Absolute neutrophil count nadir in healthy pediatric patients with the Duffy-null phenotype.
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ABSTRACT:
SUBMITTER: Merz LE
PROVIDER: S-EPMC10407121 | biostudies-literature | 2023 Aug
REPOSITORIES: biostudies-literature
Publications
Absolute neutrophil count nadir in healthy pediatric patients with the Duffy-null phenotype.
Merz Lauren E LE Li Shih-Hon SH Ney Gina G Michniacki Thomas F TF Hannibal Mark C MC Walkovich Kelly J KJ
Blood advances 20230801 15
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Project description: Not available
| S-EPMC10282887 | biostudies-literature
Project description:Many people of African ancestry have lower absolute neutrophil counts (ANCs) without increased risk for infection. This is associated with the Duffy-null phenotype (nonexpression of the Duffy antigen on red blood cells), which is commonly found in those of African descent. Currently, there are no studies that compare the ANC of individuals with Duffy-null phenotype to those with Duffy non-null phenotypes within a self-identified Black population. The aim of this study was to assess the impact of Duffy status on ANCs based on complete blood counts with differential and Duffy testing in a healthy population of self-identified Black individuals at a single primary care center. This study found that 66.7% (80 of 120) of Black individuals have the Duffy-null phenotype and that there is a significant difference in ANCs between Duffy-null and Duffy non-null individuals (median, 2820 cells per μL vs 5005 cells per μL; P < .001). Additionally, 19 of 80 (23.8%) Duffy-null individuals had an ANC of <2000 cells per μL compared with no (0) Duffy non-null individuals. The Duffy-null phenotype is clinically insignificant; however, inappropriate reference ranges can propagate systemic racism. Therefore, we advocate for the development of Duffy-null-specific ANC reference ranges as well as replacing the term benign ethnic neutropenia with Duffy-nullassociated neutrophil count.
| S-EPMC9881043 | biostudies-literature
Project description:ImportanceAbsolute neutrophil counts (ANCs) are used to determine cancer clinical trial (CCT) eligibility and systemic anticancer therapy (SACT) dose modifications. Duffy null-associated ANC (DANC) is a nonpathologic phenotype associated with lower ANC and most frequently seen in individuals with African and Middle Eastern ancestry. It is unclear whether CCTs exclude or SACT regimens modify doses for individuals with ANC within the DANC reference range.ObjectiveTo investigate CCT exclusions and SACT dose modifications for ANC within the DANC reference range.Design, setting, and participantsThis cross-sectional study of contemporary CCTs and SACT regimens included adult, interventional, phase 3 CCTs for the 5 most prevalent cancers in the US and United Kingdom (prostate, breast, melanoma, colorectal, and lung cancers) testing SACTs with start dates between November 1, 2021, and November 1, 2023, and that were registered on ClinicalTrials.gov. Preferred curative-intent SACT regimens were listed in National Comprehensive Cancer Network guidelines.ExposureCancer clinical trial exclusions and SACT regimen modifications.Main outcome and measuresProportions of CCTs that exclude and SACT regimens that modify doses for individuals with an ANC within the DANC reference range.ResultsFor CCTs, 289 of 382 trials (75.7%) were eligible, of which 221 (76.5% [95% CI, 71.1%-81.2%]) excluded patients with ANC values within the DANC reference range. Colorectal CCTs had the highest (38 of 44 [86.4% (95% CI, 72.6%-94.8%)]) and prostate CCTs had the lowest (11 of 23 [47.8% (95% CI, 26.8%-69.4%)]) proportions of exclusions. Of CCTs testing cytotoxic chemotherapy, 116 of 142 (81.7% [95% CI, 74.3%-87.7%]) had exclusions; 93 of 123 (75.6% [95% CI, 67.0%-82.9%]) CCTs testing targeted therapies alone and 12 of 24 (50.0% [95% CI, 29.1%-70.9%]) testing hormonal therapies alone had exclusions. Among the 113 US- and UK-based trials, exclusions were present in 89 (78.8% [95% CI, 70.1%-85.9%]). Of 71 SACT regimens, 38 (53.5% [95% CI, 41.3%-65.5%]) included dose modifications for ANC values within the DANC reference range. Lung cancer regimens had the highest (23 of 31 [74.2% (95% CI, 55.4%-88.1%)]) and prostate cancer had the lowest (0 of 12 [0 (95% CI, 0%-26.4%)]) proportions of modifications. Regimens including chemotherapy had modifications in 32 of 44 (72.7% [95% CI, 57.2%-85.0%]); 11 of 20 (55.0% [95% CI, 31.5%-76.9%]) of targeted therapy regimens and 0 of 16 (0% [95% CI, 0%-20.6%]) of hormonal therapy regimens had modifications. Among regimens including chemotherapy and/or targeted therapy, modifications were present in 38 of 55 (69.1% [95% CI, 49.7%-73.2%]).Conclusions and relevanceIn this cross-sectional study, substantial proportions of CCTs excluded and SACT regimens modified doses for patients with ANCs in the DANC reference range. These practices structurally discriminate against patients of African and Middle Eastern ancestry. While determining optimal SACT dose modifications requires further study, CCT exclusion criteria should be revised.
| S-EPMC11391325 | biostudies-literature
Project description: Not available
| S-EPMC11629209 | biostudies-literature
Project description:IntroductionTumor-infiltrating lymphocytes (TILs) might be associated with host-cell mediated immunity, which could be partly reflected by peripheral blood cell counts. In addition, lymphocyte-predominant breast cancer (LPBC), which was defined as tumors having high TIL levels, showed a favorable prognosis among triple-negative breast cancer or HER2-positive breast cancer. We aimed to investigate whether peripheral blood cell counts are associated with LPBC.MethodsWe evaluated the percentage of stromal TILs in breast cancer patients who underwent primary surgery, using the standardized methodology proposed by the international TIL Working Group. Lymphocyte-predominant breast cancer (LPBC) was defined as tumors having high TIL levels (≥50%). Peripheral blood cell counts including absolute neutrophil counts (ANC), absolute lymphocyte counts (ALC) and neutrophil-to-lymphocyte ratio (NLR) was obtained from pretreatment laboratory data.ResultOf the 810 patients, 132 (16.3%) had LPBC, and 678 (83.7%) had non-LBPC. In a comparison of 3 markers of peripheral blood counts, LPBC had a significantly lower mean ANC than non-LPBC (3,304 vs. 3,564; P = 0.023), but the other means were not different. In multivariable analysis, each 1K increment in ANC corresponded to an odds ratio of 0.790 (95% CI, 0.642 to 0.971) for LPBC. In the ER-negative and high-Ki67 subgroups identified by interaction tests, significant inverse correlations between continuous ANC and TILs were noted.ConclusionLow peripheral ANC could be linked with LPBC, supporting the hypothesis that systemic immune cell counts might be associated with the tumor-immune microenvironment.
| S-EPMC7375640 | biostudies-literature
Project description:Evidence suggests that effects of interleukin-6 pathway inhibitors sarilumab, tocilizumab, and sirukumab on absolute neutrophil count (ANC) are due to margination of circulating neutrophils into rapidly mobilizable noncirculating pools. We developed a population pharmacodynamic model using compartments for neutrophil margination and ANC-specific tolerance to describe rapid, transient ANC changes in blood following administration of subcutaneous sarilumab and intravenous/subcutaneous tocilizumab based on data from 322 patients with rheumatoid arthritis in two single-dose (NCT02097524 and NCT02404558) and one multiple-dose (NCT01768572) trials. The model incorporated a tolerance compartment to account for ANC nadir and beginning of recovery before maximal drug concentration after subcutaneous dosing, and absence of a nadir plateau when the ANC response is saturated after subcutaneous or intravenous dosing. The model effectively describes the ANC changes and supports neutrophil margination and tolerance as an explanation for the absence of increased infection risk associated with low ANC due to interleukin-6 pathway inhibitor treatment.
| S-EPMC7376291 | biostudies-literature
Project description:Neutrophils are well-recognized for their pathogen killing mechanisms and disorders of neutrophil count and function are associated with recurrent infections. The Duffy Antigen Receptor for Chemokines (DARC)-null genotype is predominant in sub-Saharan African ancestry populations and is the major genetic determinant of benign ethnic neutropenia which has been associated with increased risk of Human Immunodeficiency Virus (HIV)-1 acquisition and mother-to-child transmission. However, the impact of DARC-null-linked neutropenia on HIV disease progression remains controversial. While the DARC-null genotype is associated with low numbers of circulating neutrophils, the effects of the polymorphism on neutrophil functions is unknown. We investigated the impact of the DARC-null trait and lower absolute neutrophil counts (ANCs) on key neutrophil effector functions [proteolytic activity within the phagosome following Fc receptor-mediated phagocytosis, reactive oxygen species (ROS) production, and neutrophil extracellular trap (NET) formation] in 20 HIV negative and 22 HIV-1 chronically infected black South Africans. Phagosome maturation was measured by flow cytometry following Fc-mediated uptake of IgG opsonized beads; ROS production was measured by chemi-luminescence after activation of neutrophils with phorbol 12-myristate 13-acetate (PMA). Activated neutrophils were also visualized by fluorescent microscopy for NET quantification. Study subjects were genotyped for the DARC trait using TaqMan allelic discrimination assays and ANCs were measured by full blood count. As expected, the DARC-null polymorphism was highly prevalent in our participant cohort (69%) and was strongly associated with lower ANCs in uninfected (p = 0.0007) and HIV-1 infected (p = 0.03) subjects. We observed enhanced proteolytic activity within the phagosome in the absence of DARC at 10 min (p = 0.05 and p = 0.009) and 60 min (p = 0.05 and p = 0.07) in uninfected and HIV-1 infected subjects, respectively. ROS was unaffected by DARC trait irrespective of HIV status. Furthermore, formation of NETs was reduced in neutrophils from DARC-null subjects (p = 0.04) following prolonged in vitro stimulation, but only in HIV-1 infected subjects. The data indicate differential neutrophil function in the absence of DARC that may be moderately modulated by HIV-1 infection but overall, the data suggest that DARC-null trait is not deleterious to neutrophil effector functions in African populations.
| S-EPMC6443851 | biostudies-literature
Project description:BACKGROUND:The Duffy-null trait and ethnic netropenia are both highly prevalent in Africa. The influence of pre-seroconversion levels of peripheral blood cell counts (PBCs) on the risk of acquiring human immunodeficiency virus (HIV)-1 infection among Africans is unknown. METHODS:The triangular relationship among pre-seroconversion PBC counts, host genotypes, and risk of HIV acquisition was determined in a prospective cohort of black South African high-risk female sex workers. Twenty-seven women had seroconversion during follow-up, and 115 remained HIV negative for 2 years, despite engaging in high-risk activity. RESULTS:Pre-seroconversion neutrophil counts in women who subsequently had seroconversion were significantly lower, whereas platelet counts were higher, compared with those who remained HIV negative. Comprising 27% of the cohort, subjects with pre-seroconversion neutrophil counts of <2500 cells/mm(3) had a ?3-fold greater risk of acquiring HIV infection. In a genome-wide association analyses, an African-specific polymorphism (rs2814778) in the promoter of Duffy Antigen Receptor for Chemokines (DARC -46T > C) was significantly associated with neutrophil counts (P = 7.9 × 10(-11)). DARC -46C/C results in loss of DARC expression on erthyrocytes (Duffy-null) and resistance to Plasmodium vivax malaria, and in our cohort, only subjects with this genotype had pre-seroconversion neutrophil counts of <2500 cells/mm(3). The risk of acquiring HIV infection was ?3-fold greater in those with the trait of Duffy-null-associated low neutrophil counts, compared with all other study participants. CONCLUSIONS:Pre-seroconversion neutrophil and platelet counts influence risk of HIV infection. The trait of Duffy-null-associated low neutrophil counts influences HIV susceptibility. Because of the high prevalence of this trait among persons of African ancestry, it may contribute to the dynamics of the HIV epidemic in Africa.
| S-EPMC3115278 | biostudies-literature
Project description:Neutrophils are a key component of innate immunity. Individuals with low neutrophil count are susceptible to frequent infections. Linkage and association between congenital neutropenia and a single rare missense variant in TCIRG1 have been reported in a single family. Here, we report on nine rare missense variants at evolutionarily conserved sites in TCIRG1 that are associated with lower absolute neutrophil count (ANC; p = 0.005) in 1,058 participants from three cohorts: Atherosclerosis Risk in Communities (ARIC), Coronary Artery Risk Development in Young Adults (CARDIA), and Jackson Heart Study (JHS) of the NHLBI Grand Opportunity Exome Sequencing Project (GO ESP). These results validate the effects of TCIRG1 coding variation on ANC and suggest that this gene may be associated with a spectrum of mild to severe effects on ANC.
| S-EPMC5079157 | biostudies-literature
Project description:Up to one-third of those with schizophrenia fail to respond to standard antipsychotics and are considered to have treatment-resistant schizophrenia, a condition for which clozapine is the only evidence-based medication. While up to 60% of treated individuals obtain therapeutic benefits from clozapine, it is currently underprescribed worldwide, partly because of concerns related to its broad adverse effect profile. In particular, the potential effects of clozapine on the immune system have gained relevance after a recent study showed that drug plasma concentrations were inversely correlated with neutrophil counts in individuals routinely undergoing treatment. Seeking to investigate this relationship in more detail, we extracted metabolic, immune, and genetic data from a UK cohort of long-term clozapine users linked to a clozapine monitoring service, CLOZUK2 (N = 208). Whilst a correlation analysis was compatible with the original results, a multiple linear regression accounting for dose and other confounding factors additionally allowed us to estimate the decrease in absolute neutrophil counts to approximately 141 cells/mm3 for every 0.1 mg/L increase in clozapine concentration. However, this association was attenuated after controlling for the metabolic ratio between clozapine and its main metabolite, norclozapine, which was itself negatively associated with neutrophil concentrations. Further analyses revealed that these relationships are likely moderated by genetic factors, as three pharmacogenomic SNPs previously associated to norclozapine plasma concentrations and the metabolic ratio (rs61750900, rs2011425 and rs1126545) were shown to be independently associated with a variation in neutrophil counts of about 400 cells/mm3 per effect allele. Such results are compatible with an effect of norclozapine, but not necessarily clozapine, on immune cell counts, and highlight the need for further investigations into the potential role of genetic determinants of clozapine pharmacokinetics in the occurrence of adverse effects during treatment.
| S-EPMC8094024 | biostudies-literature