The Development and Evaluation of a Prediction Model for Kidney Transplant-Based Pneumocystis carinii Pneumonia Patients Based on Hematological Indicators.

BACKGROUND: This study aimed to develop a simple predictive model for early identification of the risk of adverse outcomes in kidney transplant-associated Pneumocystis carinii pneumonia (PCP) patients. METHODS: This study encompassed 103 patients diagnosed with PCP, who received treatment at our hospital between 2018 and 2023. Among these participants, 20 were categorized as suffering from severe PCP, and, regrettably, 13 among them succumbed. Through the application of machine learning techniques and multivariate logistic regression analysis, two pivotal variables were discerned and subsequently integrated into a nomogram. The efficacy of the model was assessed via receiver operating characteristic (ROC) curves and calibration curves. Additionally, decision curve analysis (DCA) and a clinical impact curve (CIC) were employed to evaluate the clinical utility of the model. The Kaplan-Meier (KM) survival curves were utilized to ascertain the model's aptitude for risk stratification. RESULTS: Hematological markers, namely Procalcitonin (PCT) and C-reactive protein (CRP)-to-albumin ratio (CAR), were identified through machine learning and multivariate logistic regression. These variables were subsequently utilized to formulate a predictive model, presented in the form of a nomogram. The ROC curve exhibited commendable predictive accuracy in both internal validation (AUC = 0.861) and external validation (AUC = 0.896). Within a specific threshold probability range, both DCA and CIC demonstrated notable performance. Moreover, the KM survival curve further substantiated the nomogram's efficacy in risk stratification. CONCLUSIONS: Based on hematological parameters, especially CAR and PCT, a simple nomogram was established to stratify prognostic risk in patients with renal transplant-related PCP.

Pneumocystis jirovecii pneumonia in people living with HIV: a review.

Pneumocystis jirovecii is a ubiquitous opportunistic fungus that can cause life-threatening pneumonia. People with HIV (PWH) who have low CD4 counts are one of the populations at the greatest risk of Pneumocystis jirovecii pneumonia (PCP). While guidelines have approached the diagnosis, prophylaxis, and management of PCP, the numerous studies of PCP in PWH are dominated by the 1980s and 1990s. As such, most studies have included younger male populations, despite PCP affecting both sexes and a broad age range. Many studies have been small and observational in nature, with an overall lack of randomized controlled trials. In many jurisdictions, and especially in low- and middle-income countries, the diagnosis can be challenging due to lack of access to advanced and/or invasive diagnostics. Worldwide, most patients will be treated with 21 days of high-dose trimethoprim sulfamethoxazole, although both the dose and the duration are primarily based on historical practice. Whether treatment with a lower dose is as effective and less toxic is gaining interest based on observational studies. Similarly, a 21-day tapering regimen of prednisone is used for patients with more severe disease, yet other doses, other steroids, or shorter durations of treatment with corticosteroids have not been evaluated. Now with the widespread availability of antiretroviral therapy, improved and less invasive PCP diagnostic techniques, and interest in novel treatment strategies, this review consolidates the scientific body of literature on the diagnosis and management of PCP in PWH, as well as identifies areas in need of more study and thoughtfully designed clinical trials.

Extracellular vesicles from Pneumocystis carinii-infected rats impair fungal viability but are dispensable for macrophage functions.

Pneumocystis spp. are host obligate fungal pathogens that can cause severe pneumonia in mammals and rely heavily on their host for essential nutrients. The lack of a sustainable in vitro culture system poses challenges in understanding their metabolism, and the acquisition of essential nutrients from host lungs remains unexplored. Transmission electron micrographs show that extracellular vesicles (EVs) are found near Pneumocystis spp. within the lung. We hypothesized that EVs transport essential nutrients to the fungi during infection. To investigate this, EVs from P. carinii- and P. murina-infected rodents were biochemically and functionally characterized. These EVs contained host proteins involved in cellular, metabolic, and immune processes as well as proteins with homologs found in other fungal EV proteomes, indicating that Pneumocystis may release EVs. Notably, EV uptake by P. carinii indicated their potential involvement in nutrient acquisition and a possibility for using engineered EVs for efficient therapeutic delivery. However, EVs added to P. carinii in vitro did not show increased growth or viability, implying that additional nutrients or factors are necessary to support their metabolic requirements. Exposure of macrophages to EVs increased proinflammatory cytokine levels but did not affect macrophages' ability to kill or phagocytose P. carinii. These findings provide vital insights into P. carinii and host EV interactions, yet the mechanisms underlying P. carinii's survival in the lung remain uncertain. These studies are the first to isolate, characterize, and functionally assess EVs from Pneumocystis-infected rodents, promising to enhance our understanding of host-pathogen dynamics and therapeutic potential.IMPORTANCEPneumocystis spp. are fungal pathogens that can cause severe pneumonia in mammals, relying heavily on the host for essential nutrients. The absence of an in vitro culture system poses challenges in understanding their metabolism, and the acquisition of vital nutrients from host lungs remains unexplored. Extracellular vesicles (EVs) are found near Pneumocystis spp., and it is hypothesized that these vesicles transport nutrients to the pathogenic fungi. Pneumocystis proteins within the EVs showed homology to other fungal EV proteomes, suggesting that Pneumocystis spp. release EVs. While EVs did not significantly enhance P. carinii growth in vitro, P. carinii displayed active uptake of these vesicles. Moreover, EVs induced proinflammatory cytokine production in macrophages without compromising their ability to combat P. carinii. These findings provide valuable insights into EV dynamics during host-pathogen interactions in Pneumocystis pneumonia. However, the precise underlying mechanisms remain uncertain. This research also raises the potential for engineered EVs in therapeutic applications.

Unintended Consequences: Risk of Opportunistic Infections Associated With Long-term Glucocorticoid Therapies in Adults.

Glucocorticoids are widespread anti-inflammatory medications used in medical practice. The immunosuppressive effects of systemic glucocorticoids and increased susceptibility to infections are widely appreciated. However, the dose-dependent model frequently used may not accurately predict the risk of infection in all patients treated with long-term glucocorticoids. In this review, we examine the risks of opportunistic infections (OIs) in patients requiring glucocorticoid therapy by evaluating the influence of the glucocorticoid dose, duration, and potency, combined with biological and host clinical factors and concomitant immunosuppressive therapy. We propose strategies to prevent OIs, which involve screening, antimicrobial prophylaxis, and immunizations. While this review focuses on patients with autoimmune, inflammatory, or neoplastic diseases, the potential risks and preventative strategies are likely applicable to other populations. Clinicians should actively assess the benefit-harm ratios of systemic glucocorticoids and implement preventive efforts to decrease their associated infections complications.

Machine Learning Models for Prediction of Severe Pneumocystis carinii Pneumonia after Kidney Transplantation: A Single-Center Retrospective Study.

BACKGROUND: The objective of this study was to formulate and validate a prognostic model for postoperative severe Pneumocystis carinii pneumonia (SPCP) in kidney transplant recipients utilizing machine learning algorithms, and to compare the performance of various models. METHODS: Clinical manifestations and laboratory test results upon admission were gathered as variables for 88 patients who experienced PCP following kidney transplantation. The most discriminative variables were identified, and subsequently, Support Vector Machine (SVM), Logistic Regression (LR), Random Forest (RF), K-Nearest Neighbor (KNN), Light Gradient Boosting Machine (LGBM), and eXtreme Gradient Boosting (XGB) models were constructed. Finally, the models' predictive capabilities were assessed through ROC curves, sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and F1-scores. The Shapley additive explanations (SHAP) algorithm was employed to elucidate the contributions of the most effective model's variables. RESULTS: Through lasso regression, five features-hemoglobin (Hb), Procalcitonin (PCT), C-reactive protein (CRP), progressive dyspnea, and Albumin (ALB)-were identified, and six machine learning models were developed using these variables after evaluating their correlation and multicollinearity. In the validation cohort, the RF model demonstrated the highest AUC (0.920 (0.810-1.000), F1-Score (0.8), accuracy (0.885), sensitivity (0.818), PPV (0.667), and NPV (0.913) among the six models, while the XGB and KNN models exhibited the highest specificity (0.909) among the six models. Notably, CRP exerted a significant influence on the models, as revealed by SHAP and feature importance rankings. CONCLUSIONS: Machine learning algorithms offer a viable approach for constructing prognostic models to predict the development of severe disease following PCP in kidney transplant recipients, with potential practical applications.

How to diagnose and treat a patient without human immunodeficiency virus infection having Pneumocystis jirovecii pneumonia?

BACKGROUND: Pneumocystis jirovecii pneumonia (PCP) incidence is increasing in patients without HIV infection. In contrast to PCP in patients infected with HIV, diagnosis is often delayed and illness is associated with increased mortality. OBJECTIVES: To provide a comprehensive review of clinical presentation, risk factors, diagnostic strategies, and treatment options for PCP in patients without HIV infection. SOURCES: Web-based literature review on PCP for trials, meta-analyses, and systematic reviews using PubMed. The restriction to the English language was applied. CONTENT: Common underlying conditions in patients without HIV infection having PCP are haematological malignancies, autoimmune and inflammatory diseases, solid organ or haematopoietic stem cell transplant, and previous corticosteroid exposure. New risk groups include patients receiving monoclonal antibodies and immunomodulating therapies. Patients without HIV infection who have PCP present with rapid onset and progression of pneumonia, increased duration of hospitalization and a significantly higher mortality rate than patients infected with HIV. PCP is diagnosed by a combination of clinical symptoms and radiological as well as mycological features. Results of immunofluorescence microscopy from bronchoalveolar lavage, PCR testing, and computed tomography imaging as well as the evaluation of clinical presentation are required. The established treatment regime consists of trimethoprim and sulfamethoxazole. IMPLICATIONS: Although the number of patients with immunosuppression due to causes different from HIV is increasing, a simultaneous rise in PCP incidence is observed. In the group of patients without HIV infection, rapid onset of symptoms, a more complex course, and a high mortality rate are recorded. Therefore, the time to diagnosis must be as short as possible to initiate effective therapy promptly. This review aims to raise awareness of PCP in an increasingly affected at-risk group and provides clinicians with a practical guide for efficient diagnosis and targeted therapy. Furthermore, it intends to display current inadequacies in research on the topic of PCP.

Previous corticosteroid exposure associates with an increased Pneumocystis jirovecii pneumonia mortality among HIV-negative patients: a global research network with a follow-up multicenter case-control study.

Background: HIV-negative patients have substantial mortality from Pneumocystis jirovecii pneumonia (PJP). We lack predictors of HIV-negative PJP-associated mortality. Objective: We aim to characterize the role of prior corticosteroid exposure in PJP-related mortality. Methods: We queried a global research network to identify adult HIV-negative patients with PJP with or without corticosteroid exposure in the preceding year before diagnosis (n = 8,021). We performed a propensity score-matched analysis to adjust baseline patient characteristics and analyzed outcomes. We follow-up the results with a multicenter ten years retrospective case-control cohort of HIV-negative patients tested for PJP by PCP Direct Fluorescent Antigen. We used a Cox proportional hazards model for survival analysis. Results: 1822 HIV-negative propensity-scored matched patients with prior corticosteroid exposure had significantly increased 10 weeks (16% versus 9%, p < 0.0001) and one-year mortality after PJP diagnosis (23% versus 14%, p < 0.0001). (1→3)-ß-D-glucan (197.6 ± 155.8 versus 63 ± 0 pg/ml, p = 0.014), ferritin levels (1227 ± 2486 versus 768 ± 1060 mcg/l, p = 0.047), lymphopenia (1.5 ± 1.5 versus 2.0 ± 1.6 103 cells/µl, p < 0.0001) and hypoxia (SatO2: 86.7% versus 91.6%, p < 0.0001) were higher or worse in those with prior steroid use. Patients who died were more likely to have previously received dexamethasone (35% versus 16%, p < 0.001) or prednisone (49% versus 29%, p < 0.001). Adjusted Cox proportional-hazard model validation showed an independently increased mortality at 10 weeks (HR: 3.7, CI: 1.5-9.2, p = 0.004) and 1 year (HR: 4.5, CI: 2.0-10.4, p < 0.0001) among HIV-negative patients with previous corticosteroid exposure. Conclusion: Preceding corticosteroids in HIV-negative patients with PJP are associated with higher mortality. A higher fungal burden may influence corticosteroid-mediated mortality. Assessment of PJP prophylaxis must become a standard clinical best practice when instituting corticosteroid therapy courses.

Pneumocystis jiroveci Pneumonia: A Review of Management in Human Immunodeficiency Virus (HIV) and Non-HIV Immunocompromised Patients.

Pneumocystis jirovecii pneumonia is an opportunistic fungal infection that was mainly associated with pneumonia in patients with advanced human immunodeficiency virus (HIV) disease. There has been a decline in Pneumocystis jirovecii pneumonia incidence in HIV since the introduction of antiretroviral medications. However, its incidence is increasing in non-HIV immunocompromised patients including those with solid organ transplantation, hematopoietic stem cell transplantation, solid organ tumors, autoimmune deficiencies, and primary immunodeficiency disorders. We aim to review and summarize the etiology, epidemiology, clinical presentation, diagnosis, and management of Pneumocystis jirovecii pneumonia in HIV, and non-HIV patients. HIV patients usually have mild-to-severe symptoms, while non-HIV patients present with a rapidly progressing disease. Induced sputum or bronchoalveolar lavage fluid can be used to make a definitive diagnosis of Pneumocystis jirovecii pneumonia. Trimethoprim-sulfamethoxazole is considered to be the first-line drug for treatment and has proven to be highly effective for Pneumocystis jirovecii pneumonia prophylaxis in both HIV and non-HIV patients. Pentamidine, atovaquone, clindamycin, and primaquine are used as second-line agents. While several diagnostic tests, treatments, and prophylactic regimes are available at our disposal, there is need for more research to prevent and manage this disease more effectively.

The cytological diagnosis of Pneumocystis jiroveci pneumonia in bronchoalveolar lavage.

Objectives: Immunosuppressed individuals are more prone for opportunistic infections. Pneumocystis jiroveci pneumonia (PJP), previously known as Pneumocystis carinii pneumonia (PCP), is the most common opportunistic infection affecting people living with HIV. As PJP can cause life threatening serious infection to a patient, treatment should not be delayed for these cases. To study clinico-cytomorphological spectrum of PJP. Material and Methods: We analysed the clinical and detailed cytological features of 15 patients with PJP who were diagnosed on examination of bronchoalveolar lavage (BAL) fluid. Results: The mean age of the patients was 38.4 years (range 13 - 61 years). A total of seven patients were HIV positive; five patients were post renal transplant, and one patient was a known case of acute leukaemia on immunosuppression. Presence of foamy alveolar casts (FACs) was the distinctive feature and was noted in 14 out of 15 cases. We detected 14 out of 15 cases accurately in BAL fluid cytology. Conclusion: BAL cytology is one of the important modes of investigations which can detect PJP infection. The history of fever, cough, immunosuppression, bilateral haziness in the radiography of lung and the characteristic alveolar cast indicate the possibility of PJP infection. Cytology can provide early diagnosis and can reduce the mortality of immunocompromised patients.

Opportunistic infections associated with Janus kinase inhibitor treatment for rheumatoid arthritis: A structured literature review.

BACKGROUND: The availability of Janus kinase (JAK) inhibitors has transformed the management of rheumatoid arthritis (RA), helping patients achieve clinical remission. However, the emergence of opportunistic infections (OIs) associated with the use of JAK inhibitors has been reported. This structured literature review was conducted to summarize reports of OIs associated with JAK inhibitor treatment for RA in clinical trials. METHODS: Structured searches were performed in MEDLINE® and Embase® to identify relevant clinical trial data through March 2021. Bibliographic searches of recent reviews were also conducted, and gray literature searches were used to supplement key gap areas. Publications were screened, extracted, and quality assessed. Data were narratively synthesized. RESULTS: Following screening, 105 publications describing 62 unique clinical trials reporting the rates of OIs in RA patients treated with JAK inhibitors were included. Overall, the highest exposure-adjusted incidence rate was reported for herpes zoster (HZ) infection (any form), followed by OI (any) and tuberculosis based on limited data from clinical trials with approved doses of JAK inhibitors. Lack of head-to-head trials and differences in trial design preclude direct comparison across JAK inhibitors. Higher rates of OIs were noted in the Asian and Australian populations compared with the global population. Higher rates of OIs were also noted with increasing dose of JAK inhibitors in most clinical trial data. CONCLUSIONS: HZ was the most common OI reported among RA patients using all currently approved JAK inhibitors in clinical trials, although tuberculosis and other OIs were also reported. More long-term safety studies in the real-world setting are needed to compare the risk of OIs between various JAK inhibitors.

Fluorodeoxyglucose Positron Emission Tomography Imaging in Pneumocystis jiroveci Pneumonia.

Fever or pyrexia of unknown origin (PUO) is commonly defined as body temperature higher than 38.3°C on several occasions for a period of at least 3 weeks with uncertain diagnosis after initial routine obligatory investigations. In most cases of PUO, there is an uncommon presentation of a common disease which includes infection, noninfectious inflammatory diseases, malignancy, and miscellaneous causes. We present an interesting case of a 48-year-old man with PUO, who is a known case of multiple myeloma on immunosuppressive therapy, where 18F-fluorodeoxyglucose positron emission tomography-computed tomography was able to detect occult cause of infective etiology.

[Clinical Characteristic, Diagnosis and Treatment of Acute Lymphoblastic Leukemia Combined with Pneumocystis Carinii Pneumonia in Children].

OBJECTIVE: To investigate the clinical characteristics and treatment of pneumocystis carinii pneumonia (PCP) in children with acute lymphoblastic leukemia (ALL), in order to improve the early diagnosis and effective treatment. METHODS: Clinical data of five children with ALL developing PCP in the post-chemotherapy granulocyte deficiency phase were analyzed retrospectively. The clinical manifestations, laboratory tests, imaging findings, treatment methods and effect were summarized. RESULTS: The male-to-female ratio of the five children was 1∶4, and the median age was 5.5 (2.9-8) years old. All patients developed PCP during granulocyte deficiency phase after induction remission chemotherapy. The clinical manifestations were generally non-specific, including high fever, tachypnea, dyspnea, non-severe cough, and rare rales in two lungs (wet rales in two patients). Laboratory tests showed elevated C-reactive protein (CRP), serum procalcitonin (PCT), (1,3)-ß-D-glucan (BDG), lactate dehydrogenase (LDH) and inflammatory factors including IL-2R, IL-6 and IL-8. Chest CT showed diffuse bilateral infiltrates with patchy hyperdense shadows. Pneumocystis carinii(PC) was detected in bronchoalveolar lavage fluid (BALF) or induced sputum by high-throughput sequencing in all patients. When PCP was suspected, chemotherapy was discontinued immediately, treatment of trimethoprim-sulfame thoxazole (TMP-SMX) combined with caspofungin against PC was started, and adjunctive methylprednisolone was used. Meanwhile, granulocyte-stimulating factor and gammaglobulin were given as the supportive treatment. All patients were transferred to PICU receiving mechanical ventilation due to respiratory distress during treatment. Four children were cured and one died. CONCLUSION: PCP should be highly suspected in ALL children with high fever, dyspnea, increased LDH and BDG, and diffuse patchy hyperdense shadow or solid changes in lung CT. The pathogen detection of respiratory specimens should be improved as soon as possible. TMP/SMZ is the first-line drug against PCP, and the combination of Caspofungin and TMP/SMZ treatment for NH-PCP may have a better efficacy. Patients with moderate and severe NH-PCP may benefit from glucocorticoid.

Concurrent COVID-19 and pneumocystis carinii pneumonia in a patient subsequently found to have underlying hairy cell leukemia.

SARS-CoV-2 infection manifestation has great diversity and it becomes even greater while co-infection occurs or there is a serious underlying disease in an affected patient. In this case report, we present a case of a 71-year-old man who underwent a chest CT scan following the development of fever, weakness, and pulmonary symptoms. Chest CT scan showed segmental consolidation with centrilobular nodular infiltration, ground glass opacifications in the inferior segment of the left upper and lower lobes, and left lung pleural thickening which was atypical for either COVID-19 infection or pneumocystis carinii pneumonia but his SARS-CoV-2 PCR result was positive and he received COVID-19 treatment. His symptoms recurred after a few months with the same chest CT findings and subsequent bronchoalveolar lavage revealed the presence of pneumocystis carinii infection. Consequently, he received cotrimoxazole which caused improvement in symptoms, nonetheless splenomegaly and anemia remained in his clinical and laboratory investigation. Accordingly, bone marrow study and flow cytometry was done and confirmed the previously undiagnosed hairy cell leukemia. This case accentuates the fact that when we face atypical clinical or paraclinical features in a COVID-19 patient, we should explore for coinfection or unknown underlying diseases.

RNA Polymerase II Transcription in Pneumocystis: TFIIB from Pneumocystis carinii Can Replace the Transcriptional Functions of Fission Yeast Schizosaccharomyces pombe TFIIB In Vivo and In Vitro.

The Pneumocystis genus is an opportunistic fungal pathogen that infects patients with AIDS and immunocompromised individuals. The study of this fungus has been hampered due to the inability to grow it in a (defined media/pure) culture. However, the use of modern molecular techniques and genomic analysis has helped researchers to understand its complex cell biology. The transcriptional process in the Pneumocystis genus has not been studied yet, although it is assumed that it has conventional transcriptional machinery. In this work, we have characterized the function of the RNA polymerase II (RNAPII) general transcription factor TFIIB from Pneumocystis carinii using the phylogenetically related biological model Schizosaccharomyces pombe. The results of this work show that Pneumocystis carinii TFIIB is able to replace the essential function of S. pombe TFIIB both in in vivo and in vitro assays. The S. pombe strain harboring the P carinii TFIIB grew slower than the parental wild-type S. pombe strain in complete media and in minimal media. The S. pombe cells carrying out the P. carinii TFIIB are larger than the wild-type cells, indicating that the TFIIB gene replacement confers a phenotype, most likely due to defects in transcription. P. carinii TFIIB forms very weak complexes with S. pombe TATA-binding protein on a TATA box promoter but it is able to form stable complexes in vitro when S. pombe TFIIF/RNAPII are added. P. carinii TFIIB can also replace the transcriptional function of S. pombe TFIIB in an in vitro assay. The transcription start sites (TSS) of the endogenous adh gene do not change when P. carinii TFIIB replaces S. pombe TFIIB, and neither does the TSS of the nmt1 gene, although this last gene is poorly transcribed in vivo in the presence of P. carinii TFIIB. Since transcription by RNA polymerase II in Pneumocystis is poorly understood, the results described in this study are promising and indicate that TFIIB from P. carinii can replace the transcriptional functions of S. pombe TFIIB, although the cells expressing the P. carini TFIIB show an altered phenotype. However, performing studies using a heterologous approach, like this one, could be relevant to understanding the basic molecular processes of Pneumocystis such as transcription and replication.

Super-resolution reconstruction of pneumocystis carinii pneumonia images based on generative confrontation network.

OBJECTIVE: Pneumocystis carinii pneumonia, also known as pneumocystis carinii pneumonia (PCP), is an interstitial plasma cell pneumonia caused by pneumocystis spp. It is a conditional lung infectious disease. Because the early and correct diagnosis of PCP has a great influence on the prognosis of patients, the image processing of PCP's high-resolution CT (HRCT) is extremely important. Traditional image super-resolution reconstruction algorithms have difficulties in network training and artifacts in generated images. The super-resolution reconstruction algorithm of generative counter-networks can optimize these two problems well. METHODS: In this paper, the texture enhanced super-resolution generative adversarial network (TESRGAN) is based on a generative confrontation network, which mainly includes a generative network and a discriminant network. In order to improve the quality of image reconstruction, TESRGAN improved the structure of the Super-Resolution Generative Adversarial Network (SRGAN) generation network, removed all BN layers in SRGAN, and replaced the ReLU function with the LeakyReLU function as the nonlinear activation function of the network to avoid the disappearance of the gradient. EXPERIMENTAL RESULTS: The TESRGAN algorithm in this paper is compared with the image reconstruction results of Bicubic, SRGAN, Enhanced Deep Super-Resolution network (EDSR), and ESRGAN. Compared with algorithms such as SRGAN and EDSR, our algorithm has clearer texture details and more accurate brightness information without extending the running time. Our reconstruction algorithm can improve the accuracy of image low-frequency information. CONCLUSION: The texture details of the reconstruction result are clearer and the brightness information is more accurate, which is more in line with the requirements of visual sensory evaluation.

Interstitial pneumonia in immunocompetent laboratory rats caused by natural infection with Pneumocystis carinii.

Pneumocystis (P.) carinii is known to cause fatal pneumonia in immunocompromised rats. Cases of P. carinii interstitial pneumonia in immunocompetent rats have been shown histologically to present with perivascular lymphoid cuffs, which have previously been attributed to rat respiratory virus. This study aims to determine the prevalence and pathological characteristics of P. carinii in immunocompetent laboratory rats in experimental facilities in Japan. An epidemiological survey for this agent was performed using PCR to assess 1,981 immunocompetent rats from 594 facilities in Japan. We observed that 6 of the 1,981 rats (0.30%) from 4 out of 594 facilities (0.67%) were positive for P. carinii without infection of other known pathogens. Gross pulmonary lesions were found in 4 of the 6 affected rats. The lungs of these rats contained scattered dark red/gray foci. Histopathologically, the lungs exhibited interstitial pneumonia with lymphoid perivascular cuffs: Pneumocystis cysts were observed using Grocott's methenamine silver stain. To our knowledge, this report is the first to reveal the prevalence of natural P. carinii infection in immunocompetent laboratory rats in Japan.

Case Report: Successful treatment of severe pneumocystis carinii pneumonia in a case series of primary nephrotic syndrome after receiving anti-CD20 monoclonal antibody therapy.

Rituximab is emerging as a new steroid sparing agent in children with difficult-to-treat nephrotic syndrome due to its ability of depleting CD20-positive B cells. Life-threatening adverse events such as pneumocystis carinii pneumonia may occur even though it seems to be well tolerated. Since rituximab is wildly used in immune-mediated diseases, it is important to manage its severe adverse events. To explore the importance of early diagnosis and treatment of pneumocystis carinii pneumonia in children with primary nephrotic syndrome (PNS) after receiving rituximab therapy, we retrospectively analyzed the clinical data of PNS patients younger than 18 years old with pneumocystis carinii pneumonia who were hospitalized in our center. Clinical features and laboratory test results were retrieved from the electronic medical records. Severe pneumocystis carinii pneumonia occurred in one child with steroid resistant nephrotic syndrome and two with steroid dependent nephrotic syndrome patients after rituximab treatment. These patients were diagnosed in time by metagenomic next-generation sequencing (mNGS) for pathogen detection. Fortunately, all three patients survived after antifungal treatment and achieved complete remission eventually. In conclusion, early diagnosis by using mNGS and timely antifungal treatment is the key to successful management of pneumocystis carinii pneumonia in children with difficult-to-treat PNS.

Clinical analysis of pneumocystis pneumonia after kidney transplantation: a report of 13 cases / 中华器官移植杂志

Objective:To explore the clinical characteristics of pneumocystis carinii pneumonia (PCP) after kidney transplantation.Methods:From January 2020 to January 2022, clinical data were retrospectively reviewed for 13 renal transplant recipients with pneumocystis pneumonia diagnosed by metagenomics next generation sequencing (mNGS). There were 3 females and 10 males with an age range of (46±10) years.The median time of postoperative onset was 10(2-21) months; The major clinical manifestations included fever ( n=11), cough ( n=7), expectoration ( n=6) and dyspnea ( n=11). Paired t-test was employed for analyzing the laboratory results at admission and discharge. Results:The diagnosis was confirmed by the detection of NGS in alveolar lavage fluid or venous blood.The levels of G test, LDH test, total T lymphocyte absolute count (CD3+ Abs), inhibitory/cytotoxic T lymphocyte count (CD3+ CD8+ Abs) and auxiliary/induced T lymphocyte absolute count (CD3+ CD4+ Abs) were (543.27±440.49) pg/ml, (529.98±222.43)U/L and (191.92±119.42)/μl, (87.33±50.59)/μl and (106.92±87.42)/μl at admission and (69.58±50.21) pg/ml, (285.38±46.62 U/L), (888.58±672.99)/μl, (336.83±305.21)/μl and (520.08±388.76)/μl at discharge.The differences were statistically significant ( P<0.001, P=0.002, 0.006, 0.017, 0.005). All of them received compound sulfamethoxazole and caspofungin.Except for one death due to septic shock after 21-day treatment, 12 cases were cured. Conclusions:mNGS test is one of the important tool for an early diagnosis of PCP.Combined use of compound sulfamethoxazole and caspofungin is an effective anti-infective regimen.And immune function monitoring is vital for adjusting antibiotic and immunosuppressive regimens.

Nursing care of pneumocystis carinii pneumonia after liver transplantation in infants / 中国实用护理杂志

Objective:To explore the nursing points of pneumocystis carinii pneumonia after liver transplantation in infants.Methods:Strengthened artificial airway management for children to improve dyspnea. Adopted nasal high-flow humidifying oxygen therapy to correct hypoxemia. Implemented individual temperature management to effectively control high fever. Strengthened children′s medication management, predictive skin management, using the protective isolation and psychological nursing.Results:After timely treatment and careful nursing, the condition of the three children was improved, SpO 2 was maintained at 0.95-1.00, and the patients were discharged successfully. One patient with respiratory failure died of multiple organ failure due to the deterioration of the condition after receiving extracorporeal membrane oxygen and supportive treatment. Conclusions:The infants with pneumocystis carinii pneumonia after liver transplantation should strengthen airway management, correct hypoxia. At the same time to do a good job of symptomatic care, strengthen the observation of the condition, can promote the rehabilitation.