Marked increase of procalcitonin after the administration of anti-thymocyte globulin in patients before hematopoietic stem cell transplantation does not indicate sepsis: a prospective study

Plasma exchange and intravenous immunoglobulin prolonged the survival of a porcine kidney xenograft in a sensitized, deceased human recipient

BACKGROUND

The primary limitation to kidney transplantation is organ shortage. Recent progress in gene editing and immunosuppressive regimens has made xenotransplantation with porcine organs a possibility. However, evidence in pig-to-human xenotransplantation remains scarce, and antibody-mediated rejection (AMR) is a major obstacle to clinical applications of xenotransplantation.

METHODS

We conducted a kidney xenotransplantation in a deceased human recipient using a porcine kidney with five gene edits (5GE) on March 25th, 2024 at Xijing Hospital, China. Clinical-grade immunosuppressive regimens were employed, and the observation period lasted 22 days. We collected and analyzed the xenograft function, ultrasound findings, sequential protocol biopsies, and immune surveillance of the recipient during the observation.

RESULTS

The combination of 5GE in the porcine kidney and clinical-grade immunosuppressive regimens prevented hyperacute rejection. The xenograft kidney underwent delayed graft function in the first week, but urine output increased later and the single xenograft kidney maintained electrolyte and pH homeostasis from postoperative day (POD) 12 to 19. We observed AMR at 24 h post-transplantation, due to the presence of pre-existing anti-porcine antibodies and cytotoxicity before transplantation; this AMR persisted throughout the observation period. Plasma exchange and intravenous immunoglobulin treatment mitigated the AMR. We observed activation of latent porcine cytomegalovirus toward the end of the study, which might have contributed to coagulation disorder in the recipient.

CONCLUSIONS

5GE and clinical-grade immunosuppressive regimens were sufficient to prevent hyperacute rejection during pig-to-human kidney xenotransplantation. Pre-existing anti-porcine antibodies predisposed the xenograft to AMR. Plasma exchange and intravenous immunoglobulin were safe and effective in the treatment of AMR after kidney xenotransplantation.

Procalcitonin elevation in febrile recipients during pre-transplant conditioning with anti-thymocyte globulin

Infection is a major contributor to non-relapse mortality in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Detecting infectious diseases in febrile patients during pretransplant conditioning is crucial for subsequent transplant success. Procalcitonin (PCT) is an auxiliary diagnostic marker of severe bacterial infections and has been proposed as a useful predictor of infection in patients undergoing allo-HSCT. Pre-transplant use of anti-thymocyte globulin (ATG) can cause side effects, such as fever and hypotension, which must be distinguished from infectious diseases. Although ATG administration may increase PCT levels, data on PCT levels in febrile patients after ATG administration are limited. Furthermore, no studies have compared PCT levels during allo-HSCT conditioning using ATG or non-ATG regimens. To investigate whether ATG increases PCT levels during febrile episodes in pre-transplant conditioning and whether PCT could be used to discriminate infections during this period, we analyzed 17 ATG and 59 non-ATG patients with fever and who underwent PCT level measurements during pre-transplant conditioning. Our findings revealed that ATG administration was the only significant factor that increased PCT positivity during fever (p = 0.01). In contrast, infectious diseases did not affect PCT positivity in the ATG group (p = 0.24). Furthermore, bloodstream infection was a significant risk factor for PCT positivity in patients who received non-ATG regimens (p < 0.01). Incorporating PCT levels into the diagnostic workup for infectious diseases requires careful consideration, particularly for patients receiving ATG regimens.

Successful Treatment of an AML Patient Infected with Hypervirulent ST463 Pseudomonas Aeruginosa Harboring Rare Carbapenem-Resistant Genes blaAFM-1 and blaKPC-2 Following Allogeneic Hematopoietic Stem Cell Transplantation

Background

Carbapenem-resistant P. aeruginosa (CRPA) is a common hospital-acquired bacterium. It exhibits high resistance to many antibiotics, including ceftazidime/avibactam and cefteolozane/tazobactam. The presence of carbapenem-resistant genes and co-existence Klebsiella pneumoniae carbapenemase (KPC) and metallo-β-lactamases (MBLs) further inactivated all β-lactams. Understanding the resistance genes of CRPA can help in uncovering the resistance mechanism and guiding anti-infective treatment. Herein, we reported a case of perianal infection with hypervirulent ST463 Pseudomonas aeruginosa.

Case Presentation

The case is a 32-year-old acute myeloid leukemia (AML) patient with fever and septic shock during hematopoietic stem cell transplantation (HSCT), and the pathogen was finally identified as a highly virulent sequence type 463 (ST463) P. aeruginosa harboring carbapenem-resistant genes blaAFM-1 and blaKPC-2, which was detected in the bloodstream and originated from a perianal infection. The strain was resistant to ceftazidime/avibactam but successfully treated with polymyxin B, surgical debridement, and granulocyte engraftment after HSCT. The AML was cured during the 19-month follow-up.

Conclusion

This case emphasizes the importance of metagenomic next-generation sequencing (mNGS) and whole-genome sequencing (WGS) in identifying microbes with rare resistant genes, and managing CRPA, especially in immunocompromised patients. Polymyxin B may be the least resistant option.

Cytokine profiling during conditioning in haploidentical stem cell transplantation and its prognostic impact on early transplant outcomes

Cytokine storm development is a major cause of many transplant-related complications, especially during the conditioning regimen. This study aimed to characterize the cytokine profile and determine its prognostic impact during conditioning in patients undergoing subsequent haploidentical stem cell transplantation. A total of 43 patients were enrolled in this study. Sixteen cytokines associated with cytokine release syndrome (CRS) during anti-thymocyte globulin (ATG) treatment were quantified in patients undergoing haploidentical stem cell transplantation. Thirty-six (83.7%) patients developed CRS during ATG treatment; most of those cases (33/36; 91.7%) were classified as grade 1 CRS, whereas only three (7.0%) developed grade 2 CRS. CRS was observed more frequently on the first (15/43; 34.9%) and second day (30/43; 69.8%) of ATG infusion. No factors were identified that could predict the development of CRS on the first day of ATG treatment. Five of the 16 cytokines (interleukins 6, 8, and 10 (IL-6, IL-8, and IL-10), C-reactive protein (CRP), and procalcitonin (PCT)) were significantly elevated during ATG treatment, although only the level of IL-6, IL-10, and PCT were associated with the severity of CRS. However, neither CRS nor the cytokine levels significantly impacted the development of acute graft-versus-host disease (GVHD) or cytomegalovirus (CMV) infection or affected overall survival.

The Clinical Value of Procalcitonin in the Neutropenic Period After Allogeneic Hematopoietic Stem Cell Transplantation

The diagnostic value of procalcitonin and the prognostic role of PCT clearance remain unclear in neutropenic period after allogeneic hematopoietic stem cell transplantation introduction. This study evaluated 219 febrile neutropenic patients (116, retrospectively; 103, prospectively) who underwent allo-HSCT from April 2014 to March 2016. The area under the receiver operator characteristic curve (AUC) of PCT for detecting documented infection (DI) was 0.637, and that of bloodstream infection (BSI) was 0.811. In multivariate analysis, the inability to decrease PCT by more than 80% within 5–7 days after the onset of fever independently predicted poor 100-day survival following allo-HSCT (P = 0.036). Furthermore, the prognostic nomogram combining PCTc and clinical parameters showed a stable predictive performance, supported by the C-index of 0.808 and AUC of 0.813 in the primary cohort, and C-index of 0.691 and AUC of 0.697 in the validation cohort. This study demonstrated the diagnostic role of PCT in documented and bloodstream infection during the neutropenic period after allo-HSCT. PCTc might serve as a predictive indicator of post-HSCT 100-day mortality. A nomogram based on PCTc and several clinical factors effectively predicted the 100-day survival of febrile patients and may help physicians identify high-risk patients in the post-HSCT neutropenic period.

Routine Use of Biomarkers to Rationalize Antibiotic Use During Febrile Episodes in Pediatric Bone Marrow Transplantation Units

BACKGROUND

Children frequently develop fever after hematopoietic stem cell transplant (HSCT). Although the etiology of many febrile episodes (FEs) is not an infection, patients often receive broad-spectrum antibiotics in response.

METHODS

To improve the judicious use of antibiotics in pediatric HSCT patients, we performed a prospective cohort study of children receiving an HSCT in Clínica Imbanaco (Cali, Colombia) between September 2016 and December 2019. We assessed all FEs occurring during 3 periods (infusion, neutropenic and engraftment). We measured procalcitonin and C-reactive protein (CRP) sequentially during each FE and compared levels among patients with fever due to significant infection (FSI) versus fever not attributable to infection (FNI) in each transplant period.

RESULTS

There were 166 FEs in 95 patients. FSI accounted for 12%, 42% and 42% of FE during infusion, neutropenic and engraftment periods, respectively. CRP had better discriminatory capacity for FSI versus FNI in the infusion period [area under the curve (AUC) 0.80 (95% confidence interval [CI], 0.62-0.96) for a CRP level of 50 mg/L]. Neither biomarker performed well in the neutropenic period. During the engraftment period, a CRP of 65 mg/L had an AUC of 0.81 (95% CI, 0.65-0.96), while a procalcitonin level of 0.25 ng/mL had an AUC of 0.83 (95% CI, 0.63-1.0). In contrast to procalcitonin, the CRP's pattern of change throughout the first 3 days of fever in each transplant period was different in FSI compared with FNI.

CONCLUSION

Sequential measurement of biomarkers, especially CRP, may allow clinicians to more appropriately manage antibiotic use in pediatric HSCT units.

Procalcitonin in special patient populations: Guidance for antimicrobial therapy

PURPOSE

Procalcitonin (PCT) is an endogenous hormone that increases reliably in response to bacterial infection, and measurement of serum PCT levels is recommended to help guide antimicrobial therapy. The utility of PCT assessment in special patient populations (eg, patients with renal dysfunction, cardiac compromise, or immunocompromised states and those undergoing acute care surgery) is less clear. The evidence for PCT-guided antimicrobial therapy in special populations is reviewed.

SUMMARY

In the presence of bacterial infection, nonneuroendocrine PCT is produced in response to bacterial toxins and inflammatory cytokines, resulting in markedly elevated levels of serum PCT. Cytokine induction in nonbacterial inflammatory processes activated by acute care surgery may alter the interpretation of PCT levels. The reliability of PCT assessment has also been questioned in patients with renal dysfunction, cardiac compromise, or immunosuppression. In many special populations, serum PCT may be elevated at baseline and increase further in the presence of infection; thus, higher thresholds for diagnosing infection or de-escalating therapy should be considered, although the optimal threshold to use in a specific population is unclear. Procalcitonin-guided antimicrobial therapy may be recommended in certain clinical situations.

CONCLUSION

Procalcitonin may be a reliable marker of infection even in special populations with baseline elevations in serum PCT. However, due to unclear threshold values and the limited inclusion of special populations in relevant clinical trials, PCT levels should be considered along with clinical criteria, and antibiotics should never be initiated or withheld based on PCT values alone. Procalcitonin measurement may have a role in guiding de-escalation of antibiotic therapy in special populations; however, the clinician should be aware of disease states and concomitant therapies that may affect interpretation of results.

Changes in Sepsis Biomarkers after Immunosuppressant Administration in Transplant Patients

Sepsis biomarkers change continuously during the postoperative period. We aimed to demonstrate the influence of immunosuppressants after transplantation (Tx) on presepsin, procalcitonin, CRP, white blood cells, and IL-6. A group of 140 patients after major surgery (86 non-Tx, 54 Tx) without any signs of sepsis or infectious complications was followed for 7 days. The changes in biomarkers were analyzed with respect to the type of surgery, organ, and induction immunosuppressant used (antithymocyte globulin, corticosteroids, or basiliximab/rituximab). Concentrations (95th percentiles) of presepsin and procalcitonin were higher in the Tx group (presepsin: Tx < 2380 vs. non‐Tx < 1368 ng/L, p < 0.05; procalcitonin: <28.0 vs. 3.49 μg/L, p < 0.05). In contrast, CRP and IL-6 were lower in the Tx group (CRP: Tx < 84.2 vs. non‐Tx < 229 mg/L, p < 0.05; IL-6: <71.2 vs. 317 ng/L, p < 0.05). Decreases in CRP and IL-6 were found for all immunosuppressants, and procalcitonin was increased after antithymocyte globulin and corticosteroids. Negligible changes were found for white blood cells. Different responses of presepsin, procalcitonin, CRP, and IL-6 were therefore found in patients without any infectious complications after major surgery or transplantation. Immunosuppression decreased significantly IL-6 and CRP in comparison to non-Tx patients, while procalcitonin was increased after corticosteroids and antithymocyte globulin only. Cautious interpretation of sepsis biomarkers is needed in the early posttransplant period. This work was conducted as a noninterventional (nonregistered) study.

Identification and Management of Fusobacterium Nucleatum Liver Abscess and Bacteremia in a Young Healthy Man

A 21-year-old previously healthy young man was admitted with five days of fever, persistent cough, worsening shortness of breath, and vomiting. On presentation, laboratory evaluation revealed extremely elevated procalcitonin and leukopenia followed by leukocytosis. The patient was started on empiric antibiotics. Further diagnostic evaluation after initiation of antibiotics included a computed tomography scan, which revealed a large hepatic abscess. Blood cultures obtained on admission grew Fusobacterium nucleatum; fluid obtained from the hepatic abscess also grew F. nucleatum. The patient’s antibiotic regimen was narrowed for specific coverage of F. nucleatum. The liver abscess was drained several times via image-guided percutaneous abscess drainage, with eventual resolution of the abscess. Patient received a prolonged course of intravenous antibiotics and, once stabilized, was discharged on two weeks of Augmentin. Here, we present a rare case of hepatic abscess and bacteremia due to F. nucleatum in a previously healthy young man with good oral hygiene. With this case, we aim to demonstrate the following: (1) the acute onset and rapid disease progression of F. nucleatum bacteremia and liver abscess; (2) how extreme procalcitonin elevation may serve to be a clinically useful early marker of F. nucleatum infection; and (3) the importance of early diagnosis, treatment, and definitive abscess drainage of F. nucleatum bacteremia and liver abscess.

Procalcitonin Kinetics After Heart Transplantation and as a Marker of Infection in Early Postoperative Course

INTRODUCTION

Procalcitonin (PCT) is a biomarker of systemic infection. Specificity of PCT is decreased because PCT is also elevated after heart transplantation (HTx). There is no established normal range of serum PCT concentrations after HTx yet. Our aim was to determine the course of PCT concentrations in patients after HTx in the early postoperative period, if we can discriminate postoperative increase in values from infectious complications.

RESULTS

Of 39 patients we diagnosed infection in 11. These patients develop acute kidney injury significantly more often than in control group (group C) (5 in infection group [group I] and 2 in group C, P < .05), and 1 patient died within 30 days in group C. Seven patients developed primary graft dysfunction (3/4 + ECMO [extracorporeal membrane oxygenation], respectively, group I/group C) and 2 neurologic disorders in group I. Reoperation due to bleeding was 3 in each group. During the 14 days after HTx, serum PCT concentrations increased with maximum on the second postoperative day (group C: 30.6 ± 15.3 ng/mL; group I: 24.9 ± 44.3 ng/mL). Normal values for PCT were reached on day 8 in group C and 11 in group I. Mean PCT levels were similar: 8.7 ± 5.7 ng/mL vs 11.9 ± 13.1 ng/mL in group I vs group C, respectively. Patients in group I stayed longer in the intensive care unit.

CONCLUSIONS

Despite increase in serum concentration of PCT in early postoperative course after HTx there is no marker of infection. Trends in PCT serum concentration may be a valuable tool in diagnosis of infection in patients after HTx, but further investigation is needed.

Prognostic factors and outcome of adult allogeneic hematopoietic stem cell transplantation patients admitted to intensive care unit during transplant hospitalization

Patients undergoing allogeneic hematopoietic stem cell transplantation have a high morbidity and mortality, especially after admission to intensive care unit (ICU) during peri-transplant period. The objective of this study was to identify new clinical and biological parameters and validate prognostic scores associated with ICU, short-and long-term survival. Significant differences between ICU survivors and ICU non-survivors for the clinical parameters invasive mechanical ventilation, urine output, heart rate, mean arterial pressure, and amount of vasopressors have been measured. Among prognostic scores (SOFA, SAPSII, PICAT, APACHE II, APACHE IV) assessing severity of disease and predicting outcome of critically ill patients on ICU, the APACHE II score has shown most significant difference (p = 0.002) and the highest discriminative power (area under the ROC curve (AUC) 0.74). An elevated level of lactate at day of admission was associated with poor survival on ICU and the most significant independent parameter (p < 0.001). In our cohort kidney damage with low urine output has a highly relevant impact on ICU, short- and long-term overall survival. The APACHE II score was superior predicting ICU mortality compared to all other tested prognostic scores for patients on ICU during peri-transplant period.

Profound but Transient Changes in the Inflammatory Milieu of the Blood During Autologous Hematopoietic Stem Cell Transplantation

Little is known about the inflammatory milieu in the blood during autologous hematopoietic stem cell transplantation (AHSCT) and how it is affected by the stem cell mobilization, collection, and reinfusion and conditioning regimen. In this study, we analyzed 92 proteins connected to inflammation at 10 time points during and after AHSCT in 16 patients with multiple sclerosis (MS). Serum from 29 patients with newly diagnosed MS and 15 healthy controls were included for comparative analysis. There were no significant differences in inflammatory serum protein levels between patients with newly diagnosed MS and healthy controls, but 29 out of 73 detectable proteins were significantly altered between at least 2 adjacent sampling time points during AHSCT. The predominant changes occurred after the conditioning regimen had been administered, whereas stem cell mobilization, collection, and reinfusion appeared to have less impact. Two distinct response patterns could be discerned, likely representing loss of basal cytokine production and homeostasis. The analyzed serum proteins gradually returned to baseline levels after treatment, with no remaining differences at 3 months after AHSCT. We conclude that treatment with AHSCT has a major but transient impact on the inflammatory milieu of peripheral blood.

Comparison of the Power of Procalcitonin and C-Reactive Protein to Discriminate between Different Aetiologies of Fever in Prolonged Profound Neutropenia: A Single-Centre Prospective Observational Study

Management of fever in prolonged, profound neutropenia remains challenging with many possible infectious and non-infectious causes. We investigated whether procalcitonin (PCT) is superior to C-reactive protein (CRP) in discriminating between different aetiologies of fever in this setting.

CRP and PCT were tested daily during 93 neutropenic episodes in 66 patients. During this study period, 121 febrile episodes occurred and were classified into four categories based on clinical and microbiological findings: microbiologically documented infection (MDI); clinically documented infection (CDI); proven or probable invasive fungal disease (IFD); fever of unknown origin (FUO). Values of PCT and CRP at fever onset as well as two days later were considered for analysis of their performance in distinguishing aetiologies of fever.

At fever onset, no significant difference in PCT values was observed between different aetiologies of fever, whereas median CRP values were significantly higher in case of IFD (median 98.8 mg/L vs 28.8 mg/L, p=0.027). Both PCT and CRP reached their peak at a median of 2 days after fever onset. Median PCT values on day 2 showed no significant difference between the aetiologies of fever. Median CRP values on day 2 were significantly higher in IFD (median 172 mg/L versus 78.4 mg/L, p=0.002). In MDI median CRP values rose > 100 mg/L, whereas they did not in CDI or FUO.

PCT has no added value over CRP for clinical management of fever in prolonged, profound neutropenia. When performing reassessment 2 days after fever onset, CRP has better discriminatory power between aetiologies of fever.

Undue Elevation of Procalcitonin in Pediatric Paracetamol Intoxication is Not Explained by Liver Cell Injury Alone

INTRODUCTION AND AIM

Procalcitonin is widely used as a biomarker to distinguish bacterial infections from other etiologies of systemic inflammation. Little is known about its value in acute liver injury resulting from intoxication with paracetamol.

MATERIAL AND METHODS

We performed a single-center retrospective analysis of the procalcitonin level, liver synthesis, liver cell damage and renal function of patients admitted with paracetamol-induced liver injury to a tertiary care children's hospital. Children with acute liver failure due to other reasons without a bacterial or fungal infection served as the control group. Twelve patients with acute paracetamol intoxication and acute liver injury were compared with 29 patients with acute liver failure.

RESULTS

The procalcitonin levels were higher in children with paracetamol intoxication than in patients with acute liver failure without paracetamol intoxication (median 24.8 (0.01-55.57) ng/mL vs. 1.36 (0.1-44.18) ng/mL; p &lt; 0.005), although their liver and kidney functions were better and the liver cell injury was similar in both groups. Outcome analysis showed a trend towards better survival without transplantation in patients with paracetamol intoxication (10/12 vs. 15/29). Within each group, procalcitonin was significantly correlated with alanine aminotransferase and aspartate aminotransferase but was not correlated with the International Normalized Ratio or paracetamol blood levels in the paracetamol group. In conclusion, paracetamol intoxication leads to a marked increase in procalcitonin serum levels, which are significantly higher than those seen in acute liver failure.

CONCLUSION

The underlying mechanism is neither caused by infection nor fully explained by liver cell death alone and remains to be determined.

Procalcitonin Monitoring as a Guide for Antimicrobial Therapy: A Review of Current Literature

Effective antimicrobial stewardship practices are increasingly essential to best utilize the current arsenal of antimicrobials for the shortest necessary duration to minimize the development of antimicrobial resistance, secondary infections, and health care costs. Monitoring of serum procalcitonin (PCT) levels represents an effective antimicrobial stewardship strategy to differentiate bacterial infections from viral infections and noninfectious inflammatory conditions. Current literature illustrates the merits of PCT monitoring in reducing duration of antibiotic therapy without detrimental effects on mortality or infection relapses. However, the interpretation of PCT levels can be challenging, especially in light of comorbid disease states that can elevate PCT levels. This review sheds light on the utility of PCT monitoring, as well as providing insight into the practical interpretation of PCT levels. Much of the current literature surrounding PCT monitoring consists of use among patients with lower respiratory tract infections or in the critically ill. Overall, studies have demonstrated shorter antibiotic therapy durations when PCT monitoring is utilized. No studies to date have found increased rates of mortality or infection relapses, suggesting that PCT monitoring is not only effective, but also safe when used as a guide for antimicrobial therapy. Nonetheless, many conditions were shown to elevate PCT serum concentrations, even in the absence of bacterial infections, which can make interpretation of PCT concentrations challenging. Two common conditions that affect the accurate interpretation of PCT levels are renal dysfunction and congestive heart failure. Limited studies have been performed in these populations, but current available data propose the need for higher PCT thresholds in those with renal dysfunction or congestive heart failure and support utilizing PCT trends to monitor clinical improvement from bacterial infections. Evidence also suggests that PCT monitoring is cost-effective, as long as the test is ordered judiciously. In summary, PCT monitoring represents a promising antimicrobial stewardship strategy to limit exposure to unnecessary antimicrobial therapy.

Role of Procalcitonin in the Management of Infected Patients in the Intensive Care Unit

The combination of molecular pathogen diagnostics and the biomarker procalcitonin (PCT) are changing the use of antimicrobials in patients admitted to critical care units with severe community-acquired pneumonia, possible septic shock, or other clinical syndromes. An elevated serum PCT level is good supportive evidence of a bacterial pneumonia, whereas a low serum PCT level virtually eliminates an etiologic role for bacteria even if the culture for a potential bacterial pathogen is positive. Serum PCT levels can be increased in any shocklike state; a low PCT level eliminates invasive bacterial infection as an etiology in more than 90% of patients.

Feasibility and applicability of antimicrobial stewardship in immunocompromised patients

PURPOSE OF REVIEW

Antimicrobial stewardship is the primary intervention in the battle against antimicrobial resistance, but clinicians do not always apply many key antimicrobial stewardship principles to patients with significant immune defects due to lack of data and fear of bad outcomes. We review evidence regarding the application of stewardship principles to immunocompromised patients, with a focus on solid organ and hematopoietic stem cell transplant recipients.

RECENT FINDINGS

Antimicrobial stewardship programs (ASPs), targeting immunocompromised patient populations such as oncology and transplant, are gaining traction. Emerging literature suggests that several stewardship interventions can be adapted to immunocompromised hosts and improve antimicrobial utilization, but data supporting improved outcomes is very limited.

SUMMARY

The application of antimicrobial stewardship principles to immunocompromised patients is feasible, necessary, and urgent. As antimicrobial stewardship programs gain momentum across a diverse range of healthcare settings more immunocompromised patients will fall under their purview. It is imperative that centers applying antimicrobial stewardship principles share their experience and establish collaborative research efforts to advance our knowledge base in applying antimicrobial stewardship initiatives to immunocompromised host populations, both in terms of programmatic success and patient outcomes.

Current use and potential role of procalcitonin in the diagnostic work up and follow up of febrile neutropenia in hematological patients

INTRODUCTION

Febrile neutropenia (FN) represents a life-threatening complication in hematological malignancies. Its etiology is most often due to infections even though FN of other origins, such as tumor-related fever and non-infectious inflammation, should rapidly be ruled out. Initially, C-reactive protein and, more recently, procalcitonin (PCT) have been proposed as useful biomarkers for differential diagnosis. PCT was shown to be a good biomarker of bacterial infections and their clinical outcomes. Definition of standard cut-offs and design of PCT-guided treatment protocols remain however to be defined. Areas covered: In this review, highlights on the current clinical use of PCT and its potential role as a diagnostic tool have been discussed by a panel of physicians from different areas of expertise. We provide current clinical evidence that PCT has been shown to be a reliable biomarker to differentiate fever of bacterial origin from other causes. Moreover, the Authors convened to a round-table to discuss their 'real-life experience' and offer their recommendations by a Delphi survey. Expert commentary: PCT has an important clinical role in FN. Issues such as the validation of a specific decision algorithm that includes PCT to monitor antibiotic choice and treatment duration will be addressed in prospective studies.

Serial measurement of presepsin, procalcitonin, and C-reactive protein in the early postoperative period and the response to antithymocyte globulin administration after heart transplantation

Differentiation between systemic inflammatory response syndrome and sepsis in surgical patients is of crucial significance. Procalcitonin (PCT) and C-reactive protein (CRP) are widely used biomarkers, but PCT becomes compromised after antithymocyte globulin (ATG) administration, and CRP exhibits limited specificity. Presepsin has been suggested as an alternative biomarker of sepsis. This study aimed to demonstrate the role of presepsin in patients after heart transplantation (HTx). Plasma presepsin, PCT, and CRP were measured in 107 patients serially for up to 10 days following HTx. Time responses of biomarkers were evaluated for both noninfected (n=91) and infected (n=16) patients. Areas under the concentration curve differed in the two groups of patients for presepsin (P<.001), PCT (P<.005), and CRP (P<.001). The effect of time and infection was significant for all three biomarkers (P<.05 all). In contrast to PCT, presepsin was not influenced by ATG administration. More than 25% of noninfected patients had PCT above 42 μg/L on the first day, and the peak concentration of CRP in infected patients was reached on the third post-transplant day (median 135 mg/L). Presepsin seems to be as valuable a biomarker as PCT or CRP in the evaluation of infectious complications in patients after HTx.

Diagnostic value of sepsis biomarkers in hematopoietic stem cell transplant recipients in a condition of high prevalence of gram-negative pathogens

OBJECTIVE/BACKGROUND

A decision about the need for antimicrobial therapy in a patient with febrile neutropenia after hematopoietic stem cell transplantation (HSCT) is often complicated because of the low frequency of culture isolation and reduced clinical manifestation of infection. Usefulness and choice of sepsis biomarkers to distinguish bloodstream infection (BSI) from other causes of febrile episode is still argued in HSCT recipients in modern epidemiological situations characterized by the emergence of highly resistant gram-negative microorganisms. In this study a comparative analysis of diagnostic values of presepsin, procalcitonin (PCT), and C-reactive protein (CRP) was performed as sepsis biomarkers in adult patients after HSCT in a condition of high prevalence of gram-negative pathogens.

METHODS

A prospective observational clinical study was performed at the Center of Hematology and Bone Marrow Transplantation in Minsk, Republic of Belarus. The biomarkers (presepsin, PCT, and CRP) were assessed in a 4-hour period after the onset of febrile neutropenia episode in adult patients after HSCT. Microbiologically-confirmed BSI caused by a gram-negative pathogen was set as a primary outcome.

RESULTS

Clinical and laboratory data were analyzed in 52 neutropenic patients after HSCT aged 18-79years. Out of the biomarkers assessed, the best diagnostic value was shown in presepsin (area under the curve [AUC]: 0.889, 95% confidence interval [CI]: 0.644-0.987, p<.0001) with 75% sensitivity and 100% specificity, then in PCT (AUC: 0.741, 95% CI: 0.573-0.869, p=.0037) with 62% sensitivity and 88% specificity. The optimal cut-off value for CRP was set as 165mg/L, while it had an average diagnostic value (AUC: 0.707, 95% CI: 0.564-0.825, p=.0049) with low sensitivity (40%) and should not be routinely recommended as a biomarker in adult patients with suspected BSI after HSCT.

CONCLUSION

Presepsin may be recommended in adult patients with suspected gram-negative BSI after HSCT as a possible additional supplementary test with a cut-off value of 218pg/mL. PCT is inferior to presepsin in terms of sensitivity and specificity, but still shows a good quality of diagnostic value with an optimal cut-off value of 1.5ng/mL. CRP showed an average diagnostic value with low sensitivity (40%) and should not be routinely recommended as a biomarker in adult patients with suspected BSI after HSCT in a condition of high prevalence of gram-negative pathogens.

Role of Biomarkers as Predictors of Infection and Death in Neutropenic Febrile Patients after Hematopoietic Stem Cell Transplantation

An ideal marker in the neutropenic population after HSCT is the one which positivetes at the onset of fever, or at most up to 24 hours after its onset, the patients at potential risk for infection due to bacterial and fungi and mortality. Several biomarkers have been used in HSCT patients in the last decade. However, it seems that C-RP and Il-6 are the most useful markers to early detected infection and risk for death

Diagnostic Value of Procalcitonin in ANCA-Associated Vasculitis (AAV) to Differentiate Between Disease Activity, Infection and Drug Hypersensitivity

Objective:

Procalcitonin (PCT) is considered to be a specific marker for severe bacterial infections and sepsis. Elevated PCT levels have been reported in active autoimmune diseases without infection.

The aim of this study was to assess the diagnostic value of PCT serum levels in ANCA-associated vasculitis (AAV) patients with respect to infection, disease activity and drug fever using a high sensitive PCT detection method.

Methods:

In 53 AAV patients with elevated C-reactive protein (CRP) PCT was determined by the Thermo Scientific BRAHMS PCT sensitive KRYPTOR assay. Patients underwent standardized diagnostic procedures for evaluation of disease activity and infection.

Results:

53 patients with AAV and elevated CRP (7.7±6.9 mg/dl, PCT 0.34±1.02 ng/ml) were assessed, 10 had infection with elevated CRP levels of 11.2±10.2 mg/dl and PCT levels of 1.06±2.07 ng/dl. 43 patients had no evidence of infection, 36 of them were presented with AAV with normal or only slightly positive PCT levels in active disease (n=36) (PCT 0.06±0.06 ng/ml). 7 patients had increased PCT levels due to azathioprine hypersensitivity (0.76±1.01 ng/ml). For discrimination between infection and vasculitis activity PCT was more useful than CRP with the best cut-off at 0.1 ng/ml (sensitivity 60%, specificity 92%).

Conclusion:

In contrast to previous studies using semiquantitative PCT assays, the KRYPTOR performs better with respect to discrimination of infection from active AAV. In all patients assessed with active AAV (and without infection) PCT levels remained below the PCT reference limit (0.5 ng/ml) for infections. Drug hypersensitivity seems to be an important differential diagnosis in the setting of elevated CRP and PCT in patients who receive azathioprine.

Comparative usefulness of inflammatory markers to indicate bacterial infection-analyzed according to blood culture results and related clinical factors

To assess relationships of inflammatory markers and 2 related clinical factors with blood culture results, we retrospectively investigated inpatients' blood culture and blood chemistry findings that were recorded from January to December 2014 using electronic medical records and analyzed the data of 852 subjects (426 culture-positive and 426 culture-negative). Results suggested that the risk of positive blood culture statistically increased as inflammatory marker levels and the number of related factors increased. Concerning the effectiveness of inflammatory markers, when the outcome definition was also changed for C-reactive protein (CRP), the odds ratio had a similar value, whereas when the outcome definition of blood culture positivity was used for procalcitonin (PCT), the greatest effectiveness of that was detected. Therefore, the current results suggest that PCT is more useful than CRP as an auxiliary indication of bacterial infection.

Reversal of severe lactic acidosis with thiamine in a renal allograft recipient

A 48-year-old female patient with end-stage renal failure developed unexplained severe lactic acidosis (LA) associated with hyperglycemia during robotic-assisted laparoscopic renal transplantation. Initial treatment with sodium bicarbonate and insulin infusion were ineffective in treating acidemia. Postoperatively, intravenous administration of thiamine resulted in rapid improvement of LA and blood sugar levels. Uremia and chronic hemodialysis might be the causes behind the quantitative/qualitative deficiency of thiamine unmasked during the surgical stress. Though a rare entity, acute thiamine deficiency should be considered in the differential diagnosis of unexplained severe LA in patients with chronic kidney disease and hemodialysis who undergo major surgery or admitted to critical illness care units.

Lower dose anti-thymocyte globulin for GvHD prophylaxis results in improved survival after allogeneic stem cell transplantation

In vivo T-cell depletion with anti-thymocyte globulin (ATG) can attenuate GvHD but may increase infection and relapse risks. ATG-Fresenius (ATG-F) at a dose of 60 mg/kg was standard GvHD prophylaxis in unrelated donor hematopoietic stem cell transplantation (HSCT) at our institution. We changed to an incremental reduced dose regimen of 35 mg/kg and extended ATG prophylaxis to include older matched-related donor transplants considered to be at higher risk of GvHD. A total of 265 adults with hematological malignancies receiving a first allogeneic HSCT after myeloablative conditioning between 2009 and 2014 were analyzed in this cohort study. Patients had either received higher dose (n=32) or lower dose ATG-F (n=88) or no ATG (n=145). ATG-F was associated with slower engraftment and less chronic GvHD, whereas no effect was noted on acute grade II-IV GvHD and relapse incidence. Transplant-related mortality (TRM) was lower and survival higher with lower dose, but not with higher dose ATG-F. Both ATG-F groups were associated with more viral reactivation, viral disease and bacterial blood stream infection, but not invasive fungal infection, and with slower immune reconstitution. The recently adopted strategy of using lower doses of ATG-F in unrelated and older age-related donor HSCT appears to reduce TRM without increasing disease relapse, leading to slightly enhanced survival.

The use and value of procalcitonin in solid organ transplantation

Procalcitonin (PCT) has been increasingly used as a biomarker of bacterial infection and as a tool to guide antimicrobial therapy, especially in lower respiratory tract and bloodstream infections. Despite its increased use, data in patients with solid organ transplants are limited. Even without the presence of infection, PCT increases as a result of surgical procedures during transplantation, implantation of devices, and use of induction immunosuppressive therapy. The risk of infection is also higher in solid organ transplant recipients when compared to the general population. Monitoring PCT in the early post-transplant period seems to be a promising method for early detection of infectious complications. It has been shown that elevated PCT levels after one wk of transplantation are correlated with infectious complications. PCT may be a useful adjunctive biomarker that may improve early identification and guide appropriate treatment of infection or rejection, with the potential to further improve clinical outcomes. The use of serial PCT measurements may be more reliable than single values. It is important to recognize which factors may lead to PCT increases in the post-transplantation period, which in turn will help understand the kinetics and utility of this biomarker in this important patient population.

Host response biomarkers in sepsis: the role of procalcitonin

Procalcitonin is the prohormone of calcitonin and present in minute quantities in health. However, during infection, its levels rise considerably and are correlated with the severity of the infection. Several assays have been developed for measurement of procalcitonin levels; in this article, we will briefly present the PCT-sensitive Kryptor(®) test (Brahms, Hennigsdorf, Germany), one of the most widely used assays for procalcitonin in recent studies. Many studies have demonstrated the value of procalcitonin levels for diagnosing sepsis and assessing disease severity. Procalcitonin levels have also been successfully used to guide antibiotic administration. However, procalcitonin is not specific for sepsis, and values need to be interpreted in the context of a full clinical examination and the presence of other signs and symptoms of sepsis.

Elevation of procalcitonin after implantation of an interventional lung assist device in critically ill patients

A pumpless interventional arteriovenous lung assist device (iLA) facilitates the removal of carbon dioxide from the blood and is used as part of the lung-protective ventilation strategy in patients with acute respiratory distress syndrome (ARDS). In case of bacterial infection, delayed antimicrobial therapy increases the mortality in this group of high-risk critically ill patients, whereas overtreatment promotes bacterial resistance and leads to increased drug toxicity and costs. Besides clinical signs and symptoms, antimicrobial treatment is based on the kinetics of biomarkers such as procalcitonin (PCT). We hereby report an up to 10-fold increase in PCT serum concentrations in four mechanically ventilated patients with ARDS detected within 12-20 hours after iLA implantation in the absence of any infection. Procalcitonin concentrations returned to nearly baseline values in all patients on the fourth day after iLA implantation. We discuss the possible mechanisms of PCT induction in this specific patient population and recommend the onset of antibiotics administration after iLA implantation to be carefully considered in the context of other clinical findings and not solely based on the PCT kinetics. Repeated PCT measurements in short time intervals should be performed in these patients.

Risk factor for death in hematopoietic stem cell transplantation: are biomarkers useful to foresee the prognosis in this population of patients?

BACKGROUND

The morbidity and mortality in hematopoietic stem cell transplantation (HSCT) occur due to infectious complications and constitute the major clinical problems in HSCT recipients. The role of the use of biomarkers in post-HSCT patients is still controversial.

OBJECTIVES

To assess the serum values of biomarkers interleukin 6 (IL-6), procalcitonin (PCT) and C-reactive protein (CRP) and risk factors for post-HSCT death.

PATIENTS AND METHODS

Prospective study conducted in patients submitted to HSCT at a university hospital. Biomarkers (IL-6, PCT and CRP) were assessed on the day afebrile neutropenia was detected, in the febrile event, 24 and 72 h after fever onset and 48 h or 5 days if fever persisted. Patients were compared as to the death outcome within 30 days from the HSCT. Variables with p < 0.15 were included in the multivariate analysis model (MVA) that were performed for all patients included in the study and separated for autologous and allogeneic HSCT patients.

RESULTS

296 patients with ages ranging between 15 and 70 years, neutropenic, submitted to HSCT, being 216 (73%) autologous and 80 (20%) allogeneic were assessed. One hundred and ninety (64.2%) patients presented fever after the transplantation and infection microbiologically controlled in 78 (26.4%). Twenty-three cases (7.8%) evolved to death. The risk factors associated with death in the bivariate analysis were age, allogeneic transplantation, unrelated transplantation, GVHD, bloodstream infection by Gram-negative, IL-6 >140 pg/mL and CRP ≥ 120 mg/L and the protective ones were lymphoma and hospital outpatient support. The independent variables in the MVA associated with death were allogeneic and unrelated transplantation, blood stream infection (BSI) by Gram-negative, LDH ≥ 390 UI/L, urea ≥ 25 mg/dL and CRP ≥ 120 mg/L for HSCT transplanted patients and BSI due to Gram-negative and CRP ≥ 120 mg/L for allogeneic HSCT, however, CRP ≥ 120 mg/L did not remain in the model when urea ≥ 25 mg/L was included. No independent risk factor was found for autologous patients.

CONCLUSIONS

Out of the biomarkers assessed, only CRP ≥ 120 mg/L was independently associated with death. Other risk factors found were: type of transplantation (allogeneic and unrelated), bloodstream infection by Gram-negative, LDH ≥ 390 UI/L and urea ≥ 25 mg/dL. For allogeneic patients only CRP ≥ 120 mg/L and BSI due to Gram-negative were risk factors for death; however, CRP did not remain in the model when urea ≥ 25 mg/L was included.

Procalcitonin for antibiotic treatment in intensive care unit patients

Procalcitonin (PCT), a 116-aminoacids prohormone, has been substantially studied over the last 2 decades in the field of sepsis. Disappointingly low sensitivity values led to the abandonment of the concept of it as a diagnostic tool and then to its being considered more as a prognostic marker with a good correlation with severe infection. Later on, growing concerns about multidrug-resistant bacteria in the ICU environment and about the cost and side effects of antibiotics suggested that PCT might prove to be a valuable asset in stewardship programs. Numerous but hardly comparable randomized controlled trials assessing either initiation or deescalation in ICU patients have been published. Stewardship encompassing PCT should focus on the latter, because of the high negative predictive value of this biomarker. However, there still would be safety concerns if a systematic implementation of PCT were to be considered in daily stewardship programs in the ICU, especially in extra-thoracic sepsis.

Can procalcitonin differentiate Staphylococcus aureus from coagulase-negative staphylococci in clustered gram-positive bacteremia?

Procalcitonin (PCT) and pro-adrenomedullin (ProADM) have been proposed as diagnostic and prognostic biomarkers of infection. Between July 2009 and January 2012, we studied the role of these biomarkers in 163 patients with clustered gram-positive and gram-negative bacteremia. PCT levels were significantly higher in patients with Staphylococcus aureus and gram-negative bacteremia than those with coagulase-negative staphylococci (CoNS) isolated from blood cultures (P = 0.29 and <0.001, respectively). ProADM levels were only significantly higher in patients with gram-negative bacteremia (median 1.46 nmol/L) than those with CoNS (median 1.01 nmol/L) (P = 0.04). Among patients with CoNS, PCT, and ProADM, levels failed to differentiate blood contamination (medians 0.24 ng/mL and 0.97 nmol/L) from true bacteremia (medians 0.26 ng/mL and 1.14 nmol/L) (P = 0.51 and 0.57, respectively). In cancer patients, PCT (and to a lesser extent, ProADM) was useful in differentiating CoNS from S. aureus and gram-negative bacteremia.

Inflammatory markers in patients after hematopoietic stem cell transplantation

Infections are one of the most common complications after hematopoietic stem cell transplantation (HSCT). Diagnosis is established by analysis of clinical symptoms and results of diagnostic tests such as biochemical panels, microbiological cultures, and visual diagnostics. As the microbiological cultures yield positive results in only some patients and visual diagnostics might miss the infectious source, the diagnosis and proper treatment often depends on clinical assessment supported by laboratory test results. The most commonly used makers of inflammation include C-reactive protein and procalcitonin. However, these tests have serious limitations when used in patients after HSCT. The drugs used in conditioning, neutropenia, and graft-versus-host disease might influence the results of the tests and misguide the physician. In this review, we summarize the current knowledge on profiles of expression of basic markers of inflammation used in clinical practice in patients after HSCT.

[Use of biological markers in the differential diagnosis of sepsis after liver transplant]

The use of biological markers is developing in the field of liver transplant. Biomarkers are being studied in different contexts: 1) detection of tolerant patient; 2) recurrence of hepatitis C virus; 3) diagnosis and prognosis of liver cancers, and 4) diagnosis of infection. The immunological changes occurring in the transplant patient given their previous cirrhotic condition, the immunosuppression received, and possible intercurrent diagnoses (rejection, recurrence of hepatitis C virus…) highlight the importance of finding useful biomarkers in clinical practice to diagnose infection. After a review of the usefulness of biomarkers, we should perhaps add the serial determination of C-reactive protein in the immediate post-operative period, and later on procalcitonin, in the infection diagnosis algorithm. Although the determination of procalcitonin appears to be the most reliable biomarker in the differential diagnosis of sepsis and rejection, the studies carried out make it difficult to establish conclusions on its real clinical usefulness.

Procalcitonin: seeking a niche

For over a decade there has been intense interest given to the role of procalcitonin in the diagnosis and management of sepsis in critically ill patients. Early opinions strongly supported the diagnostic role but data accumulating from numerous subsequent studies are less supportive, even when used in very selective settings. Although there remains sufficient reason to support the use of procalcitonin in guiding antibiotic therapy or perhaps providing prognostic information, it may be time to focus our efforts on the early diagnosis of sepsis in the critically care setting on alternative, more promising methods.