Yes, Roz. The cell to cell signals are mediated by Cytokines.
These are short range hormonelike substances.

Thromboxane initiates platelet actions during trauma.
Leukotrienes initiate the release of histamine from mast cells and signal the immune system to fight invaders.

There are families of these substances. PGE1s, PGE2s, PGE3s, etc. All with certain functions. The Series One type are for homeostatis, and the Series 2 type are mostly for inflammation
and response to trauma and stress, the Threes, are mixed.
There a just an amazing array of others.

The body favors PGE1s on a daily basis IF and only IF certain nutrients are available to make them. This is Omega-3 territory, alpha linolenic acid, from nuts and seeds..like flax.
The Omega-6 fats come from plants also, and favor making the PGE2s. When the diet is too low in Omega-3, then we don't do well...we get stuck in the inflammatory side and that causes inflammation, blood clots, allergies etc. So a balance is needed.

So far using DRUGS on this system has brought some failures.
Cox-2 inhibitors which block PGE2 inflammation and arthritis pain, fail and Vioxx actually killed people because one of the PGE2 cytokines is a vasodilating agent..the body uses in trauma (swelling), but also keeps our coronary heart arteries open. Singulair which blocks leukotrienes and reduces allergy, and asthma, will also fail to signal when bacteria get out of control in the lungs, and the result may be pneumonia and death. NSAIDs like ibuprofen work in the short term for swelling for pain, but if taken for over 6 wks in a row, they actually block healing PGE2s that we need for tissue repair.
(they are good and bad both).

In the end, it is balance we need. Our bodies will balance if we provide them with the proper nutrients. So far drugs for these systems have not worked very well.

Bacteria stimulate the release of many cytokines so our bodies will survive. Leukotrienes to motivate white cells, and PGE2s for swelling (increasing blood flow) of the area.