Lung transplant outcomes are influenced by severity of neutropenia and granulocyte colony-stimulating factor treatment

Impact of Neutropenia on Clinical Outcomes after Lung Transplantation

BACKGROUND/OBJECTIVES

Neutropenia is a frequent complication among solid organ transplant (SOT) recipients receiving immunosuppressive therapy and antimicrobial prophylaxis. However, there are limited studies analysing the frequency and impact of neutropenia in lung transplant recipients (LTRs). Our aim was to analyse the frequency of neutropenia, the need for granulocyte colony-stimulating factor (GCSF) treatment within the first 18 months post-transplant and its association with acute rejection, chronic lung allograft dysfunction (CLAD), overall survival and the development of infections.

METHODS

This observational and retrospective study recruited 305 patients who underwent lung transplantation between 2009 and 2019, with outpatient quarterly follow-up during the first 18 months post-surgery.

RESULTS

During this period, 51.8% of patients experienced at least one episode of neutropenia. Neutropenia was classified as mild in 50.57% of cases, moderate in 36.88% and severe in 12.54%. GCSF treatment was indicated in 23.28% of patients, with a mean dose of 3.53 units. No statistically significant association was observed between neutropenia or its severity and the development of acute rejection, CLAD or overall survival. However, the patients who received GCSF treatment had a higher mortality rate compared to those who did not. Sixteen patients (5.25%) developed infections during neutropenia, with bacterial infections being the most common.

CONCLUSIONS

Neutropenia is common in the first 18 months after lung transplantation and most episodes are mild. We did not find an association between neutropenia and acute rejection, CLAD, or mortality. However, the use of GCSF were associated with worse post-transplant survival.

Donor age over 55 is associated with worse outcome in lung transplant recipients with idiopathic pulmonary fibrosis

BACKGROUND

Lung transplantation (LTx) remains the only efficient treatment for selected patients with end-stage pulmonary disease. The age limit for the acceptance of donor organs in LTx is still a matter of debate. We here analyze the impact of donor organ age and the underlying pulmonary disease on short- and long-term outcome and survival after LTx.

METHODS

Donor and recipient characteristics of LTx recipients at our institution between 03/2003 and 12/2021 were analyzed. Statistical analysis was performed using SPSS and GraphPad software.

RESULTS

In 230 patients analyzed, donor age ≥ 55 years was associated with a higher incidence of severe primary graft dysfunction (PGD2/3) (46% vs. 31%, p = 0.03) and reduced long-term survival after LTx (1-, 5- and 10-year survival: 75%, 54%, 37% vs. 84%, 76%, 69%, p = 0.006). Notably, this was only significant in recipients with idiopathic pulmonary fibrosis (IPF) (PGD: 65%, vs. 37%, p = 0.016; 1-, 5-, and 10-year survival: 62%, 38%, 16% vs. 80%, 76%, 70%, p = 0.0002 respectively). In patients with chronic obstructive pulmonary disease (COPD), donor age had no impact on the incidence of PGD2/3 or survival (21% vs. 27%, p = 0.60 and 68% vs. 72%; p = 0.90 respectively). Moreover, we found higher Torque-teno virus (TTV)-DNA levels after LTx in patients with IPF compared to COPD (X2 = 4.57, p = 0.033). Donor age ≥ 55 is an independent risk factor for reduced survival in the whole cohort and patients with IPF specifically.

CONCLUSIONS

In recipients with IPF, donor organ age ≥ 55 years was associated with a higher incidence of PGD2/3 and reduced survival after LTx. The underlying pulmonary disease may thus be a relevant factor for postoperative graft function and survival.

TRIAL REGISTRATION NUMBER DKRS

DRKS00033312.

Use of letermovir for cytomegalovirus primary prophylaxis in lung transplant recipients

BACKGROUND

Cytomegalovirus (CMV) is a driver of negative outcomes after lung transplant (LTX) and primary prophylaxis (PPX) with valganciclovir (VGC) is standard-of-care. VGC is associated with myelosuppression, prompting interest in letermovir (LTV).

METHODS

Adults receiving LTX between April 1, 2015, and July 30, 2022, at our institution were evaluated. Patients were excluded if low CMV risk (D-/R-), survived <90 days post-LTX, or transferred care before PPX withdrawal. Primary outcomes were leukopenia (white blood cell count [WBC] ≤ 3.0 × 109/L), severe leukopenia (WBC ≤ 2.0 × 109/L), and neutropenia (absolute neutrophil count ≤ 1500 cells/µL) requiring granulocyte-colony stimulating factor (GCSF) on PPX. Secondary outcomes included breakthrough CMV infection and post-PPX CMV infection.

RESULTS

204 patients met inclusion criteria: 175 patients on VGC and 29 patients on LTV (after VGC conversion). Most patients received bilateral LTX (62.7%) with non-lymphocyte-depleting induction (96.6%) and moderate-risk serostatus (D+/R+, 48.5%). Patients transitioned from VGC to LTV after a mean of 178 days (SD 80.8 days) post-transplant. Patients on VGC experienced significantly more leukopenia (82.3% vs. 58.6%, p = 0.008), severe leukopenia (57.1% vs. 31.0%, p = 0.016), and neutropenia requiring GCSF (70.9% vs. 51.7%, p = 0.048). Breakthrough (5.7% vs. 3.4%, p = 0.955) and post-PPX (24.6% vs. 37.9%, p = 0.199) infections were similar. A subgroup analysis of patients with high-risk serostatus showed similar trends, though did not reach statistical significance.

CONCLUSIONS

In this single-center study, the incidence of leukopenia and neutropenia requiring GCSF were reduced with LTV compared to VGC. Breakthrough and post-PPX infections were not significantly different. This evidence suggests that LTV has comparable efficacy with reduced myelosuppression compared to VGC in LTX recipients, and may be an appropriate alternative for PPX.

Incidence of Acute Cellular Rejection After Granulocyte Colony-Stimulating Factor in Lung Transplant Recipients

BackgroundNeutropenia is a common complication in lung transplant recipients (LTRs). Filgrastim may be used to treat neutropenia in LTRs, but its consequences on acute cellular rejection (ACR) remain controversial. Objective: The purpose was to examine the association between filgrastim and incidence of ACR 6 months after filgrastim administration in LTRs. Secondary outcomes included burden of ACR, infections, chronic lung allograft dysfunction (CLAD), and survival. Methods: This was a matched cohort study of patients transplanted between January 2010 and October 2019. LTRs who received filgrastim for neutropenia were compared to a cohort who did not. LTRs were matched on transplant indication, sex, age, and time post-transplant and multivariable logistic regression models were used to evaluate the likelihood of ACR. Results: 212 patients were included in the analysis (106 in each group). 50 patients (47.2%) in the filgrastim group experienced ACR compared to 37 patients (34.9%) in the no filgrastim group (P = .070). In multivariable analysis, filgrastim use was not associated with ACR at 6 months (OR 1.409, 95% CI 0.772-2.571). Time to first ACR was shorter (P = .049) and 6-month ACR score was higher in the filgrastim group (.49 vs .33, P = .047). LTRs in the filgrastim group had higher incidence of bacterial pneumonia and 1-year mortality. Conclusions: Although not associated with increased likelihood of ACR at 6 months, our study found that filgrastim is associated with increased ACR burden and decreased time to ACR. This study can help inform clinicians of ACR risk after filgrastim use in LTRs.

Impact of recipient age on mortality among Cytomegalovirus (CMV)-seronegative lung transplant recipients with CMV-seropositive donors

BACKGROUND

Cytomegalovirus (CMV)-seronegative lung transplant recipients (LTRs) with seropositive donors (CMV D+/R-) have the highest mortality of all CMV serostatuses. Due to immunosenescence and other factors, we hypothesized CMV D+/R- status might disproportionately impact older LTRs. Thus, we investigated whether recipient age modified the relationship between donor CMV status and mortality among CMV-seronegative LTRs.

METHODS

Adult, CMV-seronegative first-time lung-only recipients were identified through the Scientific Registry of Transplant Recipients between May 2005 and December 2019. We used adjusted multivariable Cox regression to assess the relationship of donor CMV status and death. Interaction between recipient age and donor CMV was assessed via likelihood ratio testing of nested Cox models and by the relative excess risk due to interaction (RERI) and attributable proportion (AP) of joint effects.

RESULTS

We identified 11,136 CMV-seronegative LTRs. The median age was 59 years; 65.2% were male, with leading transplant indication of idiopathic pulmonary fibrosis (35.6%); and 60.8% were CMV D+/R-. In multivariable modeling, CMV D+/R- status was associated with 27% increased hazard of death (adjusted hazard ratio: 1.27, 95% confidence interval: 1.21-1.34) compared to CMV D-/R-. Recipient age ≥60 years significantly modified the relationship between donor CMV-seropositive status and mortality on the additive scale, including RERI 0.24 and AP 11.4% (p = 0.001), that is, the interaction increased hazard of death by 0.24 and explained 11.4% of mortality in older CMV D+ recipients.

CONCLUSIONS

Among CMV-seronegative LTRs, donor CMV-seropositive status confers higher risk of posttransplant mortality, which is amplified in older recipients. Future studies should define optimal strategies for CMV prevention and management in older D+/R- LTRs.

Incidence of valganciclovir-related leukopenia and neutropenia in solid organ transplant recipients at high risk of cytomegalovirus disease

BACKGROUND

Valganciclovir (VGCV) prophylaxis is associated with an increased risk of hematologic side effects. We analyzed the impact of VGCV prophylaxis on leukopenia and neutropenia rates and explored risk factors for its occurrence.

METHODS

Retrospective cohort study of adult cytomegalovirus (CMV)-seronegative solid organ transplantation (SOT) recipients of either CMV-seropositive (CMV D+/R-) or CMV-seronegative (CMV D-/R-) donors between July 2005 and March 2019. CMV D+/R- SOT recipients received 3-12 months of VGCV prophylaxis whereas CMV D-/R- SOT recipients received no VGCV prophylaxis. Competing risk regression was used to calculate risk factors for significant neutropenia (neutrophil count < 1000/μL).

RESULTS

A total of 430 CMV-seronegative SOT recipients (median age of 52.1 years, 76.5% males) were included, of which 203 (47.2%) were CMV D+/R- and 227 (52.8%) CMV D-/R-. The unadjusted incidence rate ratio of significant neutropenia attributable to VGCV exposure in the first year post-transplant was 13.50 (95% confidence interval 7.36-27.11). Acute rejection occurred more frequently in neutropenic patients at 32.5% compared to 19.1% in those without neutropenia (p = .033). On multivariate analysis, VGCV prophylaxis for 1-90 days and 91-180 days versus no VGCV were the strongest risk factors for significant neutropenia with a sub-distribution hazard ratio of 39.6 (95% CI, 8.57-182.6) and 13.2 (95% CI, 5.46-32.0), respectively.

CONCLUSIONS

VGCV prophylaxis is limited by high rates of neutropenia. Future prospective studies are needed to assess alternative CMV prophylactic strategies in SOT recipients.

What's New: Updates on Cytomegalovirus in Solid Organ Transplantation

Cytomegalovirus (CMV) is one of the most common infections occurring after solid organ transplantation. This high burden of disease, which incurs sizeable morbidity, may be worsening with the proportion of high-risk D+/R- solid organ transplantation recipients increasing in some regions globally. Cohort studies continue to support either universal prophylaxis or preemptive therapy as effective prevention strategies. Letermovir prophylaxis was noninferior to valganciclovir in adult high-risk D+/R- kidney transplant recipients with fewer drug-related adverse events in a recent clinical trial and has now been approved for such use in some regions. Maribavir preemptive therapy failed to demonstrate noninferiority when compared with valganciclovir in hematopoietic stem cell transplant recipients but looked promising for safety. Donor matching could be useful in prevention CMV disease with a survival advantage demonstrated in seronegative recipients waiting up to 30 mo for a seronegative kidney. Immune-guided prophylaxis resulted in fewer CMV infection episodes in lung transplant recipients when compared with fixed-duration prophylaxis in a recent clinical trial. For treatment of refractory or resistant CMV infection, maribavir was more efficacious and better tolerated when compared with investigator-initiated therapy in its registration trial for this condition. Further research regarding best treatment and prophylaxis of resistant or refractory CMV infection is needed to reflect best clinical practice choices. Optimal use of immune globulin or CMV-specific T cells for prevention or treatment of CMV disease remains undefined. Standardized definitions for the design of CMV clinical trials have been developed. In this review, we highlight recent updates in the field from data published since 2018.

Immune aging: biological mechanisms, clinical symptoms, and management in lung transplant recipients

While chronologic age can be precisely defined, clinical manifestations of advanced age occur in different ways and at different rates across individuals. The observed phenotype of advanced age likely reflects a superposition of several biological aging mechanisms which have gained increasing attention as the world contends with an aging population. Even within the immune system, there are multiple age-associated biological mechanisms at play, including telomere dysfunction, epigenetic dysregulation, immune senescence programs, and mitochondrial dysfunction. These biological mechanisms have associated clinical syndromes, such as telomere dysfunction leading to short telomere syndrome (STS), and optimal patient management may require recognition of biologically based aging syndromes. Within the clinical context of lung transplantation, select immune aging mechanisms are particularly pronounced. Indeed, STS is increasingly recognized as an indication for lung transplantation. At the same time, common aging phenotypes may be evoked by the stress of transplantation because lung allografts face a potent immune response, necessitating higher levels of immune suppression and associated toxicities, relative to other solid organs. Age-associated conditions exacerbated by lung transplant include bone marrow suppression, herpes viral infections, liver cirrhosis, hypogammaglobulinemia, frailty, and cancer risk. This review aims to dissect the molecular mechanisms of immune aging and describe their clinical manifestations in the context of lung transplantation. While these mechanisms are more likely to manifest in the context of lung transplantation, this mechanism-based approach to clinical syndromes of immune aging has broad relevance to geriatric medicine.

Case report: Use of granulocyte-colony stimulating factor as an immunomodulatory therapy in a patient with neuromyelitis optica spectrum disorder and comorbid immunodeficiency

Background

Autoimmune diseases can coexist with immunodeficiency. We describe a treatment approach in which granulocyte-colony stimulating factor (G-CSF) is used to restore immune competence without worsening autoimmunity. G-CSF is a polyfunctional cytokine that influences survival, proliferation, and differentiation of hematopoietic stem cells, and has immunomodulatory effects on the innate and adaptive immune systems.

Objective

To report a case of neuromyelitis optica spectrum disorder (NMOSD) with comorbid immunodeficiency and frequent infections.

Methods

Case report and review of literature.

Results

A 23 years-old man presented with a focal onset seizure with impaired awareness at age 12. At age 18, he developed headaches, recurrent multifocal seizures, and non-convulsive status epilepticus. Brain magnetic resonance imaging (MRI) showed extensive T2 hyperintense and gadolinium-enhancing periventricular and corpus callosum lesions. Serum aquaporin 4 antibody was positive 1:10,000 (normal value <1.5 titer), hence he was diagnosed with NMOSD. As a complication, patient developed mucormycotic pneumonia with cavitation, requiring thoracotomy precluding use of immunosuppressants. Gene testing demonstrated a mutation in MT-ND4 gene encoding for NADH dehydrogenase 4 in mitochondrial complex 1. Eventually, he began a treatment with filgrastim, a G-CSF analog, in addition to intravenous immunoglobulins and prednisone. Patient's NMOSD has been in remission without relapses, or coexistent infections ever since.

Conclusion

G-CSF is a polyfunctional cytokine with important immunomodulatory effects, which makes it an interesting therapeutic option when autoimmunity coexists with immunodeficiency and was used successfully in this case.

Intestinal microbiota links to allograft stability after lung transplantation: a prospective cohort study

Whether the alternated microbiota in the gut contribute to the risk of allograft rejection (AR) and pulmonary infection (PI) in the setting of lung transplant recipients (LTRs) remains unexplored. A prospective multicenter cohort of LTRs was identified in the four lung transplant centers. Paired fecal and serum specimens were collected and divided into AR, PI, and event-free (EF) groups according to the diagnosis at sampling. Fecal samples were determined by metagenomic sequencing. And metabolites and cytokines were detected in the paired serum to analyze the potential effect of the altered microbiota community. In total, we analyzed 146 paired samples (AR = 25, PI = 43, and EF = 78). Notably, we found that the gut microbiome of AR followed a major depletion pattern with decreased 487 species and compositional diversity. Further multi-omics analysis showed depleted serum metabolites and increased inflammatory cytokines in AR and PI. Bacteroides uniformis, which declined in AR (2.4% vs 0.6%) and was negatively associated with serum IL-1β and IL-12, was identified as a driven specie in the network of gut microbiome of EF. Functionally, the EF specimens were abundant in probiotics related to mannose and cationic antimicrobial peptide metabolism. Furthermore, a support-vector machine classifier based on microbiome, metabolome, and clinical parameters highly predicted AR (AUPRC = 0.801) and PI (AUPRC = 0.855), whereby the microbiome dataset showed a particularly high diagnostic power. In conclusion, a disruptive gut microbiota showed a significant association with allograft rejection and infection and with systemic cytokines and metabolites in LTRs.

Epidemiology, management, and burden of cytomegalovirus in solid organ transplant recipients in selected countries outside of Europe and North America: A systematic review

BACKGROUND

Cytomegalovirus (CMV) is a frequent infectious complication following solid organ transplantation (SOT). Considering significant differences in healthcare systems, a systematic review was conducted to describe the epidemiology, management, and burden of CMV post-SOT in selected countries outside of Europe and North America.

METHODS

MEDLINE, Embase, and Cochrane databases were searched for observational studies in SOT recipients across 15 countries in the regions of Asia, Pacific, and Latin America (search period: January 1, 2011 to September 17, 2021). Outcomes included incidence of CMV infection/disease, recurrence, risk factors, CMV-related mortality, treatment patterns and guidelines, refractory and/or resistant CMV, patient-reported outcomes, and economic burden.

RESULTS

Of 2708 studies identified, 49 were eligible (n = 43/49; 87.8% in adults; n = 34/49, 69.4% in kidney recipients). Across studies, selection of CMV preventive strategy was based on CMV serostatus. Overall, rates of CMV infection (within 1 year) and CMV disease post-SOT were respectively, 10.3%-63.2% (9 studies) and 0%-19.0% (17 studies). Recurrence occurred in 35.4%-41.0% cases (3 studies) and up to 5.3% recipients died of CMV-associated causes (11 studies). Conventional treatments for CMV infection/disease included ganciclovir (GCV) or valganciclovir. Up to 4.4% patients were resistant to treatment (3 studies); no studies reported on refractory CMV. Treatment-related adverse events with GCV included neutropenia (2%-29%), anemia (13%-48%), leukopenia (11%-37%), and thrombocytopenia (13%-24%). Data on economic burden were scarce.

CONCLUSION

Outside of North America and Europe, rates of CMV infection/disease post-SOT are highly variable and CMV recurrence is frequent. CMV resistance and treatment-associated adverse events, including myelosuppression, highlight unmet needs with conventional therapy.

Increased clonal hematopoiesis involving DNA damage response genes in patients undergoing lung transplantation

BACKGROUNDCellular stressors influence the development of clonal hematopoiesis (CH). We hypothesized that environmental, inflammatory, and genotoxic stresses drive the emergence of CH in lung transplant recipients. METHODSWe performed a cross-sectional cohort study of 85 lung transplant recipients to characterize CH prevalence. We evaluated somatic variants using duplex error-corrected sequencing and germline variants using whole exome sequencing. We evaluated CH frequency and burden using χ2 and Poisson regression, and we evaluated associations with clinical and demographic variables and clinical outcomes using χ2, logistic regression, and Cox regression. RESULTSCH in DNA damage response (DDR) genes TP53, PPM1D, and ATM was increased in transplant recipients compared with a control group of older adults (28% versus 0%, adjusted OR [aOR], 12.9 [1.7-100.3], P = 0.0002). Age (OR, 1.13 [1.03-1.25], P = 0.014) and smoking history (OR 4.25 [1.02-17.82], P = 0.048) were associated with DDR CH. Germline variants predisposing to idiopathic pulmonary fibrosis were identified but not associated with CH. DDR CH was associated with increased cytomegalovirus viremia versus patients with no (OR, 7.23 [1.95-26.8], P = 0.018) or non-DDR CH (OR, 7.64 [1.77-32.89], P = 0.024) and mycophenolate discontinuation (aOR, 3.8 [1.3-12.9], P = 0.031). CONCLUSIONCH in DDR genes is prevalent in lung transplant recipients and is associated with posttransplant outcomes including cytomegalovirus activation and mycophenolate intolerance. FUNDINGNIH/NHLBI K01HL155231 (LKT), R25HL105400 (LKT), Foundation for Barnes-Jewish Hospital (LKT), Evans MDS Center at Washington University (KAO, MJW), ASH Scholar Award (KAO), NIH K12CA167540 (KAO), NIH P01AI116501 (AEG, DK), NIH R01HL094601 (AEG), and NIH P01CA101937 (DCL).

Adaptive Immunosuppression in Lung Transplant Recipients Applying Complementary Biomarkers: The Zurich Protocol

Achieving adequate immunosuppression for lung transplant recipients in the first year after lung transplantation is a key challenge. Prophylaxis of allograft rejection must be balanced with the adverse events associated with immunosuppressive drugs, for example infection, renal failure, and diabetes. A triple immunosuppressive combination is standard, including a steroid, a calcineurin inhibitor, and an antiproliferative compound beginning with the highest levels of immunosuppression and a subsequent tapering of the dose, usually guided by therapeutic drug monitoring and considering clinical results, bronchoscopy sampling results, and additional biomarkers such as serum viral replication or donor-specific antibodies. Balancing the net immunosuppression level required to prevent rejection without overly increasing the risk of infection and other complications during the tapering phase is not well standardized and requires repeated assessments for dose-adjustments. In our adaptive immunosuppression approach, we additionally consider results from the white blood cell counts, in particular lymphocytes and eosinophils, as biomarkers for monitoring the level of immunosuppression and additionally use them as therapeutic targets to fine-tune the immunosuppressive strategy over time. The concept and its rationale are outlined, and areas of future research mentioned.

Neutropenia in pediatric solid organ transplant

Neutropenia is generally defined as an absolute neutrophil count in the circulation of less than 1500/mm³ and occurs in up to 25%-30% of pediatric solid organ transplant recipients (SOT) within the first year after transplantation. In the SOT population, neutropenia is most often a result of drug-induced bone marrow suppression but can also be secondary to viral infection, nutritional deficiencies, lymphoproliferative infiltrate, and inherited causes. Outcomes for patients with neutropenia vary by degree of neutropenia and type of solid organ transplant. Management of neutropenia should begin by addressing the underlying cause, including reducing or removing medications when appropriate, treating infections, and addressing nutrient deficiencies; however, consultation with an experienced pediatric hematologist and use of granulocyte colony-stimulating factor (G-CSF) may be helpful in some cases. Overall, data on clinical outcomes for G-CSF use remain limited, but observational studies may support its use in patients with infections or severe neutropenia.

Letermovir in lung transplant recipients with cytomegalovirus infection: A retrospective observational study

Letermovir is a new antiviral drug approved for the prophylaxis of CMV infection in allogeneic stem cell transplants. The aim of the study was to assess the therapeutic efficacy of letermovir in difficult to treat CMV infections in lung transplant recipients. All lung transplant recipients between March 2018 and August 2020, who have been treated with letermovir for ganciclovir-resistant or refractory CMV infection were included in the study and analysed retrospectively. In total, 28 patients were identified. CMV disease was present in 15 patients (53.6%). In 23 patients (82.1%), rapid response was noticed, and CMV-viral load could be significantly decreased (>1 log₁₀ ) after a median of 17 [14-27] days and cleared subsequently in all of these patients. Five patients (17.9%) were classified as non-responder. Thereof, development of a mutation of the CMV UL56 terminase (UL-56-Gen: C325Y) conferring letermovir resistance could be observed in three patients (60%). Common side effects were mild and mostly of gastrointestinal nature. Mild adjustments of the immunosuppressive drugs were mandatory upon treatment initiation with letermovir. In addition to other interventions, letermovir was effective in difficult to treat CMV infections in lung transplant recipients. However, in patients with treatment failure mutation conferring letermovir, resistance should be taken into account.

The time is now: antimicrobial stewardship in solid organ transplantation

PURPOSE OF REVIEW

To provide a summary of complications of antimicrobials and opportunities for antimicrobial stewardship (AS) in solid organ transplant (SOT) patient care.

RECENT FINDINGS

Personalized, precision antimicrobial prescribing in SOT aiming to avoid negative consequences of antimicrobials is essential to improving patient outcomes. The positive impact AS efforts in transplant care has been recognized and bespoke activities tailored to special interests of transplant patients and providers are evolving. Strategies to optimize stewardship interventions targeting antibacterial, antiviral, and antifungal drug selection and dosing in the transplant population have been recently published though clinical integration using a 'handshake' stewardship model is an optimal starting point in transplant care. Other recent studies involving transplant recipients have identified opportunities to shorten duration or avoid antimicrobials for certain commonly encountered clinical syndromes. This literature, informing recent consensus clinical practice guidelines, may help support institutional practice guidelines and protocols. Proposals to track and report stewardship process and outcome measures as a routine facet of programmatic transplant quality reporting have been published. However, developing novel metrics accounting for nuances of transplant patients and programs is critical. Important studies are needed to evaluate organizational transplant prescribing cultures and optimal behavioral science-based interventions relevant to antimicrobial use in this population.

SUMMARY

Consequences of antimicrobial use, such as drug toxicities, and Clostridiodes difficile (CDI) and multidrug-resistant organisms colonization and infection disproportionately affect SOT recipients and are associated with poor allograft and patient outcomes. Stewardship programs encompassing transplant patients aim to personalize antimicrobial prescribing and optimize outcomes. Further studies are needed to better understand optimal intervention strategies in SOT.

Short- and long-term impact of neutropenia within the first year after kidney transplantation

The aim of this retrospective single-center study was to investigate short- and long-term impact of neutropenia occurring within the first year after kidney transplantation, with a special emphasis on different neutropenia grades. In this unselected cohort, 225/721 patients (31%) developed 357 neutropenic episodes within the first year post-transplant. Based on the nadir neutrophil count, patients were grouped as neutropenia grade 2 (<1.5-1.0*10⁹ /L; n=105), grade 3 (<1.0-0.5*10⁹ /L; n=65), and grade 4 (<0.5*10⁹ /L; n=55). Most neutropenia episodes were presumably drug-related (71%) and managed by reduction/discontinuation of potentially responsible drugs (mycophenolic acid [MPA] 51%, valganciclovir 25%, trimethoprim/sulfamethoxazole 19%). Steroids were added/increased as replacement for reduced/discontinued MPA. Granulocyte colony-stimulating factor was only used in 2/357 neutropenia episodes (0.6%). One-year incidence of (sub)clinical rejection, one-year mortality as well as long-term patient and graft survival were not different among patient without neutropenia and neutropenia grade 2/3/4. However, the incidence of infections was about 3-times higher during neutropenia grade 3 and 4, but not increased during grade 2. In conclusion, neutropenia within the first year after kidney transplantation represents no increased risk for rejection and has no negative impact on long-term patient and graft survival. Adding/increasing steroids as replacement for reduced/discontinued MPA might supplement management of neutropenia.

Factors associated with neutropenia post heart transplantation

BACKGROUND

Neutropenia is a serious complication following heart transplantation (OHT); however, risk factors for its development and its association with outcomes is not well described. We sought to study the prevalence of neutropenia, risk factors associated with its development, and its impact on infection, rejection, and survival.

METHODS

A retrospective single-center analysis of adult OHT recipients from July 2004 to December 2017 was performed. Demographic, laboratory, medication, infection, rejection, and survival data were collected for 1 year post-OHT. Baseline laboratory measurements were collected within the 24 hours before OHT. Neutropenia was defined as absolute neutrophil count ≤1000 cells/mm3. Cox proportional hazards models explored associations with time to first neutropenia. Associations between neutropenia, analyzed as a time-dependent covariate, with secondary outcomes of time to infection, rejection, or death were also examined.

RESULTS

Of 278 OHT recipients, 84 (30%) developed neutropenia at a median of 142 days (range 81-228) after transplant. Factors independently associated with increased risk of neutropenia included lower baseline WBC (HR 1.12; 95% CI 1.11-1.24), pre-OHT ventricular assist device (1.63; 1.00-2.66), high-risk CMV serostatus [donor positive, recipient negative] (1.86; 1.19-2.88), and having a previous CMV infection (4.07; 3.92-13.7).

CONCLUSIONS

Neutropenia is a fairly common occurrence after adult OHT. CMV infection was associated with subsequent neutropenia, however, no statistically significant differences in outcomes were found between neutropenic and non-neutropenic patients in this small study. It remains to be determined in future studies if medication changes in response to neutropenia would impact patient outcomes.

Association of CMV-specific T-cell immunity and risk of CMV infection in lung transplant recipients

BACKGROUND

Protecting against CMV infection and maintaining CMV in latent state are largely provided by CMV-specific T-cells in lung transplant recipients. The aim of the study was to assess whether a specific T-cell response is associated with the risk for CMV infection in seronegative patients who are at high risk for delayed CMV infection.

METHODS

All CMV-seronegative recipients (R-) from CMV-seropositive donors (D+) between January 2018 and April 2019 were included and retrospectively screened for CMV infection before and after assessment of CMV-specific cell-mediated immunity.

RESULTS

Thirty-one of the 50 patients (62%) developed early-onset CMV infection. Lower absolute neutrophil counts were significantly associated with early-onset CMV infection. Antiviral prophylaxis was ceased after 137.2 ± 42.8 days. CMV-CMI were measured at a median of 5.5 months after LTx. 19 patients experienced early and late-onset CMV infection after prophylaxis withdrawal within 15 months post transplantation. Positive CMV-CMI was significantly associated with lower risk of late-onset CMV infection after transplantation in logistic and cox-regression analysis (OR=0.05, p = .01; OR=2,369, p = .026).

CONCLUSION

D+/R- lung transplant recipients are at high risk of developing early and late-onset CMV infection. Measurement of CMV-CMI soon after transplantation might further define the CMV infection prediction risk in LTx recipients being at high risk for CMV viremia.

Impact of G-CSF Therapy on Leukopenia and Acute Rejection Following Kidney Transplantation

BACKGROUND

Leukopenia is a common problem after kidney transplantation. The therapeutic approach typically includes a reduction of the immunosuppressive therapy, which is associated with an increased risk of rejection and allograft loss. Granulocyte colony-stimulating factor (G-CSF) is used as a therapeutic option to raise the leukocyte blood count; however, the effect on acute rejections is controversial.

OBJECTIVE

The goal of this study is to examine the incidence of acute rejections following G-CSF therapy.

METHODS

We retrospectively evaluated patients with leukopenia following kidney transplantation and GCSF therapy between January 2007 and December 2017 at our center compared to controls with matched minimal leucocyte blood count in a matched pair analysis.

RESULTS

We identified 12 patients, who received G-CSF therapy with a cumulative dose of 10.74 µg/kg body weight over a time frame of 4.3 days. G-CSF therapy resulted in a significantly shorter time period with leucocytes <3,000/µL (9.5 vs. 16.6 days), but also trended towards an increased risk of rejection within the next 30 days with three patients in the G-CSF group and no patient in the control group (p=0.06) developing an acute biopsy-proven rejection. Infection and mortality rate in the subsequent year were not different between groups.

CONCLUSION

G-CSF therapy decreases the duration of leukopenia post-kidney transplantation, but may also increase the risk of an acute rejection.

Surveillance for acute cellular rejection after lung transplantation

Acute cellular rejection (ACR) is a common complication following lung transplantation (LTx), affecting almost a third of recipients in the first year. Established, comprehensive diagnostic criteria exist but they necessitate allograft biopsies which in turn increases clinical risk and can pose certain logistical and economic problems in service delivery. Undermining these challenges further, are known problems with inter-observer interpretation of biopsies and uncertainty as to the long-term implications of milder or indeed asymptomatic episodes. Increased risk of chronic lung allograft dysfunction (CLAD) has long been considered the most significant consequence of ACR. Consensus is lacking as to whether this applies to mild ACR, with contradictory evidence available. Given these issues, research into alternative, minimal or non-invasive biomarkers represents the main focus of research in ACR. A number of potential markers have been proposed, but none to date have demonstrated adequate sensitivity and specificity to allow translation from bench to bedside.