Wrong test for Specific Antibody Deficiency?

[greg]

Hello,

my immunologist gave me pre- and post- pneumovax (23-valent pneumococcal vaccine) antibody titres, testing for Specific Antibody Deficiency. With the results back, I find out that only total IGG titres were done-  serotype specific titres were not measured. I have read a lot of literature around 'SAD' and it all refers to serotype specific tests, since SAD is defined as an adequate response to <70% of serotypes. Some sources state that total response/IGG is not useful, as a high response could be due to half of the serotypes, with poor responses to the rest.

I am concerned that I have been given the wrong test and - worse- that the opportunity to rule out SAD has been lost because I can no longer be tested for baseline (pre vaccine) serotype specific antibodies.

My background is recurrent infections since childhood with better and worse years: mostly bronchitis, but also pneumonia(+/-sepsis), and upper respiratory. Always with slow recovery and multiple courses of strong antibiotics (or IV antibiotics) needed to clear. My overall antibody, B/T cell and complement levels are normal.

Has anyone heard of being tested for total IGG pneumococcal and not serotype specific? Has my diagnosis been confounded?

Thanks

[s162216]

Hi Greg,

As far as I know (I did a Pharmacology degree, not Biomedical Science which would cover this sort of thing in more detail) there should be a report on each specific pneumococcal subtype as I had one of those tests a few years ago (which found I only had 1 subtype present initially, and only responded adequately to that 1 subtype after the immunisation). In theory they should have the results for the pre- blood sample and so long as they did the specific subtype testing then you still have a reference value so they could do the post- blood sample again.

The results that you've got might be the initial results though as I do know that it can take time to get back a lot of immunology tests, especially if their not very frequently requested. Those total results are also useful as they can help diagnose/rule out IgG subclass deficiency which is always another possibility.

Hope you find this helpful,

Sam

[aryani]

Hi Greg,

In addition to Sam's remarks. I had a pre- and a post- blood sample test. It took about a month to get the results for the specific subtypes. The results for IgA/IgE/IgG and IgM and the IgG-subclasses came in a lot quicker. But some other test took even longer (about 6/8 weeks). I have been tested for Haemophilus Influenza B (Hib-b) as well (vaccinated, and pre- and post blood sample test). After a month, my response to the pneumovax-23 was adequate, and just below normal for Hib-b. But....after a year the response was gone. So, if your response is adequate now and you develop complaints within a relatively short period, you might still suffer from a PID.

I hope this helps a bit....

Aryani.

[greg]

Thanks for your thoughts, Sam and Aryani.

I chased the lab directly and found they don't do serotype-specific tests. Luckily, they had not discarded my samples, so the correct tests can still be done (via another lab that does it). I agree, a follow up after 6-12 months might be another one worth lobbying for, in case I have a similar poor 'memory'.

Since CVID and other candidates have been ruled out, an alternative angle (should repeat tests look ok) is atypical cystic fibrosis, but that's another story.

Cheers