FlowSpot Enables Decentralized Phenotypic and Functional Cellular Immune Profiling from Dried Blood Spots

Area of Science:

• Immunology
• Biotechnology
• Clinical Diagnostics

Background:

• Current flow cytometry requires fresh blood, limiting decentralized immune analysis.
• Dried blood spots (DBS) offer potential for decentralized diagnostics but lack robust immune cell recovery methods.
• Existing methods cannot support flow cytometric analysis from DBS for immune cell phenotyping.

Purpose of the Study:

• To develop a novel platform for recovering intact leukocytes from DBS for flow cytometry.
• To preserve immunophenotypic characteristics of immune cells from DBS for downstream analysis.
• To enable remote and decentralized cellular immune analysis, including T cell immunophenotyping and functional profiling.

Main Methods:

• Developed FlowSpot platform for leukocyte recovery from DBS.
• Validated preservation of immune cell subset frequencies and immunophenotypic characteristics.
• Assessed clinical utility through remote CD4+ T cell enumeration in HIV patients.
• Evaluated intracellular cytokine production (IFNγ, IL-2, TNFα) post-stimulation.

Main Results:

• FlowSpot successfully recovers intact leukocytes from DBS.
• Immune cell subset frequencies show strong concordance with fresh whole blood.
• Remote CD4+ T cell counts in HIV patients align with routine clinical measurements.
• Detection of intracellular cytokine responses in CD4+ and CD8+ T cells is feasible.

Conclusions:

• FlowSpot overcomes barriers to leukocyte recovery from DBS, enabling flow cytometry.
• The platform supports ambient-temperature storage and shipment of samples.
• FlowSpot expands access to cellular immune analysis for decentralized clinical care, trials, and population research.