Age-related changes in blood lymphocyte subsets of Chinese children

Minimal residual disease assessment in B-cell precursor acute lymphoblastic leukemia by semi-automated identification of normal hematopoietic cells: A EuroFlow study

Presence of minimal residual disease (MRD), detected by flow cytometry, is an important prognostic biomarker in the management of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, data-analysis remains mainly expert-dependent. In this study, we designed and validated an Automated Gating & Identification (AGI) tool for MRD analysis in BCP-ALL patients using the two tubes of the EuroFlow 8-color MRD panel. The accuracy, repeatability, and reproducibility of the AGI tool was validated in a multicenter study using bone marrow follow-up samples from 174 BCP-ALL patients, stained with the EuroFlow BCP-ALL MRD panel. In these patients, MRD was assessed both by manual analysis and by AGI tool supported analysis. Comparison of MRD levels obtained between both approaches showed a concordance rate of 83%, with comparable concordances between MRD tubes (tube 1, 2 or both), treatment received (chemotherapy versus targeted therapy) and flow cytometers (FACSCanto versus FACSLyric). After review of discordant cases by additional experts, the concordance increased to 97%. Furthermore, the AGI tool showed excellent intra-expert concordance (100%) and good inter-expert concordance (90%). In addition to MRD levels, also percentages of normal cell populations showed excellent concordance between manual and AGI tool analysis. We conclude that the AGI tool may facilitate MRD analysis using the EuroFlow BCP-ALL MRD protocol and will contribute to a more standardized and objective MRD assessment. However, appropriate training is required for the correct analysis of MRD data.

Age-related changes in lymphocyte subpopulations in healthy Thai children

BACKGROUND

Ethnicity and environmental factors can influence the percentages of lymphocyte subpopulations. This study aimed to assess the percentages of lymphocyte subpopulations according to age in Thai children.

METHODS

This was a cross-sectional study. The percentages of lymphocyte subpopulations were measured in umbilical cord blood and peripheral blood of healthy Thai children aged 1 month-15 years. The participants were stratified into five age groups: (a) cord blood; (b) age < 2 years; (c) age 2-5 years; (d) age 5-10 years; and (e) age 10-15 years.

RESULTS

Of 182 total samples, 32, 39, 41, 28, and 42 were from cord blood, children aged <2 years, children aged 2-5 years, children aged 5-10 years, and children aged 10-15 years, respectively. The percentages of most lymphocyte subpopulations including CD8 + T cells, CD19 + cells, γδ T cells, double-negative T cells, NK cells, and NK T cells increased significantly with age. Only the CD4+ T-cell percentage decreased in older children. Moderate correlations were observed between age and the percentages of CD4+ T cells, γδ T cells, NK cells, NK T cells, and double-negative T cells. Weak correlations were observed between age and the percentages of CD8+ T cells and CD19+ cells.

CONCLUSION

Our study demonstrated age-related changes in the percentages of lymphocyte subpopulations in Thai children, which differed from those described in other countries. Therefore, the establishment of age-specific reference values for lymphocyte subsets in each country is recommended.

Increased memory T cell populations in Pb-exposed children from an e-waste-recycling area

Chronic exposure to heavy metals could affect cell-mediated immunity. The aim of this study was to explore the status of memory T cell development in preschool children from an e-waste recycling area. Blood lead (Pb) levels, peripheral T cell subpopulations, and serum levels of cytokines (IL-2/IL-7/IL-15), relevant to generation and homeostasis of memory T cells were evaluated in preschool children from Guiyu (e-waste-exposed group) and Haojiang (reference group). The correlations between blood Pb levels and percentages of memory T cell subpopulations were also evaluated. Guiyu children had higher blood Pb levels and increased percentages of CD4⁺ central memory T cells and CD8⁺ central memory T cells than in the Haojiang group. Moreover, blood Pb levels were positively associated with the percentages of CD4⁺ central memory T cells. In contrast, Pb exposure contributed marginally in the change of percentages of CD8⁺ central memory T cells in children. There was no significant difference in the serum cytokine levels between the e-waste-exposed and reference children. Taken together, preschool children from an e-waste recycling area suffer from relatively higher levels of Pb exposure, which might facilitate the development of CD4⁺ central memory T cells in these children.

Influence of sex, age, pubertal maturation and body mass index on circulating white blood cell counts in healthy European adolescents—the HELENA study

Percentiles 10th, 25th, 50th, 75th and 90th are presented for circulating white blood cells (WBC), neutrophils, lymphocytes, monocytes, eosinophils and basophils in healthy European adolescents (12.5-17.5 years, n = 405, 48.9% boys), considering age, sex, puberty and body mass index (BMI). CD3(+) (mature T cells), CD4(+) (T helper), CD8(+) (T cytotoxic), CD16(+)56(+) (natural killer), CD19(+) (B cells), CD3(+)CD45RA(+), CD4(+)CD45RA(+), CD8(+)CD45RA(+) (naïve), CD3(+)CD45RO(+), CD4(+)CD45RO(+) and CD8(+)CD45RO(+) (memory) lymphocytes were also analysed by immunophenotyping. Girls presented higher WBC, neutrophil, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) cell counts and CD3(+)/CD19(+) ratio, and lower CD3(+)CD45RA(+) and CD4(+)CD45RA(+) counts than boys. Age was associated with higher neutrophil counts and CD3(+)/CD19(+), and lower CD19(+) counts; in boys, with lower CD3(+)CD45RA(+), CD4(+)CD45RA(+) and CD8(+)CD45RA(+) counts as well; in girls, with higher WBC, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) counts. Pubertal maturation in boys was associated with lower WBC and lymphocyte counts; in girls, with higher basophil, CD3(+)CD45RO(+) and CD4(+)CD45RO(+) values. BMI was associated with higher WBC counts; in boys, also with higher lymphocyte counts; in girls, with higher neutrophil, CD4(+), CD3(+)CD45RO(+) and CD4(+)CD45RO(+) counts.

CONCLUSION

Our study provides normative values for circulating immune cells in adolescents, highlighting the importance of considering sex, age, pubertal maturation and BMI when establishing reference ranges for WBC in paediatric populations.

Clinicopathological characteristics and outcomes of pediatric patients with systemic small blood vessel vasculitis

BACKGROUND

Systemic small blood vessel vasculitis (SSV) is uncommon among pediatric patients, and the predictive value of the new histopathological classification for SSV in terms of renal outcomes in these patients is unknown.

METHODS

The study cohort comprised 38 pediatric patients and 285 adult patients with SSV who were treated in a medical center between 1993 and 2012.

RESULTS

Children accounted for 11.8 % of all patients with SSV diagnosed during the study period. In contrast to the adult patients, the pediatric patients were predominantly female (73.7 vs. 51.9 %; P < 0.05). The prevalence of skin purpura was higher and pulmonary symptoms were less common among pediatric patients than among adult ones (36.8 vs. 13.7 %, P < 0.01 and 26.3 vs. 46.0 %, P < 0.05, respectively). Subtype was correlated with the baseline levels of serum creatinine and treatment response among patients with SSV and was found to have a tendency to predict end-stage renal disease (ESRD) among pediatric patients (hazard ratio 2.273, P < 0.01). The probability of progressing to ESRD was highest in pediatric patients with the sclerotic glomerulonephritis subtype, followed by the mixed, crescentic and focal glomerulonephritis subtypes (in descending order of probability) (P < 0.01).

CONCLUSIONS

Estimated histopathological classification has a prognostic value for renal outcome and response to therapy in children with SSV.

γ/δ T cell subsets in human aging using the classical α/β T cell model

Aging is associated with an increased susceptibility to infections and diseases. It has also been associated with reduced functionality and altered distribution of immune cells, especially T cells. Whereas classical α/β T cells, especially CD8(+) T cells, were shown to be highly susceptible to aging, the effects of viral persistent stimulations on the fate of γ/δ T cells are much less documented. Healthy, elderly individuals of Chinese ethnical background were recruited under the aegis of SLAS-II. In this observational study, γ/δ T cell populations were characterized by flow cytometry and compared with the α/β CD4(+) and CD8(+) T cells in elderly and young controls. In our study, we identified a reduced frequency of γ/δ T cells but not α/β T cells with aging. The classical markers of α/β T cell aging, including CD28, CD27, and CD57, did not prove significant for γ/δ T cells. The extreme range of expression of these markers in γ/δ T cells was responsible for the lack of relationship between γ/δ T cell subsets, CD4/CD8 ratio, and anti-CMV titers that was significant for α/β T cells and, especially, CD8(+) T cells. Although markers of aging for γ/δ T cells are not clearly identified, our data collectively suggest that the presence of CD27 γ/δ T cells is associated with markers of α/β T cell aging.

Clinical characteristics and mutation analysis of X-linked severe combined immunodeficiency in China

X-linked severe combined immunodeficiency (X-SCID) is a rare, life-threatening immune disorder, caused by mutations of the gene for the γ-chain (γc) of the interleukin-2 receptor, IL2RG. We analyzed the clinical, immunologic, and molecular characteristics of children with X-SCID, attempting to improve the diagnosis and treatment of X-SCID in China.

METHODS

X-SCID was suspected in male infants with recurrent or persistent infections. Eleven male infants from ten unrelated Chinese families were included. The IL2RG gene was amplified and sequenced, followed by mutation analysis in these children and their female relatives. X-linked short tandem repeat (X-STR) typing was done to define the maternal lymphocyte engraftment.

RESULTS

The 11 children exhibited recurrent infections and 10 of them had lymphopenia. B cells were present in all patients, T cells were markedly reduced in 10, and NK cells were markedly reduced in 9. Nine IL2RG gene mutations were identified in the 11 children, with 5 novel mutations. One patient was found to have the maternal lymphocyte engraftment.

CONCLUSION

The clinical presentations and immunologic characteristics of the X-SCID patients were accordingly quite uniform despite the heterogeneity of mutations locating almost in the entire γc gene.

Expansions of NK-like αβT cells with chronologic aging: novel lymphocyte effectors that compensate for functional deficits of conventional NK cells and T cells

As the repertoire of αβT cell receptors (TCR) contracts with advancing age, there is an associated age-dependent accumulation of oligoclonal T cells expressing of a variety of receptors (NKR), normally expressed on natural killer (NK) cells. Evidences for differential regulation of expression of particular NKRs between T cells and NK cells suggest that NKR expression on T cells is physiologically programmed rather than a random event of the aging process. Experimental studies show NKRs on aged αβT cells may function either as independent receptors, and/or as costimulatory receptors to the TCR. Considering the reported deficits of conventional αβTCR-driven activation and also functional deficits of classical NK cells, NKR(+) αβT cells likely represent novel immune effectors that are capable of combining innate and adaptive functions. Inasmuch as immunity is a determinant of individual fitness, the type and density of NKRs could be important contributing factors to the wide heterogeneity of health characteristics of older adults, ranging from institutionalized frail elders who are unable to mount immune responses to functionally independent community-dwelling elders who exhibit protective immunity. Understanding the biology of NKR(+) αβT cells could lead to new avenues for age-specific intervention to improve protective immunity.

Age-related trends in pediatric B-cell subsets

There are few studies of the developmental changes in B-cell subsets in children. Recent data from adult populations demonstrate that alterations to B-cell subsets have functional consequences and can be helpful diagnostically. Comparable studies in children have been hindered by the lack of normative data and by significant changes with age. This study evaluated B-cell subsets by 4-color flow cytometry in 47 children of different ages. The use of a 4-color platform is compatible with broad use in clinical laboratories. We found that there are rapid changes in the B-cell compartment in infancy and early childhood. Total B-cell numbers decline early in life, and this correlates with a decline in transitional B cells and naïve B cells. The decline is most rapid between 1 and 5 years of age, with a slower decline later in childhood. In contrast, nonswitched and switched memory B cells both increase during the 1st 5 years of life. The decline in B-cell numbers did not occur until after 1 year of age, suggesting that the period after birth is a unique developmental window. These data provide a reference set for further studies on B-cell dysfunction in pediatric disorders. The changes occurring in early childhood document the need for age-related assessments and serve to underscore the B-cell-specific kinetics of immunologic development in humans.

Inverse correlation between CD4+ regulatory T-cell population and autoantibody levels in paediatric patients with systemic lupus erythematosus

CD4(+) CD25(+) regulatory T cells (Tregs) are critical in maintaining self-tolerance and preventing organ-specific autoimmunity. Their role in paediatric systemic lupus erythematosus (SLE), an autoimmune disease characterized by inappropriate regulation of hyperactivated B and T cells, has not been clearly defined. Using flow cytometry to determine cell populations and real-time polymerase chain reaction to assay mRNA expression for FOXP3, CTLA-4, and GITR, we characterized CD4(+) CD25(+) T cells in paediatric SLE patients and healthy subjects. The frequency of CD4(+) CD25(+) Tregs was significantly decreased in patients with active SLE compared with patients with inactive SLE and with controls (7.27% +/- 2.50%, 9.59% +/- 2.80% and 9.78% +/- 2.11%, respectively; P = 0.027 and P < 0.001, respectively), and was inversely correlated with disease activity, as assessed with the Systemic Lupus Erythematosus Disease Activity Index 2000 scores (r = -0.59, P = 0.001) and serum anti-double-stranded DNA levels (r = -0.65, P < 0.001). Our preliminary investigations found elevated surface expression of GITR in CD4(+) CD25(+) T cells, elevated mRNA expression of CTLA-4 in CD4(+) T cells and higher amounts of mRNA expression for FOXP3 in CD4(+) cells in patients with active SLE compared with patients with inactive disease and controls. We demonstrated reduced CD4(+) CD25(+) Treg levels were inversely correlated with disease activity, indicating a defective Treg population in paediatric SLE patients. The differences in the expression of FOXP3, CTLA-4 and GITR imply the possible role of CD4(+) Tregs in the pathogenesis of SLE.

Normal values for CD4 and CD8 lymphocyte subsets in healthy Chinese adults from Shanghai

The aim of this study was to establish reference ranges for lymphocyte subsets in Chinese adults. Venous blood specimens were obtained from 614 healthy, human immunodeficiency virus (HIV)-seronegative adults in Shanghai. Flow cytometry was used to determine percentages and absolute numbers of CD4 and CD8 T lymphocytes. Mean values for CD4 and CD8 lymphocytes were 727 and 540 cells/microl, respectively, yielding a CD4/CD8 ratio of 1.49. While CD8 lymphocyte values varied with age and gender, no significant differences in CD4 lymphocyte values were observed. Shanghai adults had approximately 100 fewer CD4 lymphocytes/microl on average than Caucasians, suggesting that lower CD4 lymphocyte cutoffs for classifying and monitoring HIV infection may be needed in China.

Immunophenotyping of blood lymphocytes at birth, during childhood, and during adulthood in HIV-1-uninfected Ethiopians

To obtain more insight into blood lymphocyte subpopulations of Ethiopians, we studied the immunologic profile of children and neonates and compared these data with those obtained from adults. Peripheral blood mononuclear cells (PBMCs) and cord blood mononuclear cells (CBMCs) were collected from 137 HIV-1-uninfected subjects aged 0 (cord blood) up to 40 years. Lymphocyte subsets (T, B, and NK cells, CD4+ and CD8+ T cells) were determined and T cell activation (CD38 and HLA-DR) and differentiation (CD45RO and CD27) markers were measured on CD4+ and CD8+ T cells. The absolute number and percentage values of most lymphocyte subpopulations differed substantially with age. Neonates and children were found to have significantly higher CD4+ T cell counts compared to adults. The median absolute CD4 count at birth was comparable to those reported for Caucasians. At birth 97% of the CD4+ T cells were naîve and this proportion significantly declined to 14.2% during adulthood. In addition, activation of both CD4+ and CD8+ T cells, as determined by the double expression of HLA-DR and CD38, was observed in children under the age of 16 and adults, but not in neonates. A more differentiated phenotype (CD27-) was observed in adults compared to children for both CD4+ and CD8+ T cells. The immune alterations including the remarkably low CD4 count with highly depleted naîve phenotype and a persistently activated immune system seen in adult Ethiopians are not apparent at birth, but rather develop over time.

Expression of adhesion molecules on T lymphocytes in young children and infants--a comparative study using whole blood lysis or density gradient separation

We investigated the use of two sample preparation techniques (whole blood lysis [WBL], and Ficoll-Hypaque density separation [FDS]) for flow cytometric estimation of adhesion molecule (CD54, CD62L and CD11b) expression on T lymphocytes from children less than 2 years old, comparing the results with normal adult controls. Using WBL methods, young children had lower percentages of CD3+/CD54+ and CD3+/CD11b+ lymphocytes, but not of CD3+/CD62L+ lymphocytes than adult controls. FDS was associated with significantly higher percentages of CD3+/CD62L+ and CD3+/CD11b+ lymphocytes in young children and adults alike, while the percentages of CD3+/CD54+ cells from adults was not affected by FDS. The percent expression of CD54, CD62L, and CD11b on T cells from both children and adults were significantly higher following FDS, with a greater increase in CD11b expression on T cells from young children, reaching adult levels. The mean fluorescence intensity (MFI) of CD62L on T cells from young children, which was lower than that of adults using WBL preparation, was significantly higher following FDS, reaching adult levels. The higher levels of adhesion molecule expression associated with FDS did not result from T-cell activation, as assessed by CD69, CD25, and HLA-DR expression. Thus, adhesion molecule expression on T lymphocytes from young children is more sensitive to modification by isolation procedures than that on adult T cells. Caution should therefore be exercised in interpreting adhesion molecule expression data on T cells from children.

Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year: part 2: immune cell populations

BACKGROUND

Infants fed a soy protein isolate-based formula have immunization responses similar to breast-fed infants. However, cellular aspects of the immunologic development of soy-fed infants have not been studied extensively. Nucleotides added to milk-based formula benefit infant immune status, but reports of the immunologic effects of adding nucleotides to soy-based formula are not available. This study examines immune cell populations of infants fed soy protein isolate formulas with and without added nucleotides for 1 year.

METHODS

Newborn, term infants studied in a masked 12-month feeding trial were assigned randomly to soy formula groups with and without added nucleotides (n = 94, n = 92). A nonrandomized human milk/formula-fed cohort (n = 81), was concurrently enrolled. Blood samples were collected at 6, 7, and 12 months. Thirty-two immune cell populations were characterized using three-color flow cytometry. Cellular markers were chosen to assess general pediatric immune status, emphasizing maturation and activation of B, T, and NK lymphocytes.

RESULTS

All cell populations, number and percentages, were within age-related normal ranges. The only significant difference found between soy formula and human milk/formula-fed infants was the percentage of CD57 + NK T cells at 12 months (human milk/formula > soy formula, P = 0.034). There were significant differences at some time points between human milk/formula-fed and nucleotide-supplemented soy formula-fed infants in populations of lymphocytes, eosinophils, total T, helper T, naive helper, memory/effector helper, CD57 - T, and CD11b + CD8 + NK cells. None of the cell populations differed between infants fed soy formula versus soy plus nucleotides.

CONCLUSIONS

Infants fed this commercial soy formula demonstrated immune cell status similar to human milk/formula-fed infants, consistent with normal immune system development. The addition of nucleotides to soy formula did not significantly change specific individual immune cell populations but tended to increase numbers and percentages of T cells and decreased numbers and percentages of NK cells.

Lymphocyte subsets in human immunodeficiency virus type 1-infected and uninfected children in Nairobi

BACKGROUND

Reference lymphocyte subset values for African children are lacking. This study documents these values as well as their alterations associated with perinatal and postnatal HIV-1 transmission and with protection from HIV-1 infection.

METHODS

Lymphocyte subsets were determined for HIV-1-seronegative nonpregnant women and their children (controls) and for uninfected, perinatally infected and postnatally infected children born to HIV-1-seropositive mothers in Nairobi, Kenya. The mean, median and 5th and 95th percentile values for CD4+ and CD8+ lymphocyte counts and percentages were determined and compared at the age ranges birth to 3 months, 4 months to 1 year, yearly from 1 to 5 years and from 6 to 10 years of age.

RESULTS

Among control children counts differed from published values of other populations. In all age ranges, whereas the absolute values were significantly higher than adult values, the percentages were significantly lower. Children perinatally infected with HIV-1 had clearly distinguishable differences in lymphocyte subset percentages by 3 months of age, when the median CD4+ percentage was 27.9% (5th to 95th percentile, 25.7 to 30.1%) for infected vs. 35.9% (33.3 to 38.7%) for uninfected and 39.9% (37.8 to 42.2%) for control children, P < 0.001; whereas the median CD8+ percentage was 37.0% (33.1 to 41.0%) for infected vs. 27.5% (24.2 to 30.8%) for uninfected and 27.5% (24.2 to 30.8%) for control children, P = 0.001. Differences between uninfected and control children disappeared after 1 year of age.

CONCLUSIONS

Normal lymphocyte subset values among African children differ from those in other populations. Significant differences are detectable by 3 months of age in CD4+ and CD8+ lymphocyte percentages among perinatally infected infants, which may be useful as an adjunct in diagnosis. Transient differences observed among HIV-1-exposed but uninfected infants could reflect a successful immune response to HIV-1 challenge.

Phenotypic changes of T-lymphocyte subsets induced by interleukin-12 and interleukin-15 in umbilical cord vs. adult peripheral blood mononuclear cells

The decreased incidence of graft-vs.-host disease found following umbilical cord blood (CB) transplantation, and the increased susceptibility of newborns to infections, have been attributed, in part, to functional and phenotypic immaturity of neonatal T cells. We investigated the phenotypic changes of CB T cells induced by two immunoregulary cytokines, interleukin (IL)-12 and IL-15, alone or in combination. Adult peripheral blood (APB) mononuclear cells (MNCs) were also tested for comparison. Prior to culture, the percentages of CD3+ CD8+, CD3+ CD25+, and CD3+ CD56+ cells were significantly lower in CB MNCs than in APB MNCs. IL-15, but not IL-12, significantly increased CD3+ CD8+ expression among the CB MNCs after 1 week of culture. Combining IL-12 and IL-15, however, resulted in decreased CB CD3+ CD8+ expression compared with IL-15 alone. The percentage of CD3+ CD25+ cells in CB MNCs spontaneously increased in the absence of cytokines, while that of CD3+ CD56+ cells in CB MNCs could not be enhanced with cytokines. In contrast, the percentages of CD3+ CD25+ and CD3+ CD56+ cells among the APB MNCs could be increased with IL-12, IL-15, and further with IL-12 and IL-15 combined. Thus, different patterns of T-cell subset changes were demonstrated between CB MNCs and APB MNCs in response to IL-12 and/or IL-15. These data may serve as a foundation for using cytokine therapy in newborns and children receiving CB transplants.