Differential cell division history between neutrophils and macrophages in their development from granulocyte-macrophage progenitors

Absolute Monocyte Count as Early and Safe Marker for Antibiotic Cessation in Febrile Neutropenia Without Etiology in Pediatric Oncology Patients

BACKGROUND

There is no practice standard regarding antibiotic duration in children with cancer and unexplained febrile neutropenia (FN). We hypothesized that absolute monocyte count (AMC) and absolute phagocyte count (APC= ANC + AMC + bands) are more sensitive, earlier, and safe markers of antibiotic cessation compared with absolute neutrophil count (ANC).

METHODS

A retrospective review of FN episodes (FNEs) in pediatric oncology patients was conducted between 2009 and 2016. Included patients were afebrile for 24 hours and without an identified infectious source at antibiotic cessation. Primary endpoints, including recurrent fever, readmission, bloodstream infection, microbiologically documented infection, and adverse outcomes, were assessed 10 days after antibiotic cessation and compared among different bone marrow recovery parameters (ANC, AMC, APC). Secondary endpoints included length of FN stay, antibiotic-free days, and cost.

RESULTS

Three hundred ninety-one FNEs in 235 patients were included. Three groups were compared based on ANC (cells/μL) at the time of antibiotic cessation: < 200 in 102 (26%), 200 to 500 in 111 (28%), and >500 in 178 (46%). No statistically significant differences in primary endpoints were identified among the 3 ANC groups; however, a trend toward unfavorable outcomes in the ANC ≤200 cells/μL group compared with the ANC >200 cells/μL was observed. Primary endpoints based on AMC >100 cells/μL at the time of antibiotic cessation showed statistically significant favorable outcomes compared AMC ≤100 cells/μL (80%, 88%, 90%, 89%, and 93% risk reduction in recurrent fever, readmission, new bloodstream infection, new microbiologically documented infection, and adverse events, respectively). Similar favorable results were seen when APC >300 cells/μL was used as a threshold for antibiotic cessation. The median length of stay for FN if discharged when AMC >100 cells/μL was 3 days shorter and associated with fewer unfavorable outcomes, thus resulting in fewer hospital days, fewer antibiotic days, and decreased cost.

CONCLUSION

Our results suggest that AMC >100 cells/μL (regardless of ANC) or APC >300 cells/μL may be safe thresholds for empiric antibiotic cessation and result in reduced unfavorable clinical outcomes within 10 days postdischarge, reduced antibiotic days of therapy and reduced health care costs. Further prospective studies are needed to validate AMC as an accurate surrogate marker for antibiotic cessation in FNEs in children with cancer.

Surgical approach for appendicitis in neutropenia: a case report and review of the literature

BACKGROUND

Acute appendicitis is a common abdominal pathology, particularly in younger patients presenting with abdominal pain. The clinical presentation is typically characterized by right lower quadrant pain (with local peritonitis) accompanied by fever and nausea. In neutropenic patients it is challenging to diagnose acute appendicitis. It is much more challenging because the characteristic symptoms are different, and diagnosis may be delayed or missed.

CASE PRESENTATION

We present the case of a 33-year-old Caucasian male patient with fever, abdominal pain, and an absolute granulocyte count of 0 × 10⁹/L. Abdominal CT demonstrated an uncomplicated acute appendicitis. We initiated a conservative in-hospital treatment with intravenous antibiotic therapy and simultaneous bone marrow stimulation, with close monitoring. On day three, there was evidence of monocyte increase, one of the first signs of bone marrow regeneration, and delayed laparoscopic appendectomy was performed. The perioperative and postoperative course was uneventful.

CONCLUSION

We discuss the different treatment strategies in patients with neutropenia presenting with acute appendicitis (i.e., conservative management, delayed appendectomy, and immediate appendectomy) based on our experience and a review of the literature. In summary, delayed laparoscopic appendectomy at the onset of granulocyte regeneration under antibiotic and G-CSF therapy represents a viable surgical option for adults as well as for children and should be discussed compared with conservative therapy.

Frontline Science: Cxxc5 expression alters cell cycle and myeloid differentiation of mouse hematopoietic stem and progenitor cells

CXXC5 is a member of the CXXC-type zinc finger epigenetic regulators. Various hematopoietic and nonhematopoietic roles have been assigned to CXXC5. In the present study, the role of Cxxc5 in myelopoiesis was studied using overexpression and short hairpin RNA-mediated knockdown in mouse early stem and progenitor cells defined as Lineage^- Sca-1⁺ c-Kit⁺ (LSK) cells. Knockdown of Cxxc5 in mouse progenitor cells reduced monocyte and increased granulocyte development in ex vivo culture systems. In addition, ex vivo differentiation and proliferation experiments demonstrated that the expression of Cxxc5 affects the cell cycle in stem/progenitor cells and myeloid cells. Flow cytometry-based analyses revealed that down-regulation of Cxxc5 leads to an increase in the percentage of cells in the S phase, whereas overexpression results in a decrease in the percentage of cells in the S phase. Progenitor cells proliferate more after Cxxc5 knockdown, and RNA sequencing of LSK cells, and single-cell RNA sequencing of differentiating myeloid cells showed up-regulation of genes involved in the regulation of cell cycle after Cxxc5 knockdown. These results provide novel insights into the physiologic function of Cxxc5 during hematopoiesis, and demonstrate for the first time that it plays a role in monocyte development.

Order by chance: origins and benefits of stochasticity in immune cell fate control

To protect against diverse challenges, the immune system must continuously generate an arsenal of specialized cell types, each of which can mount a myriad of effector responses upon detection of potential threats. To do so, it must generate multiple differentiated cell populations with defined sizes and proportions, often from rare starting precursor cells. Here, we discuss the emerging view that inherently probabilistic mechanisms, involving rare, rate-limiting regulatory events in single cells, control fate decisions and population sizes and fractions during immune development and function. We first review growing evidence that key fate control points are gated by stochastic signaling and gene regulatory events that occur infrequently over decision-making timescales, such that initially homogeneous cells can adopt variable outcomes in response to uniform signals. We next discuss how such stochastic control can provide functional capabilities that are harder to achieve with deterministic control strategies, and may be central to robust immune system function.

DNA methylation/hydroxymethylation regulate gene expression and alternative splicing during terminal granulopoiesis

Aim: To determine whether epigenetic modifications of DNA regulate gene expression and alternative splicing during terminal granulopoiesis. Materials & methods: Using whole genome bisulfite sequencing, reduced representation hydroxymethylation profiling and mRNA sequencing, we compare changes in DNA methylation, DNA hydroxymethylation, gene expression and alternative splicing in mouse promyelocytes and granulocytes. Results & conclusion: We show reduced DNA methylation at the promoters and enhancers of key granulopoiesis genes, indicating a regulatory role in the activation of lineage-specific genes during differentiation. Notably, increased DNA hydroxymethylation in exons is associated with preferential inclusion of specific exons in granulocytes. Overall, DNA methylation and hydroxymethylation changes at particular genomic loci may play specific roles in gene regulation or alternative splicing during terminal granulopoiesis. Data deposition: Whole genome bisulfite sequencing of mouse promyelocytes and granulocytes: Gene Expression Omnibus (GSE85517); mRNA sequencing of mouse promyelocytes and granulocytes: Gene Expression Omnibus (GSE48307); reduced representation 5-hydroxymethylation profiling of mouse promyelocytes and granulocytes: Bioproject (PRJNA495696).

Pretreatment monocyte counts and neutrophil counts predict the risk for febrile neutropenia in patients undergoing TPF chemotherapy for head and neck squamous cell carcinoma

Background

Febrile neutropenia (FN) is the most serious hematologic toxicity of systemic chemotherapy. However, accurate prediction of FN development has been difficult because the risk varies largely depending on the chemotherapy regimen and various individual factors.

Methods

We retrospectively analyzed diverse clinical factors including pretreatment hematological parameters to clarify the reliable predictors of FN development during chemotherapy with a docetaxel, cisplatin, and fluorouracil (TPF) regimen in patients with head and neck squamous cell carcinoma.

Results

Among the 50 patients, grade ≥3 neutropenia, grade 4 neutropenia, and FN developed in 36 (72%), 21 (42%), and 12 (24%) patients, respectively. Multivariate logistic regression revealed that a pretreatment absolute monocyte count (AMC) <370/mm³ is an independent predictor of TPF chemotherapy-induced FN (odds ratio=6.000, p=0.017). The predictive performance of the model combining AMC and absolute neutrophil count (ANC), in which the high-risk group was defined as having an AMC <370/mm³ and/or ANC <3500/mm³, was superior (area under the curve [AUC]=0.745) to that of the model with a cutoff for AMC alone (AUC=0.679).

Conclusions

On the basis of our results, we recommend primary prophylactic use of granulocyte colony-stimulating factor and/or antibiotics selectively for patients predicted to be at high risk for TPF chemotherapy-induced FN.

Recovery from anemia and leukocytopenia after abstinence in Japanese alcoholic men and their genetic polymorphisms of alcohol dehydrogenase-1B and aldehyde dehydrogenase-2

BACKGROUND

The combination of the fast-metabolizing alcohol dehydrogenase-1B (ADH1B*2 allele) and inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/*2) increases susceptibility to macrocytic anemia and leukocytopenia in alcoholics due to severe acetaldehydemia. More than half of Japanese drinkers with esophageal cancer have this genotype combination.

METHODS

To assess the recovery of hematologic abnormalities after drinking cessation, changes in blood erythrocyte indices and leukocyte count during 8-week hospital stay were evaluated in 925 Japanese alcoholic men. We used four categories in ascending order for high blood acetaldehyde exposure from drinking: A, ADH1B*1/*1 plus ALDH2*1/*1; B, ADH1B*2 plus ALDH2*1/*1; C, ADH1B*1/*1 plus ALDH2*1/*2; and D, ADH1B*2 plus ALDH2*1/*2.

RESULTS

Mean values of hemoglobin and hematocrit were the lowest, and those of mean corpuscular volume (MCV) were markedly the highest in the D group on admission, and returning toward normal after abstinence, but the inter-group differences remained significant throughout the 8 weeks. The mean leukocyte count was the lowest in the D group on admission, but increased during 4-week abstinence when the inter-group differences were no longer significant. Frequencies of MCV ≥110 fl (50.5%), hemoglobin levels <11.5 g/dL (32.7%), hemoglobin levels <10.0 g/dL (9.9%) and leukocytopenia <4000/μL (22.8%) were the highest in the D group on the admission day and decreased at the 4-week abstinence (28.7%, 18.8%, 4.0% and 7.9%, respectively). The inter-group differences in frequencies of the severe anemia and leukocytopenia disappeared after 4-week abstinence.

CONCLUSIONS

Drinking cessation before surgery and/or chemoradiation treatment for esophageal cancer may be effective for recovery from anemia and leukocytopenia in drinkers belonging to the D group.

Prolonged chemokine expression and excessive neutrophil infiltration in the lungs of burn-injured mice exposed to ethanol and pulmonary infection

Pulmonary infections are a major cause of mortality in the critically ill burn patient. Alcohol consumption before burn increases the risk of pulmonary infection. Previously, we have shown an elevated mortality and lung pathology in mice given ethanol before burn and intratracheal infection relative to controls. Here we examine the cellular composition at 24 and 48 h in the circulation and the alveoli of infected mice given alcohol and burn. At 24 h after injury, blood neutrophils obtained from mice exposed to ethanol before burn and infection were 2-fold above those of the experimental controls (P < 0.05). By 48 h, the number of circulating neutrophils decreased and was comparable to levels found in untreated animals. Moreover, at 24 h, bronchoalveolar lavage cells obtained from all treatment groups had similar frequencies and contained 80% neutrophils regardless of treatment. In contrast, the following day, neutrophils were elevated 2-fold only in the alveoli of infected burn animals and 5-fold when ethanol preceded the injury (P < 0.05). These data were confirmed by immunofluorescence microscopy using a neutrophil-specific marker (P < 0.05). Levels of neutrophil chemoattractants, KC and macrophage inflammatory protein 2, and the cytokine, IL-1β, were 2-fold greater in the lungs of infected mice given burn, regardless of ethanol exposure, relative to infected sham injured animals (P < 0.05). Like the number of neutrophils, by the second day after injury, KC and macrophage inflammatory protein 2 remained 5-fold higher in the animals given ethanol, burn, and infection, when compared with other groups (P < 0.05). A similar pattern was seen for pulmonary levels of IL-1β (P < 0.05). Additionally, a reduction in neutrophil apoptosis was observed at the 24-h time point in infected mice exposed to ethanol and burn (P < 0.05). Targeting proinflammatory mediators in mice exposed to ethanol before burn and infection may help alleviate prolonged neutrophil accumulation in the lungs.

An age-associated increase in pulmonary inflammation after burn injury is abrogated by CXCR2 inhibition

Burn patients over the age of 60 are at a greater risk for developing pulmonary complications than younger patients. The mechanisms for this, however, have yet to be elucidated. The objective of this study was to determine whether increased chemoattraction plays a role in the age-related differences in pulmonary inflammation after burn injury. At 6 or 24 h after receiving sham or 15% total body surface area scald injury, lungs from young and aged mice were analyzed for leukocyte content by histological examination and immunostaining. Lungs were then homogenized, and levels of neutrophil chemokines, MIP-2 and KC, were measured. At 6 h after burn, the number of neutrophils was four times higher in the lungs of both burn groups compared with aged-matched controls (P<0.05), but no age difference was evident. At 24 h, in contrast, neutrophils returned to sham levels in the lungs of young, burn-injured mice (P<0.05) but did not change in the lungs of aged, burn-injured mice. Pulmonary levels of the neutrophil chemokine KC but not MIP-2 were consistently three times higher in aged, burn-injured mice compared with young, burn-injured mice at both time-points analyzed. Administration with anti-CXCR2 antibody completely abrogated the excessive pulmonary neutrophil content by 24 h (P<0.05), while not affecting the inflammatory response of the wounds. These studies show that CXCR2-mediated chemoattraction is involved in the pulmonary inflammatory response after burn and suggest that aged individuals sustaining a burn injury may benefit from treatment strategies that target neutrophil chemokines.