Sage Journals: Discover world-class research

Abstract

Objective

Endothelial progenitor cells (EPCs) originate from hematopoietic stem cells and can be quantified in peripheral blood using flow cytometry. The anti-GM-CSFα antibody (CD116) may serve as a specific marker for EPC enumeration. This study aimed to quantify peripheral EPCs expressing CD116 and compare the results with other specific antibodies in newborns and adults.

Materials and Methods

EPC enumeration was performed by flow cytometric analysis of peripheral blood leukocytes (PBLs) obtained from 50 individuals, including 25 newborns and 25 adults. A CD34-specific antibody was used to identify hematopoietic stem/progenitor cells, while an antibody panel consisting of CD116, CD146, CD31, and CD45 was employed for EPC identification.

Results

Enumeration of CD34⁺ hematopoietic progenitor cells (HPCs) demonstrated that the mean CD34⁺ HPC count per 10⁶ PBLs was 1643 (935–1458) in newborns and 242.7 (163–190) in adults, with a statistically significant difference between the groups (p < 0.001). Using CD146 staining, the mean number of circulating EPCs per 10⁶ PBLs was 94.2 (90.5–129.0) in newborns and 9.2 (7.4–12.4) in adults (p < 0.001). Similarly, enumeration based on CD31 staining revealed mean EPC counts of 19.0 (12.5–28.0) in newborns and 6.0 (5.0–7.0) in adults (p < 0.001). Enumeration using CD116 staining showed mean EPC numbers of 29.0 (23.0–34.0) in newborns and 3.0 (2.0–4.0) in adults, also indicating a significant difference between the two groups (p < 0.001).

Conclusion

EPC numbers are significantly higher in newborns than in adults, suggesting an important developmental role for these cells. The GM-CSFα-specific antibody (CD116) may serve as a novel auxiliary marker for the identification and quantification of circulating EPCsubpopulations. Furthermore, EPC numbers appear to vary across different life stages, with higher numbers in newborns potentially reflecting the presence of a highly regenerative microenvironment.

Keywords

Endothelial progenitor cell GM-CSFα flow cytometry

Introduction

All hematopoietic progenitor cells (HPCs) originate from self-renewing hematopoietic stem cells, which are produced by a rare population of multipotent HPCs. These cells are continuously generated in the bone marrow and possess the ability to self-renew, proliferate, and differentiate to achieve functional maturation.¹

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a member of the hematopoietic growth factor family. It stimulates the proliferation and differentiation of myeloid progenitor cells while enhancing the function of mature myeloid effector cells. In addition to its myelopoietic effects, GM-CSF has anti-apoptotic properties and promotes the proliferation, mobilization, and activation of hematopoietic stem cells.^2,3

Sialomucins (CD34), an integral membrane glycoprotein, serves as a key marker for hematopoietic stem/progenitor cells. These progenitor cells, originating from the bone marrow, migrate into the peripheral circulation and mucosa, where they differentiate into mature endothelial cells.⁴ CD34 is widely used as a biomarker in hematopoietic transplant therapies due to its expression on progenitor cells. The CD34+ HPC population constitutes approximately 1%–2% of CD45+ cells in mobilized peripheral blood (mPB) and bone marrow (BM).⁵

As progenitor cells mature, they lose CD34 expression. While terminal differentiation may be completed before mature cells exit the bone marrow, many cell types finalize their maturation in peripheral tissues and secondary lymphoid organs. The enumeration of viable CD34+ cells is clinically significant in determining the dose of cells harvested from donor BM or mPB for hematopoietic progenitor cell transplantation (HPCT).

Endothelial progenitor cells (EPCs) are derived from bone marrow hematopoietic stem cells and circulate in peripheral blood. Although EPCs exhibit stem cell-like properties, their proliferation and differentiation potential is restricted, limiting them to differentiation into endothelial cells. When highly expressed, the CD34 antigen provides electrostatic repulsion to cell surfaces, reducing adhesion to tissues such as small blood vessels and preventing homotypic cell–cell adhesion.⁶

The monitoring of EPCs, HPCs, and circulating endothelial cells (CECs) in peripheral blood has gained attention as a valuable tool for assessing endothelial damage. Hematopoietic EPCs are replaced by hematopoietic cells within a few days, transitioning through an intermediate stage where cells express both hematopoietic and endothelial markers. The EPC phenotype varies depending on the stage of maturation, and additional markers such as CD146, CD31, and CD45 have been used for their identification. During EPC maturation, two possible subtypes have been identified: early-emerging EPCs (CD31(+) CD34(+)) and late-emerging EPCs (CD31(+) CD34(+) CD146(+)). The simultaneous detection of these markers enhances EPC identification. Flow cytometry is widely employed to monitor these markers simultaneously.⁷

CD146 is expressed in various cell types, including vascular cells, epithelial cells, fibroblasts, mesenchymal stem cells, and lymphocytes, but is absent in erythrocytes. Under normal physiological conditions, CD146 expression is restricted to specific mature tissues, where it facilitates strong adhesion. However, its expression in normal tissues is relatively weak. In contrast, CD146 is highly expressed in embryonic tissues compared to adult tissues.^8,9 In rapidly proliferating cells, increased CD146 expression enhances interactions with surrounding cells and the extracellular matrix, promoting proliferation and migration.¹⁰

CD31, also known as platelet endothelial cell adhesion molecule-1 (PECAM-1), is a member of the immunoglobulin superfamily. It is expressed on various cell types, including T lymphocytes, mast cells, natural killer (NK) cells, granulocytes, monocytes, and platelets. CD31 plays a crucial role in endothelial cell differentiation and is specifically involved in regulating vascular permeability.^11,12

CD116, also known as the GM-CSF α receptor, is specific for the 70–85 kD α chain of the GM-CSF receptor. The soluble form of CD116 binds GM-CSF with low affinity. GM-CSF belongs to a family of colony-stimulating hematopoietic growth factor receptors that also bind to M-CSF or G-CSF through three structurally distinct receptors.¹³ GM-CSFα is highly expressed by monocytes, granulocytes, and their precursors, as well as lymphocytes. It plays a key role in stimulating myeloid cell proliferation and granulocyte release from the bone marrow. CD116 is also present on endothelial cell surfaces. Additionally, CD116 associates with the common β chain (βc) (CDw131), which is shared with IL-3 and IL-5 receptors, forming a high-affinity receptor for GM-CSF.¹⁴

This study presents a single-center, comparative analysis involving 25 newborns and 25 adults, aiming to quantify endothelial progenitor cells (EPCs) using a spesific panel of antibodies. The primary objective was to explore age-related differences in circulating EPC numbers, indicating a developmental role for these cells and to assess the potential of novel markers in enhancing EPC identification. While existing literature offers limited data on EPC levels across different age groups, our findings provide evidence that CD116, in conjunction with established markers such as CD133, CD31 and CD146, may serve as a novel auxiliary marker for determining circulating EPC numbers. The observed variation in EPC numbers between neonates and adults underscores the dynamic nature of EPC biology throughout the human lifespan.

Patient groups

The newborns group in the study included twenty-five infants, 11 of whom were premature (<37 weeks) and 14 term newborns (≥37 weeks), with weights ranging from 0.835 to 1.920 kilograms and ages between 27 and 40 weeks. The adult group consisted of twenty-five healthy adults aged 30 to 50 years, with weights ranging from 66 to 91 kilograms. Samples from newborns were collected from infants undergoing Retinopathy of Prematurity (ROP) screening in the Ophthalmology Department and the Neonatal Unit of the Pediatric Department at Erciyes Medical School. Healthy adult samples were collected from individuals without any clinical disease who applied to the flow cytometry laboratory at Erciyes Medical School. The study was conducted using 1 ml peripheral blood samples collected in EDTA tubes one month after birth.

Ethics statement, consent statement

The study protocol was approved by the Ethics Committee of Erciyes Medical Faculty for both the adult (209) and newborn (322) groups. Written informed consent was obtained from the parents of the newborn patients for the publication of this report. The laboratory tests were conducted in the Department of Immunology.

Method

Enumeration of circulating EPCs from 25 newborns (both premature and term) and 25 adults was performed using flow cytometry. Data on the rate of circulating EPC numbers were obtained by counting 1×10⁶ per million peripheral blood leucocytes. They were labeled with CD34, CD146, CD31, and CD116-specific antibodies and the flow cytometric data were evaluated.

Enumeration of EPCs labeled with CD34, S-endo (CD146), CD31 and Gm-CSFα (CD116)

For this purpose, total white blood cells (WBC) from patients and controls were isolated from 200 μL of human peripheral blood by lysing erythrocytes in the pellet fraction, as described by Hristov and Köker et al..^15,16 After incubation, 2 ml of cell washing solution was added to remove erythrocytes, resulting in the isolation of leukocytes. Then, antibodies containing CD45-KO (Cat. No: B36294, clone: J33), CD34-ECD (Cat. No: IM2709U, clone: 581), CD116-PE (Cat. No: IM1977, clone: SCO6), CD146-PE (Cat. No: A22364, clone: TEA 1/34) (Beckman Coulter, USA), and CD31-FITC (Cat. No: IM1431U, clone: 5.6E) were added according to the manufacturer's instructions to label the remaining leukocytes in the pellet. The samples were incubated for 15 min in the dark. Following incubation, 2 ml of cell washing solution was added to each tube, and the samples were centrifuged at 1500 rpm for five minutes at room temperature. The supernatant was removed, and 2 ml of cell washing solution was added again. The centrifugation process was then repeated.

The labeled EPC cells were enumerated by flow cytometry (Navios EX, Beckman Coulter, USA). The readout was completed by counting 1×10⁶ per million peripheral blood WBC in cocktail tubes: CD45KO/CD34ECD/CD116PE+, CD45KO/CD34ECD/CD146PE+, CD45KO/CD34ECD/CD31FITC. Cells were gated using Kaluza analysis software (Beckman Coulter, USA).

CD116 expression on granulocytes and monocytes was also assessed. Nonspecific (irrelevant) conjugated mouse monoclonal antibodies of the same IgG subclass (Mouse IgG2b, K) were used as isotype controls for each channel in negative control experiments. In flow cytometric data analysis, the endothelial cell population was identified by typical forward and side scatter patterns and selected through gating. The cell numbers for each gated specific EPC marker antibody were recorded, and the mean fluorescence intensity (MFI) values were also calculated.^17,18

Statistics

All tests were two-tailed, with P < 0.05 considered statistically significant. The data were represented using scatterplot graphs and box-and-whisker charts with overlapping data points. Continuous variables between the two groups were compared using the independent t-test. Data analysis was performed using a trial version of Origin/OriginPro 2025 (https://www.originlab.com/) software. Graphs were generated, and the significance level was set at P < 0.05.

Result

Enumeration of EPCs was performed using peripheral blood cells from 50 individuals, including 25 newborns and 25 adults, through flow cytometric analysis. For this purpose, a CD34-specific antibody was used to select hematopoietic stem cells and enumerate 1×10⁶ per million peripheral blood leucocytes (WBC). During the flow cytometric readout for CD34+ hematopoietic progenitor cells (HPCs), secondary gating was applied to the CD34+ HPC population to analyze additional EPC markers, such as CD146, CD31, and CD116 (Figures 1 and 2).

Figure 1.

Gating strategies for EPC enumeration by flow cytometry. The number of circulating EPCs was shown in CD45 (faded) on the SSC graph, with a representative histogram plot displaying CD34, CD146, CD31, CD116, and CD146/CD31 positive cells. Cells were gated using Kaluza analysis software (Beckman Coulter). A newborn sample from number P1 was analyzed. The mean fluorescence intensity (MFI) values of CD34, CD146, CD31, and CD116+ expressions were measured using the geometric mean.

Figure 2.

EPC numbers and MFI values in newborns and adults. A: EPC numbers were enumerated using CD34, CD146, CD31, and CD116 antibodies by flow cytometry. A significant difference in the number of EPCs was observed between the newborn and adult groups (p < 0.001). The mean EPC numbers are presented in Table 1. The scatterplot graph style represents each sample, with the horizontal bar indicating the median value. *: p < 0.001. Data were analyzed using Origin/OriginPro 2025 Software. B: MFI levels of EPCs showing fluorescence intensity of relevant antibodies on the cell surface. A significant difference was observed between the newborn and adult groups (p < 0.001). The mean MFI value of the EPCs is presented in Table 2. The scatterplot graph style represents each sample, with the horizontal bar indicating the median value. MFI: Mean fluorescence intensity. Data were analyzed using Origin/OriginPro 2025 Software.

Table 1.

Mean EPC numbers in healthy newborns and adults.

EPC marker panels	mean EPC numbers
	Newborns(N=25)			Adults(N=25)	P
	Premature (n=11)	Term (n=14)	T. Newborns(N=25)
CD34⁺ Stem cell	1502(785-1051)	1780(950-1585)	1643(935-1458)	242(163-190)	<0.001
CD34⁺CD116⁺	31.0(29.0-35.0)	24.0(22.8-31.3)	29.0(23.0-34.0)	3.0(2.0-4.0)	<0.001
CD34⁺CD146⁺	94.5(82.1-12.4)	99.0(97.1-10.2)	94.2(90.5-12.9)	9.2(7.3-2.3)	<0.001
CD34⁺CD31⁺	17.0(12.0-29.0)	19.5(13.8-27.5)	19.0(12.5-28.0)	6.0(5.0-7.0)	<0.001
CD34+CD146+CD31+	24.7(20.5-23.7)	20.7(16.7-19.5)	19.5(13.4-16.2)	10.2(6.3-8.4)	<0.001

Table 2.

Mean MFI values of the EPCs in healthy newborns and adults.

EPC marker panels	MFI value of mean EPCs
	Newborns (N=25)			Adults(N=25)	P
	Premature (n=11)	Term (n=14)	T. Newborns (N=25)
CD34+ Stem cell	17.66(14.5-16.30)	13.2(9.8-11.2)	11.5(7.8-10.4)	2.2(1.8-2.0)	<0.001
CD34⁺CD116⁺	15.2(12.1-17.0)	18.1(14.7-3.1)	15.5(1.5-2.5)	7.4(5.5-2.6)	<0.001
CD34⁺CD146⁺	21.2(17.7-2.8)	19.8(17.1-2.9)	18.9(17.7-2.7)	12.2(10.2-1.6)	<0.001
CD34⁺CD31⁺	6.3(5.7-15.2)	11.9(7.8-17.4)	10.1(6.2-16.3)	2.7(2.4-3.6)	<0.001
CD34+CD146+CD31+	24.7(20.5-23.7)	20.7(16.7-1.5)	19.5(13.4-16.2)	10.2(6.3-8.4)	<0.001

MFI: Mean fluorecence Intensity

Enumeration of CD34+ HPCs showed that the mean CD34+ HPC number were 1643 (935–1458) (mean ± standard deviation) in newborns, with values of 1502 (785–1051) in premature newborns and 1780 (950–1585) in term newborns. In adults, the mean CD34+ HPC number were 242.7 (163–190) (Figure 1, Table 1). A significant difference was observed between the newborn and adult groups (p < 0.001). The mean CD34 channel MFI values were calculated as 11.5 (7.8–10.4) in newborns, 17.6 (14.5–16.30) in premature newborns, and 13.2 (9.8–11.2) in term newborns. In adults, the mean CD34 channel MFI value was 2.2 (1.8–2.0) (Figure 1, Table 2). The mean CD34 MFI values in newborns were significantly higher than in adults (p < 0.001). No significant difference in EPC numbers was observed based on gender.

Characterization of Circulating EPCs

To date, numerous markers have been identified for EPC characterization. In this study, in addition to CD45(−/dim) gating, four markers were used: CD34, CD146, CD31, and CD116. When these markers were analyzed for the identification of mature EPCs (CD34(+) CD146(+)), two possible subtypes were also identified: CD31(+) CD34(+) early-emerging EPCs, CD31(+)CD34(+)CD146(+) late-emerging EPCs.

Secondary gates on the CD34+ HPC population were used to identify EPC markers:

Enumeration of mature EPCs with CD34+/CD146+:

The mean CD34+/CD146+ HPC number in newborns was 94.2 (90.5–12.9), with values of 94.5 (82.1–12.4) in premature newborns and 99.0 (97.1–10.2) in term newborns. In adults, the mean number were 9.2 (7.3–2.3) (Figure 1, Table 1), with a significant difference observed between the newborn and adult groups (p < 0.001).

The mean MFI values for CD34+/CD146+ cells in newborns were also calculated. These were found to be 18.9 (17.7–2.7) in newborns, 21.2 (17.7–2.8) in premature newborns, 19.8 (17.1–2.9) in term newborns, and 12.2 (10.2–1.6) in adults (Table 2). It was observed that the mean CD34+/CD146+ MFI values in newborns were significantly higher than in adults (p < 0.001).

Enumeration of early emerging EPCs with CD34+/CD31+ ;

The mean CD34+/CD31+ HPC cell number in newborns was 19.0 (12.5–28.0), with values of 17.0 (12.0–29.0) in premature newborns and 19.5 (13.8–27.5) in term newborns. In adults, the mean number were 6.0 (5.0–7.0) (Figure 1, Table 1), with a significant difference observed between the newborn and adult groups (p < 0.001).

The mean MFI values for CD34+/CD31+ cells in newborns were also calculated. These were found to be 10.1 (6.2–16.3) in newborns, 6.3 (5.7–15.2) in premature newborns, 11.9 (7.8–17.4) in term newborns, and 2.7 (2.4–3.6) in adults (Table 2). It was observed that the mean CD34+/CD31+ MFI values in newborns were significantly higher than in adults (p < 0.001).

Enumeration of late emerging EPCs with CD34+/CD146+/CD31+;

The mean CD34+/CD146+/CD31+ HPC cell number in newborns was 19.5 (13.4–16.2), with values of 24.7 (20.5–23.7) in premature newborns and 20.7 (16.7–19.5) in term newborns. In adults, the mean number were 10.28 (6.3–8.4) (Figure 1, Table 1), with a significant difference observed between the newborn and adult groups (p < 0.001).

The mean MFI values for CD34+/CD146+/CD31+ cells in newborns were also calculated. These were found to be 10.8 (5.3–8.9) in newborns, 13.7 (6.2–10.1) in premature newborns, 12.5 (7.4–11.2) in term newborns, and 12.5 (7.4–11.2) in adults (Table 2). It was observed that the mean CD34+/CD146+/CD31+ MFI values in newborns were significantly higher than in adults (p < 0.001).

Enumeration of EPCs with CD34+/CD116+ ;

The mean CD34+/CD116+ HPC cell number in newborns was 29.0 (23.0–34.0), with values of 31.0 (29.0–35.0) in premature newborns and 24.0 (22.8–31.3) in term newborns. In adults, the mean number were 3.0 (2.0–4.0) (Figure 1, Table 1), with a significant difference observed between the newborn and adult groups (p < 0.001).

The mean MFI values for CD34+/CD116+ cells in newborns were also calculated. These were found to be 15.5 (13.5–2.5) in newborns, 15.2 (12.1–17.0) in premature newborns, 18.1 (14.7–3.1) in term newborns, and 7.4 (5.5–2.6) in adults (Table 2), with a significant difference observed (p < 0.001). It was observed that the mean CD34+/CD116+ MFI values in newborns were significantly higher than in adults (p < 0.001).

Discussion and conclusion

Enumeration of EPCs was performed using peripheral blood cells from 50 individuals, including 25 newborn infants and 25 adults, by flow cytometric analysis. For this purpose, the CD34-specific marker was used to select hematopoietic stem cells, and an antibody panel including CD116, CD146, CD31, and CD45 was used for the selection of EPCs. EPCs are divided into two subtypes based on CD146 expression.

CD34 is a well-established marker for hematopoietic stem and progenitor cells and is expressed on cells with progenitor characteristics. Previous studies have shown that CD34⁺ hematopoietic progenitor cells constitute approximately 1–2% of CD45⁺ cells in mobilized peripheral blood and bone marrow, supporting their use as an indicator of circulating hematopoietic reserve. Flow cytometry-based multiparametric analysis enables reliable quantification of CD34⁺ cells and reveals developmental differences in hematopoietic activity. Consistent with the literature, our study demonstrated that the mean number of CD34⁺ hematopoietic progenitor cells per 10⁶ peripheral blood leukocytes was higher in newborns than in adults, reflecting increased hematopoietic activity during early life.^15,16 Accordingly, both the mean CD34⁺ cell count and mean fluorescence intensity (MFI) values for the CD34 channel were significantly elevated in newborns (p < 0.001). These findings suggest age-dependent differences in receptor density, potentially related to ongoing organogenesis and vascular development during the neonatal period (Figure 2; Tables 1–2; Supplementary Tables 1–4).

EPCs represent a heterogeneous population of circulating cells capable of differentiating toward endothelial lineages and contributing to neovascularization and endothelial maintenance. However, their identification remains challenging due to overlapping marker expression with hematopoietic progenitor cells, including CD34, CD133, and CD146. Previous studies have shown that both circulating EPC numbers and surface marker density are higher in newborns than in adults, likely reflecting increased proliferative activity and vascular remodeling demands early in life.^19,20 In line with these observations, our study demonstrated that both the mean CD34⁺ cell count and CD34-related MFI values were significantly higher in newborns than in adults, supporting the presence of age-associated phenotypic and functional differences in EPCs.

CD146 is an endothelial adhesion molecule associated with endothelial integrity and junctional stability. It has been implicated in the regulation of cell–cell interactions, paracellular permeability, and cytoskeletal organization. In addition, CD146 expression is associated with actin cytoskeletal organization, thereby contributing to endothelial monolayer stability and intracellular permeability control.^21,22 Recent studies indicate that CD146 defines a more mature EPC subpopulation with enhanced angiogenic properties. Increased numbers of CD34⁺/CD146⁺ cells have been reported in conditions involving endothelial injury, suggesting a compensatory role in vascular repair.^21,22 In our study, significant differences were observed between newborns and adults in CD34⁺/CD146⁺ cell frequencies and MFI values, supporting CD146 as a marker of EPC maturation.

CD31 is commonly used as a marker of endothelial and hematopoietic progenitor cells and is involved in adhesion, transendothelial migration, and vascular integrity. Higher frequencies of CD31-positive cells have been reported in the neonatal period. In our cohort, co-expression of CD31 with CD34 and CD146 identified EPC subsets with developmental plasticity, highlighting EPC heterogeneity in early life.²³

The combined CD34⁺CD146⁺CD31⁺ phenotype has been proposed as an intermediate EPC population with increased endothelial differentiation capacity and involvement in vascular repair. The frequent use of CD31 and CD146 in identifying endothelial-derived cells underscores their close association with vascular activity and function. In our cohort, the significantly higher frequency of CD146⁺/CD31⁺ EPCs in newborns suggests a potential role for these cells in vascular development and hematopoietic–endothelial interface dynamics during early life, consistent with current literature.^24–26

CD116, the α subunit of the GM-CSF receptor, is predominantly expressed on myeloid cells and plays a role in innate immune signaling.²⁷ In the present study, CD116 expression and MFI values were significantly higher in newborns and declined with age in parallel with circulating EPC numbers (p < 0.001), suggesting an association with early-life hematopoietic and endothelial progenitor activity.

Overall, the combined use of CD116, CD146, and CD31 enables more refined and functionally informative identification of circulating EPC subpopulations. This multiparametric approach improves flow cytometric resolution of progenitor cell populations at the intersection of hematopoiesis, vascular biology, and innate immunity. Collectively, these findings contribute to the refinement of EPC immunophenotyping strategies.

Supplemental Material

sj-docx-1-ini-10.1177_17534259261438615 - Supplemental material for Endothelial progenitor cell numbers vary in newborns and adults; anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration

Supplemental material, sj-docx-1-ini-10.1177_17534259261438615 for Endothelial progenitor cell numbers vary in newborns and adults; anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration by Sevil Simsek, Cagatay Karaca, Nezihe Koker, Adnan Öztürk and Mustafa Yavuz Koker in Innate Immunity

Supplemental Material

sj-docx-2-ini-10.1177_17534259261438615 - Supplemental material for Endothelial progenitor cell numbers vary in newborns and adults; anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration

Supplemental material, sj-docx-2-ini-10.1177_17534259261438615 for Endothelial progenitor cell numbers vary in newborns and adults; anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration by Sevil Simsek, Cagatay Karaca, Nezihe Koker, Adnan Öztürk and Mustafa Yavuz Koker in Innate Immunity

Footnotes

ORCID iDs

Sevil Simsek

Cagatay Karaca

Nezihe Koker

Mustafa Yavuz Koker

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Bilimsel Araştırma Projeleri, Erciyes Üniversitesi, (grant number TYL-2017-7276 and BAP-TSAÜ-2025-14284).

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Supplemental material

Supplemental material for this article is available online.

References

Lee

Hong

. Hematopoietic stem cells and their roles in tissue regeneration. Int J Stem Cells 2020; 13: 1–12.

Lazarus

Ragsdale

Gale

, et al.

Sargramostim (Rhu GM-CSF) as cancer therapy (Systematic review) and an immunomodulator. A drug before its time?

Front Immunol 2021; 12: 706186.

Sudo

Motomura

Okuzaki

, et al. Group 2 innate lymphoid cells support hematopoietic recovery under stress conditions. J Exp Med 2021; 218.

Zhang

, et al. Interleukin-1β-induced IRAK1 ubiquitination is required for T_H-GM-CSF cell differentiation in T cell-mediated inflammation J. Otoimmün 2019; 102: 50–64.

Dauber

Becker

Odendahl

, et al. Enumeration of viable CD34 cells by fl ow cytometry in blood, bone marrow and cord blood: results of a study of the novel BD ™ stem cell enumeration kit. Cytotherapy 2011; 13: 449–458.

Hughes M

Canals Hernaez

Cait

, et al. A sticky wicket: defining molecular functions for CD34 in hematopoietic cells. Exp Hematol 2020; 86: 1–14.

Shim

Nam

Hyuk

, et al. Concurrent hypermulticolor monitoring of CD31, CD34, CD45 and CD146 endothelial progenitor cell markers for acute myocardial infarction. Anal Chim Acta 2015; 853: 501–507.

Kamp

Leentjens

Pillay

. Modulation of granulocyte kinetics by GM-CSF/IFN-γ in a human LPS re-challenge model. J Leukoc Biol 2013; 94: 513–520.

Regenfuss

Cursiefen

. Concept of angiogenic privilege. Encyclop Eye 2010; 1: 334–338.

10.

Alexander

SPH

Fabbro

Kelly

, et al. The concise guide to pharmacology 2015/16: catalytic receptors. Br. J. Pharmacol 2015; 172: 5979–6023.

11.

Wang

, et al. Enforced expression of METCAM/MUC18 increases tumorigenesis of human prostate cancer LNCaP cells in nude mice. J. Urol 2011; 185: 1504–1512.

12.

Lertkiatmongkol

Liao

Mei

, et al. Endothelial functions of PECAM-1 (CD31). Curr Opin Hematol 2016; 23: 253–259.

13.

Hristov

Erl

Weber

. Endothelial progenitor cells isolation and characterization. Trends Cardiovasc Med 2003; 13: 201–206.

14.

Köker

Camcıoğlu

van Leeuwen

, et al. Clinical, functional, and genetic characterization of chronic granulomatous disease in 89 Turkish patients. J Allergy Clin Immunol 2013; 132: 1156–1163.

15.

Favaro

Glass

Borges

, et al. Quantification of intrinsic regulatory factors refines human hematopoietic progenitor definitions and reveals early erythroid lineage priming. Cell Rep 2025; 44: 115913.

16.

Hagenkötter

Mika

Ladigan-Badura

, et al. Comparison of peripheral blood automated hematopoietic progenitor cell count and flow cytometric CD34⁺ cell count. J Clin Apher 2024; 39.

17.

Goldstein

Kominsky

Jacobson

, et al. Defective leukocyte GM-CSF receptor (CD116) expression and function in inflammatory bowel disease. Gastroenterology 2011; 141: 208–216.

18.

Yang

Guo

. Microencapsulation of low-passage poorly-diferentiated human mucoepidermoid carcinoma cells by alginate microcapsules: in vitro profling of angiogenesis-related molecules. Cancer Cell Int 2017; 17.

19.

Burlacu

Grigorescu

Rosca

, et al. Factors secreted by endothelial progenitor cells and their role in angiogenesis. Cell Tissue Res 2020; 379: 161–187.

20.

Gaafar

Hamza

Yousif

, et al. Distinct phenotypic and molecular characteristics of CD34⁻ and CD34⁺ hematopoietic stem/progenitor cell subsets in cord blood and bone marrow samples: implications for clinical applications. Diagnostics 2025; 15: 47.

21.

Wang

Yan

. CD146, A multi-functional molecule beyond adhesion. Cancer Lett 2013; 330: 150–162.

22.

Bingol

Elcik

Kutuk

, et al. Endothelial progenitor cells and NADPH oxidase enzyme activity in the development of an aortic aneurysm. Braz J Cardiovasc Surg 2022; 37: 501–510.

23.

Sullivan

Gonzalez

, et al. Mechanotransduction via endothelial adhesion molecule CD31 initiates transmigration and reveals a role for VEGFR2 in diapedesis. Immunity 2023; 56: 2311–2324.

24.

Beckman

Zhang

Nguyen

, et al. Missing the mark(ers): circulating endothelial cells and endothelial-derived extracellular vesicles are elevated in sickle cell disease plasma. Front Immunol 2024; 15: 1493904.

25.

Shakoora

Muley

, et al. Lymphatic endothelial cell defects in congenital cardiac patients with postoperative chylothorax. J Vasc Anom (Phila) 2021; 2. doi:10.1097/JOVA.0000000000000016

26.

Dight

Zhao

Styke

, et al. Resident vascular endothelial progenitor definition and function: the age of reckoning. Angiogenesis 2022; 25: 15–33.

27.

Guerrero

Bono

Sobén

, et al. GM-CSF receptor expression determines opposing innate memory phenotypes at different stages of myelopoiesis. Blood 2024; 143: 2763–2777.

Endothelial progenitor cell numbers vary in newborns and adults;anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration

Abstract

Objective

Materials and Methods

Results

Conclusion

Keywords

Introduction

Patient groups

Ethics statement, consent statement

Method

Enumeration of EPCs labeled with CD34, S-endo (CD146), CD31 and Gm-CSFα (CD116)

Statistics

Result

Discussion and conclusion

Supplemental Material

sj-docx-1-ini-10.1177_17534259261438615 - Supplemental material for Endothelial progenitor cell numbers vary in newborns and adults; anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration

Supplemental Material

sj-docx-2-ini-10.1177_17534259261438615 - Supplemental material for Endothelial progenitor cell numbers vary in newborns and adults; anti-gm-CSFα (CD116) antibody as a novel marker for EPC enumeration

Footnotes

ORCID iDs

Funding

Declaration of conflicting interests

Supplemental material

References