I'm trying to understand the results of the AUCell run.

I tested my single-cell data set with specific DC cell-types gene sets. The image below shows two fo the gene sets. for cDC2 i have a very high AUC score, but for some reason no cells are assigned to this category.

If I understand the way the AUC scores are calculated, a high AUC means, many of the genes in the cDC2 gene-set are expressed in the cells, but in the middle plot (created with AUCell_plotTSNE) none of the cells are assigned to this category.

From what I've read, the reason might be connected to the histogram to the left. As I don't have the expected bi-modal behavior, AUCell has difficulties setting a "better" threshold and prefers a somewhat more conservative value. As there are no cells higher of this value, I get an empty UMAP scoring.

On the UMAP to the right though I can see cells with activity in this category. But these cells are not really localized as a cluster, but more spread over multiple regions.

My question is therefore, can I trust AUCell with this value, or do I need to manually assign a lower AUC score to this cell-type. How would I choose a "better" score?

thanks