Protocol for the systematic review of the Pneumocystis jirovecii-associated pneumonia in non-HIV immunocompromised patients.

INTRODUCTION: Pneumocystis jirovecii pneumonia (PJP) is a well-known and frequent opportunistic infection in HIV patients. However, there has been an increase in the number of reports of PJP in other immunosuppressed patients with autoimmune inflammatory disorders or because of chemotherapy and high doses of steroids, especially when used in combination as part of immunosuppressive therapy. OBJECTIVE: Despite the increasing importance of PJP in non-HIV patients, there is a lack of comprehensive and updated information on the epidemiology, pathogenesis, diagnosis, microbiology, treatments, and prophylaxis of this infection in this population. Therefore, the objective of this systematic review is to synthesize information on these aspects, from a perspective of evidence-based medicine. METHODS: The protocol is prepared following the preferred reporting items for systematic reviews and meta-analyses (PRISMA-P) guidelines. We will perform a systematic review of literature published between January 2010 and July 2023, using the databases PubMed, Google Scholar, ScienceDirect, and Web of Science. In addition, manual searches will be carried out through related articles, and references to included articles. The main findings and clinical outcomes were extracted from all the eligible studies with a standardized instrument. Two authors will independently screen titles and abstracts, review full texts, and collect data. Disagreements will be resolved by discussion, and a third reviewer will decide if there is no consensus. We will synthesize the results using a narrative or a meta-analytic approach, depending on the heterogeneity of the studies. EXPECTED RESULTS: It is expected that this systematic review will provide a comprehensive and up-to-date overview of the state-of-the-art of PJP in non-HIV patients. Furthermore, the study will highlight possible gaps in knowledge that should be addressed through new research. CONCLUSIONS: Here, we present the protocol for a systematic review which will consider all existing evidence from peer-reviewed publication sources relevant to the primary and secondary outcomes related to diagnosing and managing PJP in non-HIV patients.

Description of a Murine Model of Pneumocystis Pneumonia.

Pneumocystis pneumonia is a serious lung infection caused by an original ubiquitous fungus with opportunistic behavior, referred to as Pneumocystis jirovecii. P. jirovecii is the second most common fungal agent among invasive fungal infections after Candida spp. Unfortunately, there is still an inability to culture P. jirovecii in vitro, and so a great impairment to improve knowledge on the pathogenesis of Pneumocystis pneumonia. In this context, animal models have a high value to address complex interplay between Pneumocystis and the components of the host immune system. Here, we propose a protocol for a murine model of Pneumocystis pneumonia. Animals become susceptible to Pneumocystis by acquiring an immunocompromised status induced by iterative administration of steroids within drinking water. Thereafter, the experimental infection is completed by an intranasal challenge with homogenates of mouse lungs containing Pneumocystis murina. The onset of clinical signs occurs within 5 weeks following the infectious challenge and immunosuppression can then be withdrawn. At termination, lungs and bronchoalveolar lavage (BAL) fluids from infected mice are analyzed for fungal load (qPCR) and immune response (flow cytometry and biochemical assays). The model is a useful tool in studies focusing on immune responses initiated after the establishment of Pneumocystis pneumonia.

MiR-150 levels are related to in-hospital mortality in non-HIV Pneumocystis pneumonia patients.

Pneumocystis pneumonia (PCP) is a common opportunistic infection that occurs in immunocompromised patients. Compared with HIV patients, PCP in non-HIV patients tends to follow up a more urgent course and poorer prognosis. Therefore, markers that could predict survival of PCP patients in non-HIV population are of great value. MiRNA-150 has been widely studied in many diseases since it has been identified as a vital regulator of immune cell differentiation and activation. We thus conduct this study aiming to evaluate the prognostic value of miR-150 level in non-HIV PCP. First, the expression levels of miR-150 were compared between PCP patients and healthy volunteers. The miR-150 levels in immune cells were also detected in PCP mouse models. Then the prognostic value of miR-150 was further assessed in another PCP population (n = 72). The expression levels of miR-150 were measured by reverse transcription real-time PCR (RT-PCR) technique. Our data demonstrated significantly decreased miR-150 expression levels in PCP patients and mouse models compared to controls. The miR-150 levels also decreased in various immune cells of PCP mouse models. With a cut-off value of 3.48, the area under the curve, sensitivity, specificity of miR-150 to predicate PCP mortality were 0.845, 68.2% and 96.0%, respectively. In conclusion, miR-150 expression value might serve as a potential biomarker to identify PCP patients at high risk of death.

Pneumocystis pneumonia (PCP) remains a fatal risk for immunosuppressed patients. MiR-150 takes part in immune regulation, and thus is involved in infection control. Our study indicated that the miR-150 expression may act as a potential biomarker for predicting mortality of PCP patients.

Leukotriene B4-induced neutrophil extracellular traps impede the clearance of Pneumocystis.

Pneumocystis pneumonia (PCP) is a fungal pulmonary disease with high mortality in immunocompromised patients. Neutrophils are essential in defending against fungal infections; however, their role in PCP is controversial. Here we aim to investigate the effects of neutrophil extracellular traps (NETs) on Pneumocystis clearance and lung injury using a mouse model of PCP. Intriguingly, although neutrophils play a fundamental role in defending against fungal infections, NETs failed to eliminate Pneumocystis, but instead impaired the killing of Pneumocystis. Mechanically, Pneumocystis triggered Leukotriene B4 (LTB4)-dependent neutrophil swarming, leading to agglutinative NET formation. Blocking Leukotriene B4 with its receptor antagonist Etalocib significantly reduced the accumulation and NET release of neutrophils in vitro and in vivo, enhanced the killing ability of neutrophils against Pneumocystis, and alleviated lung injury in PCP mice. This study identifies the deleterious role of agglutinative NETs in Pneumocystis infection and reveals a new way to prevent NET formation, which provides new insights into the pathogenesis of PCP.

Additional C-type lectin receptors mediate interactions with Pneumocystis organisms and major surface glycoprotein.

Introduction. Pathogen-associated molecular patterns' (PAMPs) are microbial signatures that are recognized by host myeloid C-type lectin receptors (CLRs). These CLRs interact with micro-organisms via their carbohydrate recognition domains (CRDs) and engage signalling pathways within the cell resulting in pro-inflammatory and microbicidal responses.Gap statement. In this article, we extend our laboratory study of additional CLRs that recognize fungal ligands against Pneumocystis murina and Pneumocystis carinii and their purified major surface glycoproteins (Msgs).Aim. To study the potential of newly synthesized hFc-CLR fusions on binding to Pneumocystis and its Msg.Methods. A library of new synthesized hFc-CLR fusions was screened against Pneumocystis murina and Pneumocystis carinii organisms and their purified major surface glycoproteins (Msgs) found on the respective fungi via modified ELISA. Immunofluorescence assay (IFA) was implemented and quantified to verify results. mRNA expression analysis by quantitative PCR (q-PCR) was employed to detect respective CLRs found to bind fungal organisms in the ELISA and determine their expression levels in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model.Results. We detected a number of the CLR hFc-fusions displayed significant binding with P. murina and P. carinii organisms, and similarly to their respective Msgs. Significant organism and Msg binding was observed for CLR members C-type lectin domain family 12 member A (CLEC12A), Langerin, macrophage galactose-type lectin-1 (MGL-1), and specific intracellular adhesion molecule-3 grabbing non-integrin homologue-related 3 (SIGNR3). Immunofluorescence assay (IFA) with the respective CLR hFc-fusions against whole P. murina life forms corroborated these findings. Lastly, we surveyed the mRNA expression profiles of the respective CLRs tested above in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model and determined that macrophage galactose type C-type lectin (Mgl-1), implicated in recognizing terminal N-acetylgalactosamine (GalNAc) found in the glycoproteins of microbial pathogens was significantly up-regulated during infection.Conclusion. The data herein add to the growing list of CLRs recognizing Pneumocystis and provide insights for further study of organism/host immune cell interactions.

Semiquantitative Real-Time PCR to Distinguish Pneumocystis Pneumonia from Colonization in a Heterogeneous Population of HIV-Negative Immunocompromised Patients.

Pneumocystis jirovecii is a threat to iatrogenically immunosuppressed individuals, a heterogeneous population at rapid growth. We assessed the ability of an in-house semiquantitative real-time PCR assay to discriminate Pneumocystis pneumonia (PCP) from colonization and identified risk factors for infection in these patients. Retrospectively, 242 PCR-positive patients were compared according to PCP status, including strata by immunosuppressive conditions, human immunodeficiency virus (HIV) infection excluded. Associations between host characteristics and cycle threshold (CT) values, semiquantitative real-time PCR correlates of fungal loads in lower respiratory tract specimens, were investigated. CT values differed significantly according to PCP status. Overall, a CT value of 36 allowed differentiation between PCP and colonization with sensitivity and specificity of 71.3% and 77.1%, respectively. A CT value of less than 31 confirmed PCP, whereas no CT value permitted exclusion. A considerable diversity was uncovered; solid organ transplant (SOT) recipients had significantly higher fungal loads than patients with hematological malignancies. In SOT recipients, a CT cutoff value of 36 resulted in sensitivity and specificity of 95.0% and 83.3%, respectively. In patients with hematological malignancies, a higher CT cutoff value of 37 improved sensitivity to 88.5% but reduced specificity to 66.7%. For other conditions, assay validity appeared inferior. Corticosteroid usage was an independent predictor of PCP in a multivariable analysis and was associated with higher fungal loads at PCP expression. Semiquantitative real-time PCR improves differentiation between PCP and colonization in immunocompromised HIV-negative individuals with acute respiratory syndromes. However, heterogeneity in disease evolution requires separate cutoff values across intrinsic and iatrogenic predisposition for predicting non-HIV PCP. IMPORTANCE Pneumocystis jirovecii is potentially life threatening to an increasing number of individuals with compromised immune systems. This microorganism can cause severe pneumonia in susceptible hosts, including patients with cancer and autoimmune diseases and people undergoing solid organ transplantation. Together, these patients constitute an ever-diverse population. In this paper, we demonstrate that the heterogeneity herein has important implications for how we diagnose and assess the risk of Pneumocystis pneumonia (PCP). Specifically, low loads of microorganisms are sufficient to cause infection in patients with blood cancer compared to those in solid organ recipients. With this new insight into host versus P. jirovecii biology, clinicians can manage patients at risk of PCP more accurately. As a result, we take a significant step toward offering precision medicine to a vulnerable patient population. One the one hand, these patients have propensity for adverse effects from antimicrobial treatment. On the other hand, this population is susceptible to life-threatening infections, including PCP.

Effect of Subcutaneous Anti-CD20 Antibody-Mediated B Cell Depletion on Susceptibility to Pneumocystis Infection in Mice.

Prior work has shown that parenterally administered anti-CD20 (5D2) inhibits CD4+ T cell priming in response to challenge with Pneumocystis murina and predisposes to pneumonia. In this study, we investigated the effect of subcutaneous anti-CD20 antibody and Pneumocystis infection. In mice with primary infection, anti-CD20 antibody treatment depleted both CD19+ and CD27+ CD19+ cells but not T cells in the lung at days 14 and 28 after Pneumocystis inoculation. Although anti-CD20 antibody treatment impaired fungal clearance at day 14 postinfection, fungal burden in the lungs was substantially reduced at day 28 in both depleted and control mice in the low-dose group. Subcutaneous anti-CD20 antibody treatment did not alter antigen-specific serum immunoglobulin levels in mice compared with control mice, and there were no significant differences in the numbers of lung gamma interferon-positive (IFN-γ+) CD4+, interleukin 4-positive (IL-4+) CD4+, IL-5+ CD4+, and IL-17A+ CD4+ cells between depleted and control mice after infection. In mice with secondary infection, the lung fungal burden was comparable between depleted and control mice 14 days after reinfection. Low-dose subcutaneous anti-CD20 antibody treatment may delay fungal clearance, but it did not impair the ability of the host to clear Pneumocystis infection, irrespective of primary or secondary infection.IMPORTANCE Anti-CD20 antibody therapy is used for both cancer and autoimmune disease but has been shown to be associated with Pneumocystis pneumonia in humans. This study shows that low-dose subcutaneous anti-CD20 can modulate B cell populations without grossly perturbing fungal immunity against Pneumocystis lung infection.

The Changing Landscape of Pneumocystis Jiroveci Infection in Kidney Transplant Recipients: Single-Center Experience of Late-Onset Pneumocystis Pneumonia.

BACKGROUND: Pneumocystis jiroveci pneumonia (PCP) is a life-threatening pulmonary infection after kidney transplantation (KTx). Its onset in the current era of modern immunosuppression and of routine use of universal PCP prophylaxis seems to differ from its onset in previous decades in terms of late onset with subtle clinical presentation, indicating a need for increased vigilance. METHODS: We retrospectively studied all KTx recipients from our center who underwent bronchoscopy and bronchoalveolar lavage (BAL) between 2009 and 2018. Of these, all cases with confirmed PCP any time after the first post-KTx year were included in the analysis. RESULTS: Among 60 patients with KTx who had undergone bronchoscopy and BAL, 12 cases with late-onset PCP were identified. PCP appeared late at a median of 10.8 (interquartile range, 2.4-15.8) years after transplantation. Patients' mean age was 59 years, and all were receiving stable low-dose immunosuppression. Most of the patients (67%) had received PCP prophylaxis after KTx. Five out of 12 patients (42%) had concomitant cytomegalovirus (CMV) reactivation at the time of PCP. In almost all cases, clinical presentation was mild. Treatment consisted of trimethoprim-sulfamethoxazole (TMP-SMX) and intravenous corticosteroid administration, and concomitant immunosuppression was temporarily reduced or withdrawn. Outcome was generally good. None of the patients developed respiratory insufficiency or required mechanical ventilation. One patient died as a result of sepsis, and 3 more with preexisting advanced chronic kidney disease subsequently lost their grafts. CONCLUSION: Renal transplant recipients are at risk of late-onset PCP, even at a steady state of low-dose maintenance immunosuppression. Because of its subtle clinical presentation, high suspicion of the disease is warranted. Its early recognition and proper management are essential for a successful outcome.

Lymphocyte subset analysis to evaluate the prognosis of HIV-negative patients with pneumocystis pneumonia.

OBJECTIVES: We analysed the peripheral blood lymphocyte subsets of human immunodeficiency virus (HIV)-negative patients infected with pneumocystis pneumonia (PCP) to determine the relationships between the levels of different types of lymphocytes and the prognosis of patients. METHODS: We retrospectively reviewed HIV-negative patients with PCP diagnosed in our department. All the eligible patients underwent lymphocyte subset analysis on admission. RESULTS: A total of 88 HIV-negative PCP patients were enrolled in the study. In univariate analyses, low CD4+ T cell count, low CD8+ T cell count, and low natural killer cell (NK cell) count were associated with higher in-hospital mortality. CD8+ T cell count ≤300/µL was found to be an independent risk factor for poor prognosis in multivariate logistical regression analysis (p = 0.015, OR = 11.526, 95% CI = 1.597-83.158). Although low CD4+ T cell and NK cell counts were not independent risk factors, the mortality rates of PCP patients decreased as the CD4+ T cell and NK cell counts increased. CONCLUSION: The immune process of Pneumocystis jirovecii infection is complex but important. We propose that lymphocyte subsets could give clinicians a better understanding of patient immune status, helping with the early identification of potentially lethal infections and treatment decision making, such as adjusting the immunosuppressive regimen and choosing an appropriate patient monitoring level.

Diagnostic accuracy of the 1,3-beta-D-glucan test and lactate dehydrogenase for pneumocystis pneumonia in non-HIV patients.

We evaluated the serum levels of (1-3)-beta-D-glucan (BG) and lactate dehydrogenase (LDH) as a tool to support pneumocystis pneumonia (PCP) diagnostic procedures in non-HIV patients. We retrospectively collected non-HIV (human immunodeficiency virus) patients presenting clinical features of PCP between April 1st, 2013, and December 31st, 2018. A total of 225 included patients were tested for Pneumocystis jirovecii by polymerase chain reaction (PCR) and methenamine silver staining. Based on different exclusion criteria, 179 cases were included in the BG group, and 196 cases were included in the LDH group. In each group, cases with positive immunofluorescence (IF) microscopy and PCR were considered proven PCP, while cases with only positive PCR were considered probable PCP. Fifty patients with negative IF and PCR results and proven to be non-PCP infection were chosen randomly as the control group. The cut-off levels of BG and LDH to distinguish non-PCP from probable PCP were 110 pg/mL and 296 U/L with 88% sensitivity and 86% specificity, and 66% sensitivity and 88% specificity, respectively. The cut-off levels of BG and LDH to distinguish non-PCP from proven PCP were 285.8 pg/mL and 379 U/L with 92% sensitivity and 96% specificity, and 85% sensitivity and 77% specificity, respectively. The cut-off levels of BG and LDH to distinguish non-PCP from proven/probable PCP were 144.1 pg/mL and 363 U/L with 90% sensitivity, 86% specificity and 80% sensitivity, 76% specificity respectively. BG and LDH are reliable indicators for detecting P. jirovecii infection in HIV-uninfected immunocompromised patients.

Is cotrimoxazole prophylaxis against Pneumocystis jirovecii pneumonia needed in patients with systemic autoimmune rheumatic diseases requiring immunosuppressive therapies?

The incidence of Pneumocystis jirovecii pneumonia (PJP) has increased over recent years in patients with systemic autoimmune rheumatic diseases (SARD). PJP prognosis is poor in those receiving immunosuppressive therapy and glucocorticoids in particular. Despite the effectiveness of cotrimoxazole against PJP, the risk of adverse effects remains significant, and no consensus has emerged regarding the need for PJP prophylaxis in SARD patients undergoing immunosuppressor therapies.Objective: To evaluate the efficacy and safety of cotrimoxazole prophylaxis against PJP in SARD adult patients receiving immunosuppressive therapies. Methods: We performed a systematic review, consulting MEDLINE, EMBASE, and Cochrane Library databases up to April 2020. Outcomes covered prevention of PJP, other infections, morbidity, mortality, and safety. The information obtained was summarized with a narrative review and results were tabulated. Of the 318 identified references, 8 were included. Two were randomized controlled trials and six observational studies. The quality of studies was moderate or low. Despite disparities in the cotrimoxazole prophylaxis regimens described, results were consistent in terms of efficacy, particularly with glucocorticoid doses > 20 mg/day. However, cotrimoxazole 400 mg/80 mg/day, prescribed three times/ week, or 200 mg/40 mg/day or in dose escalation, exhibited similar positive performances. Conversely, cotrimoxazole 400 mg/80 mg/day showed higher incidences of withdrawals and adverse effects. Cotrimoxazole prophylaxis against PJP exhibited efficacy in SARD, mainly in patients taking glucocorticoids ≥ 20 mg/day. All cotrimoxazole regimens exposed seemed equally efficacious, although, higher quality trials are needed. Adverse effects were observed 2 months after initiation, particularly with the 400 mg/80 mg/day regimen. Conversely, escalation dosing or 200 mg/40 mg/day regimens appeared better tolerated.

Toward a humanized mouse model of Pneumocystis pneumonia.

Pneumocystis is an important opportunistic fungus that causes pneumonia in children and immunocompromised individuals. Recent genomic data show that divergence of major surface glycoproteins may confer speciation and host range selectivity. On the other hand, immune clearance between mice and humans is well correlated. Thus, we hypothesized that humanize mice may provide information about human immune responses involved in controlling Pneumocystis infection. CD34-engrafted huNOG-EXL mice controlled fungal burdens to a greater extent than nonengrafted mice. Moreover, engrafted mice generated fungal-specific IgM. Fungal control was associated with a transcriptional signature that was enriched for genes associated with nonopsonic recognition of trophs (CD209) and asci (CLEC7A). These same genes were downregulated in CD4-deficient mice as well as twins with bare lymphocyte syndrome with Pneumocystis pneumonia.

A Comprehensive Evaluation of Risk Factors for Pneumocystis jirovecii Pneumonia in Adult Solid Organ Transplant Recipients: A Systematic Review and Meta-analysis.

BACKGROUND: There is no consensus guidance on when to reinitiate Pneumocystis jirovecii pneumonia (PJP) prophylaxis in solid organ transplant (SOT) recipients at increased risk. The 2019 American Society of Transplantation Infectious Diseases Community of Practice (AST IDCOP) guidelines suggested to continue or reinstitute PJP prophylaxis in those receiving intensified immunosuppression for graft rejection, cytomegalovirus (CMV) infection, higher dose of corticosteroids, or prolonged neutropenia. METHODS: A literature search was conducted evaluating all literature from existence through April 22, 2020, using MEDLINE and EMBASE. (The International Prospective Register of Systematic Reviews registration number: CRD42019134204). RESULTS: A total of 30 studies with 413 276 SOT recipients were included. The following factors were associated with PJP development: acute rejection (pooled odds ratio [pOR], 2.35; 95% confidence interval [CI], 1.69-3.26); study heterogeneity index [I2] = 23.4%), CMV-related illnesses (pOR, 3.14; 95% CI, 2.30-4.29; I2 = 48%), absolute lymphocyte count <500 cells/mm3 (pOR, 6.29; 95% CI, 3.56-11.13; I2 = 0%), BK polyomavirus-related diseases (pOR, 2.59; 95% CI, 1.22-5.49; I2 = 0%), HLA mismatch ≥3 (pOR, 1.83; 95% CI, 1.06-3.17; I2 = 0%), rituximab use (pOR, 3.03; 95% CI, 1.82-5.04; I2 = 0%), and polyclonal antibodies use for rejection (pOR, 3.92; 95% CI, 1.87-8.19; I2 = 0%). On the other hand, sex, CMV mismatch, interleukin-2 inhibitors, corticosteroids for rejection, and plasmapheresis were not associated with developing PJP. CONCLUSIONS: PJP prophylaxis should be considered in SOT recipients with lymphopenia, BK polyomavirus-related infections, and rituximab exposure in addition to the previously mentioned risk factors in the American Society of Transplantation Infectious Diseases Community of Practice guidelines.

Expression Pattern of the Pneumocystis jirovecii Major Surface Glycoprotein Superfamily in Patients with Pneumonia.

BACKGROUND: The human pathogen Pneumocystis jirovecii harbors 6 families of major surface glycoproteins (MSGs) encoded by a single gene superfamily. MSGs are presumably responsible for antigenic variation and adhesion to host cells. The genomic organization suggests that a single member of family I is expressed at a given time per cell, whereas members of the other families are simultaneously expressed. METHODS: We analyzed RNA sequences expressed in several clinical samples, using specific weighted profiles for sorting of reads and calling of single-nucleotide variants to estimate the diversity of the expressed genes. RESULTS: A number of different isoforms of at least 4 MSG families were expressed simultaneously, including isoforms of family I, for which confirmation was obtained in the wet laboratory. CONCLUSION: These observations suggest that every single P. jirovecii population is made of individual cells with distinct surface properties. Our results enhance our understanding of the unique antigenic variation system and cell surface structure of P. jirovecii.

Fatal outcome of anti-MDA5 juvenile dermatomyositis in a paediatric COVID-19 patient: a case report.

Anti-melanoma differentiation-associated gene 5 juvenile dermatomyositis (anti-MDA5 JDM) is associated with high risk of developing rapidly progressive interstitial lung disease (RP-ILD). Here we report an 11-year-old girl with anti-MDA5 JDM and RP-ILD which led to a fatal outcome, further aggravated by SARS-CoV-2 infection. She was referred to our hospital after being diagnosed with anti-MDA5 JDM and respiratory failure due to RP-ILD. On admission, fibrobronchoscopy with bronchoalveolar lavage (BAL) revealed Pneumocystis jirovecii infection so treatment with intravenous trimethoprim-sulfamethoxazole was initiated. Due to RP-ILD worsening, immunosuppressive therapy was intensified using methylprednisolone pulses, cyclophosphamide, tofacitinib and intravenous immunoglobulin without response. She developed severe hypoxemic respiratory failure, pneumomediastinum and pneumothorax, further complicated with severe RP-ILD and cervical subcutaneous emphysema. Three real-time RT-PCR for SARS-CoV-2 were made with a negative result. In addition, she was complicated with a secondary hemophagocytic lymphohistiocytosis and a fourth real-time PCR for SARS-CoV-2 performed in BAS sample was positive. Despite aggressive treatment of RP-ILD due to anti-MDA5 JDM, there was no improvement of respiratory failure in the following days and patient developed refractory septic shock and died. Anti-MDA5 JDM patients with RP-ILD have a poor prognosis with a high mortality rate. For this reason, intensive immunosuppressive therapy is essential including the use of promising drugs such as tofacitinib. COVID-19 in children with underlying health conditions like anti-MDA5 JDM may still be at risk for disease and severe complications.

Role of Serum (1,3)-Β-D-Glucan to Screen for Pneumocystis Pneumonia in Kidney Transplant Recipients.

BACKGROUND: Pneumocystis pneumonia is a common opportunistic infection in kidney transplant recipients caused by the ascomycetous fungi Pneumocystis jirovecii. Its clinical presentation of a progressive nonproductive cough, shortness of breath, and fever is nonspecific and often delays diagnosis and appropriate treatment. Moreover, the plain radiograph may show a spectrum of findings from normal to bilateral diffuse infiltrates. Detection of serum (1,3)-ß-D-glucan along with consistent clinical findings can be used as early screening tools to diagnose and initiate treatment for Pneumocystis pneumonia pending confirmation by bronchoscopy. METHODS: This case series describes 6 kidney transplant recipients who were diagnosed as having Pneumocystis pneumonia. The baseline demographic variables, presenting symptoms, radiographic findings, laboratory findings including lactate dehydrogenase and serum (1,3)-ß-D-glucan levels, bronchoscopy findings, and its timing in relation to a positive serum (1,3)-ß-D-glucan test, and response to treatment were collected. RESULTS: All 6 patients who completed the first 3 months of prophylaxis against Pneumocystis pneumonia with sulfamethoxazole-trimethoprim were diagnosed as having Pneumocystis pneumonia between 2 to 24 years post transplant. They initiated treatment early based on a positive serum (1,3)-ß-D-glucan and negative Histoplasma antigen and serum galactomannan test with a presumptive diagnosis of Pneumocystis pneumonia, which was later confirmed with a positive polymerase chain reaction on bronchoalveolar lavage fluid. CONCLUSIONS: Pneumocystis pneumonia is a common opportunistic fungal infection in immunosuppressed kidney transplant recipients, and use of serum (1,3)-ß-D-glucan can be used as an initial screening test for its early diagnosis and treatment.

Risk factors associated with Pneumocystis jirovecii pneumonia in juvenile myositis in North America.

OBJECTIVES: Pneumocystis jirovecii pneumonia (PJP) is associated with significant morbidity and mortality in adult myositis patients; however, there are few studies examining PJP in juvenile myositis [juvenile idiopathic inflammatory myopathy (JIIM)]. The purpose of this study was to determine the risk factors and clinical phenotypes associated with PJP in JIIM. METHODS: An research electronic data capture (REDCap) questionnaire regarding myositis features, disease course, medications and PJP infection characteristics was completed by treating physicians for 13 JIIM patients who developed PJP (PJP+) from the USA and Canada. Myositis features and medications were compared with 147 JIIM patients without PJP (PJP-) from similar geographic regions who enrolled in National Institutes of Health natural history studies. RESULTS: PJP+ patients were more often of Asian ancestry than PJP- patients [odds ratio (OR) 8.7; 95% CI 1.3, 57.9]. Anti- melanoma differentiation associated protein 5 (MDA5) autoantibodies (OR 12.5; 95% CI 3.0, 52.4), digital infarcts (OR 43.8; 95% CI 4.2, 460.2), skin ulcerations (OR 12.0; 95% CI 3.5, 41.2) and interstitial lung disease (OR 10.6; 95% CI 2.1, 53.9) were more frequent in PJP+ patients. Before PJP diagnosis, patients more frequently received pulse steroids, rituximab and more immunosuppressive therapy compared with PJP- patients. Seven PJP+ patients were admitted to the intensive care unit and four patients died due to PJP or its complications. CONCLUSIONS: PJP is a severe infection in JIIM that can be associated with mortality. Having PJP was associated with more immunosuppressive therapy, anti-MDA5 autoantibodies, Asian race and certain clinical features, including digital infarcts, cutaneous ulcerations and interstitial lung disease. Prophylaxis for PJP should be considered in juvenile myositis patients with these features.

Current State of Carbohydrate Recognition and C-Type Lectin Receptors in Pneumocystis Innate Immunity.

Pneumocystis jirovecii is one of the most common fungal pathogens in immunocompromised individuals. Pneumocystis jirovecii pneumonia (PJP) causes a significant host immune response that is driven greatly by the organism's cell wall components including ß-glucans and major surface glycoprotein (Msg). These ligands interact with a number of C-type lectin receptors (CLRs) leading to downstream activation of proinflammatory signaling pathways. This minireview provides a brief overview summarizing known CLR/Pneumocystis interactions.

Of "Cotton Balls" and "Owl's eyes".

Report of a 3-month old girl child who died due to multi-systemic infection of cytomegalovirus (CMV) involving the lungs, liver and kidneys along with pneumocystis jiroveci pneumonia (PJP). The mother of the child tested positive for CMV IgG and HIV with a very low CD4 count (160/ µl). Co-infection of cytomegalovirus and pneumocystis jiroveci always occurs in the setting of immunocompromise. Congenital CMV infection is transmitted through the placenta, especially during the first trimester and causes severe multi-systemic disease whereas perinatal infection is acquired during childbirth/ breastfeeding where the babies have maternal protective antibodies leading to much milder or asymptomatic infection. PJP is more common in infancy and presents as hypoxic pneumonia. CMV causes cyto-nucleomegaly and classic "owl's eye" inclusions on histology while PJP presents with characteristic fluffy "cotton ball" alveolar exudates.