Lymphocyte subsets: reference ranges in an age- and gender-balanced population of Omani healthy adults

Determining reference ranges for immunological cells of healthy indigenous individuals from a region in Brazil

Morais et al. conducted a pioneering study with Brazilian indigenous populations to determine reference values for immunologic cells from healthy adult individuals. The main findings included a higher relative median for T lymphocyte subsets in females than males, and T CD3+, T CD4+, and T CD8+ relative values were statistically different when compared with Brazilian populations from other Brazilian regions. The relative medians of CD3+, CD4+, and CD8+ T cells were significantly higher in women than in men in a healthy indigenous population. Demographic and ethnic diversity of the Brazilian population can be associated with quantitative modifications in the immunologic cells of healthy individuals.

OBJECTIVE

The establishment of reference values for a subset of leukocytes is common in clinical practice, and ethnic variations are strongly associated with disease development. In Brazil, indigenous people are vulnerable to infections, and few studies have described the health and disease conditions of this population. This study aimed to provide reference values for immunological cell subsets in indigenous Brazilians living in the state of Mato Grosso do Sul.

METHODS

Flow cytometry and 4-color combinations of monoclonal antibodies were used to characterize cells. A total of 115 healthy adults, mostly females (72%), were included in the study. The results are presented as mean and median (2.5%-97.5% percentiles) for T and B lymphocytes, CD4+ T cells, CD8+ T cells, Natural Killer cells, monocytes, and dendritic cells, providing an average immunological profile for the population in question.

RESULTS

The relative medians of CD3+, CD4+, and CD8+ T cells were significantly higher in women than in men in a healthy indigenous population.

CONCLUSION

To our knowledge, cell reference data from indigenous Brazilians are unknown in the literature. The immune cell results presented in this pioneering study will contribute to the clinical and laboratory evaluation of the Brazilian indigenous population, especially given the important differences when compared with other Brazilian ethnic groups.

Recommendations for Management of Secondary Antibody Deficiency in Multiple Myeloma

Secondary antibody deficiency (SAD) is a subtype of secondary immunodeficiency characterized by low serum antibody concentrations (hypogammaglobulinemia) or poor antibody function. SAD is common in patients with multiple myeloma (MM) due to underlying disease pathophysiology and treatment-related immune system effects. Patients with SAD are more susceptible to infections and infection-related morbidity and mortality. With therapeutic advancements improving MM disease control and survival, it is increasingly important to recognize and treat the often-overlooked concurrent immunodeficiency present in patients with MM. The aims of this review are to define SAD and its consequences in MM, increase SAD awareness, and provide recommendations for SAD management. Based on expert panel discussions at a standalone meeting and supportive literature, several recommendations were made. Firstly, all patients with MM should be suspected to have SAD regardless of serum antibody concentrations. Patients should be evaluated for immunodeficiency at MM diagnosis and stratified into management categories based on their individualized risk of SAD and infection. Infection-prevention strategy education, early infection reporting, and anti-infective prophylaxis are key. We recommend prophylactic antibiotics or immunoglobulin replacement therapy (IgRT) should be considered in patients with severe hypogammaglobulinemia associated with a recurrent or persistent infection. To ensure an individualized and efficient treatment approach is utilized, patient's immunoglobin G concentration and infection burden should be closely monitored throughout treatment. Patient choice regarding route and IgRT treatment is also key in reducing treatment burden. Together, these recommendations and proposed management algorithms can be used to aid physician decision-making to improve patient outcomes.

Effect of ethanolic extract of rosella (Hibiscus sabdariffa L.) on vital signs, kidney, and liver safety

Introduction: Rosella (Hibiscus sabdariffa L) extract is often used as immune-stimulant because it contains flavonoids, especially anthocyanin and quercetin with antioxidant activities.

Objective: This study aimed to determine the safety of the rosella extract consumed in the form of capsules on the vital signs, haematologic parameters as well as kidney and liver function.

Methods: This research was conducted using clinical trial pre- and post-test design in healthy participants. There were 21 healthy participants (52% male, age ranged 8–45) consuming rosella capsules for thirty days, in a dose of 500 mg extract daily. Leukocytes, lymphocytes, blood urea nitrogen (BUN), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and vital signs were consecutively evaluated on days 0, 31, and 45, respectively. The Wilcoxon and paired sample t-test were used to compare the parameters among the evaluated times.

Results: The result showed that no significant difference for all parameters among the three time points (p>0.05).

Conclusion: These findings suggested that the administration of ethanolic extract of rosella is potential safe and does not negatively affect the vital signs, haemoglobin, leukocytes, lymphocytes, BUN, SGOT, and SGPT.

Hematological indices reference intervals for a healthy Arab population in Qatar: Effect of age, gender, and geographic location

Hematologic reference intervals vary with gender, age, ethnicity, and geographic area. Therefore, local or national laboratory reference ranges are essential to enhance the accuracy when diagnosing health conditions. Still, no comprehensive list of reference ranges tailored to the Arab population living in Qatar. Accordingly, this study aims at establishing a hematology reference guide for Arabs in Qatar.This is a retrospective study where 750 healthy volunteers (18-69 years) from 2015 to 2019 were included, analyzed by an automated hematology analyzer. Arab adults were divided into African (Egypt, Libya, Tunisia, Morocco) and Asian (Syria, Lebanon, Jordon, Palestine, Qatar). The Cell-Dyn and Sysmex were used for measuring hematological parameters.The mean +/- 2SD were established for all the study groups. Arab males had significantly higher Hb, Hct, red cell distribution width, absolute neutrophil count, lymphocytes, and monocyte counts than females. Asian-Arab males had significantly higher Hb concentration and higher WBC, lymphocytes, and eosinophils than African Arabs. Asian-Arab young (>18: < 40 years) males had significantly higher Hb and lymphocytes and lower monocytes than older males (>40 years). African-Arab young males had significantly higher lymphocytes and lower monocytes than older males. Asian-Arab young females had higher WBC and absolute neutrophil count than older Asian Arabs.The findings of this study will help in establishing specific reference intervals in the Arab world. The differences in hematology reference intervals considering age, gender, and geographical location highlight the importance of establishing blood reference intervals in each country considering the ethnic diversity of each country.

Reference ranges of T lymphocyte subsets by single-platform among healthy population in southwest China

BACKGROUND

Appropriate reference ranges of T lymphocyte subsets are essential for immune status evaluation of patients with immunological diseases. We aim to establish the age- and sex-related reference intervals of T lymphocyte subsets by single-platform for the southwest China population using the indirect method with the data resulting from 53,822 cases of periodic health examination individuals in the Laboratory Information System (LIS) of West China Hospital from 2018 to 2020.

METHODS

We used the Box-Cox conversion combined with the Tukey method to normalize the data and eliminate the outliers, and the nonparametric method to estimate the 95% distribution reference intervals.

RESULTS

We initially established the reference ranges of T lymphocyte subsets by single-platform among healthy population in southwest China by indirect method (See text for details). Using the standard normal deviate test (z-test) suggested by Harris and Boyd according to CLSI EP28-A3C, which is more scientific, we found the reference ranges of T lymphocyte subsets should be differentiated by ages and genders since the reference ranges of T lymphocyte subsets by single-platform in different ages and genders are significantly different.

CONCLUSIONS

We further demonstrated the absolute count of CD3 + T cell, CD3 + CD4 + T cell, CD3 + CD8 + T cell decreased with aging, which is more marked in men and CD3 + CD8 + T cell count, and the obtained reference intervals were superior to the reference intervals derived from the reagent specification currently in use.

A Critical Review on the Standardization and Quality Assessment of Nonfunctional Laboratory Tests Frequently Used to Identify Inborn Errors of Immunity

Inborn errors of immunity (IEI), which were previously termed primary immunodeficiency diseases, represent a large and growing heterogeneous group of diseases that are mostly monogenic. In addition to increased susceptibility to infections, other clinical phenotypes have recently been associated with IEI, such as autoimmune disorders, severe allergies, autoinflammatory disorders, benign lymphoproliferative diseases, and malignant manifestations. The IUIS 2019 classification comprises 430 distinct defects that, although rare individually, represent a group affecting a significant number of patients, with an overall prevalence of 1:1,200-2,000 in the general population. Early IEI diagnosis is critical for appropriate therapy and genetic counseling, however, this process is deeply dependent on accurate laboratory tests. Despite the striking importance of laboratory data for clinical immunologists, several IEI-relevant immunoassays still lack standardization, including standardized protocols, reference materials, and external quality assessment programs. Moreover, well-established reference values mostly remain to be determined, especially for early ages, when the most severe conditions manifest and diagnosis is critical for patient survival. In this article, we intend to approach the issue of standardization and quality control of the nonfunctional diagnostic tests used for IEI, focusing on those frequently utilized in clinical practice. Herein, we will focus on discussing the issues of nonfunctional immunoassays (flow cytometry, enzyme-linked immunosorbent assays, and turbidimetry/nephelometry, among others), as defined by the pure quantification of proteins or cell subsets without cell activation or cell culture-based methods.

Sex, immunity, and cancer

The composition of the tumor microenvironment is the complex result of the interaction between tumoral and host factors. Since there are several differences in the regulation of gene circuits between sexes, mainly influenced by sex hormones, the tumor-host interaction presents some differences, leading tumors to evolve under different conditions. Nowadays, it is well known the existence of sexual dimorphism in the regulation of the immune system, where women present an improved immunity to various infectious agents and, on the other hand, a higher incidence of autoimmune diseases than men. In oncology, differences in cancer susceptibility, response to treatment, and clinical outcomes between men and women patients are well known. Recently, sex-specific differences have also been reported in mutations in driver genes and the prognostic value of several biomarkers. Sex has been a widely forgotten biomarker in cancer therapy, but it has recently acquired great relevance due to the different results seen in immunotherapy treatment.

Characteristics of and reference ranges for peripheral blood lymphocytes and CD4 T cell subsets in healthy adults in Shanxi Province, North China

Objective

To guide clinical decision making, race-, age- and gender-specific reference ranges for lymphocytes and CD4+ T-cell subsets are required.

Methods

Single platform flow cytometry to determine reference intervals for lymphocyte subpopulations and CD4+ T-cell subsets in 196 healthy Han Chinese adults.

Results

The frequencies and absolute numbers of B cells were slightly lower in Han Chinese individuals of the Shanxi region than in individuals from Hong Kong, Germany and Singapore, while percentages and absolute numbers of NK cells were slightly higher compared with individuals from Hong Kong. CD4+/CD8+ T-cell ratios, CD4+ T cell percentages and Th2 cell counts were higher, while frequencies and numbers of CD8+ T cells, numbers of NK cells and percentages of Th1 cells were lower, in females compared with males. CD4+ T cell percentages, CD4+/CD8+ T-cell ratios, numbers of CD8+ T cells and Treg cells, and Th17/Treg cell ratios differed by age.

Conclusion

We established lymphocyte and CD4+ T-cell subset reference intervals for healthy Han Chinese adults of the Shanxi region. Ethnicity, gender and age affected lymphocyte subset composition.

Clinical Impact of Percentage of Natural Killer Cells and Natural Killer-Like T Cell Population in Acute Myeloid Leukemia

Background

Natural killer (NK) function defects have been seen in many hematological malignancies, including acute myeloid leukemia (AML). AML is associated with deficient human leukocyte antigen (HLA) expression on leukemia blasts which become targets for killing by NK and natural killer-like T (NKT) cells. However, NK and NKT cells are not effective in killing autologous leukemia blasts, maybe due to number or functional abnormalities. The aim of the work was to detect the number and percentage of NK and NKT cells in patients with AML and the impact of their percentage on the prognosis, response to treatment and survival.

Methods

Bone marrow and peripheral blood samples were collected from 50 adult patients diagnosed as de novo AML who presented to the Hematology Unit in the Oncology Center Mansoura University (OCMU) at time of diagnosis. NK and NKT cells were detected by using immunophenotyping by expression of cell surface and cytoplasmic markers (anti-CD3 fluorescein isothiocyanate (FITC), anti-CD16/56 phycoerythrin (PE)).

Results

We observed significant reduction in the median values of NK and NKT cells in AML patients in comparison to normal values. There was an insignificant correlation to response to induction treatment. While a significant correlation to overall survival (OS) (P = 0.03) was observed. The correlation to risk stratification was significant with NK cells (P < 0.001), but not with NKT cells (P = 0.23).

Conclusion

We concluded that the number and percentage of NK and NKT cells decreased significantly in AML patients and the frequency of NK and NKT cells is inversely proportionate with prognosis and OS in studied AML patients. We recommend correlating both number and function of NK and NKT cells in future studies to help provide a wide field of interest for possibility of demonstrating novel therapies using NK cells for curing AML.

Characteristics and reference ranges of CD4+T cell subpopulations among healthy adult Han Chinese in Shanxi Province, North China

BACKGROUND

Immunophenotyping of blood lymphocytes is an essential tool to evaluate the immune function of patients with immunodeficiency or autoimmunity. Predominately identified CD4⁺T cell subsets, Th1, Th2, Th17, as well as regulatory T (Treg) cells, play crucial roles in several immunological and pathological conditions. Considering the variations in cell counts among populations and ethnicities, specific CD4⁺T cell subset reference values need to be locally established to enable meaningful comparisons and accurate data interpretation in clinical and research settings. Therefore, the aim of this study was to establish distributions and reference ranges for blood CD4⁺T cell subpopulations in age- and sex-balanced healthy adults of a Han Chinese population in Shanxi Province, North China.

METHODS

Peripheral blood CD4⁺T cell subsets were examined in 150 healthy volunteers (75 males, 75 females) aged 20-70 years with a four-color FACSCalibur flow cytometer.

RESULTS

Reference value percentages (absolute counts, cells/μl) were defined as 95% of the population for cell types as follows: CD4⁺T, 23.78-51.07 (360-1127); Th1, 0.43-39.62 (2.64-276.21); Th2, 0.27-3.57 (1.80-27.14); Th17, 0.22-2.62 (1.10-19.54); and Treg, 2.17-7.94 (13.47-64.58). The ranges for the Th1:Th2 and Th17:Treg ratios were 0.59-52.37 and 0.04-0.76, respectively. Notably, a significant increase was observed in the values of Treg cells in older individuals, and the numbers of Treg cells in females also tended to decrease when compared to those in males. Therefore, we established the distribution and reference range of CD4⁺T cell subsets based on age and sex, demonstrating the lowest values of Treg cells in younger females.

CONCLUSIONS

Collectively, our data provide population-, age-, and sex-specific distributions and reference ranges of circulating CD4⁺T cell subpopulations, which can be adopted to guide clinical decisions and interpretation of immunophenotyping data in the Han Chinese population in Taiyuan, Shanxi Province, China. In addition, the low expression of peripheral Treg cells in younger females may be associated with the predisposition of females to autoimmune diseases.

Genetic and clinical predictors of CD4 lymphocyte recovery during suppressive antiretroviral therapy: Whole exome sequencing and antiretroviral therapy response phenotypes

Increase of peripheral blood CD4 lymphocyte counts is a key goal of combined antiretroviral therapy (cART); most, but not all, recipients respond adequately and promptly. A small number of studies have examined specific genetic factors associated with the extent of CD4 recovery. We report a genome-wide examination of factors that predict CD4 recovery in HIV-infected women. We identified women in in a cohort study who were on cART with viral load below 400 copies, and drew racially and ethnically matched samples of those with good CD4 response over 2 years or poor response. We analyzed the exomes of those women employing next generation sequencing for genes associated with CD4 recovery after controlling for non-genetic factors identified through forward stepwise selection as important. We studied 48 women with good CD4 recovery and 42 with poor CD4 recovery during virologically-suppressive cART. Stepwise logistic regression selected only age as a statistically significant (p<0.05) non-genetic predictor of response type (each additional year of age reduced the odds of good recovery by 11% (OR = 0.89, CI = 0.84–0.96, p = 0.0009). After adjustment for age and genomic estimates of race and ethnicity, 41 genes harbored variations associated with CD4 recovery group (p≤0.001); 5 of these have been previously reported to be associated with HIV infection, 4 genes would likely influence CD4 homeostasis, and 13 genes either had known functions or were members of product families that had functions for which interactions with HIV or effects on lymphocyte homeostasis were biologically plausible. Greater age was the strongest acquired factor that predicted poor CD4 cell recovery. Sequence variations spanning 41 genes were independently predictive of CD4 recovery. Many of these genes have functions that impact the cell cycle, apoptosis, lymphocyte migration, or have known interactions with HIV. These findings may help inform new hypotheses related to responses to HIV therapy and CD4 lymphocyte homeostasis.

Comprehensive haematological indices reference intervals for a healthy Omani population: First comprehensive study in Gulf Cooperation Council (GCC) and Middle Eastern countries based on age, gender and ABO blood group comparison

Background

Reference intervals for venous blood parameters differs with age, gender, geographic region, and ethnic groups. Hence local laboratory reference intervals are important to improve the diagnostic accuracy of health assessments and diseases. However, there have been no comprehensive published reference intervals established in Oman, the Gulf Cooperation Council or Middle Eastern countries. Hence, the aim of this study was to establish reference intervals for full blood count in healthy Omani adults.

Methods

Venous blood specimens were collected from 2202 healthy individuals aged 18 to 69 years from January 2012 to April 2017, and analysed by Sysmex XS-1000i and Cell-Dyn Sapphire automated haematology analysers. Results were statistically analysed and compared by gender, age, and ABO blood group. The lower and upper reference limits of the haematology reference intervals were established at the 2.5th and 97.5th percentiles respectively.

Results

Reference intervals were calculated for 17 haematology parameters which included red blood cell, white blood cell, and platelet parameters. Red blood cell (RBC), haemoglobin (HGB), haematocrit (HCT), platelet and platelet haematocrit counts of the healthy donors were significantly different between males and females at all ages (p < 0.05), with males having higher mean values of RBC, HGB and HCT than females. Other complete blood count parameters showed no significant differences between genders, age groups, instruments, or blood groups. Our study showed a lower haemoglobin limit for the normal reference interval in males and females than the currently used in Oman.

Conclusions

Data from this study established specific reference intervals which could be considered for general use in Oman. The differences in haematology reference intervals highlights the necessity to establish reference intervals for venous blood parameters among the healthy population in each country or at least in each region.

Biobran/MGN-3, an arabinoxylan rice bran, enhances NK cell activity in geriatric subjects: A randomized, double-blind, placebo-controlled clinical trial

Aging is associated with a decline in natural killer (NK) and natural killer T (NKT) cell function that may contribute to increased susceptibility to malignancy and infection. A preliminary investigation was conducted examining the hypothesis that arabinoxylan rice bran (Biobran/MGN-3), a denatured hemicellulose with known immunomodulatory activity, could counteract this decline in NK/NKT cell activity in geriatrics. A total of 12 healthy geriatric subjects of both sexes and over 56 years old, participated in a randomized, double-blind, placebo-controlled clinical trial. A total of six subjects served as control and six subjects ingested Biobran/MGN-3 (500 mg/day) for 30 days. The effect of Biobran/MGN-3 supplementation on NK/NKT cell activity was assessed using the degranulation assay. All study subjects were monitored for the development of any inadvertent side effects. In addition, the pharmacological effects of Biobran/MGN-3 on blood cell components and liver and kidney functions were also assessed. Results demonstrated that Biobran/MGN-3 had no effect on the total percentage of NK cells, however it enhanced the cytotoxic activity of induced NK cell expression of cluster of differentiation 107a, when compared with baseline values and with the placebo group (P<0.05). Furthermore, there were no side effects observed, indicating that Biobran/MGN-3 supplementation was safe at the utilized dosage and for the duration of administration. Various additional beneficial effects were observed, including improved mean corpuscular volume and reduced hepatic aspartate aminotransferase enzyme levels, which suggested improved liver function. It was concluded that Biobran/MGN-3 induces a significant increase in NK activity which may increase resistance to viral infections and cancers in the geriatric population. However, additional clinical trials should be conducted in the future to verify these findings.

High Levels of (Un)Switched Memory B Cells Are Associated With Better Outcome in Patients With Advanced Atherosclerotic Disease

BACKGROUND

Atherosclerosis is an inflammatory lipid disorder and the main underlying pathology of acute ischemic events. Despite a vast amount of data from murine atherosclerosis models, evidence of B-cell involvement in human atherosclerotic disease is limited. We therefore investigated the association of circulating B-cell subtypes with the occurrence of secondary cardiovascular events in advanced atherosclerotic disease.

METHODS AND RESULTS

This cohort study consists of 168 patients who were included in the Athero-Express biobank between 2009 and 2011. Before surgery, peripheral blood mononuclear cells were isolated and stored in liquid nitrogen. After gentle thawing of the peripheral blood mononuclear cells, different B-cell subtypes including naïve, (un)switched memory, and CD27+CD43+ B1-like B cells, were analyzed by flow cytometry. Univariable and multivariable Cox proportional hazard models were used to analyze associations between B-cell subtypes, circulating antibodies and secondary cardiovascular manifestations during the 3-year follow-up period. Mean age was 70.1±9.6 years, males represented 62.8% of the population, and 54 patients had secondary manifestations during follow-up. High numbers of unswitched memory cells were protective against secondary outcome (hazard ratio, 0.30 [95% CI, 0.13-0.69]; P<0.01). Similar results were obtained for the switched memory cells that also showed to be protective against secondary outcome (hazard ratio, 0.33 [95% CI, 0.14-0.77]; P=0.01).

CONCLUSIONS

A high number of (un)switched memory B cells is associated with better outcome following carotid artery endarterectomy. These findings suggest a potential role for B-cell subsets in prediction and prevention of secondary cardiovascular events in patients with atherosclerosis.

Age-Related Differences in Percentages of Regulatory and Effector T Lymphocytes and Their Subsets in Healthy Individuals and Characteristic STAT1/STAT5 Signalling Response in Helper T Lymphocytes

The dynamic process of the development of the immune system can in itself result in age-related immune malfunctions. In this study, we analysed lymphocyte subsets in the peripheral blood of 60 healthy donors, divided into groups of children, adolescents, and adults, focusing on effector (Teff) and regulatory (Treg) T lymphocytes and STAT1/STAT5 signalling response in helper T lymphocytes (Th) in adults, using flow cytometry. Our results demonstrate a decrease in the percentage of total Tregs and an increase in the percentage of total Teffs with age and a consequential immense increase in the Teff/Treg ratio. The increase of Teffs was most apparent in Th1, Th1Th17, and Th17CD161- subsets. Significant Th lymphocyte STAT1 expression differences were observed between children and adolescents, which were associated with the decrease in activated Tregs. Higher expression of STAT1 was found in FoxP3hi than in FoxP3low Th lymphocytes, while significant IL-2 induced STAT5 phosphorylation differences were found among the subsets of Th lymphocytes in adults. Our study demonstrates age-related changes in circulating Teff and Treg, as well as significant differences in STAT5/STAT1 signalling among FoxP3+ Th lymphocytes, providing new advances in the understanding of immunosenescence.

Reference ranges of lymphocyte subsets balanced for age and gender from a population of healthy adults in Chongqing District of China

The enumeration of lymphocyte subsets plays an essential role in the monitoring of immunological disorders. Immunophenotyping values have been found to be influenced by race, age, gender, and environmental conditions. Therefore, it is important to establish reference ranges for healthy adults from the local population for clinical decision-making. The current study aimed to establish a normal reference range for peripheral blood lymphocyte subsets in healthy adults from the Chongqing District of China by using single-platform flow cytometry. Age- and gender-specific reference ranges were established in 268 healthy adult males and females between 21 and 60 years of age. The CD8+ cell counts decreased with age, CD4+ cell percentages and counts increased with age, and total T cell percentages were higher in the female population. Our results are similar to those reported from other parts of China but different from some results reported from other countries; this further stresses the need to establish local reference ranges by region. Our results will help in the management of patients with human immunodeficiency virus and other immunological disorders in Chongqing District. © 2015 International Clinical Cytometry Society.

Lymphocyte Subsets in a Population of Nonfrail Elderly Individuals

Age-related frailty is characterized by increased vulnerability to stress due to decline in homeostatic reserve, which results in increased risk of adverse health outcomes including disability, hospitalization, and death. The relationship between frailty and immunological system alterations is well established. Thus, analysis of immunological changes, such as alterations in lymphocyte subsets, during senescence may provide useful markers for frailty and associated pathologies. Since reference ranges currently used for lymphocyte subsets do not specifically differentiate the elderly group, the aim of this study was to (1) establish reference ranges in nonfrail elderly individuals and (2) assess the evolution of these parameters with age. Further, the influence of other physiological and lifestyle factors was also evaluated. The study was performed on 144 elderly individuals (aged 65-95) from Galicia (in northwestern Spain). Percentages of lymphocyte subpopulations (CD3(+) T lymphocytes, CD4(+) T-helper lymphocytes, CD8(+) T-cytotoxic lymphocytes, CD19(+) B lymphocytes, and CD56(+)16(+) natural killer cells) were analyzed in peripheral blood by flow cytometry, and reference ranges were calculated. The individual status as nonfrail or prefrail did not markedly affect the immunological parameters, but an apparent influence of age was obtained for %CD3(+), %CD4(+), and %CD19(+) cells, all of which fell with increasing age. Women showed higher levels of %CD19(+) lymphocytes. No significant influence of smoking habits, physical activity, or drinking alcohol or caffeine beverages was observed. The results obtained may serve as a basis to establish comparisons between frail and nonfrail elderly individuals, in order to determine the usefulness of lymphocyte subsets as immunological biomarkers of frailty.

Reference ranges of lymphocyte subsets in healthy Qatari adults

AIM

Determine reference ranges of lymphocyte subsets in healthy Qatari adults.

PATIENTS & METHODS

Blood samples (n = 150) were investigated using four colors flow cytometery.

RESULTS

The mean percentage and absolute values of the lymphocyte subsets were: CD3: 73.6 ± 6.1%; 2,072 ± 644 cells/μl; CD4: 41.1 ± 7.9%; 1,167 ± 396 cells/μl; CD8: 33.8 ± 7.1%; 967 ± 364 cells/μl; B cells (CD19(+)): 11.3 ± 3.9%; 318 ± 144 cells/μl and natural killer (NK) cells (CD16/56(+)): 16.5 ± 6.3%, 440 ± 401 cells/μl, respectively. The CD4/CD8 ratio was 1.3 ± 0.5. The ratio, CD3(+) and CD4(+) percentage and CD4(+) cell counts were significantly higher in females; CD8(+) and NK cell count and CD8(+) percentage were significantly higher in males. The impact of age was less certain.

CONCLUSION

The reference values of lymphocyte subsets appear to be specific to this population, demonstrating the importance of establishing local reference ranges.