Hi Martyn,
Being 'Asplenic' just means you have had your spleen removed for one reason or another. Many people who have damaged spleens...i.e through road traffic accidents etc.... have to have them removed. If the spleen is ruptured for any reason you can very quickly bleed to death.
In the case of CML, the spleen becomes involved as the disease progresses to more advanced stage..as in my own case, my spleen was very enlarged when I was diagnosed which is why my doctors considered my disease was quite advanced even though my wbc was only 17! I later learned that this was because most of my CML cells had taken up residence in my spleen which was why it was so swollen.
This was a good few months before the phase ll trials for imatinib (then STI571) were due to open in the US. I was due to go for transplant and so my spleen was taken out for safety as well as clinical reasons.
I am not aware that pre-conditioning chemotherapy would have adversely affected your spleen- you did not have TBI so I cannot see why your spleen would be under-functioning and therefore affecting your immune response. I was told be a couple of haematologists who worked in the Asia/pacific region that they did not routinely give anti-biotic cover to their asplenic patients because the bacteria strains in question were already resistant.
Really this is entirely down to you and how you feel. You could just keep on having the conversation with your consultant and get to the bottom of why you are now being advised to do this 5 years down the line from transplant with your spleen intact!... is it that you are really at risk (like we all are) from this kind of opportunistic and very serious bacterial infection (which is I believe resistant to all antibiotics presently in use- which is why it is so difficult to treat) or is it that doctors in general are becoming more and more risk averse and are taking steps to cover themselves should you pick up this strain of bacteria. It is a risk we all take- life is full of them...
on questioning my doctor did admit that it was rare- but more of a risk for those without spleens.
Try a search on this subject- I am sure there are lots of articles on the web, which might or might not change your mind. Always best to be fully informed ;o)
Good to hear you are doing so well by the way,
best.. Sandy