Variation of CD4+ and CD8+ T Lymphocytes as Predictor of Outcome in Renal Allograft Recipients Who Developed Acute Respiratory Distress Syndrome Caused by Cytomegalovirus Pneumonia

A Statistical Prediction Model for Survival After Kidney Transplantation from Deceased Donors

Background

In an environment of limited kidney donation resources, patient recovery and survival after kidney transplantation (KT) are highly important. We used pre-operative data of kidney recipients to build a statistical model for predicting survivability after kidney transplantation.

Material/Methods

A dataset was constructed from a pool of patients who received a first KT in our hospital. For allogeneic transplantation, all donated kidneys were collected from deceased donors. Logistic regression analysis was used to change continuous variables into dichotomous ones through the creation of appropriate cut-off values. A regression model based on the least absolute shrinkage and selection operator (LASSO) algorithm was used for dimensionality reduction, feature selection, and survivability prediction. We used receiver operating characteristic (ROC) analysis, calibration, and decision curve analysis (DCA) to evaluate the performance and clinical impact of the proposed model. Finally, a 10-fold cross-validation scheme was implemented to verify the model robustness.

Results

We identified 22 potential variables from which 30 features were selected as survivability predictors. The model established based on the LASSO regression algorithm had shown discrimination with an area under curve (AUC) value of 0.690 (95% confidence interval: 0.557–0.823) and good calibration result. DCA demonstrated clinical applicability of the prognostic model when the intervention progressed to the possibility threshold of 2%. An average AUC value of 0.691 was obtained on the validation data.

Conclusions

Our results suggest that the proposed model can predict the mortality risk for patients after kidney transplants and could help kidney specialists choose kidney recipients with better prognosis.

CD4 and CD8 Lymphocyte Counts as Surrogate Early Markers for Progression in SARS-CoV-2 Pneumonia: A Prospective Study

BACKGROUND

COVID-19 pathophysiology and the predictive factors involved are not fully understood, but lymphocytes dysregulation appears to play a role. This paper aims to evaluate lymphocyte subsets in the pathophysiology of COVID-19 and as predictive factors for severe disease.

PATIENT AND METHODS

A prospective cohort study of patients with SARS-CoV-2 bilateral pneumonia recruited at hospital admission. Demographics, medical history, and data regarding SARS-CoV-2 infection were recorded. Patients systematically underwent complete laboratory tests, including parameters related to COVID-19 as well as lymphocyte subsets study at the time of admission. Severe disease criteria were established at admission, and patients were classified on remote follow-up according to disease evolution. Linear regression models were used to assess associations with disease evolution, and Receiver Operating Characteristic (ROC) and the corresponding Area Under the Curve (AUC) were used to evaluate predictive values.

RESULTS

Patients with critical COVID-19 showed a decrease in CD3+CD4+ T cells count compared to non-critical (278 (485 IQR) vs. 545 (322 IQR)), a decrease in median CD4+/CD8+ ratio (1.7, (1.7 IQR) vs. 3.1 (2.4 IQR)), and a decrease in median CD4+MFI (21,820 (4491 IQR) vs. 26,259 (3256 IQR)), which persisted after adjustment. CD3+CD8+ T cells count had a high correlation with time to hospital discharge (PC = -0.700 (-0.931, -0.066)). ROC curves for predictive value showed lymphocyte subsets achieving the best performances, specifically CD3+CD4+ T cells (AUC = 0.756), CD4+/CD8+ ratio (AUC = 0.767), and CD4+MFI (AUC = 0.848).

CONCLUSIONS

A predictive value and treatment considerations for lymphocyte subsets are suggested, especially for CD3CD4+ T cells. Lymphocyte subsets determination at hospital admission is recommended.

Bacteria Isolated From Respiratory Tract Specimens of Renal Recipients With Acute Respiratory Distress Syndrome Due to Pneumonia: Epidemiology and Susceptibility of the Strains

OBJECTIVE

We estimated species distribution and frequency of antimicrobial resistance among bacterial pathogens isolated from respiratory tract specimens of renal recipients with acute respiratory distress syndrome (ARDS) due to pneumonia.

METHODS

We retrospectively collected patient demographics and clinical characteristics and microbiologic culture data with the use of standard microbiologic procedures and commercially available tests.

RESULTS

From January 2001 to August 2014, 320 respiratory tract specimens were obtained from 94 renal recipients with ARDS. Bacterial cultures were positive in 134 specimens from 68 recipients (72.3%), yielding 139 bacterial strains. The most commonly isolated species were gram-negative bacteria (111 isolates) with dominance of Acinetobacter baumanii (29.7%) and Pseudomonas aeruginosa (18.0%). The gram-negative bacteria were relatively resistant to 1st- and 2nd-generation cephalosporin and monocyclic beta-lactam and relatively sensitive to levofloxacin and meropenem, with rates of resistance of 80.2%, 76.6%, 73.9%, 36.0%, and 44.1%, respectively. The gram-positive bacteria, excluding Streptococcus uberis, were sensitive to glycopeptides and oxazolidone.

CONCLUSIONS

Gram-negative bacteria predominated as 79.9% of isolates from respiratory tract specimens of renal recipients with ARDS. The gram-negative bacteria were relatively sensitive to levofloxacin and meropenem and the gram-positive bacteria were sensitive to glycopeptides and oxazolidone.

Mortality predictors in recipients developing acute respiratory distress syndrome due to pneumonia after kidney transplantation

BACKGROUND

The aim of the present study was to investigate the risk factors related to hospital mortality due to infection in kidney recipients with ARDS meeting the Berlin definition.

METHODS

Univariate and multivariate logistic regression analysis were used to confirm the independent risk factors related to infection-associated mortality.

RESULTS

From January 2001 to August 2014, a total of 94 recipients with acute respiratory dress syndrome (ARDS) caused by pneumonia following kidney transplantation were enrolled in the present study. The most common type of infection was bacterial (52/94; 55.3%), viral (25/94; 26.6%), and polymicrobial (14/94; 14.9%). The most common ARDS was diagnosed within 6 months after transplantation (76/94; 80.9%). There were 39 deaths in these recipients (39/94; 41.5%). Eleven (11.7%) patients had mild, 47 (50.0%) moderate, and 36 (38.3%) severe ARDS; mortality was 27.3, 27.7, and 63.9%, respectively. The independent predictors of infection-related mortality were serum creatinine level >1.5 mg/dL at ARDS onset (OR 3.5 (95%CI 1.2-10.1), p = 0.018) and severe ARDS (OR 3.6 (95%CI 1.4-9.7), p = 0.009) in the multivariate analysis.

CONCLUSION

Infection-related mortality in kidney transplant patients with ARDS was associated with high serum creatinine level and severe ARDS.

Long-term renal function and survival of renal transplant recipients admitted to the intensive care unit

INTRODUCTION

We determined the long-term mortality and renal allograft function of renal transplant recipients admitted to the intensive care unit (ICU).

METHODS

A single institution retrospective observational cohort study of all renal transplant patients admitted to the ICU was performed. Serum creatinine was recorded up to one yr after hospital discharge and survival data were collected for three yr.

RESULTS

Chest sepsis was the commonest reason for ICU admission. ICU and hospital mortality were 32% and 19% respectively. Predictors of hospital mortality included the presence of sepsis and duration of mechanical ventilation (MV). Of the patients who were discharged from ICU, three-yr mortality was 50%. Renal function at one yr was worse than that at hospital discharge and at baseline, though not statistically significant. Death-censored allograft loss was 11% over the three-yr follow up period.

CONCLUSIONS

Sepsis and requirement for MV are independent predictors of mortality in renal transplant recipients admitted to ICU. Renal transplant recipients with chest sepsis may warrant earlier ICU admission. Any loss of renal allograft function during an episode of critical illness appears to have a lasting effect, and longterm patient and allograft survival is poor.

Viral pneumonias in immunocompromised adult hosts

Viral infections have always been considered pediatric diseases. However, viral pneumonia has become an important cause of morbidity and mortality in immuncompromised adults. Improved diagnostic techniques, such as the introduction of highly sensitive nucleic acid amplification tests, have not only allowed us to discover new viruses but also to determine the etiology of viral pneumonia in immunocompromised adult hosts. Unfortunately, only a few antiviral agents are available. Thus, early diagnosis and treatment are crucial to patient outcome. In this article, we review the most common viruses that have been implicated as etiologic agents of viral pneumonia in immunocompromised adults. We discuss the epidemiologic characteristics and clinical presentation of these viral infections and the most appropriate diagnostic approaches and therapies when available.

Immunoregulation of thymosin alpha 1 treatment of cytomegalovirus infection accompanied with acute respiratory distress syndrome after renal transplantation

We are the first to report the use of thymosin alpha1 to treat cytomegalovirus infection accompanied with acute respiratory distress syndrome after renal transplantation. The patients were divided into the thymosin alpha1 group (Zadaxin group, n = 32) and the control group (n = 14). All patients received the same rescue therapy protocol. Suitable antiviral (ganciclovir, 5 mg/kg every 12 hours, intravenously), antibacterial, or antifungal treatment was given if needed. In addition, patients in the Zadaxin group received thymosin alpha1, (1.6 mg) subcutaneously every other day or every day. The rescue success rate was significantly higher in the Zadaxin than in the control group (78.1% vs 50.0%) while the death rate was greatly reduced (21.9% vs 50%). In the Zadaxin group, the CD4(+) lymphocyte level was significantly increased on day 14; so was the ratio of CD4(+) and CD8(+) T-lymphocyte subsets. In the survival group, CD4(+) and CD8(+) lymphocyte cell counts were significantly increased on days 7, 14, and 21 compared with admission. This study suggested that thymosin alpha1 significantly promoted CD4(+) and CD8(+) lymphocytes, repairing cellular immunity and successfully reinforcing resistance to cytomegalovirus disease.

An aggressive systematic strategy for acute respiratory distress syndrome caused by severe pneumonia after renal transplantation

Acute respiratory distress syndrome (ARDS) caused by pneumonia after renal transplantation was usually associated with overimmunosuppression and high mortality rate. We evaluated the efficacy of an aggressive systemic protocol including strategies improving body's immune function. Twenty-one recipients were enrolled in this study. Patients were subjected to a protocol including (i) withdrawal of most immunosuppressants, (ii) early use of immunoenhancers and continuous renal replacement therapy (CRRT), (iii) reasonable administration of antibiotic regimen, (iv) prompt mechanical ventilating strategy, and (v) adequate nutrition. Immunosuppressants were adjusted according to the value of CD4+, CD8+T lymphocytes in peripheral blood. CRRT was conducted at once when patients were admitted to the intensive care unit (ICU), regardless the graft function. Thirteen (62%) survived and eight died finally. This is a high survival rate for this kind of patients. Eighteen patients had received thymosin treatment. All patients who survived experienced renal allograft dysfunction during CRRT, but when CRRT stopped, the function of all grafts gradually recovered. No acute rejection episodes were documented during the treatment. The aggressive systemic protocol including strategies improving the body's immune function and CRRT can improve the outcome of patients with ARDS after renal transplantation. The count of CD4+, CD8+T lymphocytes of peripheral blood is useful in the adjustment of immunosuppressants and the prediction of patient outcome.

Tacrolimus combined with mycophenolate mofetil can effectively reverse C4d-positive steroid-resistant acute rejection in Chinese renal allograft recipients

BACKGROUND

Tacrolimus (TAC) combined with mycophenolate mofetil (MMF) has been suggested to play a critical role in the reversal of C4d-positive acute humoral rejection (AHR) in renal transplantation, but the efficacy of using only TAC-MMF without immunoadsorption or plasmapheresis has not been investigated. On the other hand, Chinese recipients of renal grafts usually need lower doses of immunosuppressants, and their optimal treatment for acute humoral rejection has not been established.

METHODS

Since 1999, we have used TAC-MMF to treat steroid-resistant acute rejection (AR). C4d staining was retrospectively performed in 32 patients with steroid-resistant AR, and the treatments of 19 patients with C4d-positive steroid-resistant AR were investigated.

RESULTS

Thirteen of 19 patients received TAC-MMF treatment only; 11 episodes of rejection in them were reversed (7 completely, 4 partially) and only 2 recipients lost their graft. Another 6 patients received immunoadsorption also. One of them failed to respond and lost her graft. Four of 5 patients treated with immunoadsorption and TAC-MMF recovered (3 completely, 1 partially), but 3 of them had severe pneumonia, a complication rate statistically higher than in patients treated with only TAC-MMF (P<0.05). AR occurring during the first two weeks after transplantation had a statistically better outcome than that occurring later (P = 0.003).

CONCLUSION

Our study suggests that the combination of TAC and MMF is a potentially safe and economic treatment for most Chinese renal allograft recipients with C4d-positive steroid-resistant AR, especially for rejections developing within the first two weeks after transplantation.