Conventional and Computational Flow Cytometry Analyses Reveal Sustained Human Intrathymic T Cell Development From...

Area of Science:

• Immunology
• Developmental Biology
• Computational Biology

Background:

• The thymus is crucial for T cell maturation and immune system function.
• The thymus undergoes involution, a decline in cellularity, in two phases: early life and adulthood.
• Understanding early thymic involution's impact on T cell development is vital.

Purpose of the Study:

• To investigate the effect of early thymic involution on thymic immune subset frequencies from birth to 14 years.
• To develop and apply a novel computational analysis pipeline for flow cytometry data.

Main Methods:

• Multi-color flow cytometry on human thymus samples (birth to 14 years).
• Development of a novel computational pipeline adapted from single-cell RNA sequencing analysis.
• Utilized batch correction, subsampling, and KNN-graph-based clustering for robust analysis.

Main Results:

• Successfully identified rare, distinct, and gradually developing immune subsets in human thymus.
• No significant alterations in T-lineage developmental intermediate proportions were observed from birth to puberty.
• Early thymic involution primarily limits overall T cell output, not T cell subset development.

Conclusions:

• The novel computational pipeline offers an effective strategy for analyzing thymus flow cytometry data.
• Early human thymic involution does not impede T-cell development, but rather reduces the total T cell production.
• Human T cell development remains largely unaffected during the initial phase of thymic involution.