CD4+ T cell lymphopenia predicts mortality from Pneumocystis pneumonia in kidney transplant patients

Clinical characteristics and risk factors for mortality in pneumonia-associated acute respiratory distress syndrome patients: a single center retrospective cohort study

Background

Pathogenic diversity may have contributed to the high mortality of pneumonia-associated acute respiratory distress syndrome (p-ARDS). Metagenomics next-generation sequencing (mNGS) serves as a valuable diagnostic tool for early pathogen identification. However, its clinical utility in p-ARDS remains understudied. There are still limited researches on the etiology, clinical characteristics and risk factors for 28-day mortality in p-ARDS patients.

Methods

A single center retrospective cohort study of 75 p-ARDS patients was conducted. Patients were categorized into survival and deceased groups based on their 28-day outcomes. A comprehensive clinical evaluation was conducted, including baseline characteristics, laboratory indicators, outcomes and pathogen identification by mNGS and traditional microbiological testing. We then evaluated the diagnostic value of mNGS and identified clinical characteristics and risk factors for 28-day mortality in p-ARDS.

Result

The overall ICU mortality was 26.67%, and the 28-day mortality was 57.33%, with 32 cases (42.67%) in the survival group, and 43 cases (57.33%) in the deceased group. Patients in the deceased group were older than those in the survival group (68(59,73) years vs. 59(44,67) years, P=0.04). The average lengths of ICU and hospital stay were 9(5,13) days and 14(7,21) days, respectively. The survival group had longer lengths of ICU and hospital stay (ICU: 11(7,17) days and hospital: 17(9,27) days) compared to the deceased group (ICU: 8(4,11) days and hospital: 12(6,19) days) (P<0.05). Survival patients exhibited lower Acute Physiology and Chronic Health Evaluation (APACHE) II score on the 3rd and 7th days, higher lymphocyte counts, higher CD3+ and CD8+ T cell counts compared to deceased patients (P<0.05). Multivariate logistic regression analysis identified age, APACHE II scores on 3rd and 7th days, CD8+ T cell count and length of ICU as independent risk factors for 28-day mortality in p-ARDS patients. mNGS demonstrated a significantly higher overall pathogen detection rate (70/75, 93.33%) compared to the traditional method (50/75, 66.67%, P=0.022). The average turnaround time (TAT) for mNGS was significantly shorter at 1(1,1) day compared to 4(3,5) days for the traditional method (P<0.001).

Conclusion

Metagenome next-generation sequencing can be used as a valuable tool for identifying pathogens in p-ARDS, reducing diagnostic time and improving accuracy. Early application of mNGS alongside traditional methods is recommended for p-ARDS. Furthermore, older age, higher APACHE II scores, lower lymphocyte counts and lymphocyte subset counts were associated with increased mortality in p-ARDS patients, highlighting the importance of timely assessment of immune status and disease severity, especially in elderly.

Pneumocystis jirovecii pneumonia in non-HIV patients: need for a more extended prophylaxis

Background

Pneumocystis jirovecii pneumonia (PCP) has a significant mortality rate for non-HIV immunocompromised patients. Prevention is primarily based on combined trimethoprim and sulfamethoxazole (TMP-SMX) but guidelines on pneumocystosis prophylaxis are scattered and not consensual.

Objectives

This study aims to describe PCP in non-HIV patients and to review case by case the prior indication of prophylaxis according to specific guidelines.We included patients with confirmed diagnosis of PCP admitted to one university hospital from 2007 to 2020. Prior indication for pneumocystis prophylaxis was assessed according to the specific guidelines for the underlying pathology or treatment.

Results

Of 150 patients with a medical diagnosis of PCP, 78 were included. Four groups of underlying pathologies were identified: hematological pathologies (42%), autoimmune diseases (27%), organ transplantation (17%), and other pathologies at risk of PCP (14%). A small subgroup of 14 patients (18%) had received a prior prescription of pneumocystis prophylaxis but none at the time of the episode. Transfer to intensive care was necessary for 33 (42%) patients, and the mortality rate at 3 months was 20%. According to international disease society guidelines, 52 patients (59%) should have been on prophylaxis at the time of the pneumocystis episode. Lowest compliance with guidelines was observed in the hematological disease group for 24 patients (72%) without prescription of indicated prophylaxis.

Conclusion

Infectious disease specialists should draw up specific prophylactic guidelines against pneumocystis to promote a better prevention of the disease and include additional criteria in their recommendations according to individual characteristics to prevent fatal cases.

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

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

Clinical characteristics and risk factors for late-onset pneumocystis jirovecii pneumonia in kidney transplantation recipients

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is a common and troublesome complication of kidney transplantation. In the era of prophylaxis, the peak incidence of PJP after kidney transplantation and specific characteristics of late-onset PJP have always been debated.

METHODS

We performed a retrospective study by analysing the data of post-transplantation pneumonia in adult kidney transplantation recipients between March 2014 and December 2021 in The Affiliated First Hospital of University of Science and Technology of China (USTC). A total of 361 patients were included and divided into early-onset PJP, late-onset PJP and non-PJP groups. The characteristics of each group and related risk factors for the late-onset patients were investigated.

RESULTS

Some patients developed PJP 9 months later with a second higher occurrence between month 10 and 15 after transplantation. Compared with non-PJP, ABO-incompatible and cytomegalovirus (CMV) viremia were significantly associated with late onset of PJP in multivariate analysis. The use of tacrolimus, CMV viremia, elevated CD8(+) T cell percent and hypoalbuminemia were risk factors for late PJP. Receiver operating characteristic curve analysis demonstrated that a combination of those factors could increase the sensitivity of prediction remarkably, with an area under the curve of 0.82, a sensitivity of 80% and a specificity of 83%.

CONCLUSIONS

PJP could occur months after kidney transplantation. ABO-incompatible transplant recipients are at high risk of PJP. In the later stages of transplantation, CMV viremia, T lymphocyte subsets percentage and serum albumin levels should be monitored in patients using tacrolimus.

Negative serum (1,3) -β-D-glucan has a low power to exclude Pneumocystis jirovecii pneumonia (PJP) in HIV-uninfected patients with positive qPCR

OBJECTIVE

The current study evaluated the diagnostic performance of serum (1,3)-beta-D Glucan (BDG) in differentiating PJP from P. jirovecii-colonization in HIV-uninfected patients with P. jirovecii PCR-positive results.

METHODS

This was a single-center retrospective study between 2019 and 2021. The diagnosis of PJP was based on the following criteria: detection of P. jirovecii in sputum or BAL specimen by qPCR or microscopy; Meet at least two of the three criteria: (1) have respiratory symptoms of cough and/or dyspnea, hypoxia; (2) typical radiological picture findings; (3) receiving a complete PJP treatment. After exclusion, the participants were divided into derivation and validation cohorts. The derivation cohort defined the cut-off value of serum BDG. Then, it was verified using the validation cohort.

RESULTS

Two hundred and thirteen HIV-uninfected patients were enrolled, with 159 PJP and 54 P. jirovecii-colonized patients. BDG had outstanding specificity, LR, and PPV for PJP in both the derivation (90.00%, 8.900, and 96.43%) and the validation (91.67%, 9.176, and 96.30%) cohorts at ≥ 117.7 pg/mL. However, it had lower sensitivity and NPV in the derivation cohort (89.01% and 72.97%), which was even lower in the validation cohort (76.47% and 57.89%). Of note, BDG ≥ 117.7 pg/mL has insufficient diagnostic efficacy for PJP in patients with lung cancer, interstitial lung disease (ILD) and nephrotic syndrome. And although lymphocytes, B cells, and CD4+ T cells in PJP patients were significantly lower than those in P. jirovecii-colonized patients, the number and proportion of peripheral blood lymphocytes did not affect the diagnostic efficacy of serum BDG.

CONCLUSIONS

Serum BDG ≥ 117.7 pg/mL could effectively distinguish P. jirovecii-colonization from infection in qPCR-positive HIV-uninfected patients with infectious diseases, solid tumors (excluding lung cancer), autoimmune or inflammatory disorders, and hematological malignancies. Of note, for patients with lung cancer, ILD, and nephrotic diseases, PJP should be cautiously excluded at BDG < 117.7 pg/mL.

Late-Onset Granulomatous Pneumocystis jirovecii Pneumonia in A Renal Transplant Recipient: A Clinical Grand Round Conference Case in 2022

Late-onset Pneumocystis jirovecii pneumonia (PCP) can be developed in solid organ transplant (SOT) patients. Granulomatous P. jirovecii pneumonia (GPCP) can occur in immunocompromised patients, but has rarely been reported in SOT recipients. The diagnosis of GPCP is difficult since the sensitivity of sputum and bronchoalveolar lavage is low and atypical patterns are shown. A 60-year-old man, who had undergone renal transplantation 24 years ago presented with nodular and patchy lung lesions. He was asymptomatic and stable. After empirical treatment with a fluoroquinolone, the condition partially resolved but relapsed 4 months later. The pulmonary nodule was resected, and GPCP was confirmed. The pathogenesis of GPCP remains unclear, but in SOT recipients presenting with an atypical lung pattern, GPCP should be considered. This case was discussed at the Grand Clinical Ground of the Korean Society of Infectious Disease conference on November 3, 2022.

Clinical characteristics and risk factors of in-hospital mortality in patients coinfected with Pneumocystis jirovecii and Aspergillus

OBJECTIVE

To analyze clinical characteristics and risk factors for in-hospital mortality in patients coinfected with P. jirovecii and Aspergillus.

METHODS

This study included 53 patients with coinfection of P. jirovecii pneumonia (PJP) and invasive pulmonary aspergillosis (IPA) in our center from January 2011 to December 2021. All cases were divided into survivor (n=27) and non-survivor groups (n=26). Medical records, laboratory and radiology data were collected. Risk factors for in-hospital mortality were identified by multivariable analyses.

RESULTS

HIV-positive patients accounted for 3.8%. Fever (77.4%), dyspnea (69.8%) and wet cough (24.5%) were common symptoms. Ground-glass opacity (83.0%), consolidation (71.7%), septal thickening (66.0%), and nodules (54.7%) were the most common radiological signs. CD4+ T cell count and serum albumin (ALB) level were significantly lower in non-survival group than in the survival group. Conversely, serum lactate dehydrogenase (LDH) and procalcitonin (PCT) levels were higher in non-survival group than in survival group. Lactic acidosis [odds ratio (OR): 33.999,95% confidential interval (CI): 3.112-371.409; p=0.004], low CD4+ T cell count (<114 cell/µL) [OR: 19.343, 95% CI: 1.533-259.380; p=0.022] and high level of LDH (> 519 U/L) [OR: 11.422, 95% CI: 1.271-102.669; p=0.030] were independent risk factors for mortality.

CONCLUSION

PJP coinfected with IPA incurs high mortality with nonspecific clinical characteristics and is more likely to involve HIV-negative patients. Lactic acidosis, low CD4+ T cell count and high LDH level are independent risk factors for mortality, close monitoring of these parameters is necessary to help distinguish high-risk patients and make appropriate clinical decisions.

Metagenomic next-generation sequencing shotgun for the diagnosis of infection in connective tissue diseases: A retrospective study

Objective

Patients with connective tissue diseases (CTDs) are at high risk of infection due to various reasons. The purpose of the study was to investigate the infection diagnosis value of metagenomic next-generation sequencing (mNGS) shotgun in CTDs to guide the use of anti-infective therapy more quickly and accurately.

Methods

In this retrospective study, a total of 103 patients with CTDs admitted with suspected infection between December 2018 and September 2021 were assessed using mNGS as well as conventional microbiological tests (CMT).

Results

Among these 103 patients, 65 were confirmed to have an infection (Group I) and 38 had no infection (Group II). mNGS reached a sensitivity of 92.31% in diagnosing pathogens in Group I. Moreover, mNGS showed good performance in identifying mixed infection. In all infection types, lung infection was the most common. mNGS also played an important role in detecting Pneumocystis jirovecii, which was associated with low CD4+ T-cell counts inextricably.

Conclusion

mNGS is a useful tool with outstanding diagnostic potential in identifying pathogens in patients with CTDs and conduce to provide guidance in clinical practice.

Supplementary Role of Immunological Indicators in the Diagnosis and Prognosis of Pneumocystis Pneumonia in Non-HIV Immunocompromised Patients

Background

Pneumocystis pneumonia (PCP) has a high mortality in HIV-negative immunocompromised patients. The occurrence and development of PCP are believed to be correlated with the level of lymphocytes and their subsets. The aim of this study was to determine if the levels of lymphocyte subpopulations and immunoglobulin are associated with PCP.

Methods

A total of 74 immunocompromised patients were enrolled in this single-center cohort study. Diagnosis of PCP was based on the relevant pulmonary symptoms and radiological imaging, and the detection of Pneumocystis jirovecii in BAL fluid or biopsy tissue by metagenomic next-generation sequencing (mNGS). All patients were divided into two groups (PCP group and non-PCP group) and the patients in PCP group were then divided into two groupsbased on the outcome of the disease during the hospitalization.

Results

We observed a significant lower level of IgG (p=0.000) and B lymphocyte counts (p=0.017) in the PCP group comparing to that in the non-PCP group. CD4+ T cell counts, as well as the ratio of CD4+/CD8+ T cells in circulation and BAL fluid were also lower in the PCP group comparing to those in the non-PCP group. Lactate dehydrogenase (LDH) in the PCP group was significantly higher than that in the non-PCP group (p=0.029). In the PCP group, a lower level of total lymphocytes (p=0.004), T cells (p=0.001), CD4+ cells (p=0.001), and CD8+ cells (p=0.007), as well as the proportion of lymphocytes in BAL fluid (p=0.000) were found in deceased patients comparing to those in the survived group.

Conclusion

Our study revealed an important role of humoral immunity in the infection of Pneumocystis jirovecii. The level of B cells and IgG could be used as a supplement to predict the occurrence of PCP. The level of CD4+ and CD8+ lymphocytes was significantly correlated with the outcome of PCP.

High incidence and mortality of Pneumocystis jirovecii infection in anti-MDA5-antibody-positive dermatomyositis: experience from a single center

BACKGROUND

Idiopathic inflammatory myopathies (IIM) are associated with a significantly higher risk of opportunistic infections including Pneumocystis jirovecii pneumonia (PJP), a potentially fatal opportunistic infection. However, no prior studies have evaluated PJP infection in subtypes of IIM.

OBJECTIVES

To investigate the prevalence and mortality rate of PJP infection in subgroups of IIM patients stratified according to myopathy-specific antibodies.

METHODS

In the first part of the study, 463 consecutive patients with IIM were prospectively followed for a period of at least 1 year to analyze the incidence of PJP. In the second part of the study, we enrolled 30 consecutive PJP patients with any rheumatic disease in order to identify the mortality rate and risk factors by Cox regression analysis. The Kaplan-Meier method with log-rank testing was used to assess differences in survival.

RESULTS

The prevalence of PJP in IIM patients was found to be 3.0/100 person-years, while in MDA5+ DM patients it was 7.5/100 person-years and in MDA5- IIM patients 0.7/100 person-years (P < 0.05). PJP typically occurred in the first 2 months in the case of MDA5+ DM patients who had a significant decrease in their CD4+ T cell counts and lymphocyte counts (P < 0.05). In PJP patients, 3-month mortality was higher for MDA5+ DM patients than in those with other rheumatic diseases (83.3% vs 38.9%, P < 0.05). Alarmingly, MDA5+ DM patients seemed not to benefit from prompt anti-PJP treatment, unlike patients with other rheumatic diseases whose survival improved when anti-PJP treatment was started within 6 days (P < 0.05).

CONCLUSION

PJP has an alarming high incidence and mortality in MDA5+ DM patients. Timely treatment for PJP seems not to improve the prognosis of patients with this particular subtype. Hence, there remains a crucial unmet need to develop PJP prophylaxis for MDA5+ DM patients.

New Insights into Blood Circulating Lymphocytes in Human Pneumocystis Pneumonia

The host lymphocyte response is decisive in Pneumocystis pneumonia (PCP) pathophysiology but little is known of the specific roles of lymphocyte subpopulations in this fungal infection. Peripheral NK, NKT, B, TCD4+ and TCD8+ subpopulations were compared by immunophenotyping between 20 patients diagnosed with PCP (PCP(+)] and 20 uninfected immunosuppressed patients (PCP(−)). Among PCP(+) subjects, the lymphocyte populations were also compared between surviving and deceased patients. Low B cell count (<40 cells/µL) was more frequent in PCP(+) than in PCP(−) patients (p = 0.03), while there was no difference for the TCD4 count. Among the PCP(+) group, the 7 deceased patients had lower Th1 (p = 0.02) and Tc1 (p = 0.03) populations, higher Th2 response (p = 0.03), higher effector TCD8 (p < 0.01), lower central memory TCD8 (p = 0.04) and reduced NK cells (p = 0.02) compared with the 13 survivors. Th1/Th2 ratio < 17, CD8 Tc1 < 44%, effector TCD8 < 25%, central memory TCD8 < 4%, NK cells < 50 cells/µL and total lymphocytes < 0.75 G/L were associated with a higher risk of mortality (p = 0.003, p = 0.007, p = 0.0007, p = 0.004, p = 0.02 and p = 0.019, respectively). The traditional analysis of TCD4 and TCD8 populations may be insufficient in the context of PCP. It could be completed by using B cells to predict the risk of PCP, and by using lymphocyte subpopulations or total lymphocyte count, which are easy to obtain in all health care facilities, to evaluate PCP prognosis.

Immunization with Pneumocystis carinii A121-85 antigen activates immune function against P. carinii

BACKGROUND

Pneumocystis pneumonia (PcP), which is caused by Pneumocystis carinii, is a life-threatening infection that affects immunocompromised individuals. Unfortunately, chemoprophylaxis and dapsone are only effective for half of the patients with PcP, indicating that additional preventive methods are needed. We predicated the pneumocystis surface protein A12 sequence 1-85 by DNAStar software and BepiPred, and identified it as a potential vaccine candidate by bioresearch.

METHODS

We used recombinant A121-85 as antigen to immunized mice and detected serum titer of IgG, expression of inflammatory factors by EILSA, qRT-PCR and flow cytometry.

RESULTS

Our results showed that immunization with recombinant A121-85 increased the serum titer of IgG, promoted the secretion of T lymphocytes, increased the expression of inflammatory factors, and elevated lung inflammatory injury in mice.

CONCLUSIONS

Our findings suggest that A121-85 is a potential vaccine target for preventing Pneumocystis carinii. The evaluation of A121-85-elicited antibodies in the prevention of PcP in humans deserves further investigation.

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

Objectives

We analysed the peripheral blood lymphocyte subsets of human immunodeficiency virus (HIV)-negative patients infected with pneumocystis pneumonia (PCP) to determine the relationships between the levels of different types of lymphocytes and the prognosis of patients.

Methods

We retrospectively reviewed HIV-negative patients with PCP diagnosed in our department. All the eligible patients underwent lymphocyte subset analysis on admission.

Results

A total of 88 HIV-negative PCP patients were enrolled in the study. In univariate analyses, low CD4+ T cell count, low CD8+ T cell count, and low natural killer cell (NK cell) count were associated with higher in-hospital mortality. CD8+ T cell count ≤300/μL was found to be an independent risk factor for poor prognosis in multivariate logistical regression analysis (p = 0.015, OR = 11.526, 95% CI = 1.597–83.158). Although low CD4+ T cell and NK cell counts were not independent risk factors, the mortality rates of PCP patients decreased as the CD4+ T cell and NK cell counts increased.

Conclusion

The immune process of Pneumocystis jirovecii infection is complex but important. We propose that lymphocyte subsets could give clinicians a better understanding of patient immune status, helping with the early identification of potentially lethal infections and treatment decision making, such as adjusting the immunosuppressive regimen and choosing an appropriate patient monitoring level.

Single-Center Retrospective Analysis of Prophylaxis and Treatment of Pneumocystis carinii Pneumonia in Patients with Renal Dysfunction After Renal Transplantation

BACKGROUND Pneumocystis carinii is an opportunistic pathogen that can cause severe lung infections after renal transplantation. Trimethoprim-sulfamethoxazole (TMP-SMX) has been recognized as a first-line treatment for chemoprophylaxis of Pneumocystis carinii pneumonia (PCP). This study aimed to establish a personalized chemoprophylaxis prescription specifically for those recipients with renal insufficiency. MATERIAL AND METHODS This retrospective study included 68 patients with confirmed PCP after renal transplantation. Patients were divided into 2 groups: an abnormal renal function (ARF) group (creatinine ≥1.5 ng/dl; n=37) and a normal renal function (NRF) group (creatinine <1.5 ng/dl; n=31). Clinical characteristics and prognosis of PCP in both groups were compared and analyzed. RESULTS Patients in the ARF group had more prophylaxis after transplantation (15 [40.5%] vs. 2 [6.5%], p=0.047), had more biopsy-proven rejections (10 [27%] vs. 1 [3.2%], p=0.008), and had lower lymphocyte counts (0.6 [05-0.9] vs. 1.1 [0.7-1.6], p<0.01). Renal function after treatment was obviously improved in the ARF group, which had a significant decrease rate in creatinine (-13.2% [-22~4.8%] vs. -4.4% [-12.6~20.9%], p=0.043). CONCLUSIONS PCP prophylaxis regimens for recipients after renal transplantation are still needed regardless of whether the renal functions were normal or abnormal, especially for recipients with persistent lymphopenia or rejection after transplantation.

Novel non-cystic features of polycystic kidney disease: having new eyes or seeking new landscapes

For decades, researchers have been trying to decipher the complex pathophysiology of autosomal dominant polycystic kidney disease (ADPKD). So far these efforts have led to clinical trials with different candidate treatments, with tolvaptan being the only molecule that has gained approval for this indication. As end-stage kidney disease due to ADPKD has a substantial impact on health expenditures worldwide, it is likely that new drugs targeting kidney function will be developed. On the other hand, recent clinical observations and experimental data, including PKD knockout models in various cell types, have revealed unexpected involvement of many other organs and cell systems of variable severity. These novel non-cystic features, some of which, such as lymphopenia and an increased risk to develop infections, should be validated or further explored and might open new avenues for better risk stratification and a more tailored approach. New insights into the aberrant pathways involved with abnormal expression of PKD gene products polycystin-1 and -2 could, for instance, lead to a more directed approach towards early-onset endothelial dysfunction and subsequent cardiovascular disease. Furthermore, a better understanding of cellular pathways in PKD that can explain the propensity to develop certain types of cancer can guide post-transplant immunosuppressive and prophylactic strategies. In the following review article we will systematically discuss recently discovered non-cystic features of PKD and not well-established characteristics. Overall, this knowledge could enable us to improve the outcome of PKD patients apart from ongoing efforts to slow down cyst growth and attenuate kidney function decline.