Crayfish use their native immune system to avoid infections. They produce new stem cells and blood cells (hemocytes) continuously throughout their lifetimes. The hemocytes are produced by stem cells in the hematopoietic tissue and released into the circulation. The release occurs when the cytokine astakine 1 inhibits the crosslinking between TGase in the extracellular matrix in the hematopoietic lobules. The stem cells can differentiate into different types of cells. They mainly differentiate into different types of immune cells, but also a minor population that gets transported to the brain. One of these are neuronal precursor cells that gets transported to the brain. There are several cell-type specific markers that can be used to identify the types of cells produced from the hematopoietic tissue. By injecting astakine, different methods can be used to investigate how this protein is affecting the immune response in the crayfish. In this study, RT-qPCR and RNA-FISH are used to detect different types of cells after an injection of astakine, compared to a crayfish saline injection. Samples are gathered at different time-points after the injection to investigate the effects over time. RT-qPCR measured the total mRNA expression of several cell-type specific markers. This was furthered studied with RNA-FISH to investigate the cause of the change in mRNA expression. In conclusion this study shows some results using only a few replicates, but further studies with more replicates and RNA-FISH as the main method is necessary.