Methods: Current asthmatic (n=20) and non-asthmatic (n=20) children were recruited from Fresno, CA. Asthma diagnosis was determined by current NHLBI criteria. PBMCs were stored in liquid nitrogen. Cells were thawed, stimulated for 4 hours using PMA-ION and stained for cell surface markers, intracellular markers, transcription factors and cytokines. Single cell mass cytometry was then used to collect data on 500,000 to 1,000,000 single cells per subject.
Results: There was a difference in the number of memory T cell subsets when comparing asthmatics versus non-asthmatics using t-tests, with CD8+ central memory T cells being reduced in asthmatics (p<0. 002), but there were not significant differences between various basic cell types (Monocytes, B cells, T cells, TCRgd). However, when applying Elastic Net Regression Analysis with fivefold cross-validation, there were 4 relevant features that were selected with misclassification error=0.22. The frequency of CD8+ terminally differentiated effector memory CCR5+ cells positively predicted asthma. The frequency of CD8+ central memory CD226+ cells, CD8+central memory cells CD49d+cells and CD8+ central memory cells were negative predictors of asthma.
Conclusions: There are differences in T cell subsets of asthmatic versus non-asthmatic children that can be detected using mass cytometry and sophisticated computational modeling, such as elastic net regression.