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Determination of Reference Values for Double-Negative T Lymphocytes in Cuban Adults
Insights
This study establishes preliminary reference values for double-negative T lymphocytes in healthy Cuban adults, finding that their numbers significantly decrease with age, particularly after 50 years.
Area of Science:
- Immunology
- Hematology
- Clinical Chemistry
Background:
- Double-negative T lymphocytes (CD4-CD8-) are crucial immunomodulators involved in various diseases.
- Their role in immunopathogenesis necessitates understanding normal population values.
- Previous studies in Cuba lacked established reference ranges for this lymphocyte subset.
Purpose of the Study:
- To estimate preliminary reference values for double-negative T lymphocytes in healthy Cuban adults.
- To analyze these values based on sex and age.
- To provide a baseline for immunological assessments in the Cuban population.
Main Methods:
- A cross-sectional study involving 182 healthy adults (18-80 years) from Havana.
- Peripheral blood immunophenotyping using flow cytometry to quantify CD45+/CD3+/CD4-/CD8-/CD56- cells.
- Calculation of medians and ranges (5th-95th percentiles) for percentages and absolute values, stratified by sex and age.
Main Results:
- Median total percentage of double-negative T lymphocytes was 3.4% (range 1.6-7.4), and absolute count was 57.5 cells/μL (range 23.0-157.0).
- Age significantly impacted lymphocyte values, with lower counts observed in the 51-80 years age group (p <0.001).
- Values decreased with age, showing a more pronounced decline after 50 years, consistent across both sexes.
Conclusions:
- Preliminary reference values for double-negative T lymphocytes were established for healthy Cuban adults, considering sex and age.
- Age is a significant factor influencing the quantity of these lymphocytes.
- These findings provide essential reference data for immunological studies and clinical diagnostics in Cuba.
Abstract:
INTRODUCTION Double-negative T lymphocytes act as immunomodulators in immune response. This subpopulation is rare in blood but important in the immunopathogenesis of autoimmune diseases, viral infections, cancer and transplant rejection. These disorders have been studied in Cuba using fl ow cytometry, but normal values of these cells have not yet been established. OBJECTIVE Estimate preliminary reference values for doublenegative T lymphocytes according to sex and age in Cuban adults. METHODS A cross-sectional study was carried out in a population of 182 healthy adult residents of Havana: 93 women and 89 men aged 18-80 years with no chronic diseases, toxic habits (smoking, excessive alcohol or caffeine intake) or medications that might alter quantity or functioning of immune-system cells. Peripheral blood was drawn to determine immunophenotype with monoclonal antibodies. The phenotype of double-negative T lymphocytes was quantifi ed as CD45+/CD3+/CD4- /CD8- /CD56- using a Gallios fl ow cytometer (Beckman-Coulter, France). Medians and ranges (to the 5th and 95th percentiles) were calculated for sex and age, for both percentages and absolute values. To evaluate the effects of sex and age, both variables as well as their interaction were included in a linear model. RESULTS Respective median and range values were total percentage values 3.4 (1.6-7.4) and total absolute values (cells/μL) 57.5 (23.0-157.0). The effect of age on lymphocyte values (percentage and absolute) was signifi cant, with lower numbers in the 51-80 years' age group (p <0.001). Percentage values according to age group were: 18-25 years, 3.8 (2.2- 7.4); 26-50 years, 3.7 (1.7-8.7); and 51-80 years 2.6 (1.3-6.6). Absolute values by age group were: 18-25 years, 90 (32.6-163.7); 26-50 years, 65 (28.8-184.0); and 51-80 years 38.5 (17.9-90.1). Desegregating data by sex and age: percentage of women aged 18-25 years 5.2 (2.1-7.8), 26-50 years 4.0 (1.8-7.7), and 51-80 years 2.5 (1.3-5.8); percentage of men aged 18-25 years 3.4 (2.3-7.3), 26-50 years 3.8 (1.5-8.7), and 51-80 years 2.6 (1.2-7.3). Absolute values: women aged 18-25 years 112.0 (40.0-153.1), 26-50 years 67.0 (26.7-138.3), and 51-80 years 40 (18.6-92.0); and men aged 18-25 years 71.5 (32.1-166.7), 26-50 years 61.5 (29.9-188.7), and 51-80 years 36 (13.5-81.7). The low sex*age interaction confi rms these differences occur in both men and women. Values decrease with age, with a more abrupt fall starting at 50 years. CONCLUSIONS Estimated reference values were determined for absolute values and relative proportions of double-negative T lymphocytes in healthy Cuban adults according to sex and age. Age was found to have a signifi cant effect. KEYWORDS Reference values, T lymphocytes, fl ow cytometry, immunology, Cuba.
