We describe the application of epigenetic quantification of CD3+, CD8+, CD4+, including T regulatory (Treg) cells, B cells, NK cells, monocytes and neutrophils from fresh or stored blood. This method yields identical results to flow cytometry from blood samples of healthy donors and allows precise quantification of cell subsets such as Treg cells that are challenging to quantify. It is also suitable for less than 100 µl blood or for samples with low cell number such as from patients after hematopoietic stem cell transplantation (HSCT) or with primary or acquired immune deficiencies.
Patients with Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-Linked (IPEX) and IPEX-like were evaluated by analyzing Tregs relative to CD3+ T cells. Despite the dysfunctional FOXP3 mutated protein, IPEX patients exhibited elevated Treg/CD3+ cell ratios which seemed to correlate with disease severity. In contrast, most of the patients with IPEX-like symptoms without FOXP3 mutations exhibited decreased Treg/CD3+ cell ratios.
When applied to sequential blood samples during reconstitution post-HSCT, the epigenetic method allowed for identification of the immune subsets, including Tregs, at earlier time points than flow cytometry according to current clinical practice. This paves the way to a better understanding of the correlation between immune reconstitution and HSCT-related complications.
These results demonstrate suitability of epigenetic immune method to quantify highly specialized subpopulations where established methods lack standardization. To further extend the utility of this method in immune-mediated diseases of different origin we are extending the epigenetic immune cell panel to follicular and IL-17 producing T helper cells.