splenectomy and chemotherapy

Bump- I hope that someone can answer this for you.

Good luck to you.

A brief history of immunology, as it relates to splenectomies and chemotherapy...

The biggest health risk with either splenectomy or chemotherapy is the increased susceptibility to bacterial infections.  Viruses are not such a big problem, because they're handled through mechanisms that aren't as messed up by splenectomy or chemo.  But bacterial infections can be killers, especially if they aren't contained quickly and are able to spread into the blood ( = bacteremia or septicemia).  That's why our oncos pay so much attention to our white blood cell (WBC) count and to whether or not we have a fever during chemo.

So, what does that have to do with hulatalulala's question?... 

Well, the spleen is the #1 most important place in the body for removal of bacteria that happen to get into the blood stream.  Billions of macrophages are parked in the spleen, just waiting for bacteria to come tumbling along in the blood, so they can gulp them up and kill them. There really is no better way to get rid of blood-borne bacteria, than to have them cleared by those cells in the spleen.  So, someone who does not have a spleen does not have that nifty mechanism, and must rely on a combination of other, less-effective mechanisms to do the job.

Okay, so how about chemo?  Well, once again, it's bacteria that pose the greatest threat to those of us who are getting chemo.  That's because chemo kills many types of rapidly growing cells -- not just tumor cells, but also young, developing WBC that are in the bone marrow.  The immature WBC that are most likely to be killed off incidentally by chemo are the ones with the shortest lifespans, and those would be the neutrophils.  That's why oncos pay particular attention to our "ANC" during chemo.  That's the "absolute neutrophil count," which is the relevant part of the WBC as far as chemo is concerned.  When the chemo drugs kill off our immature neutrophils, our ANC goes down ... and so does our ability to fight off bacterial infections.

How does this all fit together?  Turns out, neutrophils are the most important mechanism for capturing and killing bacteria that are not in the blood.  And, since most infections start out in the skin or the membrane of the nose or the bladder lining or somewhere other than the blood, those neutrophils can often stop things before they get out-of-hand.  But, if there aren't enough neutrophils ('cause chemo has put a dent in the population), the infection often can't be controlled at that early stage and the bacteria can multiply and spread into the blood. Once they're in the blood, the situation can become deadly unless 1) the bacteria can be cleared by macrophages in the spleen, or/and 2) we get put on a powerful antibiotic -- quickly.  The most effective antibiotics in situations like this are the ones that must be given i.v., which means a hospital stay.

Class is dismissed.

otter 

I agree, Otter has a gift for explaining things well, and I think she provides clear, careful, and thoughtful analyses.  We are so lucky to have her on this board.