Table 4.

Most pressing biological and technical considerations

	Biological questions
1	What is the precise fate of monocyte subsets once they have entered lesions and do they contribute differentially to disease progression?
2	Does specific ablation or inhibition of a monocyte subtype result in descreased lesion burden while sparing host defense and repair mechanisms?
3	Do the findings for mouse monocyte subsets hold true in humans?

	Technical challenges
1	Validation of intravital imaging technologies with subcellular resolution to study the complexity of the host response in target sites (atheromata, draining lymph nodes)
2	Development of new agents that permit to distinguish leukocyte subtypes (monocyte, macrophage and DC subsets, and other cells present in atheromata)
3	Development of injectable agents that target cell populations of interest, can be used in humans, and have theranostic potential