Critical care management and outcome of severe Pneumocystis pneumonia in patients with and without HIV infection

Pneumocystis pneumonia in intensive care: clinical spectrum, prophylaxis patterns, antibiotic treatment delay impact, and role of corticosteroids. A French multicentre prospective cohort study

PURPOSE

Severe Pneumocystis jirovecii pneumonia (PJP) requiring intensive care has been the subject of few prospective studies. It is unclear whether delayed curative antibiotic therapy may impact survival in these severe forms of PJP. The impact of corticosteroid therapy combined with antibiotics is also unclear.

METHODS

This multicentre, prospective observational study involving 49 adult intensive care units (ICUs) in France was designed to evaluate the severity, the clinical spectrum, and outcomes of patients with severe PJP, and to assess the association between delayed curative antibiotic treatment and adjunctive corticosteroid therapy with mortality.

RESULTS

We included 158 patients with PJP from September 2020 to August 2022. Their main reason for admission was acute respiratory failure (n = 150, 94.9%). 12% of them received antibiotic prophylaxis for PJP before ICU admission. The ICU, hospital, and 6-month mortality were 31.6%, 35.4%, and 40.5%, respectively. Using time-to-event analysis with a propensity score-based inverse probability of treatment weighting, the initiation of curative antibiotic treatment after 96 h of ICU admission was associated with faster occurrence of death [time ratio: 6.75; 95% confidence interval (95% CI): 1.48-30.82; P = 0.014]. The use of corticosteroids for PJP was associated with faster occurrence of death (time ratio: 2.48; 95% CI 1.01-6.08; P = 0.048).

CONCLUSION

This study showed that few patients with PJP admitted to intensive care received prophylactic antibiotic therapy, that delay in curative antibiotic treatment was common and that both delay in curative antibiotic treatment and adjunctive corticosteroids for PJP were associated with accelerated mortality.

Clinical course and prognostic factors of Pneumocystis pneumonia with respiratory failure in non-HIV patients

Background

Compared with Human Immunodeficiency Virus (HIV) patients, non-HIV patients with Pneumocystis pneumonia (PCP) have more rapid onset, more rapid progression, and higher mortality.

Objectives

To investigate the predictive value of variables obtained upon hospital admission for in-hospital death and 90-day outcomes in non-HIV-PCP patients with respiratory failure (RF).

Methods

This was a single center retrospective study in a tertiary care institution over 15 years. It included all adults inpatients (≥18 years old) with laboratory confirmed non-HIV-PCP with RF who were discharged or died from Peking University First Hospital between April 1st, 2007 and November 1st, 2022. Epidemiological, clinical, laboratory, imaging and outcome data were collected from patient records.

Results

In this study, a total of 146 non-HIV-PCP patients with RF were included. There were 57 patients (39%) died during hospitalization, 44 patients (53%) died in Intensive care unit (ICU). A total of 137 patients completed 90 days of follow-up, of which 58 (42.3%) died. The multivariable regression analysis revealed that a CD8+ T cell count <115/μl (P=0.009), bronchoalveolar lavage fluid (BALF)-neutrophil percentage ≥50% (P=0.047), the time from corticosteroids withdrawal to symptom onset ≤5 days (P=0.012), and the time from visit to initiation of sulfonamides ≥2 days (P=0.011) were independent risk factors for in-hospital death. Furthermore, a CD8+ T cell count < 115/μl (P=0.001) and the time from visit to initiation of sulfonamides therapy ≥2 days (P=0.033) was independently associated with 90-day all-cause death.

Conclusions

A low CD8+ T cell count in peripheral blood, a high percentage of BALF-neutrophils, a short time from corticosteroids withdrawal to symptom onset, and a long time from visit to initiation of sulfonamides are associated with poor prognosis in non-HIV-PCP patients with RF.

Pneumocystis pneumonia in French intensive care units in 2013-2019: mortality and immunocompromised conditions

PURPOSE

The recent epidemiology of Pneumocystis pneumonia (PCP) requiring intensive care unit (ICU) admission and the associated spectrum of immunocompromising conditions are poorly described.

METHODS

We analyzed all adult PCP cases admitted to French ICUs via the French medical database system (PMSI), over the period from 2013 to 2019.

RESULTS

French ICUs admitted a total of 4055 adult patients with PCP. Among all hospitalized PCP cases, the proportion requiring ICU admission increased from 17.8 in 2014 to 21.3% in 2019 (P < 0.001). The incidence of severe PCP rose from 0.85 in 2013 to 1.32/100,000 adult inhabitants in 2019 (P < 0.0001), primarily due to the proportion of HIV-negative patients that increased from 60.6% to 74.4% (P < 0.0001). Meanwhile, the annual number of severe PCP cases among patients with HIV infection remained stable over the years. In-hospital mortality of severe PCP cases was 28.5% in patients with HIV infection and 49.7% in patients without. Multivariable logistic analysis showed that patients with HIV infection had a lower adjusted risk of death than patients without HIV infection (Odds Ratio [OR]: 0.30, 95% confidence interval [95CI]: 0.17-0.55). Comorbidities or conditions strongly associated with hospital mortality included the patient's age, Simplified Acute Physiologic Score II, congestive heart failure, coagulopathy, solid organ cancer, and cirrhosis. A vast array of autoimmune inflammatory diseases affected 19.9% of HIV-negative patients.

CONCLUSIONS

The number of PCP cases requiring ICU admission in France has risen sharply. While the yearly count of severe PCP cases in HIV-infected patients has remained steady, this rise predominantly affects cancer patients, with a recent surge observed in patients with autoimmune inflammatory diseases, affecting one in five individuals.

Clinical and Radiological Features of Pneumocystis jirovecii Pneumonia in Children: A Case Series

BACKGROUND

Pneumocytis jirovecii pneumonia (PJP) has high mortality rates in immunocompromised children, even though routine prophylaxis has decreased in incidence. The aim of this case series is to present the radiological and clinical pathway of PJP in a pediatric population.

DESCRIPTION OF CASES

All PJP cases in non-HIV/AIDS patients diagnosed at Istituto Giannina Gaslini Pediatric Hospital in Genoa (Italy) from January 2012 until October 2022 were retrospectively evaluated. Nine cases were identified (median age: 8.3 years), and of these, 6/9 underwent prophylaxis with trimethoprim/sulfamethoxazole (TMP/SMX; five once-a-week schedules and one three times-a-week schedule), while 3/9 did not receive this. PJP was diagnosed by real-time PCR for P. jirovecii-DNA in respiratory specimens in 7/9 cases and two consecutive positive detections of β-d-glucan (BDG) in the serum in 2/9 cases. Most patients (6/8) had a CT scan with features suggestive of PJP, while one patient did not undergo a scan. All patients were treated with TMP/SMX after a median time from symptoms onset of 3 days. In 7/9 cases, empirical TMP/SMX treatment was initiated after clinical suspicion and radiological evidence and later confirmed by microbiological data. Clinical improvement with the resolution of respiratory failure and 30-day survival included 100% of the study population.

DISCUSSION

Due to the difficulty in obtaining biopsy specimens, PJP diagnosis is usually considered probable in most cases. Moreover, the severity of the clinical presentation often leads physicians to start TMP/SMX treatment empirically. BDG proved to be a useful tool for diagnosis, and CT showed good accuracy in identifying typical patterns. In our center, single-day/week prophylaxis was ineffective in high-risk patients; the three-day/week schedule would, therefore, seem preferable and, in any case, should be started promptly in all patients who have an indication of pneumonia.

Efficacy of initial caspofungin plus trimethoprim/sulfamethoxazole for severe PCP in patients without human immunodeficiency virus infection

BACKGROUND

The number of pneumocystis pneumonia (PCP) cases is increasing in immunocompromised patients without human immunodeficiency virus infection (HIV), causing serious morbidity with high mortality. Trimethoprim/sulfamethoxazole (TMP/SMZ) monotherapy has limited effectiveness in the treatment of PCP. Clinical data on whether initial caspofungin plus TMP/SMZ for this disease is superior to monotherapy in non-HIV-infected patients are limited. We aimed to compare the clinical effectiveness of these regimens for severe PCP in non-HIV patients.

METHODS

A retrospective study reviewed 104 non-HIV-infected patients with confirmed PCP in the intensive care unit between January 2016 and December 2021. Eleven patients were excluded from the study because TMP/SMZ could not be used due to severe hematologic disorders or clinical data were missing. All enrolled patients were divided into three groups according to different treatment strategies: Group 1 received TMP/SMZ monotherapy, Group 2 received caspofungin combined with TMP/SMZ as first-line therapy, and Group 3 initially received TMP/SMZ monotherapy and later received caspofungin as salvage therapy. The clinical characteristics and outcomes were compared among the groups.

RESULTS

A total of 93 patients met the criteria. The overall positive response rate of anti-PCP treatment was 58.06%, and the overall 90-day all-cause mortality rate was 49.46%. The median APACHE II score was 21.44. The concurrent infection rate was 74.19%, among whom 15.05% (n = 14) of those patients had pulmonary aspergillosis, 21.05% (n = 20) had bacteremia, and 23.65% (n = 22) had CMV infections. The patients who received initial caspofungin combination with TMP/SMZ had the best positive response rate (76.74%) compared to others (p = 0.001). Furthermore, the group that received initial caspofungin combined with TMP/SMZ had a 90-day all-cause mortality rate (39.53%) that was significantly different from that of the shift group (65.51%, p = 0.024), but this rate showed no statistically significant difference compared with that in the monotherapy group (48.62%, p = 0.322). None of the patients had serious adverse events from caspofungin therapy.

CONCLUSIONS

For non-HIV-infected patients with severe PCP, initial combination therapy with caspofungin and TMP/SMZ is a promising first-line treatment option compared with TMP/SMZ monotherapy and combination therapy as salvage therapy.

How to diagnose and treat a non-HIV patient with Pneumocystis jirovecii pneumonia (PCP)?

BACKGROUND

Pneumocystis jirovecii Pneumonia (PCP) incidence is increasing in non-HIV infected patients. In contrast to PCP in patients infected with HIV, diagnosis is often delayed, and illness is associated with an increased mortality.

OBJECTIVE

To provide a comprehensive review of clinical presentation, risk factors, diagnostic strategies, and treatment options of PCP in non-HIV-infected patients.

SOURCES

Web-based literature review on PCP for trials, meta-analyses and systematic reviews using PubMed. Restriction to English language was applied.

CONTENT

Common underlying conditions in non-HIV-infected patients with PCP are haematological malignancies, autoimmune and inflammatory diseases, solid organ or haematopoietic stem cell transplant and prior exposure to corticosteroids. New risk groups include patients receiving monoclonal antibodies and immunomodulating therapies. Non-HIV-infected patients with 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, radiological and mycological features. Immunofluorescence microscopy from bronchoalveolar lavage (BAL) or PCR testing CT imaging and evaluation of the clinical presentation are required. The established treatment regime consists of trimethoprim and sulfamethoxazole.

IMPLICATIONS

While the number of patients immunosuppressed for other causes than HIV is increasing, a simultaneous rise in PCP incidence is observed. In the group of non-HIV-infected patients, a rapid onset of symptoms, a more complex course, and a higher mortality rate are recorded. Therefore, 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 provide 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.

Prophylaxis for Pneumocystis carinii pneumonia in non-Hodgkin's lymphoma undergoing R-CHOP21 in China: a meta-analysis and cost-effectiveness analysis

OBJECTIVE

Rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone, once every 3 weeks (R-CHOP21) is commonly used in non-Hodgkin's lymphoma (NHL), but accompanied by Pneumocystis carinii pneumonia (PCP) as a fatal treatment complication. This study aims to estimate the specific effectiveness and cost-effectiveness of PCP prophylaxis in NHL undergoing R-CHOP21.

DESIGN

A two-part decision analytical model was developed. Prevention effects were determined by systemic review of PubMed, Embase, Cochrane Library and Web of Science from inception to December 2022. Studies reporting results of PCP prophylaxis were included. Enrolled studies were quality assessed with Newcastle-Ottawa Scale. Costs were derived from the Chinese official websites, and clinical outcomes and utilities were obtained from published literature. Uncertainty was evaluated through deterministic and probabilistic sensitivity analyses (DSA and PSA). Willingness-to-pay (WTP) threshold was set as US$31 315.23/quality-adjusted life year (QALY) (threefold the 2021 per capita Chinese gross domestic product).

SETTING

Chinese healthcare system perspective.

PARTICIPANTS

NHL receiving R-CHOP21.

INTERVENTIONS

PCP prophylaxis versus no prophylaxis.

MAIN OUTCOME MEASURES

Prevention effects were pooled as relative risk (RR) with 95% CI. QALYs and incremental cost-effectiveness ratio (ICER) were calculated.

RESULTS

A total of four retrospective cohort studies with 1796 participants were included. PCP risk was inversely associated with prophylaxis in NHL receiving R-CHOP21 (RR 0.17; 95% CI 0.04 to 0.67; p=0.01). Compared with no prophylaxis, PCP prophylaxis would incur an additional cost of US$527.61, and 0.57 QALYs gained, which yielded an ICER of US$929.25/QALY. DSA indicated that model results were most sensitive to the risk of PCP and preventive effectiveness. In PSA, the probability that prophylaxis was cost-effective at the WTP threshold was 100%.

CONCLUSION

Prophylaxis for PCP in NHL receiving R-CHOP21 is highly effective from retrospective studies, and routine chemoprophylaxis against PCP is overwhelmingly cost-effective from Chinese healthcare system perspective. Large sample size and prospective controlled studies are warranted.

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.

Targeting β-glucans, vital components of the Pneumocystis cell wall

β-glucan is the most abundant polysaccharide in the cell wall of Pneumocystis jirovecii, which has attracted extensive attention because of its unique immunobiological characteristics. β-glucan binds to various cell surface receptors, which produces an inflammatory response and accounts for its immune effects. A deeper comprehension of the processes by Pneumocystis β-glucan recognizes its receptors, activates related signaling pathways, and regulates immunity as required. Such understanding will provide a basis for developing new therapies against Pneumocystis. Herein, we briefly review the structural composition of β-glucans as a vital component of the Pneumocystis cell wall, the host immunity mediated by β-glucans after their recognition, and discuss opportunities for the development of new strategies to combat Pneumocystis.

Risk factors for Pneumocystis pneumonia with acute respiratory failure among kidney transplant recipients

PURPOSE

One of the rare life-threatening fungal infections is pneumocystis pneumonia (PCP). Immunocompromised patients are the main vulnerable population. We investigate the risk factors associated with the development of severe PCP infection with acute respiratory failure after kidney transplantation.

MATERIALS AND METHODS

This is a retrospective, single-center, case-control study. PCP patients who are kidney transplant recipients and required high-flow oxygen support or mechanical ventilation between March 2009 and February 2017 were included in the study. The comparison was conducted between the non-severe and severe PCP groups. To identify associated risk factors, we performed univariate and multivariate logistic regression.

RESULTS

Among the total 2,330 kidney transplant recipients, 50 patients (2.1%) were diagnosed with PCP. Of these, 27 patients (54.0%) had severe PCP and 7 patients (14.0%) died, all of them were severe PCP patients. In the severe PCP group, the time from transplantation to PCP diagnosis (23.4 ± 24.9 months vs. 13.7 ± 9.9 months, p = 0.090) was insignificantly faster than in the non-severe PCP group. According to multiple logistic regression analysis, the significant risk factors associated with severe PCP were as follows, age (odds ratios (OR) 1.07; 95% confidence intervals (CI): 1.01-1.13; p = 0.027), time from transplantation to PCP diagnosis (odds ratios (OR) 0.92; 95% confidence intervals (CI): 0.86-0.99; p = 0.024), lymphopenia (OR 6.48; 95% CI: 1.05-40.09; p = 0.044), and history of acute rejection within 1 year (OR 8.28; 95% CI: 1.29-53.20; p = 0.026).

CONCLUSION

Patients who have lymphopenia at the time of hospital admission or have been recently treated with acute rejection are more likely to progress to severe PCP, requiring intensive monitoring and aggressive treatment.

Is there a role for Pneumocystis jiroveci pneumonia prophylaxis in giant cell arteritis or polymyalgia rheumatica?

BACKGROUND

Pneumocystis jiroveci pneumonia (PJP) is an opportunistic fungal infection that affects immunocompromised patients. The objective of this study was to describe the incidence of PJP among patients with giant cell arteritis (GCA) or polymyalgia rheumatica (PMR).

METHODS

A retrospective cohort study of incident cases of GCA and PMR was conducted using claims data from the TriNetX database to describe the incidence of PJP during the first 6 months of therapy. Additionally, a systematic review was performed to identify other publications describing PJP among patients with GCA or PMR.

RESULTS

During 547 patient-years of follow-up time, no cases of PJP were identified among 1,168 cases of GCA (incident rate 0 per 1,000 person-years); during 7,446 patient-years of follow up time, one case of PJP was identified out of 15,575 cases of PMR (incident rate 0.07 cases per 1,000 patient-years). This patient was alive at last follow up. Our systematic review identified 1 case-control study, 4 cohort studies, and 18 case series / case reports of PJP among patients with GCA or PMR. The incident rate of PJP was reported from one additional study for GCA and was estimated at 0.08 cases per 1,000 person years; no additional cohort studies were identified for patients with PMR. Over the entirety of the published literature, the total number of cases identified among case series and case reports was 33, from which 4 total deaths were identified.

CONCLUSIONS

Patients with newly diagnosed GCA or PMR rarely develop PJP. Existing data does not support routine prescribing of PJP prophylaxis for either group of patients.

Pneumocystis pneumonia in COVID-19 patients: A comprehensive review

The admitted patients of intensive care units with coronavirus disease 2019 (COVID-19) meet the challenges of subsequent infections. Opportunistic fungal infections such as Pneumocystis pneumonia (PCP) are among the important factors in the context of COVID-19 patients affecting illness severity and mortality. We reviewed the literature on COVID-19 patients with PCP to identify features of this infection. Although studies confirmed at least the presence of one immunosuppressive condition in half of PCP patients, this disease can also occur in immunocompetent patients who developed the immunosuppressive condition during Covid-19 treatment. The major risk factors associated with COVID-19 patients with PCP can be considered low lymphocyte counts and corticosteroid therapy. Diagnostic and treatment options are complicated by the overlapping clinical and radiologic characteristics of PCP and COVID-19 pneumonia. Therefore, physicians should comprehensively evaluate high-risk patients for PCP prophylaxis.

The diagnostic value of metagenomic next-generation sequencing for identifying Pneumocystis jirovecii infection in non-HIV immunocompromised patients

Background

Pneumocystis jirovecii pneumonia (PJP) remains an important cause of morbidity and mortality in non-HIV immunocompromised patients especially in transplant recipients. But its diagnosis remains challenging due to the insuffificient performance of conventional methods for diagnosing Pneumocystis jirovecii(P. jirovecii) infection. Therefore, the auxiliary diagnostic function of metagenomics next-generation sequencing (mNGS) in clinical practice is worth of exploring.

Method

34 non-HIV immunocompromised patients who were diagnosed as PJP by clinical manifestations, imaging findings, immune status of the host, and Methenamine silver staining were tested by mNGS from October 2018 to December 2020 in Sichuan Provincial People’s Hospital. The clinical performances of mNGS for P. jirovecii infection diagnosis were also evaluated with genome reads abundance and comparing with other traditional diagnostic methods.

Results

We diagnosed a total of 34 non-HIV PJP patients by the clinical composite diagnosis. Our data shows that, compared with the clinical microbiological test, the detection rate of mNGS for P. jirovecii in non-HIV infected PJP patients is significantly higher than that of Methenamine silver staining and serum 1-3-β-D-glucan. mNGS can be used as an auxiliary diagnostic tool to help diagnosis. The number of reads mapped to the genome of P. jirovecii and the duration of patients from onset to sampling collection were statistically significant between the two groups (Reads>100 and Reads ≤ 100) (8days vs. 23days, p=0.020). In addition, univariate analysis showed that C-reactive protein (15.8mg/L vs.79.56mg/L, p=0.016), lactate dehydrogenase (696U/l vs. 494U/l, p=0.030) and procalcitonin (0.09ng/ml vs. 0.59ng/ml, p=0.028) was also statistically significant between the two groups.

Conclusions

An effective detection rate was achieved in PJP patients using mNGS testing of bronchoalveolar lavage fluid (BALF) or blood. The study also confirmed that the abundance of reads of P. jirovecii is related to the interval between the onset and sample collection. And the inflammation status during simultaneous mNGS detection might determine the abundance of pathogens. Hence, we conclude that the mNGS strategy could benefit disease diagnosis as well as treatment when complicated clinical infections appeared.

Pneumocystis jiroveci pneumonia prophylaxis in patients with autoimmune hepatitis

Content available: Author Interview and Audio Recording.

Metagenomic Next-Generation Sequencing Is Highly Efficient in Diagnosing Pneumocystis Jirovecii Pneumonia in the Immunocompromised Patients

Purposes

To explore the value of metagenomic next-generation sequencing (mNGS) in diagnosing pneumocystis jiroveciipneumonia (PJP) in the immunocompromised patients.

Methods

Data of 122 patients with PJP in an immunosuppressed state and 67 non-PJP patients were collected. The diagnostic efficacy of mNGS was compared with the conventional methods, including Gomori methenamine silver (GMS) staining and serum (1,3)-β-D-glucan (BDG). Changes of anti-microbial therapy for patients with PJP based on mNGS results were also reviewed.

Results

The diagnostic sensitivity of mNGS to PJP was higher than that of GMS and BDG (100% vs. 15 and 74.5%, p < 0.001). The diagnostic specificity (91.%) was lower than that of GMS (100%), and similar with BDG (89.6%). In addition to P. jirovecii, mNGS revealed co-pathogens like human β-herpesvirus 5, human γ-pesvirus 4, and some other opportunistic pathogens. The reads of mNGS were remarkably higher in BALF than in blood samples. Initial antimicrobial treatment was modified in 89.3% patients based on the mNGS results, and 74 cases (60.7%) were treated with anti-P. jirovecii therapy.

Conclusion

mNGS is highly efficient in diagnosing PJP and good at identifying pathogens in mixed infections.

A Clinically Applicable Nomogram for Predicting the Risk of Invasive Mechanical Ventilation in Pneumocystis jirovecii Pneumonia

Objective

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening disease associated with a high mortality rate among immunocompromised patient populations. Invasive mechanical ventilation (IMV) is a crucial component of treatment for PCP patients with progressive hypoxemia. This study explored the risk factors for IMV and established a model for early predicting the risk of IMV among patients with PCP.

Methods

A multicenter, observational cohort study was conducted in 10 hospitals in China. Patients diagnosed with PCP were included, and their baseline clinical characteristics were collected. A Boruta analysis was performed to identify potentially important clinical features associated with the use of IMV during hospitalization. Selected variables were further analyzed using univariate and multivariable logistic regression. A logistic regression model was established based on independent risk factors for IMV and visualized using a nomogram.

Results

In total, 103 patients comprised the training cohort for model development, and 45 comprised the validation cohort to confirm the model's performance. No significant differences were observed in baseline clinical characteristics between the training and validation cohorts. Boruta analysis identified eight clinical features associated with IMV, three of which were further confirmed to be independent risk factors for IMV, including age (odds ratio [OR] 2.615 [95% confidence interval (CI) 1.110-6.159]; p = 0.028), oxygenation index (OR 0.217 [95% CI 0.078-0.604]; p = 0.003), and serum lactate dehydrogenase level (OR 1.864 [95% CI 1.040-3.341]; p = 0.037). Incorporating these three variables, the nomogram achieved good concordance indices of 0.829 (95% CI 0.752-0.906) and 0.818 (95% CI 0.686-0.950) in predicting IMV in the training and validation cohorts, respectively, and had well-fitted calibration curves.

Conclusions

The nomogram demonstrated accurate prediction of IMV in patients with PCP. Clinical application of this model enables early identification of patients with PCP who require IMV, which, in turn, may lead to rational therapeutic choices and improved clinical outcomes.

Nomograms for Death from Pneumocystis jirovecii Pneumonia in HIV-Uninfected and HIV-Infected Patients

Purpose

Pneumocystis jirovecii pneumonia (PCP) is a major cause of death in immunocompromised patients. Many risk factors for poor prognosis have been reported, but few studies have created predictive models with these variables to calculate the death rate accurately. This study created nomogram models for the precise prediction of mortality risk in human immunodeficiency virus (HIV) uninfected and HIV-infected patients with PCP.

Patients and Methods

A retrospective study was performed over a 10-year period to evaluate the clinical characteristics and outcomes of PCP in HIV-uninfected and HIV-infected adults treated in Beijing, China from 2010 to 2019. Univariate and multivariate logistic regression analyses were used to identify mortality risk factors to create the nomograms. Nomogram models were evaluated by using a bootstrapped concordance index, calibration plots and receiver operating characteristic (ROC) curves.

Results

A total of 167 HIV-uninfected and 193 HIV-infected PCP patients were included in the study. Pneumothorax, duration of fever after admission, CD4+ T cells ≤100/µL and trimethoprim-sulfamethoxazole (TMP-SMX) combined with caspofungin (CAS) treatment were independent risk factors for death in HIV-uninfected PCP patients. We derived a well calibrated nomogram for mortality by using these variables. The area under the curve was 0.865 (95% confidence interval 0.799–0.931). Independent risk factors for death in HIV-infected PCP patients were pneumothorax, platelet (PLT) ≤80×10⁹/L, haemoglobin (HGB) ≤90 g/L, albumin (ALB), cytomegalovirus (CMV) coinfection and TMP-SMX combined with CAS treatment. The nomogram showed good discrimination, with a C-index of 0.904 and excellent calibration.

Conclusion

The nomograms which were derived may be useful tools for the precise prediction of mortality in HIV-uninfected and HIV-infected patients, but require validation in clinical practice.

Non-HIV-infected patients with Pneumocystis pneumonia in the intensive care unit: A bicentric, retrospective study focused on predictive factors of in-hospital mortality

BACKGROUND

The incidence of Pneumocystis pneumonia (PCP) among patients without human immunodeficiency virus (HIV) infection continues to increase. Here, we identified potential risk factors for in-hospital mortality among HIV-negative patients with PCP admitted to the intensive care unit (ICU).

METHODS

We retrospectively analyzed medical records of 154 non-HIV-infected PCP patients admitted to the ICU at Peking Union Medical College Hospital (PUMCH) and China-Japan Friendship Hospital (CJFH) from October 2012 to July 2020. Clinical characteristics were examined, and factors related to in-hospital mortality were analyzed.

RESULTS

A total of 154 patients were enrolled in our study. Overall, the in-hospital mortality rate was 65.6%. The univariate analysis indicated that nonsurvivors were older (58 vs. 52 years, P = 0.021), were more likely to use high-dose steroids (≥1 mg/kg/day prednisone equivalent, 39.62% vs. 55.34%, P = 0.047), receive caspofungin during hospitalization (44.6% vs. 28.3%, P = 0.049), require invasive ventilation (83.2% vs. 47.2%, P < 0.001), develop shock during hospitalization (61.4% vs. 20.8%, P < 0.001), and develop pneumomediastinum (21.8% vs. 47.2%, P = 0.001) and had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores on ICU admission (20.32 vs. 17.39, P = 0.003), lower lymphocyte counts (430 vs. 570 cells/μl, P = 0.014), and lower PaO2/FiO2 values (mmHg) on admission (108 vs. 147, P = 0.001). Multivariate analysis showed that age (odds ratio [OR] 1.03; 95% confidence interval [CI] 1.00-1.06; P = 0.024), use of high-dose steroids (≥1 mg/kg/day prednisone equivalent) during hospitalization (OR 2.29; 95% CI 1.07-4.90; P = 0.034), and a low oxygenation index on admission (OR 0.99; 95% CI 0.99-1.00; P = 0.014) were associated with in-hospital mortality.

CONCLUSIONS

The mortality rate of non-HIV-infected patients with PCP was high, and predictive factors of a poor prognosis were advanced age, use of high-dose steroids (≥1 mg/kg/day prednisone equivalent) during hospitalization, and a low oxygenation index on admission. The use of caspofungin during hospitalization might have no contribution to the prognosis of non-HIV-infected patients with PCP in the ICU.

Primary prophylaxis for Pneumocystis jirovecii pneumonia in patients receiving rituximab

BACKGROUND

Although previous studies suggested that rituximab increases the risk of Pneumocystis jirovecii pneumonia (PJP), it is uncertain whether its primary prophylaxis for PJP is justified.

RESEARCH QUESTION

Does the benefit of primary prophylaxis for PJP in patients receiving rituximab treatment outweigh the potential risk of the prophylaxis?

STUDY DESIGN AND METHODS

This retrospective study included 3524 patients (hematologic diseases=2500; rheumatic diseases=559; pre/post-solid organ transplantation=465) first exposed to rituximab between 2002 and 2018 in a tertiary referral center in South Korea. Patients were classified into a control group (n=2523) and a prophylaxis group (n=1001) according to the administration of prophylactic TMP-SMX during the first 28 days after the start of rituximab (intention-to-treat analysis). In addition, exposure to TMP-SMX was examined as a time-varying variable (time-varying analysis). Primary outcome was the prophylactic effect of TMP-SMX on the 1-year incidence of PJP. Inverse probability of treatment weights was applied to minimize the baseline imbalance. Secondary outcome included the incidence of adverse drug reactions (ADRs) related to TMP-SMX.

RESULTS

Over 2759.9 person-years, 92 PJP infections occurred, with a mortality rate of 27.2%. The prophylaxis group showed a significantly lower incidence of PJP (adjusted sub-distribution hazard ratio (aSHR), 0.20 [95% CI, 0.10-0.42]) than the control group. This result was consistent with the results of time-varying analysis, in which only one PJP infection occurred during TMP-SMX administration (aSHR, 0.01 [0.003-0.16]). The incidence of adverse drug reactions (ADRs) related to TMP-SMX was 18.1 (14.6-22.2)/100 person-years, and most were of mild-to-moderate severity. Based on ten severe ADRs, the number needed to harm was 101 (61.9-261.1), whereas the number needed to prevent one PJP infection was 32 (24.8-39.4).

INTERPRETATION

TMP-SMX prophylaxis significantly reduces PJP incidence with a tolerable safety profile in patients receiving rituximab treatment.

Epidemiology and clinical impact of respiratory co-infections at diagnosis of Pneumocystis jirovecii Pneumonia

OBJECTIVES

To describe the epidemiology and clinical impact of respiratory co-infections at diagnosis of Pneumocystis jirovecii Pneumonia (PcP).

METHODS

A retrospective observational study was conducted between January 2011 and April 2019 to evaluate respiratory co-infections at diagnosis of PcP patients, in two tertiary care hospitals. Respiratory co-infection was defined by the identification of pathogens from P. jirovecii-positive samples.

RESULTS

Of the 7 882 respiratory samples tested for P. jirovecii during the 8-year study period, 328 patients with final diagnosis of PcP were included in this study. Mean age was 56.7 ± 14.9 years, 193 (58.8%) were male, 74 (22.6%) had a positive HIV serology, 125 (38.1%) had a viral co-infections, 76 (23.2%) a bacterial co-infections and 90-day mortality was 25.3%. In overall population, 90-Day mortality was independently associated with a solid tumor underlying disease (OR 11.8, 1.90-78, p=0.008), SOFA score at admission (OR 1.62, 1.34-2.05; p<0.001) and CMV respiratory co-infection (OR 3.44, 1.24-2.90; p=0.02). Among HIV-negative patients, respiratory CMV co-infection was associated with a worse prognosis, especially when treated with adjunctive corticosteroid therapy.

CONCLUSIONS

Respiratory CMV co-infection at diagnosis of PcP was independently associated with increased 90-day mortality, specifically in HIV-negative patients.

A novel droplet digital polymerase chain reaction for diagnosis of Pneumocystis pneumonia (PCP)-a clinical performance study and survey of sulfamethoxazole-trimethoprim resistant mutations

Objectives To determine the performance of droplet digital polymerase chain reaction (ddPCR) assays in diagnosing Pneumocystis pneumonia (PCP), and to survey the sulfamethoxazole-trimethoprim (SMX-TMP) resistant mutations in our PCP cohort. Methods A prospective study was conducted from January 2017 to June 2018. Adult immunocompromised subjects with pneumonia were enrolled. Bronchoalveolar lavage fluid samples were obtained for standard microscopic testing and ddPCR to quantify the Pneumocystis MSG gene. DHPS and DHFR gene sequencings were performed to detect SMX-TMP resistance. Results Of 54 subjects, 12 had definite PCP, 7 had probable PCP, and 35 were non-PCP. In the PCP cohort, 10 (53%) had HIV infections. Using a cutoff value of ≥ 1.94 copies/µL, the ddPCR exhibited an overall sensitivity of 91.7% (61.5-99.8%) and specificity of 88.1% (74.4-96%). It showed a better performance when different cutoff values were used in subjects with HIV (≥ 1.80 copies/µL) and non-HIV (≥ 4.5 copies/µL). ROC curves demonstrated an AUC of 0.80 (95% CI, 0.56-1.0) for the HIV group, and 0.99 (95% CI, 0.95-1.0) for the non-HIV group. Of 16 PCP samples tested for DHPS- and DHFR-mutations, only DHPS mutations were detected (2). Most of the subjects, including those with DHPS mutations, demonstrated favorable outcomes. Conclusions The ddPCR exhibited a satisfactory diagnostic performance for PCP. Based on very limited data, the treatment outcomes of PCP did not seem to be affected by the DHPS mutations.

Pneumocystis jiroveci pneumonia with cytomegalovirus infection diagnosed by metagenomic next-generation sequencing in a patient with nephrotic syndrome: A case report

INTRODUCTION

Opportunistic infection with multiple pathogens currently has become less uncommon since the application of immunosuppressant or corticosteroid in non- Human immunodeficiency virus patients. However, the clinical diagnosis of the co-infection remains difficult since the uncertainty and deficiency of the microbiologic testing methods.

PATIENT CONCERNS

A 66-year-old male patient was admitted to our hospital with chest stuffiness, shortness of breath and elevated body temperature.

DIAGNOSIS

He was diagnosed with the co-infection of Pneumocystis jiroveci and cytomegalovirus by metagenomic next-generation sequencing of bronchoalveolar lavage fluid after bronchoscopy.

INTERVENTIONS

The patient was empirically treated with broad-spectrum antibiotics, trimethoprim/ sulfamethoxazole and ganciclovir in the beginning of the admission.

OUTCOMES

The condition of this patient was not improved even with the intervention at the early stage of the disease. His family requested discharge after 24 inpatient days.

LESSONS

This case highlights the application of metagenomic next-generation sequencing in the clinical diagnosis of pulmonary co-infection. Suitable prophylaxis, necessary clinical awareness and accurate diagnosis are indispensable for immunocompromised patients with pulmonary infection.

Rapid and precise diagnosis of pneumonia coinfected by Pneumocystis jirovecii and Aspergillus fumigatus assisted by next-generation sequencing in a patient with systemic lupus erythematosus: a case report

Background

Pneumocystis jirovecii and Aspergillus fumigatus, are opportunistic pathogenic fungus that has a major impact on mortality in patients with systemic lupus erythematosus. With the potential to invade multiple organs, early and accurate diagnosis is essential to the survival of SLE patients, establishing an early diagnosis of the infection, especially coinfection by Pneumocystis jirovecii and Aspergillus fumigatus, still remains a great challenge.

Case presentation

In this case, we reported that the application of next -generation sequencing in diagnosing Pneumocystis jirovecii and Aspergillus fumigatus coinfection in a Chinese girl with systemic lupus erythematosus (SLE). Voriconazole was used to treat pulmonary aspergillosis, besides sulfamethoxazole and trimethoprim (SMZ-TMP), and caspofungin acetate to treat Pneumocystis jirovecii infection for 6 days. On Day 10 of admission, her chest radiograph displayed obvious absorption of bilateral lung inflammation though the circumstance of repeated fever had not improved. Unfortunately, the patient discharged from the hospital since the financial burden, and during the follow-up, it was documented the patient died within one week after discharge.

Conclusions

This successful application of the next generation sequencing assisting the rapid diagnosis of Pneumocystis jirovecii and Aspergillus fumigatus coinfection provides a new perspective in the clinical approach against the systematic fungi infections and highlights the potential of this technique in rapid etiological diagnosis.

Detection of Pneumocystis jirovecii from Clinical Specimens Utilizing a TaqMan-Based Real-Time PCR Assay on the Luminex ARIES

Pneumocystis jirovecii can cause severe pneumonia in immunocompromised patients, which can be life threatening if left untreated. Despite the widespread use of polymerase chain reaction (PCR) within the clinical laboratory setting, FDA-approved PCR assays are not readily available for the detection of Pneumocystis from respiratory samples. Using the Luminex ARIES system-an open-channel, automated, sample-to-answer PCR platform-the cell division cycle 2 (cdc-2) gene can be targeted for the detection of Pneumocystis. This novel TaqMan-based, real-time PCR assay offers improved sensitivity compared to staining or immunofluorescence while reducing turnaround time and eliminating the challenges surrounding microscopic identification. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Primer/probe master mix preparation Basic Protocol 2: Positive control (cdc-2) plasmid preparation Basic Protocol 3: Mucus digestion Basic Protocol 4: Cell lysis Basic Protocol 5: Carrier RNA/proteinase K preparation Basic Protocol 6: Cassette assembly Basic Protocol 7: Running the assay Basic Protocol 8: Interpreting results.

Narrative review of the relationship between COVID-19 and PJP: does it represent coinfection or colonization?

Background

Pneumocystis jirovecii (P. jirovecii) is increasingly identified on lower respiratory tract specimens of COVID-19 patients. Our narrative review aims to determine whether the diagnosis of pneumocystis jirovecii pneumonia (PJP) in COVID-19 patients represents coinfection or colonization based on the evidence available in the literature. We also discuss the decision to treat COVID-19 patients with coinfection by PJP.

Methods

A literature search was performed through the Pubmed and Web of Science databases from inception to March 10, 2021.

Results

We identified 12 COVID-19 patients suspected to have PJP coinfection. All patients were critically ill and required mechanical ventilation. Many were immunosuppressed from HIV or long-term corticosteroids and other immunosuppressive agents. In both the HIV and non-HIV groups, severe lymphocytopenia was encountered with absolute lymphocyte and CD4+T cell count less than 900 and 200 cells/mm, respectively. The time to PJP diagnosis from the initial presentation was 7.8 (range 2–21) days. Serum lactate dehydrogenase and beta-D-glucan were elevated in those coinfected with PJP. All patients were treated with anti-PJP therapy, predominantly sulfamethoxazole-trimethoprim with corticosteroids. The overall mortality rate was 41.6%, and comparable for both HIV and non-HIV groups.

Conclusion

As the current evidence is restricted to case reports, the true incidence, risk factors, and prognosis of COVID-19 patients with PJP coinfections cannot be accurately determined. Comorbidities of poorly controlled HIV with lymphocytopenia and multiple immunosuppressive therapies are likely predisposing factors for PJP coinfection.

Prevention of infective complications in systemic lupus erythematosus: A systematic literature review for the APLAR consensus statements

Systemic lupus erythematosus (SLE) is a more common autoimmune rheumatic disease in the Asia-Pacific region. The prognosis of SLE remains unsatisfactory in some Asian countries because of delayed diagnosis, limited access to medications, increased complications and issues of tolerability and adherence to treatment. The Asia-Pacific League of Associations for Rheumatology SLE special interest group has recently published a set of consensus recommendations on the management of SLE for specialists, family physicians, specialty nurses, and other healthcare professionals in the Asia-Pacific region. This article reports a systematic literature review of the infective complications of SLE in Asia and evidence for prevention of these infections by pre-emptive antimicrobial therapy and vaccination.

Pneumocystis jirovecii Disease: Basis for the Revised EORTC/MSGERC Invasive Fungal Disease Definitions in Individuals Without Human Immunodeficiency Virus

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) causes substantive morbidity in immunocompromised patients. The EORTC/MSGERC convened an expert group to elaborate consensus definitions for Pneumocystis disease for the purpose of interventional clinical trials and epidemiological studies and evaluation of diagnostic tests.

METHODS

Definitions were based on the triad of host factors, clinical-radiologic features, and mycologic tests with categorization into probable and proven Pneumocystis disease, and to be applicable to immunocompromised adults and children without human immunodeficiency virus (HIV). Definitions were formulated and their criteria debated and adjusted after public consultation. The definitions were published within the 2019 update of the EORTC/MSGERC Consensus Definitions of Invasive Fungal Disease. Here we detail the scientific rationale behind the disease definitions.

RESULTS

The diagnosis of proven PCP is based on clinical and radiologic criteria plus demonstration of P. jirovecii by microscopy using conventional or immunofluorescence staining in tissue or respiratory tract specimens. Probable PCP is defined by the presence of appropriate host factors and clinical-radiologic criteria, plus amplification of P. jirovecii DNA by quantitative real-time polymerase chain reaction (PCR) in respiratory specimens and/or detection of β-d-glucan in serum provided that another invasive fungal disease and a false-positive result can be ruled out. Extrapulmonary Pneumocystis disease requires demonstration of the organism in affected tissue by microscopy and, preferably, PCR.

CONCLUSIONS

These updated definitions of Pneumocystis diseases should prove applicable in clinical, diagnostic, and epidemiologic research in a broad range of immunocompromised patients without HIV.

Using Routine Laboratory Markers and Immunological Indicators for Predicting Pneumocystis jiroveci Pneumonia in Immunocompromised Patients

Background

Pneumocystis jiroveci pneumonia (PJP) is the most common opportunistic infection in immunocompromised patients. The accurate prediction of PJP development in patients undergoing immunosuppressive therapy remains challenge.

Methods

Patients undergoing immunosuppressive treatment and with confirmed pneumocystis jiroveci infection were enrolled. Another group of matched patients with immunosuppressant treatment but without signs of infectious diseases were enrolled to control group.

Results

A total of 80 (40 PJP, 40 non-PJP) participants were enrolled from Tongji Hospital. None of the patients were HIV positive. The routine laboratory indicators, such as LYM, MON, RBC, TP, and ALB, were significantly lower in PJP patients than in non-PJP patients. Conversely, LDH in PJP patients was significantly higher than in non-PJP controls. For immunological indicators, the numbers of T, B, and NK cells were all remarkably lower in PJP patients than in non-PJP controls, whereas the functional markers such as HLA-DR, CD45RO and CD28 expressed on CD4⁺ or CD8⁺ T cells had no statistical difference between these two groups. Cluster analysis showing that decrease of host immunity markers including CD3⁺, CD4⁺ and CD8⁺ T cells, and increase of tissue damage marker LDH were the most typical characteristics of PJP patients. A further established model based on combination of CD8⁺ T cells and LDH showed prominent value in distinguishing PJP from non-PJP, with AUC of 0.941 (95% CI, 0.892-0.990).

Conclusions

A model based on combination of routine laboratory and immunological indicators shows prominent value for predicting the development of PJP in HIV-negative patients undergoing immunosuppressive therapy.

Performance of Existing Definitions and Tests for the Diagnosis of Invasive Fungal Diseases other than Invasive Candidiasis and Invasive Aspergillosis in Critically Ill, Adult Patients: A Systematic Review with Qualitative Evidence Synthesis

The Fungal Infections Definitions in Intensive Care Unit (ICU) patients (FUNDICU) project aims to provide standard sets of definitions for invasive fungal diseases (IFDs) in critically ill, adult patients, including invasive aspergillosis (IA), invasive candidiasis (IC), Pneumocystis jirovecii pneumonia (PJP), and other non-IA, non-IC IFDs. The first step of the project was the conduction of separated systematic reviews of the characteristics and applicability to critically ill, adult patients outside classical populations at risk (hematology patients, solid organ transplant recipients) of available definitions and diagnostic tests for IFDs. We report here the results of two systematic reviews exploring the performance of available definitions and tests, for PJP and for other non-IA, non-IC IFDs. Starting from 2585 and 4584 records for PJP and other IFDs, respectively, 89 and 61 studies were deemed as eligible for full-text evaluation. However, only two studies for PJP and no studies for other IFDs met the FUNDICU protocol criteria for inclusion in qualitative synthesis. Currently, there is no sufficient solid data for directly evaluating the performance of existing definitions and laboratory tests for the diagnosis of PJP and other non-IA, non-IC IFDs in critically ill adult patients outside classical populations at risk.

Clinical characteristics and prognosis of patients with Pneumocystis jirovecii pneumonia without a compromised illness

Objective

Pneumocystis jirovecii pneumonia (PCP) is a fatal respiratory infection, mostly associated with immunocompromised conditions. Several reports have described PCP development in patients who were not immunocompromised, but the clinical course and prognosis of PCP are not well understood. We compared the clinical characteristics and prognoses between patients with and without immunocompromised conditions who developed PCP.

Methods

We retrospectively analyzed patients who had been treated for PCP from three hospitals. We defined immunocompromised (IC) status as following: human immunodeficiency virus (HIV) infection; hematological malignancy; solid organ tumor under chemotherapy; rheumatic disease; medication with immunosuppressive agents. Patients without immunocompromised status were defined as being non-immunocompromised (non-IC).

Results

The IC and non-IC groups comprised 173 and 14 patients. The median ages were 62.0 and 74.0 years in the IC and the non-IC group, respectively. The median interval between admission and anti-PCP treatment was significantly longer for patients in the non-IC group than that for patients in the IC group (7 vs. 2 days). The in-hospital mortality rates were significantly higher for patients in the non-IC group than that for patients in the IC group (71.4% vs. 43.9%; P = 0.047). A longer interval between admission and anti-PCP therapy was associated with increased 90-day mortality rate in patients with PCP (hazard ratio, 1.082; 95% confidence interval, 1.015–1.153; P = 0.016).

Conclusions

Patients with PCP with no predisposing illnesses were older and had higher mortality rates than IC patients with PCP. Delayed anti-PCP treatment was associated with increased 90-day mortality.

Pneumocystis Jirovecii Pneumonia in a Kidney Transplant Recipient 13 Months after Transplantation: A Case Report and Literature Review

Summary. Background.

Pneumocystis jirovecii pneumonia (PCP) is an opportunistic and prevalent fungal infection in immunocompromised hosts, including patients after kidney transplantation (KTx). It is a life threatening infection. While with effective prophylaxis it became less common, it still remains an issue among solid organ transplant (SOT) recipients during the first year. There are no specific clinical signs for PCP. Computed tomography (CT) is a better method for detecting PCP, but definite diagnosis can only be made by identification of the microorganism either by a microscopy or by a polymerase chain reaction (PCR).

Clinical case.

We present a case of a 17 year old with severe PCP 13 months after KTx followed by reduction in kidney function and respiratory compromise. The pathogen was detected by PCR from bronchoalveolar lavage fluid (BALF) and patient was treated successfully with trimethoprim-sulfamethoxazole (TMPSMX). Patient’s condition, respiratory status and kidney function gradually improved. Our presented case is unusual because patient had no known risk factors for PCP and he was more than one year after KTx, what is considered rare. In addition patient and his parents delayed in notifying the treating physician about ongoing symptoms because did not deem them important enough.

Conclusions.

Clinicians treating patients in risk groups for PCP must always remain vigilant even in era of effective prophylaxis. The vigilance should also extend to the patient and patient’s family.

Characteristics and outcome according to underlying disease in non-AIDS patients with acute respiratory failure due to Pneumocystis pneumonia

In the non-AIDS group, several underlying conditions and immune defects could lead to different PCP presentations. This study compared PCP presentation and outcome according to the underlying disease. A secondary analysis of a previously published prospective observational study including 544 PCP patients was done. Only non-AIDS patients were included. Underlying disease was defined as chronic lymphocytic leukemia (CLL), organ transplantation, solid cancer, allogeneic hematopoietic stem cell transplant (AHSCT), other hematological diseases, and immunosuppressive treatment. Clinical characteristics and outcomes were compared between groups. Multiple correspondent analyses compared clinical characteristics at diagnosis. Day 30 mortality was analyzed. Three hundred and twenty-one patients were included in the study. The underlying diseases were hematological malignancy (n = 75), AHSCT (n = 14), CLL (n = 19), solid organ transplant (n = 94), solid tumor (n = 39), and immunosuppressive treatment (n = 57). Compared with other underlying diseases, PCP related to CLL was closer to PCP related to AIDS presentation (long duration of symptoms before diagnosis, high level of dyspnea, and low oxygen saturation at diagnosis). Day 30 mortality was associated with underlying disease, oxygen flow, and shock at ICU admission. PCP presentations may vary according to the underlying reason for immunosuppression. Response to treatment and adjuvant steroid therapy should be analyzed regarding this result.

Caspofungin combined with TMP/SMZ as a first-line therapy for moderate-to-severe PCP in patients with human immunodeficiency virus infection

OBJECTIVES

The effectiveness of trimethoprim/sulfamethoxazole (TMP/SMZ) for pneumocystis pneumonia (PCP) is limited with adverse events. Caspofungin, by inhibiting the cyst form of Pneumocystis jirovecii, may be an alternative therapy for PCP. However, the availability of clinical data about caspofungin combined with TMP/SMZ in the treatment of PCP in HIV-infected patients is limited. Thus, we aimed to examine the clinical effectiveness and safety of caspofungin combined with TMP/SMZ as a first-line therapy for moderate-to-severe PCP in HIV-infected patients.

METHODS

From January 2017 to December 2019, data of HIV-infected patients with moderate-to-severe PCP who received either TMP/SMZ alone or caspofungin combined with TMP/SMZ as first-line therapy were retrospectively reviewed to assess the effectiveness and safety of each regimen. The Kaplan-Meier curve and log-rank test were used for survival analysis.

RESULTS

A total of 278 patients met the criteria. The overall positive response rate of PCP treatment was 48.92%, and the overall all-cause in-hospital mortality rate was 33.09%. Patients who received combination therapy consisting of caspofungin and TMP/SMZ had a better positive response rate (59.44% vs. 37.78%, P < 0.001) and lower all-cause in-hospital mortality rate (24.48% vs. 42.22%, P = 0.003). Also, patients who received combination therapy had higher survival rate during a hospital stay (75.52% vs. 57.78%, P = 0.004), and those who received longer combination therapy were more likely to have higher survival rate (P = 0.042). We found that age (P = 0.019), CD4 cell count (P = 0.001) and therapeutic regimen (P = 0.002) were significant risk factors for all-cause in-hospital mortality rate in univariate analysis. In multivariate analysis, only CD4 cell count and therapeutic regimen were statistically significant factors associated with all-cause in-hospital mortality rate. Patients with a CD4 count of > 30 cells/µL and patients who received combination therapy consisting of caspofungin and TMP/SMZ were more likely to survive from PCP (P = 0.011 and P = 0.002, respectively). There were no additional severe adverse events caused by adding caspofungin.

CONCLUSIONS

For HIV-infected patients with moderate-to-severe PCP, combination therapy with caspofungin and TMP/SMZ is an effective and promising first-line therapy with no greater number of adverse events compared with TMP/SMZ monotherapy. Patients who received caspofungin had better positive response rates and lower all-cause in-hospital mortality rates. Also, we recommend early initiation of caspofungin.

Pneumocystis jirevocii and SARS-CoV-2 Co-Infection: A Common Feature in Transplant Recipients?

COVID-19 might potentially give rise to a more severe infection in solid organ transplant recipients due to their chronic immunosuppression. These patients are at a higher risk of developing concurrent or secondary bacterial and fungal infections. Co-infections can increase systemic inflammation influencing the prognosis and the severity of the disease, and can in turn lead to an increased need of mechanical ventilation, antibiotic therapy and to a higher mortality. Here we describe, for the first time in Europe, a fatal case of co-infection between SARS-CoV-2 and Pneumocystis jirevocii in a kidney transplant recipient.

Molecular diagnosis of Pneumocystis pneumonia in immunocompromised patients

PURPOSE OF REVIEW

Pneumocystis pneumonia (PCP) is a frequent opportunistic infection associated with a high mortality rate. PCP is of increasing importance in non-HIV immunocompromised patients, who present with severe respiratory distress with low fungal loads. Molecular detection of Pneumocystis in broncho-alveolar lavage (BAL) has become an important diagnostic tool, but quantitative PCR (qPCR) needs standardization.

RECENT FINDINGS

Despite a high negative predictive value, the positive predictive value of qPCR is moderate, as it also detects colonized patients. Attempts are made to set a cut-off value of qPCR to discriminate between PCP and colonization, or to use noninvasive samples or combined strategies to increase specificity.

SUMMARY

It is easy to set a qPCR cut-off for HIV-infected patients. In non-HIV IC patients, a gain in specificity could be obtained by combining strategies, that is, qPCR on BAL and a noninvasive sample, or qPCR and serum beta-1,3-D-glucan dosage.

Possible Diagnostic Delays and Missed Prevention Opportunities in Pneumocystis Pneumonia Patients Without HIV: Analysis of Commercial Insurance Claims Data-United States, 2011-2015

Background

Pneumocystis pneumonia (PCP) is a life-threatening but treatable and preventable fungal infection in immunocompromised persons. Previous studies suggest that persons without HIV who develop PCP (PCPHIV-) experience more acute, severe illness than persons with HIV who develop PCP (PCPHIV+). We analyzed health insurance claims data to compare demographics, underlying conditions, symptoms, and prescriptions for PCPHIV+ and PCPHIV-.

Methods

We used the IBM MarketScan Research Databases to identify patients diagnosed with PCP during 2011-2015. We analyzed claims 1 year before to 3 months after diagnosis to compare PCPHIV+ and PCPHIV-.

Results

Among 3938 patients, 70.4% were PCPHIV-. Compared with PCPHIV+, PCPHIV- were more likely to be older (median, 60 vs 45 years; P < .0001), female (51.5% vs 20.2%; P < .0001), hypoxemic (13.5% vs 7.1%; P < .0001), and to die within 90 days (6.6% vs 4.2%; P < .0001). The most common underlying conditions among PCPHIV- included chronic pulmonary diseases (54.6%), solid tumors (35.1%), hematologic malignancies (20.1%), and rheumatologic conditions (14.0%). The median time between the first visit for PCP-related symptoms and PCP diagnosis was longer for PCPHIV- than PCPHIV+ (25 vs 16 days; P < .0001). In the 3 months before PCP diagnosis, PCPHIV- were less likely to have an outpatient prescription for PCP prophylaxis than PCPHIV+ (6.9% vs 10.6%; P = .0001).

Conclusions

PCPHIV- may experience a prolonged illness course and diagnostic delays compared with PCPHIV+. Clinicians should maintain a high index of suspicion for PCP in immunocompromised patients with compatible symptoms, regardless of HIV status.

Missed opportunity to diagnose HIV with Pneumocystis carinii pneumonia as its sequela

Pneumocystis carinii pneumonia (PCP) is an opportunistic infection of the lung occurring primarily in patients with HIV infection with a CD4 cell count <200 mm3, solid organ transplant recipients and those taking immunosuppressive therapy. The 1980s heralded the HIV pandemic, turning PCP into a major medical and public health problem worldwide. Manifestations of unusual infections such as pneumocystis and Kaposi's sarcoma, were, after all, the first signs of the emerging pandemic to be recognised and may indeed, be the presenting feature of a previously undiagnosed HIV infection. With the advent of pneumocystis chemoprophylaxis and the initiation of highly active antiretroviral therapy, there has been a decreased incidence in developed countries, but it remains high in developing countries. Unfortunately, late presentation of HIV remains a problem resulting in significant morbidity and mortality. The authors report the case of a new diagnosis of HIV infection in a 45-year-old woman, presenting with a dry cough, dyspnoea, unintentional weight loss and PCP. Two weeks after commencing highly active antiretroviral therapy, she was diagnosed with immune reconstitution inflammatory syndrome. Research shows that stigma and discrimination in the healthcare setting contributes to keeping individuals from accessing HIV prevention, care and treatment services and adopting key preventive behaviours. The barriers to HIV testing and stigma eradication in primary care will be explored as well as missed opportunities to diagnosis HIV in primary care in individuals presenting with signs and symptoms of immunosuppression, in this case shingles.

Pneumocystis jirovecii Pneumonia-Associated Acute Respiratory Distress Syndrome Complicated by Pneumomediastinum and Pneumopericardium in a Non-Human Immunodeficiency Virus-Infected Patient

Pneumocystis jirovecii pneumonia is widely known as a life-threatening opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). However, with the widespread use of highly active antiretroviral therapy (HAART) and effective anti-Pneumocystis antimicrobial prophylaxis, this entity has declined substantially in patients with human immunodeficiency virus (HIV) infection. Interestingly, the incidence of Pneumocystis jirovecii pneumonia has been increasing among patients without HIV infection, mainly as a consequence of the expanding use of chemotherapy and other immunosuppressive agents. Nevertheless, Pneumocystis jirovecii pneumonia remains an important cause of HIV- and non-HIV-related catastrophic complications. Pneumomediastinum and pneumopericardium are extremely uncommon events in patients with Pneumocystis jirovecii pneumonia. In this report, we described a unique case of Pneumocystis jirovecii pneumonia-associated acute respiratory distress syndrome (ARDS), complicated by pneumomediastinum and pneumopericardium in a non-HIV infected patient.

Pneumocystis jirovecii Pneumonia in Patients with Nephrotic Syndrome: Application of Lymphocyte Subset Analysis in Predicting Clinical Outcomes

Purpose

With immunosuppressants being widely used, Pneumocystis jirovecii pneumonia (PCP) has been increasing and could be life-threatening among HIV-negative patients. This study aimed at identifying prognostic factors of PCP in patients with nephrotic syndrome.

Methods

We retrospectively investigated patients with nephrotic syndrome who were diagnosed with PCP. The diagnosis of PCP was based on clinical manifestations, radiological findings, and microbiological confirmatory tests. Predictors of outcome were determined with multivariate logistic regression analysis.

Results

A total of 57 patients were included in this study. The PCP mortality was 33.3%, which increased to 48.6% if ICU admission was required and to 60% when mechanical ventilation was needed. The T lymphocyte count and CD4/CD8 ratio independently predicted the outcome of PCP, so did the CD4⁺ T lymphocyte count (OR, 0.981; 95% CI, 0.967–0.996; p=0.001). The cut-off value of 71 cells/μl for the CD4⁺ T lymphocyte count was determined to identify patients with poor prognosis. No association was found between PCP mortality and the type of immunosuppressant used.

Conclusions

PCP is a fatal complication among nephrotic syndrome patients receiving immunosuppressive therapy. The CD4⁺ T lymphocyte count is suggested as an independent predictor of prognosis, which can be used clinically to identify patients with high risk of unfavorable outcomes.

Anidulafungin as an alternative treatment for Pneumocystis jirovecii pneumonia in patients who cannot tolerate trimethoprim/sulfamethoxazole

Evidence supporting the use of an echinocandin alone as an alternative agent for the treatment of Pneumocystis jirovecii pneumonia (PCP) is limited and controversial. This retrospective cohort study was conducted at National Taiwan University Hospital from 1 July 2015 to 31 December 2017. Using multivariable Cox regression analyses, the outcomes of patients receiving trimethoprim/sulfamethoxazole (TMP-SMZ) or anidulafungin single therapy as an alternative treatment for PCP were investigated. A total of 207 patients with PCP were screened and 170 patients were included in the final analysis, among whom 134 (78.8%) received TMP-SMZ and 36 (21.2%) received anidulafungin as alternative anti-PCP treatment. Overall 60-day mortality was 34.1% (58/170), and 60-day mortality did not differ significantly between the anidulafungin group (38.9%; 14/36) and the TMP-SMZ group (32.8%; 44/134) (P = 0.554). Age ≥60 years [hazard ratio (HR) = 1.840, 95% confidence interval (CI) 1.039-3.259; P = 0.036] and HIV infection (HR = 0.102, 95% CI 0.013-0.771; P = 0.027) independently predicted 60-day mortality. Patients with lower SpO₂/FiO₂ ratio (HR = 0.994, 95% CI 0.990-0.998; P = 0.005) showed a higher 60-day mortality. In the Kaplan-Meier survival analysis, anidulafungin as alternative anti-PCP treatment was not correlated with higher mortality (P = 0.605). Using TMP-SMZ or anidulafungin as alternative anti-PCP treatment had similar 60-day mortality. These findings suggest that anidulafungin therapy may be an effective and alternative treatment for PCP in patients who cannot tolerate TMP-SMZ.

Ground Glass Opacity with Mixed Consolidation on Chest Computed Tomography Reflects the Severe Condition of Pneumocystis Pneumonia in Association with a Poor Prognosis in Patients with Connective Tissue Diseases

Objective Pneumocystis pneumonia (PCP) is a serious fungal infection that can be life threatening in immunocompromised hosts. We evaluated the association between the radiological patterns of PCP on high-resolution computed tomography (HRCT) and clinical characteristics and the prognosis of patients with connective tissue disease (CTD). Methods All CTD patients who developed PCP from January 1999 to April 2017 were retrospectively evaluated. Patients were divided into three groups based on their chest HRCT findings: Ground glass opacity (GGO) sharply demarcated from the adjacent normal lung by interlobular septa (demarcated GGO), diffuse GGO without obvious demarcation (diffuse GGO), and GGO with mixed consolidation (mixed GGO). We compared the clinical characteristics at the onset of PCP and the outcomes among the groups. Results A total of 35 cases were identified: demarcated GGO (n=8, 23%), diffuse GGO (n=19, 54%), and mixed GGO (n=8, 23%). The mixed GGO group showed a higher serum C-reactive protein level (p<0.0001), lower lymphocyte count (p=0.07), lower serum albumin (p<0.001), and lower partial pressure of arterial oxygen/fraction of inspiratory oxygen ratios (p<0.001) in comparison to the demarcated and diffuse GGO groups. The mixed GGO group showed significantly higher mortality in comparison to the demarcated and diffuse GGO groups (88% vs. 7%, p<0.0001). Conclusion GGO with mixed consolidation on chest HRCT was associated with a poor outcome of PCP in patients with CTD.

Outcome and prognostic factors of Pneumocystis jirovecii pneumonia in immunocompromised adults: a prospective observational study

Background

Pneumocystis jirovecii pneumonia (PJP) remains a severe disease associated with high rates of invasive mechanical ventilation (MV) and mortality. The objectives of this study were to assess early risk factors for severe PJP and 90-day mortality, including the broncho-alveolar lavage fluid cytology profiles at diagnosis.

Methods

We prospectively enrolled all patients meeting pre-defined diagnostic criteria for PJP admitted at Nantes university hospital, France, from January 2012 to January 2017. Diagnostic criteria for PJP were typical clinical features with microbiological confirmation of P. jirovecii cysts by direct examination or a positive specific quantitative real-time polymerase chain reaction (PCR) assay. Severe PJP was defined as hypoxemic acute respiratory failure requiring high-flow nasal oxygen with at least 50% FiO₂, non-invasive ventilation, or MV.

Results

Of 2446 respiratory samples investigated during the study period, 514 from 430 patients were positive for P. jirovecii. Of these 430 patients, 107 met criteria for PJP and were included in the study, 53 (49.5%) patients had severe PJP, including 30 who required MV. All patients were immunocompromised with haematological malignancy ranking first (n = 37, 35%), followed by solid organ transplantation (n = 27, 25%), HIV-infection (n = 21, 20%), systemic diseases (n = 13, 12%), solid tumors (n = 12, 11%) and primary immunodeficiency (n = 6, 8%). By multivariate analysis, factors independently associated with severity were older age (OR, 3.36; 95% CI 1.4–8.5; p < 0.05), a P. jirovecii microscopy-positive result from bronchoalveolar lavage (BAL) (OR, 1.3; 95% CI 1.54–9.3; p < 0.05); and absence of a BAL fluid alveolitis profile (OR, 3.2; 95% CI 1.27–8.8; p < 0.04). The 90-day mortality rate was 27%, increasing to 50% in the severe PJP group. Factors independently associated with 90-day mortality were worse SOFA score on day 1 (OR, 1.05; 95% CI 1.02–1.09; p < 0.001) whereas alveolitis at BAL was protective (OR, 0.79; 95% CI 0.65–0.96; p < 0.05). In the subgroup of HIV-negative patients, similar findings were obtained, then viral co-infection were independently associated with higher 90-day mortality (OR, 1.25; 95% CI 1.02–1.55; p < 0.05).

Conclusions

Older age and P. jirovecii oocysts at microscopic examination of BAL were independently associated with severe PJP. Both initial PJP severity as evaluated by the SOFA score and viral co-infection predicted 90-day mortality. Alveolitis at BAL examination was associated with less severe PJP. The pathophysiological mechanism underlying this observation deserves further investigation.

Changing Trends in the Epidemiology and Risk Factors of Pneumocystis Pneumonia in Spain

Objective: The information about the epidemiology of Pneumocystis pneumonia (PcP) in Europe is scarce, and in Spain there are only data nationwide on patients with HIV infection. This study has been carried out with the aim of knowing in our country the current epidemiological spectrum and the risk factors of PcP.

Methods: Observational, descriptive transversal study that included all patients admitted in Spain with diagnosis upon discharge of PcP registered in the National Health System's Hospital Discharge Records Database of Spain, between 2008 and 2012.

Results: Four thousand five hundred and fifty four cases of PcP were reported, 1,204 (26.4%) in HIV-negative patients. During the study period, mean annual incidence (cases per million) was 19.4, remaining globally stable, increasing from 4.4 to 6.3 in HIV-negative patients and decreasing from 15.5 to 13.4 among HIV-infected patients. Risk factors were identified in 85.5% of HIV-negative cases, the most frequent being hematological neoplams (29%), chronic lung diseases (15.9%), and non-hematological cancers (14.9%). Mean mortality and hospitalization cost were high (25.5% and 12,000 euros, respectively).

Conclusions: The results of this first nationwide study in Spain allow a change in the misconception that, after the AIDS epidemic, PcP is an infrequent disease, showing that today it is an emerging problem in patients without HIV infection. These findings underlines the need for increased efforts toward a better characterization of risk groups to improve prophylactic strategies and reduce the burden of disease.

Association of time-to-treatment with outcomes of Pneumocystis pneumonia with respiratory failure in HIV-negative patients

Background

The prevalence of pneumocystis pneumonia (PCP) and associated hypoxic respiratory failure is increasing in human immunodeficiency virus (HIV)-negative patients. However, no prior studies have evaluated the effect of early anti-PCP treatment on clinical outcomes in HIV-negative patient with severe PCP. Therefore, this study investigated the association between the time to anti-PCP treatment and the clinical outcomes in HIV-negative patients with PCP who presented with hypoxemic respiratory failure.

Methods

A retrospective observational study was performed involving 51 HIV-negative patients with PCP who presented in respiratory failure and were admitted to the intensive care unit between October 2005 and July 2018. A logistic regression model was used to adjust for potential confounding factors in the association between the time to anti-PCP treatment and in-hospital mortality.

Results

All patients were treated with appropriate anti-PCP treatment, primarily involving trimethoprim/sulfamethoxazole. The median time to anti-PCP treatment was 58.0 (28.0–97.8) hours. Thirty-one (60.8%) patients were treated empirically prior to confirmation of the microbiological diagnosis. However, the hospital mortality rates were not associated with increasing quartiles of time until anti-PCP treatment (P = 0.818, test for trend). In addition, hospital mortality of patients received early empiric treatment was not better than those of patients received definitive treatment after microbiologic diagnosis (48.4% vs. 40.0%, P = 0.765). In a multiple logistic regression model, the time to anti-PCP treatment was not associated with increased mortality. However, age (adjusted OR 1.07, 95% CI 1.01–1.14) and failure to initial treatment (adjusted OR 13.03, 95% CI 2.34–72.65) were independently associated with increased mortality.

Conclusions

There was no association between the time to anti-PCP treatment and treatment outcomes in HIV-negative patients with PCP who presented in hypoxemic respiratory failure.

Combination of β-(1, 3)-D-glucan testing in serum and qPCR in nasopharyngeal aspirate for facilitated diagnosis of Pneumocystis jirovecii pneumonia

BACKGROUND

Currently, the biological diagnosis of Pneumocystis jirovecii pneumonia (PjP infection) usually relies on microbiological investigations in bronchial-alveolar lavage fluid (BALF) by conventional staining methods and/or molecular biology. However, bronchial-alveolar lavage is sometimes complicated to manage, especially in weakened patients. Therefore, alternative clinical samples-easier to collect-are warranted in such specific contexts.

OBJECTIVE

Over a four-year period, diagnostic performance of an original method based on combination of quantitative real-time polymerase chain reaction (qPCR) in nasopharyngeal aspirate (NPA) with measurement of β-(1, 3)-D-glucan antigen (BDG) in serum was prospectively assessed in a single centre.

PATIENTS/METHODS

Results were compared with those obtained in BALF through direct staining methods and qPCR. True positives were defined by an independent committee based on clinical, radiological and biological data. Overall, 48 individuals with a definitive diagnosis of PjP infection were included, and 48 controls were selected upon matching for age, sex and underlying disease(s).

RESULTS

qPCR results were strongly correlated between BALF and NPA (P < .0001). Altogether, greater diagnostic performance was achieved when establishing the positive cut-off of BDG antigen at 143 pg/mL. In such conditions, sensitivity of the testing based on either positive BDG measurement or positive qPCR in NPA was then calculated at 93.75%, _95% CI [82.37%-98.40%], and specificity at 97.87%, _95% CI [87.66%-100.00%].

CONCLUSIONS

Further validation through multicentre studies is now required, especially for establishing clear cut-offs. However, one could already state that combination of qPCR in the NPA with BDG measurement in serum may be a valuable substitute for BALF examination.

Transcriptomic and Proteomic Approaches to Finding Novel Diagnostic and Immunogenic Candidates in Pneumocystis

Pneumocystis pneumonia is the most common serious opportunistic infection in patients with HIV/AIDS. Furthermore, Pneumocystis pneumonia is a feared complication of the immunosuppressive drug regimens used to treat autoimmunity, malignancy, and posttransplantation rejection. With an increasing at-risk population, there is a strong need for novel approaches to discover diagnostic and vaccine targets. There are multiple challenges to finding these targets, however. First, Pneumocystis has a largely unannotated genome. To address this, we evaluated each protein encoded within the Pneumocystis genome by comparisons to proteins encoded within the genomes of other fungi using NCBI BLAST. Second, Pneumocystis relies on a multiphasic life cycle, as both the transmissible form (the ascus) and the replicative form (the trophozoite [troph]) reside within the alveolar space of the host. To that end, we purified asci and trophs from Pneumocystis murina and utilized transcriptomics to identify differentially regulated genes. Two such genes, Arp9 and Sp, are differentially regulated in the ascus and the troph, respectively, and can be utilized to characterize the state of the Pneumocystis life cycle in vivo Gsc1, encoding a β-1,3-glucan synthase with a large extracellular domain previously identified using surface proteomics, was more highly expressed on the ascus form of Pneumocystis GSC-1 ectodomain immunization generated a strong antibody response that demonstrated the ability to recognize the surface of the Pneumocystis asci. GSC-1 ectodomain immunization was also capable of reducing ascus burden following primary challenge with Pneumocystis murina Finally, mice immunized with the GSC-1 ectodomain had limited fungal burden following natural transmission of Pneumocystis using a cohousing model.IMPORTANCE The current report enhances our understanding of Pneumocystis biology in a number of ways. First, the current study provided a preliminary annotation of the Pneumocystis murina genome, addressing a long-standing issue in the field. Second, this study validated two novel transcripts enriched in the two predominant life forms of Pneumocystis These findings allow better characterization of the Pneumocystis life cycle in vivo and could be valuable diagnostic tools. Furthermore, this study outlined a novel pipeline of -omics techniques capable of revealing novel antigens (e.g., GSC-1) for the development of vaccines against Pneumocystis.

Pneumocystis jirovecii pneumonia at chest High-resolution Computed Tomography (HRCT) in non-HIV immunocompromised patients: Spectrum of findings and mimickers

Pneumocystis jirovecii pneumonia (PJP) has emerged as a main issue in non Human Immunodeficiency Virus (HIV) immunocompromised hosts, exposing patients to high mortality rates, especially when the diagnosis is delayed. Since microbiological confirmation is often unfeasible or difficult to obtain, High-resolution Computed Tomography (HRCT) represents a main tool for guiding the diagnosis in the appropriate clinical scenario. Nevertheless, radiologists must be aware that PJP at HRCT is a multifaceted process, with a variety of common and less frequent findings, along with a broad spectrum of infectious (e.g., viral and certain fungal and bacterial pneumonias) and non-infectious (e.g., pulmonary oedema, diffuse alveolar haemorrhage, and drug toxicity) differential diagnoses. In this review we resume background clinical information on PJP in non-HIV immunocompromised patients, illustrate both typical and less frequent HRCT findings, and present the spectrum of infectious and non-infectious mimickers at HRCT, highlighting the similarities with PJP and providing clues for the differential diagnosis.

The Contribution of Host Cells to Pneumocystis Immunity: An Update

Pneumocystis is a ubiquitous atypical fungus that is distributed globally. The genus comprises morphologically similar but genetically heterogeneous species that have co-evolved with specific mammalian hosts as obligate intra-pulmonary pathogens. In humans, Pneumocystis jirovecii is the causative organism of Pneumocystis pneumonia (PCP) in immunocompromised individuals, a serious illness frequently leading to life-threatening respiratory failure. Initially observed in acquired immunodeficiency syndrome (AIDS) patients, PCP is increasingly observed in immunocompromised non-AIDS patients. The evolving epidemiology and persistently poor outcomes of this common infection will require new strategies for diagnosis and treatment. A deeper understanding of host immune responses and of the cells that mediate them will improve the chance of developing new treatment strategies. This brief review provides an update on recent studies on the role of host immunity against Pneumocystis.