Reference values for peripheral blood lymphocyte subsets of healthy children in China

Immunophenotyping of peripheral blood lymphocyte subsets can provide important information for the diagnosis and treatment of immunological and hematological disorders. Lymphocyte compartments undergo dramatic changes during childhood; age-matched reference values derived from healthy individuals are crucial and have been evaluated in various ethnic populations.1Shearer W. Rosenblatt H. Gelman R. Oyomopito R. Plaeger S. Stiehm E.R. Lymphocyte subsets in healthy children from birth through 18 years of age— the Pediatric AIDS Clinical Trials Group P1009 study.J Allergy Clin Immunol. 2003; 112: 973-980Abstract Full Text Full Text PDF PubMed Scopus (634) Google Scholar, 2van Gent R. van Tilburg C.M. Nibbelke E.E. Otto S.A. Gaiser J.F. Janssens-Korpela P.L. et al.Refined characterization and reference values of the pediatric T- and B-cell compartments.Clin Immunol. 2009; 133: 95-107Crossref PubMed Scopus (137) Google Scholar, 3Huenecke S. Behl M. Fadler C. Zimmermann S.Y. Bochennek K. Tramsen L. et al.Age-matched lymphocyte subpopulation reference values in childhood and adolescence: application of exponential regression analysis.Eur J Haematol. 2008; 80: 532-539Crossref PubMed Scopus (70) Google Scholar, 4Tosato F. Bucciol G. Pantano G. Putti M.C. Sanzari M.C. Basso G. et al.Lymphocytes subsets reference values in childhood.Cytometry A. 2015; 87: 81-85Crossref PubMed Scopus (76) Google Scholar, 5Jia L. Li J. Zhang Y. Shi Y. Yuan E. Liu J. et al.Age- and sex-related reference intervals of lymphocyte subsets in healthy ethnic Han Chinese children.Cytometry A. 2015; 87: 1116-1126Crossref PubMed Scopus (11) Google Scholar However, extensively detailed immunophenotyping reference values of peripheral blood lymphocytes in whole spectrum of childhood are rare. Our aim was to determine the relative and absolute numbers of lymphocyte subpopulations in healthy Chinese children from birth to age 18 years. We recruited 1075 Chinese children (604 males and 471 females) who were grouped into 7 categories according to age: group 1, 0 to 28 days; group 2, 1 to 6 months; group 3, 6 to 12 months; group 4, 1 to 4 years; group 5, 4 to 8 years; group 6, 8 to 12 years; and group 7, 12 to 18 years. Whole blood was used and staining for lymphocyte surface markers was performed after red cell lysis, according to a standard flow cytometric multicolor protocol. A total of 20 subpopulations were examined: T cells (CD45+SSClowCD3+), CD4 T cells (CD45+SSClowCD3+CD4+), CD8 T cells (CD45+SSClowCD3+CD8+), B cells (CD45+SSClowCD19+), natural killer cells (CD45+SSClowCD3−CD56+/CD16+), TCRαβ+ double-negative T (DNT) cells (CD3+TCRαβ+CD4−CD8−), γδ T cells (γδT, CD3+TCRγδ+), double-positive T (DPT) cells (CD3+CD4+CD8+), naive differentiated helper T cells (CD4 Naive, CD3+CD4+CD45RA+CD27+), central memory helper T cells (CD4 CM, CD3+CD4+CD45RA−CD27+), effector memory helper T cells (CD4 EM, CD3+CD4+CD45RA−CD27−), terminally differentiated effector memory helper T cells (CD4 TEMRA, CD3+CD4+CD45RA+CD27−), naive differentiated cytotoxic T cells (CD8 Naive, CD3+CD8+CD45RA+CD27+), central memory cytotoxic T cells (CD8 CM, CD3+CD8+CD45RA−CD27+), effector memory cytotoxic T cells (CD8 EM, CD3+CD8+CD45RA−CD27−), terminally differentiated effector memory cytotoxic T cells (CD8 TEMRA, CD3+CD8+CD45RA+CD27−), naive B cells (CD19+CD27−IgD+), memory B cells (CD19+CD27+IgD−), transitional B cells (CD19+CD24++CD38++), and plasmablasts (CD19+CD24−CD38++). (See Table E1 in this article's Online Repository at www.jacionline.org; information about samples, subjects, and staining protocol is detailed in this article's Online Repository at www.jacionline.org.) For the T-cell compartment, marked age-specific variations in the percentages and numbers of CD4 and CD8 T-cell subsets were observed (Tables I and II). The proportion of naive CD4 T cells showed a gradual decrease from the median value of 87.67% in the first month of life to 53.40% in children aged 12 to 18 years, whereas the percentage of memory CD4 T cells increased (CD4 CM from 12.11% to 37.60%, and CD4 EM from 0.11% to 7.30%). A similar pattern of changes was observed in the relative proportion of naive CD8 T cells and memory CD8 T cells. The central memory pool, which is thought to maintain long-lived T-cell memory in a stem cell-like fashion, constituted most memory cell subsets in all age groups. Both CD4 and CD8 terminal effector differentiated memory (TEMRA) cells constituted only a small proportion of T cells in newborns (median of 0.05% and 0.21%, respectively), rose markedly during the first year of life (median of 0.45% and 8.59%, respectively), and plateaued in children aged 4 to 18 years (see Fig E1 in this article's Online Repository at www.jacionline.org). We found a clear difference between CD4 and CD8 TEMRA cells. The CD4 TEMRA remained very low in both percentage and number, whereas the proportions and absolute number of CD8 TEMRA were greater. A few CD3+CD4+CD8+ DPT cells could be detected, which slowly decreased both in relative proportion and in absolute numbers. Although γδT cells constitute a minor population of T cells, they play a crucial role in both the innate and adaptive immunity, as reported by Wu et al.6Wu M. Yang J. Li X. Chen J. The role of gammadelta T cells in systemic lupus erythematosus.J Immunol Res. 2016; 2016: 2932531Crossref PubMed Scopus (21) Google Scholar Here, we showed that the relative size of the γδT population gradually increased with age and peaked at 8 to 12 years (median of 12.45%). We found that the proportion of DNT cells showed a gradual increase from birth but to no more than a median of 1.5%, while the absolute number remained relatively stable. To our knowledge, only few pediatric reference values are available for peripheral blood DNT-cell levels, and our findings provide useful reference in the evaluation of autoimmune lymphoproliferative syndrome and other related diseases.Table IDistribution of the percentage of total T and B cells and their subsets by age and sex in the peripheral blood of 1075 healthy children (%)SubsetSexGroup 10-28 d (n = 21)Group 21-6 mo (n = 104)Group 36-12 mo (n = 97)Group 41-4 y (n = 289)Group 54-8 y (n = 271)Group 68-12 y (n = 158)Group 712-18 y (n = 135)Total TM68.29 (54.26-80.94)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).63.31 (54.28-71.67)64.04 (55.32-73.11)65.84 (53.88-72.87)68.00 (60.05-74.08)66.90 (57.10-73.43)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).66.94 (56.84-75.02)F75.78 (74.15-82.16)66.61 (57.45-75.22)67.00 (60.15-72.29)64.17 (53.37-71.91)67.19 (59.50-75.56)70.00 (62.06-76.54)68.01 (61.29-73.13)CD4M47.70 (41.90-55.58)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).41.96 (33.72-52.43)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).38.36 (28.17-47.74)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).35.17 (24.08-42.52)33.26 (26.17-40.76)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).30.21 (24.00-38.72)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).30.80 (22.25-39.00)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).F53.76 (51.37-58.57)45.13 (37.71-56.05)44.54 (35.23-51.41)35.96 (26.19-45.48)35.00 (28.49-41.07)34.09 (28.47-41.39)34.53 (26.36-40.90)CD8M19.10 (16.94-26.18)18.45 (14.08-24.70)22.98 (15.88-31.48)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).25.04 (19.00-32.51)26.98 (19.68-34.06)27.00 (21.01-33.94)28.58 (21.91-36.80)F19.44 (17.27-27.18)17.83 (12.61-25.08)19.00 (14.11-27.77)21.81 (16.29-29.88)25.28 (19.70-32.04)27.98 (22.50-32.37)27.40 (20.99-33.73)Total BM18.69 (7.70-35.29)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).25.25 (17.34-36.03)22.23 (17.20-29.71)19.00 (13.23-26.39)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).14.62 (10.21-20.12)13.69 (9.19-19.48)13.00 (8.84-17.76)F9.26 (7.49-17.71)22.74 (14.71-31.04)22.21 (16.57-27.65)20.57 (13.93-30.49)15.65 (10.46-21.77)13.58 (9.23-18.15)12.58 (7.73-16.84)NKM8.64 (5.90-15.56)9.00 (5.89-14.85)8.88 (5.67-15.90)12.24 (7.21-20.90)14.80 (9.00-22.24)17.00 (10.01-26.98)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).18.06 (10.12-28.34)F8.26 (6.92-14.19)8.04 (4.92-13.45)8.00 (4.84-15.47)11.03 (6.53-22.24)13.77 (7.83-20.99)13.72 (7.75-23.47)17.55 (11.43-27.57)DNTM0.62 (0.33-0.86)0.64 (0.33-1.12)0.86 (0.41-1.55)1.01 (0.37-1.80)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.31 (0.18-2.81)1.60 (0.82-2.91)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.48 (0.61-2.31)F0.40 (0.22-0.94)0.71 (0.40-1.16)1.05 (0.57-1.53)1.13 (0.56-2.36)1.25 (0.19-2.43)1.32 (0.68-2.16)1.40 (0.80-2.52)γδTM3.09 (2.54-5.30)4.88 (3.32-7.40)6.47 (3.95-10.40)9.80 (4.94-17.98)12.20 (6.92-19.84)12.60 (8.10-20.76)10.80 (6.55-20.28)F3.33 (2.52-11.47)5.58 (3.49-8.29)5.77 (3.80-9.20)10.20 (5.07-17.60)11.30 (7.00-19.60)12.30 (7.80-23.35)11.45 (6.40-18.50)DPTM0.63 (0.35-3.30)0.59 (0.33-0.92)0.44 (0.22-1.23)0.34 (0.15-1.01)0.29 (0.15-0.68)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).0.41 (0.23-0.94)0.37 (0.20-0.80)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).F0.79 (0.60-1.56)0.62 (0.33-1.17)0.53 (0.31-0.82)0.37 (0.15-0.96)0.39 (0.22-0.71)0.51 (0.21-0.92)0.55 (0.32-1.08)CD4/CD8M2.28 (1.98-3.10)2.28 (1.47-3.23)1.69 (0.93-2.52)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.44 (0.90-2.13)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.25 (0.87-1.94)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.08 (0.81-1.66)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.03 (0.65-1.65)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).F2.76 (1.97-3.32)2.66 (1.62-3.77)2.36 (1.28-3.40)1.65 (1.05-2.53)1.34 (1.02-2.05)1.24 (0.92-1.73)1.26 (0.85-1.76)CD4 NaiveM87.67 (80.47-93.49)82.40 (69.15-88.10)78.45 (59.28-88.09)70.30 (46.14-84.40)62.20 (45.56-75.28)57.80 (39.72-69.59)53.20 (39.50-66.26)F87.27 (78.15-90.70)84.15 (67.52-89.73)80.30 (65.58-87.86)67.50 (46.42-81.20)62.85 (40.75-72.70)58.55 (39.85-71.80)54.65 (43.30-63.20)CD4 CMM12.11 (6.37-19.02)15.10 (10.11-28.20)18.40 (10.15-33.38)26.40 (13.88-48.12)32.90 (22.06-46.46)34.55 (24.24-52.73)37.80 (25.34-49.90)F12.55 (8.94-21.70)14.50 (9.21-32.18)16.90 (11.74-32.72)28.85 (17.12-47.60)32.05 (21.66-52.74)35.30 (23.25-51.30)36.50 (30.85-45.25)CD4 EMM0.09 (0.05-0.27)1.02 (0.28-2.10)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1.33 (0.42-3.96)2.80 (0.94-6.46)4.30 (2.08-8.78)6.20 (3.40-11.17)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).8.10 (4.68-15.70)F0.12 (0.05-0.50)0.70 (0.16-1.82)1.01 (0.42-2.26)2.50 (0.90-5.17)4.05 (1.90-9.20)5.05 (2.65-9.90)6.75 (4.20-16.25)CD4 TEMRAM0.05 (0.02-0.34)0.23 (0.00-1.64)0.30 (0.00-1.49)0.20 (0.00-1.36)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).0.20 (0.00-1.06)0.25 (0.10-1.29)0.20 (0.00-1.54)F0.05 (0.01-0.25)0.20 (0.00-0.68)0.30 (0.00-1.07)0.10 (0.00-0.50)0.20 (0.00-1.47)0.30 (0.07-1.65)0.40 (0.10-2.10)CD8 NaiveM88.92 (82.14-96.93)81.40 (68.90-94.60)72.50 (47.36-92.45)63.50 (36.80-83.16)61.30 (41.58-77.90)55.85 (41.41-73.04)52.80 (35.34-72.32)F90.20 (84.66-92.62)80.45 (63.39-94.29)72.70 (53.16-90.14)65.40 (38.19-86.18)62.00 (38.03-79.08)55.05 (36.05-72.25)53.90 (37.00-69.35)CD8 CMM10.53 (3.01-16.90)13.05 (5.14-25.55)11.00 (4.82-24.11)15.80 (5.18-31.66)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).20.60 (12.08-30.54)24.95 (13.21-37.89)21.00 (10.96-31.00)F8.99 (7.23-11.85)13.45 (5.51-27.25)11.30 (7.09-31.70)20.20 (6.66-34.14)22.05 (11.91-36.87)26.70 (13.05-39.45)24.05 (14.00-36.85)CD8 EMM0.05 (0.03-0.53)0.78 (0.10-4.95)2.01 (0.20-8.94)3.40 (0.70-11.22)4.90 (1.58-13.18)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).5.60 (1.53-15.39)7.50 (2.38-15.84)F0.19 (0.06-0.55)0.64 (0.02-4.74)2.00 (0.18-7.06)3.10 (0.60-12.01)3.75 (1.11-14.51)6.60 (2.00-16.75)5.00 (2.40-15.50)CD8 TEMRAM0.12 (0.03-0.73)0.65 (0.02-9.61)9.30 (0.15-28.32)15.50 (0.84-33.02)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).10.30 (1.70-24.62)8.40 (2.01-21.65)13.80 (5.08-31.24)F0.24 (0.05-1.16)0.34 (0.00-10.48)3.63 (0.12-20.70)6.75 (0.50-24.45)9.80 (1.30-22.85)8.60 (1.35-21.50)12.75 (3.90-27.25)Naive BM87.20 (77.80-92.90)93.15 (87.55-94.85)87.80 (75.28-92.77)77.60 (65.54-86.62)64.50 (48.36-75.84)64.85 (51.84-77.61)67.26 (53.78-78.64)F88.75 (70.95-93.72)92.40 (87.99-94.63)87.20 (79.08-93.04)76.20 (59.59-85.28)62.35 (52.04-75.78)64.70 (44.95-75.80)68.55 (48.38-77.85)Memory BM2.47 (0.96-3.63)2.16 (0.99-4.71)3.96 (1.77-7.06)7.40 (2.98-14.18)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).12.90 (7.76-19.90)14.60 (8.96-24.09)13.50 (7.15-23.10)F2.93 (1.85-20.45)2.18 (0.93-4.23)4.40 (1.24-7.81)7.70 (3.60-18.55)14.20 (8.61-20.19)13.95 (8.85-22.90)15.40 (8.94-23.75)Transitional BM31.60 (9.50-56.50)19.90 (15.05-29.95)12.60 (6.04-21.62)9.80 (5.24-17.22)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).6.70 (2.58-12.30)5.30 (2.50-9.07)∗The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).3.70 (1.38-9.42)F23.55 (9.83-38.68)21.45 (11.77-30.45)13.30 (5.84-18.76)8.80 (4.73-15.68)6.35 (3.41-11.17)4.30 (1.75-10.30)3.05 (1.35-5.50)PlasmablastsM1.30 (0.50-3.40)1.35 (0.60-3.95)2.43 (0.71-5.88)2.00 (0.50-7.06)2.80 (0.90-7.36)2.25 (0.70-5.67)1.80 (0.49-7.06)F2.74 (0.39-8.06)1.70 (0.69-3.42)2.80 (0.44-7.40)2.20 (0.60-10.31)2.45 (0.80-9.75)2.20 (0.70-7.95)1.75 (0.46-5.80)The proportions of CD4 T cells, CD8 T cells, and DPT cells were calculated as percentages of total lymphocytes; the proportions of DNT cells and γδT cells were calculated as percentages of total T cells; subsets of CD4, CD8 T cells and B cells as percentages of CD4, CD8 T or B cells. Values of each population were presented as medians (upper line) and (10th to 90th) percentiles (lower line).DNT, TCRαβ+ CD4 and CD8 double-negative T cell; F, female; M, male; NK, natural killer; TEMRA, terminally differentiated effector memory CD45RA+ T cell.∗ The differences of values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant). Open table in a new tab Table IIThe numbers of total T and B cells and their subsets by age and sex in the peripheral blood of 1075 healthy childrenSubsetSexGroup 10-1 mo (n = 21)Group 21-6 mo (n = 104)Group 36-12 mo (n = 97)Group 41-4 y (n = 289)Group 54-8 y (n = 271)Group 68-12 y (n = 158)Group 712-18 y (n = 135)Lymphocytes (× 109/L)M4.47 (3.47-6.63)5.31 (3.68-7.34)5.89 (3.73-8.76)4.44 (2.79-6.35)2.94 (2.28-3.82)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).2.53 (2.02-3.61)2.44 (1.78-3.44)F4.44 (3.27-6.11)5.12 (4.02-6.45)5.71 (3.78-8.11)4.39 (2.98-5.95)3.04 (2.37-4.29)2.65 (2.02-3.50)2.49 (1.76-3.00)Total T(cells/μL)M3073 (1856-4021)3488 (2179-4424)3595 (2187-6352)2843 (1794-4247)1989 (1424-2664)1686 (1325-2276)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1661 (1184-2144)F3636 (2421-4577)3369 (2766-4068)3625 (2488-5422)2778 (1775-3953)2092 (1480-2847)1864 (1297-2480)1617 (1169-2071)CD4(cells/μL)M2156 (1330-3105)2279 (1461-3018)2188 (1125-3768)1467 (902-2253)960 (686-1358)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).794 (531-1110)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).776 (522-1084)F2548 (1744-3226)2287 (1890-2988)2539 (1433-3874)1518 (948 -2477)1066 (767-1592)897 (621-1258)843 (554-1109)CD8(cells/μL)M880 (657-1152)979 (556-1687)1396 (686-2278)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1131 (580-1735)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).754 (518-1125)690 (480-1112)713 (489-1009)F1026 (609-1348)956 (658-1276)1059 (710-1843)979 (531-1521)773 (553-1127)714 (509-1050)672 (423-900)Total B(cells/μL)M774 (344-2090)1234 (734-2265)1302 (916-1832)822 (461-1456)423 (280-623)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).350 (216-536)316 (203-476)F466 (292.26-858.94)1058 (667.15-2044.69)1226 (807.44-1803.72)867 (537.11-1464.39)473 (303.52-777.25)333 (247.05-578.16)309 (176.56-415.64)NK(cells/μL)M350 (267-730)471 (290-780)588 (306-896)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).508 (270-1053)406 (258-727)423 (246-792)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).425 (210-804)F377 (266-602)411 (221-722)416 (243-924)473 (241-978)432 (227-668)366 (203-584)404 (232-789)DNT(cells/μL)M20 (11-26)18 (11-45)29 (16-58)27 (9-57)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).23 (4-55)26 (13-48)23 (12-37)F17 (6-35)23 (13-38)37 (19-72)31 (16-58)26 (4-49)23 (12-41)22 (13-44)γδT(cells/μL)M97 (51-240)141 (92-279)238 (128-436)267 (114-539)233 (124-410)210 (124-388)198 (81-343)F139 (71-356)187 (94-301)205 (143-409)283 (128-520)243 (134-428)234 (121-462)176 (85-358)DPT(cells/μL)M34 (16-121)28 (16-56)25 (9-67)16 (6-50)9 (4-21)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).10 (6-26)9 (4-21)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).F37 (30-70)31 (19-73)29 (13-50)15 (6-50)12 (6-25)13 (5-29)13 (7-30)CD4 Naive(cells/μL)M1943 (1182-2585)1839 (1170-2595)1802 (764-2972)918 (472-1760)595 (321-972)407 (294-683)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).410 (230-627)F1982 (1592-2853)1908 (1433-2546)1967 (1042-3160)929 (530-1837)633 (339-1037)489 (299-857)442 (276-654)CD4 CM(cells/μL)M227 (145-387)318 (213-647)362 (206-796)377 (212-735)305 (211-478)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).268 (165-475)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).257 (182-403)F339 (162-544)341 (239-676)384 (236-803)448 (220-800)341 (232-601)317 (219-463)296 (203-422)CD4 EM(cells/μL)M3 (1-6)21 (5-48)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).29 (11-60)41 (15-87)40 (23-84)45 (24-87)60 (29-117)F3 (2-13)16 (3-42)23 (12-56)33 (14-93)41 (20-97)42 (24-94)53 (31-128)CD4 TEMRA(cells/μL)M2 (1-4)5 (0-40)5 (0-33)4 (0-22)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).1 (0-13)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).2 (0-9)2 (0-12)F2 (0-4)4 (0-16)7 (0-23)2 (0-12)2 (0-17)2 (1-15)3 (1-18)CD8 Naive(cells/μL)M775 (535-1054)800 (503-1276)909 (535-1677)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).653 (356-1095)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).462 (297-730)380 (245-657)375 (231-568)F892 (519-1205)741 (484-1009)726 (461-1235)589 (295-971)447 (293-768)387 (232-665)328 (210-560)CD8 CM(cells/μL)M101 (29-140)124 (41-305)165 (51-316)156 (56-406)158 (85-268)179 (92-287)152 (74-228)F93 (45-127)124 (46-256)131 (59-381)177 (54-379)173 (80-350)178 (100-301)154 (87-275)CD8 EM(cells/μL)M1 (0-5)6 (1-70)28 (2-120)39 (6-145)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).38 (10-129)40 (9-130)55 (16-109)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).F2 (1-4)6 (0-52)22 (2-116)28 (4-163)28 (8-104)45 (14-157)35 (13-110)CD8 TEMRA(cells/μL)M1 (0 -6)5 (0-133)146 (2-430)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).154 (9-440)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).80 (11-218)56 (12-164)100 (29-269)F2 (1-13)3 (0-109)54 (1-220)75 (3-294)69 (9-210)64 (11-175)68 (20-218)Naive B(cells/μL)M675 (268-1674)1157 (691-2132)1146 (726-1626)629 (323-108)264 (147-431)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).233 (123-362)206 (116-347)F432 (196-801)947 (597-1941)1032 (729-1474)677 (371-1197)295 (171-469)203 (140-381)185 (98-296)Memory B(cells/μL)M15 (8-67)29 (12-54)51 (22-103)52 (26-124)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).51 (31-94)∗The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant).52 (28-89)40 (20-86)F20 (14-48)25 (10-44)52 (16-124)72 (33-146)64 (38-115)51 (30-90)42 (27-70)Transitional B(cells/μL)M282 (33-526)250 (136-464)164 (65-288)78 (35-172)27 (10-66)18 (7-37)11 (4-37)F95 (36-384)223 (122-445)172 (74-266)70 (33-181)28 (14-60)15 (5-37)9 (3-19)Plasmablasts(cells/μL)M12 (2-27)19 (6-42)33 (9-72)17 (4-63)11 (4-28)7 (3-21)6 (1-23)F18 (1-29)18 (8-36)30 (6-109)23 (4-88)11 (4-40)8 (2-36)5 (1-15)The total numbers of white blood cells, lymphocytes, and T cells, B cells, NK cells, and their subsets for each age group are shown as the median (upper line) and (10th to 90th) percentiles (lower line).DNT, TCRαβ+ CD4 and CD8 double-negative T cell; F, female; M, male; NK, natural killer; TEMRA, terminally differentiated effector memory CD45RA+ T cell.∗ The differences in values between males and females were statistically significant (Wilcoxon rank sum test was used and a 2-sided P value of <.05 was regarded as statistically significant). Open table in a new tab The proportions of CD4 T cells, CD8 T cells, and DPT cells were calculated as percentages of total lymphocytes; the proportions of DNT cells and γδT cells were calculated as percentages of total T cells; subsets of CD4, CD8 T cells and B cells as percentages of CD4, CD8 T or B cells. Values of each population were presented as medians (upper line) and (10th to 90th) percentiles (lower line). DNT, TCRαβ+ CD4 and CD8 double-negative T cell; F, female; M, male; NK, natural killer; TEMRA, terminally differentiated effector memory CD45RA+ T cell. The total numbers of white blood cells, lymphocytes, and T cells, B cells, NK cells, and their subsets for each age group are shown as the median (upper line) and (10th to 90th) percentiles (lower line). DNT, TCRαβ+ CD4 and CD8 double-negative T cell; F, female; M, male; NK, natural killer; TEMRA, terminally differentiated effector memory CD45RA+ T cell. Naive B cells were the predominant B-cell subset in all age groups. In particular, the percentage of naive B cells was the highest in infants aged 1 to 6 months (92.50%), and lowest among children aged 4 to 8 years (63.90%). The absolute numbers of naive B cells were high during the first year of life and gradually decreased, reaching a plateau in children aged 8 to 18 years (see Fig E2 in this article's Online Repository at www.jacionline.org). Memory B cells were scarce in terms of both relative proportion (median of 2.18%) and number during the first years of life, which is a plausible explanation for the transient immaturity of the antibody response against T-cell–independent antigens, which is characteristic of this period in childhood.7Aranburu A. Piano Mortari E. Baban A. Giorda E. Cascioli S. Marcellini V. et al.Human B-cell memory is shaped by age- and tissue-specific T-independent and GC-dependent events.Eur J Immunol. 2017;