immune reconstitution inflammatory syndrome (IRIS) three days after initiation of cART. We reviewed published cases of IRIS after Pneumocystis pneumonia (PCP), in particular the time from initiation of cART to IRIS event. The median duration from the initiation of cART to the onset of IRIS was 15 days in the 33 patients reviewed. This report alerts clinicians to the rapidity of the development of pulmonary IRIS following PCP after the initiation of cART.

Dectin immunoadhesins and pneumocystis pneumonia

The opportunistic pathogen Pneumocystis jirovecii is a significant cause of disease in HIV-infected patients and others with immunosuppressive conditions. Pneumocystis can also cause complications in treatment following antiretroviral therapy or reversal of immunosuppressive therapy, as the newly reconstituted immune system can develop a pathological inflammatory response to remaining antigens or a previously undetected infection. To target β-(1,3)-glucan, a structural component of the Pneumocystis cell wall with immune-stimulating properties, we have developed immunoadhesins consisting of the carbohydrate binding domain of Dectin-1 fused to the Fc regions of the 4 subtypes of murine IgG (mIgG). These immunoadhesins bind β-glucan with high affinity, and precoating the surface of zymosan with Dectin-1:Fc can reduce cytokine production by macrophages in an in vitro stimulation assay. All Dectin-1:Fc variants showed specificity of binding to the asci of Pneumocystis murina, but effector activity of the fusion molecules varied depending on Fc subtype. Dectin-1:mIgG2a Fc was able to reduce the viability of P. murina in culture through a complement-dependent mechanism, whereas previous studies have shown the mIgG1 Fc fusion to increase macrophage-dependent killing. In an in vivo challenge model, systemic expression of Dectin-1:mIgG1 Fc significantly reduced ascus burden in the lung. When administered postinfection in a model of immune reconstitution inflammatory syndrome (IRIS), both Dectin-1:mIgG1 and Dectin-1:mIgG2a Fc reduced hypoxemia despite minimal effects on fungal burden in the lung. Taken together, these data indicate that molecules targeting β-glucan may provide a mechanism for treatment of fungal infection and for modulation of the inflammatory response to Pneumocystis and other pathogens.

Evaluation of respiratory disease

The spectrum of HIV-associated pulmonary diseases is broad. Opportunistic infections, neoplasms, and noninfectious complications are all major considerations. Clinicians caring for persons infected with HIV must have a systematic approach. The approach begins with a thorough history and physical examination and often involves selected laboratory tests and a chest radiograph. Frequently, the clinical, laboratory, and chest radiographic presentation suggests a specific diagnosis or a few diagnoses, which then prompts specific diagnostic testing and treatment. This article presents an overview of the evaluation of respiratory disease in persons with HIV/AIDS.

Pneumocystis pneumonia associated with human immunodeficiency virus

Pneumocystis pneumonia (PCP) is caused by the yeastlike fungus Pneumocystis. Despite the widespread availability of specific anti-Pneumocystis prophylaxis and of combination antiretroviral therapy (ART), PCP remains a common AIDS-defining presentation. PCP is increasingly recognized among persons living in Africa. Pneumocystis cannot be cultured and bronchoalveolar lavage is the gold standard diagnostic test to diagnose PCP. Use of adjunctive biomarkers for diagnosis requires further evaluation. Trimethoprim-sulfamethoxazole remains the preferred first-line treatment regimen. In the era of ART, mortality from PCP is approximately 10% to 12%. The optimal time to start ART in a patient with PCP remains uncertain.

HIV & immune reconstitution inflammatory syndrome (IRIS)

Antiretroviral therapy (ART) initiation in HIV-infected patients leads to recovery of CD4+T cell numbers and restoration of protective immune responses against a wide variety of pathogens, resulting in reduction in the frequency of opportunistic infections and prolonged survival. However, in a subset of patients, dysregulated immune response after initiation of ART leads to the phenomenon of immune reconstitution inflammatory syndrome (IRIS). The hallmark of the syndrome is paradoxical worsening of an existing infection or disease process or appearance of a new infection/disease process soon after initiation of therapy. The overall incidence of IRIS is unknown, but is dependent on the population studied and the burden of underlying opportunistic infections. The immunopathogenesis of the syndrome is unclear and appears to be result of unbalanced reconstitution of effector and regulatory T-cells, leading to exuberant inflammatory response in patients receiving ART. Biomarkers, including interferon-γ (INF-γ), tumour necrosis factor-α (TNF-α), C-reactive protein (CRP) and inter leukin (IL)-2, 6 and 7, are subject of intense investigation at present. The commonest forms of IRIS are associated with mycobacterial infections, fungi and herpes viruses. Majority of patients with IRIS have a self-limiting disease course. ART is usually continued and treatment for the associated condition optimized. The overall mortality associated with IRIS is low; however, patients with central nervous system involvement with raised intracranial pressures in cryptococcal and tubercular meningitis, and respiratory failure due to acute respiratory distress syndrome (ARDS) have poor prognosis and require aggressive management including corticosteroids. Paradigm shifts in management of HIV with earlier initiation of ART is expected to decrease the burden of IRIS in developed countries; however, with enhanced rollout of ART in recent years and the enormous burden of opportunistic infections in developing countries like India, IRIS is likely to remain an area of major concern.

Pulmonary manifestations of the immune reconstitution inflammatory syndrome

PURPOSE OF REVIEW

Immune reconstitution inflammatory syndrome (IRIS) is a common occurrence in HIV patients starting antiretroviral therapy (ART), and pulmonary involvement is an important feature of tuberculosis-IRIS and pneumocystis-IRIS. Pulmonologists need an awareness of the timing, presentation and treatment of pulmonary IRIS.

RECENT FINDINGS

Case definitions for tuberculosis-IRIS and cryptococcal-IRIS have been published by the International Network for the Study of HIV-associated IRIS (INSHI). A number of studies have addressed validation of clinical case definitions and the optimal time to commence ART after diagnosis of an opportunistic infection in HIV patients. The pathogenesis of IRIS is being assessed at a molecular level, increasing our understanding of mechanisms and possible targets for future preventive and therapeutic strategies.

SUMMARY

Tuberculosis-IRIS, nontuberculosis mycobacterial-IRIS and pneumocystis-IRIS occur within days to weeks of starting ART, causing substantial morbidity, but low mortality. Cryptococcal-IRIS usually occurs later in the course of ART, and may be associated with appreciable mortality. Early recognition of unmasking and paradoxical IRIS affecting the lung allows timely initiation of antimicrobial and/or immunomodulatory therapies.

Clinical and translational research in pneumocystis and pneumocystis pneumonia

Pneumocystis pneumonia (PcP) remains a significant cause of morbidity and mortality in immunocompromised persons, especially those with human immunodeficiency virus (HIV) infection. Pneumocystis colonization is described increasingly in a wide range of immunocompromised and immunocompetent populations and associations between Pneumocystis colonization and significant pulmonary diseases such as chronic obstructive pulmonary disease (COPD) have emerged. This mini-review summarizes recent advances in our clinical understanding of Pneumocystis and PcP, describes ongoing areas of clinical and translational research, and offers recommendations for future clinical research from researchers participating in the "First centenary of the Pneumocystis discovery".

Immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) must be considered in the differential diagnosis for any patient infected with HIV who has begun ART in the preceding months. Distinguishing between manifestations of IRIS and active infection is of paramount importance and poses a diagnostic challenge to the provider in the acute care setting. Presentations of IRIS are often atypical for the precipitating pathogen, and novel presentations are likely. Of the diseases associated with IRIS, mycobacteria and cryptococcal infections are commonly encountered, as are dermatologic symptoms in general. The most clinically significant complications of IRIS are those involving the central nervous system, lungs, and eye, and in many of these scenarios systemic steroids may be of benefit. Management should rarely include interruption of ART, except possibly in severe, life-threatening complications.