The substantial decline in the Pneumocystis jirovecii pneumonia (PCP) incidence in HIV-infected patients after the introduction of antiretroviral therapy (ART) in resource-rich settings and the growing number of non-HIV-infected immunocompromised patients at risk leads to considerable epidemiologic changes with clinical, diagnostic, and treatment consequences for physicians. HIV-infected patients usually develop a subacute course of disease, while non-HIV-infected immunocompromised patients are characterized by a rapid disease progression with higher risk of respiratory failure and higher mortality. The main symptoms usually include exertional dyspnea, dry cough, and subfebrile temperature or fever. Lactate dehydrogenase may be elevated. Typical findings on computed tomography scans of the chest are bilateral ground-glass opacities with or without cystic lesions, which are usually associated with the presence of AIDS. Empiric treatment should be initiated as soon as PCP is suspected. Bronchoalveolar lavage has a higher diagnostic yield compared to induced sputum. Immunofluorescence is superior to conventional staining. A combination of different diagnostic tests such as microscopy, polymerase chain reaction, and (1,3)-β-D-glucan is recommended. Trimeth-oprim/sulfamethoxazole for 21 days is the treatment of choice in adults and children. Alternative treatment regimens include dapsone with trimethoprim, clindamycin with primaquine, atovaquone, or pentamidine. Patients with moderate to severe disease should receive adjunctive corticosteroids. In newly diagnosed HIV-infected patients with PCP, ART should be initiated as soon as possible. In non-HIV-infected immunocompromised patients, improvement of the immune status should be discussed (e.g., temporary reduction of immunosuppressive agents). PCP prophylaxis is effective and depends on the immune status of the patient and the underlying immunocompromising disease.

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Clinical, Diagnostic, and Treatment Disparities between HIV-Infected and Non-HIV-Infected Immunocompromised Patients with Pneumocystis jirovecii Pneumonia

T lymphocyte-mediated immune responses in the heart are potentially dangerous because they can interfere with the electromechanical function. Furthermore, the myocardium has limited regenerative capacity to repair damage caused by effector T cells. Myocardial T cell responses are normally suppressed by multiple mechanisms of central and peripheral tolerance. T cell inhibitory molecules, so called immune checkpoints, limit the activation and effector function of heart antigen-reactive T cells that escape deletion during development in the thymus. Programmed cell protein death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) are checkpoint molecules homologous to the costimulatory receptor CD28, and they work to block activating signals from the T cell antigen receptor and CD28. Nonetheless, PD-1 and CTLA-4 function in different ways and at different steps in a T cell response to antigen. Studies in mice have established that genetic deficiencies of checkpoint molecules, including PD-1, PD-L1, CTLA-4, and lymphocyte activation gene-3, result in enhanced risk of autoimmune T cell-mediated myocarditis and increased pathogenicity of heart antigen-specific effector T cells. The PD-1/PD-L1 pathway appears to be particularly important in cardiac protection from T cells. PD-L1 is markedly up-regulated on myocardial cells by interferon-gamma secreted by T cells and PD-1 or PD-L1 deficiency synergizes with other defects in immune regulation in promoting myocarditis. Consistent with these studies, myocarditis has emerged as a serious adverse reaction of cancer therapies that target checkpoint molecules to enhance anti-tumour T cell responses. Histopathology and immunohistochemical analyses of myocardial tissue from immune checkpoint blockade (ICB)-treated patients echoes findings in checkpoint-deficient mice. Many questions about myocarditis in the setting of cancer immunotherapy still need to be answered, including the nature of the target antigens, genetic risk factors, and variations in the disease with combined therapies. Addressing these questions will require further immunological analyses of blood and heart tissue from patients treated with ICB.

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T cell checkpoint regulators in the heart.

The advent of immune checkpoint inhibitors in the treatment of certain types of cancers has revolutionized cancer therapy. In general, these novel agents are more tolerable and have better safety profiles than conventional chemotherapy agents. Although a low incidence of myocarditis was noted as a side effect of immune checkpoint inhibitors in clinical trials, it is being increasingly cited in the literature as their use also increases. Using a combination of search terms in the PubMed/Medline database and manual searches on Google Scholar and the bibliographies of articles identified, we reviewed all cases reported in the English language citing myocarditis associated with either pembrolizumab, nivolumab, ipilimumab, or any combination of these agents. A total of 42 cases were included in the study. Mean age was 65.5 years; 64% were male, 36% were female. One or two doses preceded the onset of myocarditis in 33% and 29% of cases, respectively. Steroids were used as the first-line therapy in 90% of cases. Complete heart block occurred in 36% of cases. Fourteen (33%) deaths were reported, with 64% and 29% of deaths occurring after one or two doses, respectively. Most cases and fatalities of myocarditis occurred shortly after initiation of immune checkpoint inhibitor therapy. Arrhythmias, particularly complete heart block, appear to be related to the occurrence of more severe and fatal cases. The use of serial electrocardiograms or biomarkers of myocardial injury may be crucial in detecting early stages of the disease process. Further research establishing more specific guidelines is necessary in dealing with this potentially fatal side effect.

Immune checkpoint inhibitor therapy and myocarditis: a systematic review of reported cases

Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal disease process in which pulmonary hypertension (PH) develops in the setting of malignancy. The purpose of this study is to present a detailed analysis of cases of PTTM reported in literature in the hopes of achieving more ante-mortem diagnoses. We conducted a systematic review of currently published and available cases of PTTM by searching the term "pulmonary tumor thrombotic microangiopathy" on the Pubmed.gov database. Seventy-nine publications were included consisting of 160 unique cases of PTTM. The most commonly reported malignancy was gastric adenocarcinoma (94 cases, 59%). Cough and dyspnea were reported in 61 (85%) and 102 (94%) cases, respectively. Hypoxemia was reported in 96 cases (95%). Elevation in D-dimer was noted in 36 cases (95%), presence of anemia in 32 cases (84%), and thrombocytopenia in 30 cases (77%). Common findings on chest computed tomography (CT) included ground-glass opacities (GGO) in 28 cases (82%) and nodules in 24 cases (86%). PH on echocardiography was noted in 59 cases (89%) with an average right ventricular systolic pressure of 71 mmHg. Common features of PTTM that are reported across the published literature include presence of dyspnea and cough, hypoxemia, with abnormal CT findings of GGO, nodules, and mediastinal/hilar lymphadenopathy, and PH. PTTM is a universally fatal disease process and this analysis provides a detailed examination of all the available published data that may help clinicians establish an earlier diagnosis of PTTM.

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Pulmonary tumor thrombotic microangiopathy: a systematic review.

The development of immune checkpoint inhibitors (ICIs) has revolutionized the treatment of patients with advanced stage cancers. However, immune-related adverse events are frequently observed. Cardiac toxicity from ICI therapy can range from asymptomatic troponin-I elevations to conduction abnormalities of the heart and even fulminant myocarditis. Although rare, myocarditis is a potentially fatal adverse effect of ICI therapy. We present a series of five cases of ICI-related cardio-toxicity diagnosed and managed at Roswell Park Comprehensive Cancer Center along with a review of published case reports in the literature. Our series highlights the importance of high clinical suspicion, early diagnosis of myocarditis, and prompt initiation of immunosuppressive therapy.

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Cardiac Toxicity Associated with Immune Checkpoint Inhibitors: Case Series and Review of the Literature.

A 41-year-old woman, who underwent breast resection for cancer of the right breast and adjuvant chemotherapy 2 years ago, was admitted to our hospital due to shortness of breath upon exertion. High-resolution computed tomography of the chest showed small nodular opacities in the peribronchiolar area in both lungs, as well as mediastinal and hilar lymphadenopathy. A transbronchial lung biopsy revealed breast cancer metastasis and pulmonary tumor thrombotic microangiopathy (PTTM). Treatment of PTTM is rarely reported due to the difficulty of antemortem diagnosis; however, the patient was effectively treated with chemotherapy and oxygen and anticoagulation therapies for 3 months.

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A Case of Pulmonary Tumor Thrombotic Microangiopathy Diagnosed by Transbronchial Lung Biopsy and Treated with Chemotherapy and Long-Term Oxygen and Anticoagulation Therapies

Fulminant Myocarditis Caused by an Immune Checkpoint Inhibitor: A Case Report With Pathologic Findings.

A 24-year-old man was admitted with a 7-month history of non-productive cough, and recent onset of fever and progressive dyspnea. A chest X-ray film and computed tomography (CT) scan showed bilateral infiltrates that indicated pneumocystis pneumonia (PCP). A transbronchial lung biopsy specimen demonstrated Pneumocystis jirovecii infection on Grocott staining, and was positive for acid-fast bacilli without necrotizing granuloma, which indicated coinfection with both Pneumocystis jirovecii and Mycobacterium tuberculosis. A test for human immunodeficiency virus (HIV) infection was positive, and his CD4 + T-lymphocyte count was 92 cells per cubic millimeter. Chest CT findings and pathological findings.were atypical for active tuberculosis (TB). It is important that clinicians should be aware that HIV-infected patients may have concurrent pulmonary TB and PCP, because the diagnosis is difficult.

[Coinfection with Pneumocystis jirovecii and Mycobacterium tuberculosis in a patient with AIDS: a first report in Japan].

We experienced a case of nephrotic syndrome (membranous nephropathy) complicated by extensive small cell carcinoma of unknown primary etiology that was diagnosed based on the findings of bilateral cervical and mediastinal lymphadenopathy. A complete cancer response and proteinuria remission following radical chemoradiation therapy were documented. The status of a complete response and nephrosis remission persisted for more than three years. This is the first report to demonstrate the long-term survival of a patient with extensive small cell carcinoma of unknown primary etiology complicated by paraneoplastic nephrotic syndrome.

Long-term Survival of a Patient with Extensive Small Cell Carcinoma of Unknown Primary Etiology Complicated by Nephrotic Syndrome

Chest radiography showed a right posterior mass on the mediastinum of an 84-year-old woman. The mass had been growing gradually for four years. Surgical excision was performed, and a pathological examination found the mass to be consistent with primary synovial sarcoma (SS) of the mediastinum. To our knowledge, this is a rare case in which follow-up imaging was able to be performed over a period of four years. This disease is aggressive, and its early diagnosis is key to achieving a cure. It is important to consider primary SS in the differential diagnosis of a primary intra-thoracic tumor, even if the tumor grows slowly.

Koyu Suzuki

Papers

A Case of Pulmonary Tumor Thrombotic Microangiopathy Diagnosed by Transbronchial Lung Biopsy and Treated with Chemotherapy and Long-Term Oxygen and Anticoagulation Therapies

Fulminant Myocarditis Caused by an Immune Checkpoint Inhibitor: A Case Report With Pathologic Findings.

[Coinfection with Pneumocystis jirovecii and Mycobacterium tuberculosis in a patient with AIDS: a first report in Japan].

Long-term Survival of a Patient with Extensive Small Cell Carcinoma of Unknown Primary Etiology Complicated by Nephrotic Syndrome

Primary Synovial Sarcoma of the Mediastinum with Long-term Follow-up