Timing of lymphocyte activation in neonates infected with human immunodeficiency virus.

Human immunodeficiency virus (HIV) infection in children is associated with qualitative and quantitative changes in the peripheral lymphocyte surface phenotype beyond the normal maturational changes. Neonates, however, have been reported to have a delayed immune response to HIV compared to HIV-infected adults. We prospectively performed immunophenotyping of T lymphocytes by three-color immunofluorescent labeling and laser flow cytometry to determine the timing of phenotypic alterations in 112 neonates born to HIV-infected mothers. Serial testing was performed at birth (cord blood) and at 2, 6, and 12 weeks of age. Data were divided retrospectively for analysis into those for HIV-infected (n = 14) infants and those for exposed, uninfected infants. Our results show that both infected and uninfected infants had a decline in the percentages and numbers of CD4 cells beginning at 2 weeks of age but that the decline was greater in the HIV-infected group. The activation and differentiation of CD8 T cells in HIV+ infants were shown by a significant increase in CD45RA- CD45RO+ CD8+ cells by 6 weeks of age and by increases in CD8+ S6F1+ CD3+ cells and HLA-DR+ CD38+ CD8+ cells by 2 weeks of age. These results indicate that HIV-infected neonates show alterations in T-cell phenotype reflecting those reported for older HIV-infected children. Most importantly, neonatal T cells are able to respond to HIV within the first weeks of life.     

Cytotoxic T lymphocyte activity and CD8 subpopulations in children at risk of HIV infection.

HIV-specific cytotoxic T lymphocytes (CTL) are thought to play a major role in viral control in HIV-infected adults. Changes in the relative proportions of CD8 lymphocyte subpopulations are also thought to be associated with disease progression. Less is known about the relative effectiveness of CTL against different HIV targets, or about the relationship, if any, between CTL activity and CD8 subpopulations. We have measured CTL activity against four HIV gene products (gag, tat, pol and env) and expression of CD45RO, CD45RA, HLA-DR, CD29, S6F1, and CD57 surface markers on CD8 cells from nine HIV-infected and 11 HIV-uninfected children. Of nine HIV-infected children, six showed antigen-specific CTL activity on at least one occasion: 4/6 directed against tat, 6/6 against pol, 1/6 against env, and 1/6 against gag. However, the specificity of the CTL activity varied between children and within individual children with time. Furthermore, two uninfected children showed CTL activity, one to HIV-gag, -pol and -tat, and the other to HIV-pol. All the HIV-infected and two uninfected children had abnormal proportions of CD8 subpopulations in whole blood compared with age-matched controls. There was no correlation between CTL activity and CD8 subsets in whole blood. Five children changed from CTL-positive to CTL-negative (or vice versa) during the study. In these, the occasions when CTL activity was detected coincided with an increase in CD8 cells, an expansion of HLA-DR+ CD8 cells and a loss of CD45RA+ CD8 cells.     

Plasma levels of viro-immunological markers in HIV-infected and non-infected Ethiopians: correlation with cell surface activation markers

Cross-sectional studies were conducted to measure soluble viral and immunological markers in plasma in order to determine the prognostic value of these markers for HIV disease progression in Ethiopians and to see their association with cell surface markers in HIV-1-infected and noninfected Ethiopians. Whole blood samples were collected from 52 HIV-1-negative Ethiopians, 32 HIV-1-positive Ethiopians with absolute CD4(+) T-cell count >200/microl whole blood and no AIDS defining conditions, and 39 HIV-positive Ethiopians with CD4(+) T-cell count <200/microl and/or AIDS defining conditions. Plasma levels of b(2)-microglobulin (b(2)m), soluble CD27 (sCD27), soluble tumor necrosis factor alpha receptor type II (sTNFR-II), IgG, IgA, IGE, and IL12 were elevated in HIV-1-infected individuals. The plasma levels of sTNFR-II, sCD27, b(2)m, IL12, and IgG were inversely correlated with numbers of CD4(+) T-cells, the proportion of na?ve (CD45RA(+)CD27(+)) CD8(+) T-cells, and the proportion of CD8(+) T-cells expressing CD28 (CD8(+)CD28(+)) were positively correlated with the proportions of activated (HLA-DR(+)CD38(+)) CD4(+) T-cells, as well as activated (HLA-DR(+)CD38(+)) CD8(+) T-cells. A strong positive correlation was also observed when soluble immune markers were compared to each other. Multivariate regression analyses of soluble markers with numbers of CD4(+) T-cells showed that sCD27 is the best independent marker for CD4(+) T-cell decline in the HIV-1-infected Ethiopians. Our results indicate that measurement of soluble immune markers, which is relatively easy to perform, could be a good alternative to the quantification of T-cell subsets for monitoring HIV-1 disease progression in places where there is no facility for flow cytometric measurements.     

广州市健康儿童和成人淋巴细胞亚群数量的对比分析

目的比较儿童和成人淋巴细胞亚群百分率和绝对数量的异同,更好地为本地区临床诊断和治疗提供参考。方法采用双色流式细胞术分析健康儿童和成人外周血T淋巴细胞亚群(CD3+细胞、CD3+CD4+细胞、CD3+CD8+细胞)、B淋巴细胞(CD19+)、CD3-CD56+NK细胞(自然杀伤细胞)的数量。结果儿童组总淋巴细胞(百分率和绝对数)、CD19+淋巴细胞(百分率和绝对数)、CD3+淋巴细胞百分率、CD3+CD4+淋巴细胞百分率、CD3+CD8+淋巴细胞绝对数、CD3-CD56+细胞绝对数、CD4+/CD8+细胞比值与成人组比较差异均有统计学意义;CD3+CD8+淋巴细胞百分率、CD3-CD56+细胞百分率、CD3+淋巴细胞绝对数和CD3+CD4+淋巴细胞绝对数与成人组比较差异无统计学意义。儿童组CD3+CD8+淋巴细胞、CD19+淋巴细胞、CD3-CD56+细胞的百分率和绝对数均高于成人组,CD3+淋巴细胞(百分率和绝对值)、CD3+CD4+淋巴细胞(百分率和绝对值)和CD4+/CD8+细胞比值低于成人组。相同与不同性别组内均有多个指标存在显著差异。结论淋巴细胞亚群的分布受年龄、性别因素的影响,淋巴细胞亚群绝对数与百分率随年龄的变化不总是保持一致的。用于血液性和免疫性疾病诊断时,采用淋巴细胞亚群绝对数作为参考指标优于百分比率。     

脐带血CD4~+和CD8~+ T细胞中T细胞特异转录因子Elf-1表达特点

目的:了解脐带血单个核细胞(CBMCs)及其CD4+和CD8+ T细胞亚群中转录因子Elf-1的表达特点。方法:采用SYBR GreenⅠ荧光定量PCR和相对定量分析法检测12例脐带血CBMCs、CD4+和CD8+ T细胞亚群中Elf-1基因的表达情况,以β2微球蛋白基因(β2M)作为内参照,10例健康成人作为对照,采用相对定量公式:2-△Ct×100%,计算Elf-1mRNA相对表达量。结果:脐带血和健康成人外周血单个核细胞(PBMC)、CD4+和CD8+ T细胞均表达Elf-1,具体表达量呈现明显的个体差异性。Elf-1 mRNA相对表达量在CBMCs为18.55%±2.48%(其中最高为36.22%,最低为6.45%),在脐带血CD8+ T细胞为3.52%±0.45%(其中最高为6.75%,最低为1.71%),均明显高于健康成人PBMC(9.16%±1.92%)及其CD8+ T细胞(2.02%±0.27%)(P0.01,P0.05),而脐带血CD4+T细胞Elf-1 mRNA相对表达量为3.83%±0.61%,与健康成人外周血CD4+ T细胞(2.73±0.52%)比较,无显著差异。结论:本研究率先报道脐带血T细胞亚群中Elf-1 mRNA表达特点,结果提示Elf-1基因在CBMCs及其CD8+ T细胞亚群中的高表达可能是T细胞的免疫学特点之一。     

Development of lymphocyte subpopulations in preterm infants

In preterm neonates the immune system is thought to be less developed at birth, but very little is known about the actual size of lymphocyte subpopulations, and even less about the maturation of these subpopulations during the first months after a premature birth. To evaluate the development of lymphocyte subpopulations in preterm infants during the first 3 months after birth, we performed a prospective longitudinal study in two hospitals in the Netherlands. Preterm neonates (n = 38) of all post-menstrual ages were included and blood samples were taken from cord blood, and at 1 week, 6 weeks, and 3 months. Lymphocyte subpopulations were measured by four-colour flow cytometry. The data were compared with follow-up data obtained in healthy term neonates (n = 8), and with single samples from school age children (n = 5) and adults (n = 5). Overall, we found a similar pattern of post-natal development of lymphocyte subpopulations in the term and preterm infants. Both B lymphocytes and helper and cytotoxic T lymphocytes mainly consist of naive cells at birth and during the 3 months of follow-up in all neonatal age groups. So, the preterm immune system seems to be able to generate an outburst of naive T and B lymphocytes from the thymus and bone marrow within the same time span after the start of post-natal antigenic stimulation from the environment as the term immune system, but, with lower post-menstrual age, the absolute counts of naive helper T lymphocytes are lower.     

Moroccan lymphocyte subsets reference ranges: age,gender, ethnicity,and socio-economic factors dependent differences

ABSTRACT

Lymphocyte subsets reference ranges are helpful for a precise diagnosis and therapy of various diseases. We attempted in the current study to establish Moroccan lymphocyte reference range and reveal age, gender, ethnicity, income, and instructional levels dependent differences. Lymphocyte subsets percentage and absolute count were determined by 4-color flow cytometry in a population study of 145 adults Moroccan healthy volunteers. Analysis showed significant age-dependent changes. Age was associated with a decrease of naïve CD4+ and CD8+ T cells and an increase of memory CD4+ or CD8+ T cells. Activated CD4+ CD38+ and CD8+ CD38+ T cells, Treg as well as NK cell showed age-dependent alterations. In contrast, B cells remained unchanged. A higher percentage of CD3+ and CD4+ T cells was observed in females while CD8+, B and NK cells count were higher in men. Ethnicity, instructional levels, and personal income seem to not influence lymphocyte subsets reference values. This study provides reference ranges for lymphocyte subsets of healthy Moroccan adults. These results can be used for other North African (Maghrebian) countries considering their geographic, ethnic, economic, and cultural similarities.     

Marked increase in L-selectin-negative T cells in neonatal pertussis. The lymphocytosis explained?

The detailed immunophenotype of peripheral blood lymphocytes from a neonate with pertussis was determined by flow cytometry and compared with results from cord blood from healthy newborns. Most (72%) of the lymphocytes were CD3+ T cells with a normal CD4/CD8 ratio (2.5). The T cells were largely HLA-DR negative and CD45RA+, consistent with unstimulated na?ve T cells. Almost all of the CD4+ T cells were Leu8 (L-selectin, CD62L) negative, while almost all of the CD8+ T cells were CD28+. There was no increase in CD7- CD4+ T cells (Th2-like). No relative increase in CD16/56+ NK cells (5%) or CD19/20+ B cells was seen. The most dramatic finding in this case was the remarkable lack of expression of L-selectin by the T cells. L-selectin expression is associated with homing of peripheral blood lymphocytes to lymph nodes. The dramatic reduction in L-selectin expression of the T lymphocytes in pertussis, perhaps induced by pertussis toxin, likely prevents homing of the T cells to peripheral lymphoid tissues and provides a likely explanation for the marked lymphocytosis noted in this disease.     

Expression of the costimulator molecules, CD40 and CD154, on lymphocytes from neonates and young children

Differential expression of the costimulator molecules CD40 and CD154 on neonatal lymphocytes may be one explanation for limited T-dependent antibody responses in human neonates. CD40 was expressed at similar levels on resting B cells from adults, young children (2-20 months of age) or cord blood. CD40 expression was higher on cord blood B cells compared to adult B cells after stimulation with PMA and ionomycin, but similar on adult and cord blood B cells activated by CD3-stimulated T cells. In contrast to previous reports, cord blood T cells stimulated with PMA and ionomycin expressed adult levels of CD154 initially, but this expression was more transient on cord blood T cells. When adult and cord blood mononuclear cells were stimulated with CD3 mAb, T cells from some cord blood specimens showed different kinetics of CD154 expression compared with adult T cells. However, some cord blood specimens showed adult patterns of T cell CD154 expression. When mononuclear cells were depleted of B cells and monocytes prior to stimulation with CD3 mAb, the MFI and percentage of T cells expressing CD154 increased, with adult and cord T cells showing similar patterns of expression. These results show some differences in expression of CD40 and CD154 between neonatal and adult lymphocytes, but do not directly account for the relative deficiencies of humoral immunity in neonates.     

Development of lymphocyte subsets in pigtailed macaques

The early development of eight lymphocyte subsets was determined for pigtailed macaque infants from 0 to 800 days of age using two-color flow cytometry and fluorescein- and R-phycoerythrin-conjugated monoclonal antibodies specific for human leukocyte antigens. Four major lymphocyte subsets in monkeys (B, CD4+ T, CD8+ T, and NK cells) could be further divided using two-color analysis. In neonates, the frequency of lymphocyte subpopulations having surface phenotypes found principally on dense, resting cells (IgD+ B cells, Lp220+ CD4+ T cells, and CD18dull CD8+ T cells) was much higher than subpopulations having phenotypes present principally on buoyant, activated cells (IgD- B cells, Lp220- CD4+ T cells, CD18bri CD8+ T cells). There was a complete absence of two CD18bri CD8+ subsets (CD8dull and CD8bri) during the first 300 days of life. The relative proportion of lymphocyte subsets with resting phenotype decreased with increasing age, while the subpopulations associated with activation gradually increased with age. These findings suggest that during early development immunocompetent cells gradually differentiate into activated lymphocytes.     

Distribution of lymphocyte subsets in healthy human immunodeficiency virus-negative adult Ethiopians from two geographic locales.

Immunological values for 562 factory workers from Wonji, Ethiopia, a sugar estate 114 km southeast of the capital city, Addis Ababa, Ethiopia, were compared to values for 218 subjects from Akaki, Ethiopia, a suburb of Addis Ababa, for whom partial data were previously published. The following markers were measured: lymphocytes, T cells, B cells, NK cells, CD4(+) T cells, and CD8(+) T cells. A more in depth comparison was also made between Akaki and Wonji subjects. For this purpose, various differentiation and activation marker (CD45RA, CD27, HLA-DR, and CD38) expressions on CD4(+) and CD8(+) T cells were studied in 60 male, human immunodeficiency virus-negative subjects (30 from each site). Data were also compared with Dutch blood donor control values. The results confirmed that Ethiopians have significantly decreased CD4(+) T-cell counts and highly activated immune status, independent of the geographic locale studied. They also showed that male subjects from Akaki have significantly higher CD8(+) T-cell counts, resulting in a proportional increase in each of the CD8(+) T-cell compartments studied: na?ve (CD45RA(+)CD27(+)), memory (CD45RA(-)CD27(+)), cytotoxic effector (CD45RA(+)CD27(-)), memory/effector (CD45RA(-)CD27(-)), activated (HLA-DR(+)CD38(+)), and resting (HLA-DR(-)CD38(-)). No expansion of a specific functional subset was observed. Endemic infection or higher immune activation is thus not a likely cause of the higher CD8 counts in the Akaki subjects. The data confirm and extend earlier observations and suggest that, although most lymphocyte subsets are comparable between the two geographical locales, there are also differences. Thus, care should be taken in extrapolating immunological reference values from one population group to another.     

Peripheral human CD8(+)CD28(+)T lymphocytes give rise to CD28(-)progeny, but IL-4 prevents loss of CD28 expression.

At birth, virtually all peripheral CD8(+) T cells express the CD28 co-stimulatory molecule, but healthy human adults accumulate CD28(-)CD8(+) T cells that often express the CD57 marker. While these CD28(-) subpopulations are known to exert effector-type functions, the generation, maintenance and regulation of CD28(-) (CD57(+) or CD57(-)) subpopulations remain unresolved. Here, we compared the differentiation of CD8(+)CD28(bright)CD57(-) T cells purified from healthy adults or neonates and propagated in IL-2, alone or with IL-4. With IL-2 alone, CD8(+)CD28(bright)CD57(-) T cell cultures yielded a prevailing CD28(-) subpopulation. The few persisting CD28(dim) and the major CD28(-) cells were characterized by similar telomere shortening at the plateau phase of cell growth. Cultures from adults donors generated four final CD8(+) phenotypes: a major CD28(-)CD57(+), and three minor CD28(-)CD57(-), CD28(dim)CD57(-) and CD28(dim)CD57(dim). These four end-stage CD8(+) subpopulations displayed a fairly similar representation of TCR V(beta) genes. In cultures initiated with umbilical cord blood, virtually all the original CD8(+)CD28(bright) T cells lost expression of CD28, but none acquired CD57 with IL-2 alone. IL-4 impacted on the differentiation pathways of the CD8(+)CD28(bright)CD57(-) T cells: the addition of IL-4 led both the neonatal and the adult lymphocytes to keep their expression of CD28. Thus, CD8(+)CD28(bright)CD57(-) T cells can give rise to four end-stage subpopulations, the balance of which is controlled by both the cytokine environment, IL-4 in particular, and the proportions of naive and memory CD8(+)CD28(+) T cells.     

CD8+CD60+ T cells, cells expressing epsilon specific mRNA and Th1/Th2 cytokines in cord blood and at 7 months of age

IgE levels in cord blood have been investigated as predictors of atopy, but no definitive findings have been made. Other factors, including cells and/or cytokines may serve as predictors of this disease. Cord blood and peripheral blood was obtained at birth and at 7 months of age, respectively, from children ( n  = 2) with a family history of allergy. Cells in cord blood and peripheral blood were phenotyped and levels of serum immunoglobulins (IgM, IgG, IgA and IgE) were determined. In addition, placentas from these pregnancies were obtained and stained for IgE+ cells and CD8+CD60+ T cells. We found immunoglobulin levels were within normal ranges although IgE levels were negligible in cord blood and at 7 months of age. Similar numbers of CD8+ T cells and CD19+ B cells were detected in cord blood and at 7 months of age. However, CD4+ T cells increased (twofold) and CD16+/CD56+ natural killer precursor cells decreased (twofold) at 7 months of age. CD8+ T cells in their cord blood and at 7 months of age comprised of >50% CD8+CD60+ T cells. Cord blood cells expressed epsilon-specific mRNA and mRNA for interleukin-2 (IL-2), IL-4, IL-10 and interferon-γ (IFN-γ) but not IL-6. At 7 months of age, peripheral blood mononuclear cells expressed epsilon-specific mRNA and mRNA for all cytokines. In the placental membrane, we detected IgE+ cells, while CD8+CD60+ T cells were detected in the chorionic villi. CD8+CD60+ T cells, cells expressing epsilon-specific and IL-6-specific mRNA may contribute to the pathobiology and provide important prognostic indicators of atopy.     

Changing survival, memory cell compartment, and T-helper balance of lymphocytes between severe and mild asthma

Background

In rural Gambia, birth season predicts infection-related adult mortality, providing evidence that seasonal factors in early life may programme immune development. This study tested whether lymphocyte subpopulations assessed by automated full blood count and flow cytometry in cord blood and at 8, 16 and 52 weeks in rural Gambian infants (N = 138) are affected by birth season (DRY = Jan-Jun, harvest season, few infections; WET = Jul-Dec, hungry season, many infections), birth size or micronutrient status.

Results

Geometric mean cord and postnatal counts were higher in births occurring in the WET season with both season of birth and season of sampling effects. Absolute CD3+, CD8+, and CD56+ counts, were higher in WET season births, but absolute CD4+ counts were unaffected and percentage CD4+ counts were therefore lower. CD19+ counts showed no association with birth season but were associated with concurrent plasma zinc status. There were no other associations between subpopulation counts and micronutrient or anthropometric status.

Conclusion

These results demonstrate a seasonal influence on cell counts with a disproportionate effect on CD8+ and CD56+ relative to CD4+ cells. This seasonal difference was seen in cord blood (indicating an effect in utero) and subsequent samples, and is not explained by nutritional status. These findings are consistent with the hypothesis than an early environmental exposure can programme human immune development.     

Proliferation of CD8+ in culture of human T cells derived from peripheral blood of adult donors and cord blood of newborns

As during replicative senescence either in vivo or in vitro, the growing up subpopulation of CD8+CD28- cells is observed, we compared replicative senescence of T cells derived from mononuclear cells of peripheral blood (PBMC) of adults with those from cord blood (CBMC), not having yet CD8+CD28- subpopulation. In PHA-stimulated and IL-2-dependent cultures, T cells from both cord blood and peripheral blood of young adults displayed similar pattern of replicative senescence characterised by gradual decrease of proliferation capacity (assessed by CFSE assay) and reduction of CD28+ subpopulation of CD8+ cells. We were also interested whether CD8+CD28- were just progeny of CD28+ cells or if they were able to proliferate by themselves. After PHA stimulation of cells from adult donors at different ages, including centenarians, the transient up-regulation of CD28+ was observed. In CBMC and PBMC from young donors, the entire CD28+ subpopulation entered the cell cycle. In PBMC, from the majority of middle-aged subjects and all centenarians both CD28+ and CD28- were proliferating. All together we can conclude that in vitro CD8+CD28- are the progeny of both CD8+CD28+ and CD8+CD28- subpopulations.     

Lymphocyte subpopulations during a longitudinal survey in an endemic malaria zone

In a longitudinal survey conducted in savanna area (Burkina Faso, West Africa) where malarial transmission is seasonal, we studied modifications of T, B lymphocytes, NK cells, and CD4+, CD8+ and activated T subpopulations of 61 patients (31 adults and 30 children, among them 20 showed at least one malarial attack during the survey). Analysis was made by direct immunofluorescence on a cytofluorimeter. Our study did not show any significant differences in lymphocytes subpopulations according to age or presence of malarial attack. None of the lymphocyte markers in the peripheral blood are related to premunition, may be because host/parasite conflict mainly occurs in deep organs.     

Two-color flow cytometric analysis of preterm and term newborn lymphocytes

Immune system maturation proceeds postnatally in humans. Therefore, newborns, especially those of a lower gestational age, are not fully immunocompetent and are more likely to acquire perinatal infections. In order to investigate the neonatal immune system status, the major lymphocyte subpopulations were studied in newborns of different gestational age, comparing term newborns and adults. The cord blood from 66 newborns and the peripheral blood from 23 adults were analyzed using fluorochrome labelled monoclonal antibodies and two-color flow cytometry. The newborns were divided into three groups according to their gestational age. Ten prematures were under 32 weeks of gestation, 35 were of 32-37 weeks and there were 21 term newborns. The percentage of cytotoxic T lymphocytes (CD4 CD8+) was lower in term newborns as compared to the adult controls (17.8 versus 30.3%), and so were the percentages of activated T lymphocytes (CD3+Ia+; 0.3 versus 3.7%), cytotoxic non-MHC restricted T lymphocytes (CD3+CD16+CD56+; 0.2 versus 1.8%) and NK cells (CD3-CD16+CD56+; 4.8 versus 15.5%). On the contrary, the proportions of unlabelled cells were increased in term cord blood. The expression of CD45R0 marker on neonatal lymphocytes was very low (1%). In comparison to the higher-gestation newborns, the lower gestation prematures had reduced percentages of T lymphocytes (CD3+; 43 versus 65%), mostly helper T lymphocytes (CD4+CD8-; 35 versus 50%), and increased percentages of unlabelled cells. The percentages of NK cells (CD3+CD16+CD56+) and B lymphocytes (CD3-CD19+; CD3-Ia+) did not differ among the tested newborn groups. There were no significant differences in major lymphocyte subpopulations between the group of highest-gestation prematures and the group of term newborns that differed significantly when compared to adults. The lowest-gestation newborns showed the most immature lymphocyte phenotype with the highest percentages of unlabelled cells.     

Longitudinal follow-up of lymphocyte subsets during the first year of life

A longitudinal study of lymphocyte subsets during infancy was evaluated by using the flow cytometric immunophenotyping method. Two hundred and thirteen blood samples were obtained from 92 healthy, full-term infants of the following ages: 1-7 days old (n = 43), 3 months old (n = 55), 6 months old (n = 57) and 11 months old (n = 58). The absolute numbers of CD3+ and CD3+/CD4+ T lymphocytes increased from birth to 3 months of age, and remained stable thereafter. The absolute number of CD3+/CD8+ T lymphocytes increased from birth to 11 months of age. The absolute number of CD19+ B lymphocytes and NK cells increased rapidly (3 months) after birth and continued to increase throughout the study period. However, the changes in the relative counts of lymphocyte subsets did not always correspond with the changes in their absolute numbers. These results demonstrate the age-related changes in lymphocyte subpopulations and provide reference ranges for lymphocyte subsets during infancy.     

Progressive polarization towards a T helper/cytotoxic type-1 cytokine pattern during age-dependent maturation of the immune response inversely correlates with CD30 cell expression and serum concentration.

In order to investigate the T cell cytokine profile during age-dependent maturation of the immune response, we evaluated the cytokine expression of CD4+ and CD8+ circulating cells by flow cytometric single-cell analysis after non-specific stimulation in vitro in different age groups of normal individuals, from cord blood to adulthood. Moreover, we correlated these lymphocyte cytokine patterns with the expression/release of CD30, a member of the tumour necrosis factor (TNF) receptor superfamily, which has been suggested to be related to the T helper/cytotoxic (Th(c))2-type immune responses, in order to verify this association in vivo, in non-pathological conditions. The results showed a progressive increase of circulating Th(c)1-type, interferon-gamma (IFN-gamma)- and/or IL-2-producing T cells along with ageing and, conversely, a stable number, although higher than in cord blood samples, of CD4+/IL-4+ T cells in the post-natal groups. In addition, serum levels of soluble CD30 (sCD30) and numbers of circulating CD4+/CD30+ and CD8+/CD30+ T cells were significantly higher in children aged < 5 years in comparison with those found either in cord blood or in blood from both older children and adults. These data support the concept of a progressive polarization of the Th(c) cell cytokine profile towards the Th(c)1 pattern during age-dependent maturation of the immune response. Moreover, the peak of CD30 expression/release in early infancy before the Th(c)1 shifting occurs, although not associated with a significant increase of circulating IL-4+ T cells, raises the question of the possible relationship in vivo between CD30 and Th(c)2-type immune responses.     

Reciprocal changes of naïve and effector/memory CD8+ T lymphocytes in chronic hepatitis B virus infection

Persistent viruses, such as cytomegalovirus or human immunodeficiency virus, cause major perturbations of CD8+ T-lymphocyte subpopulations. To test whether chronic infection with hepatitis B virus (HBV) could also be responsible for such modifications, we analyzed the expression of CD27, CD28, CCR7, and perforin in blood CD8+ T lymphocytes. In comparison to healthy subjects and patients recovering from acute hepatitis B, chronic hepatitis B patients showed higher percentages of na?ve CD8+ T lymphocytes (CD45RA+CD27+CD28+), and lower percentages of intermediately-differentiated CD27+CD28?CD8+ T cells. The late differentiated CD45RA+CD27?CD28? subset was also present in a large percentage in some patients, but no statistically significant difference with healthy controls was observed. Removal from the circulation of intermediately-differentiated CD8+ T lymphocytes may occur during chronic HBV infection, favoring the recruitment of na?ve cells. This may result in impairment of the generation of functionally-competent memory cells, and an inability to achieve control of HBV replication.