And as for human KCs that were generally characterized as CD68+ TIMD4+ cells, VSIG4 was found to be one of the best human KC markers according to cellular indexing of transcriptomes and epitomes by sequencing (CITE-seq) data, while CD5L, FOLR2, CD163, and CD169 were also useful markers to identify human KCs (28). This evidence concerns the gene FOLR2 and dry eye syndrome.