How long the second immunization will need to induce antibody?

[Yanxia]

There is a question about how often we need to do antibody screening test, so I want to know what antibody is induced the fastest than other in the first and second immunization respectively and how long will it need .

Thanks in advance!

[bbbirder]

Shily,

AABB standards say a new specimen (and new antibody screen) is needed every three days.

I don't have the references, but I am sure there were studies supporting this time for the detection of newly formed antibody. Some anemnistic responses can be faster than 3 days.

For initial antibody formation after exposure, I think it can vary with the antigen/antibody, some are days and some are weeks.

[Yanxia]

Thank you, bbbirder.

As you say some anemnistic responses( sorry, I don't know what is the meaning of anemnistic. I guess it is the same as second responses, is it right?) can be faster than 3 days, why don't we do the testing less than 3 days if the patient need transfusion everyday or the distance is less than 3 days?

Thank you again for the quick response.

[Mabel Adams]

Yes, anamnestic means a secondary response, particularly if the antibody titer had become too low to detect prior to the second stimulation. It probably varies greatly between patients, antigens and other concurrent factors. AABB used to require new specimens after 2 days, although I think that had more to do with the persistence of complement in the serum. The 3 day rule is a compromise between the use of resources to repeat testing on a patient every day and the risk of antibody formation over a short period of time. The level of compatibility problems found with the 3 day rule is considered an acceptable risk.

[Yanxia]

Thank you, Mabel.

[rcurrie]

The story I was told was that the 3-day rule came from a desire to not have to perform repeat compatibility testing over the weekend, and is thus completely arbitrary, to allow a specimen collected on Friday to be good until Monday.

BC

[Mabel Adams]

The blood bank world should collect data on the number of patients with newly detectable antibodies within 4 days of a confirmed negative antibody screen. Particularly interesting would be any that had not been transfused during that 4 day period, but maybe had been over the 3 months prior to the first specimen being drawn.

If we ever get any nationwide data collection system (like biovigilance or error reporting) there should be a way to also collect data on some rare events like this that no one facility would see too many of by themselves.

[galvania]

There was a paper in 'Transfusion' fairly recently (Red Cell Antibodies after transfusion: factors influencing incidence and specificity. Transfusion 46:250-256) that, as the title suggests, looked at antibody formation after transfusion. They looked at 1710 immunized patients. They found that:...'in 299 (16.8%) of all immunized patients, new antibodies were detected within 14 days after transfusion and in 1479 patients (83.2%) after more than 14 days....Eleven of 2932 patients (0.4%) retested up to 3 days after transfusion had formed a new antibody'

I'm not sure whether in the biggest group of patients the reason was that they made antibodies later, or whether they were just tested later - I've only got the abstract here in front of me. I'll go and look for the full article later and see if it clarifies things

Anna

[galvania]

Me again. I've now got the original paper in front of me - it's from Feb 2006 (so not that recent - why does time seem to go so much more quickly as we get older!!??). this is a really interesting paper (not sure if it's available on-line) because it shows that some antibodies seem to take a really long time to develop while others develop really quickly. Also seems to confirm that 3 days is about right, even though there might be a 'small risk' involved in not testing sooner.

Anna

[Yanxia]

Galvania, does "new antibodies"you mentioned above means first response or first and secondary response? Thank you!

[galvania]

Both 'old' and 'new'