Case Scenario: Single Antigen Bead is positive, is it donor specific?
Case Study: 40 y/o Female with ESRD (Ankita) and on dialysis for 1 month with unknown etiology, with her husband as donor. Rest of her workup is normal. Immunological workup is below.
| Sensitization History | 2 Pregnancies | |||||
| HLA Typing | A | B | C | DRB1 | DQB1 | DQA1 |
| Donor | 02:11, 24:07 | 08:01, 52:01 | 03:01, 10:01 | 02:01, 05:01 | 01:01, 01:01/04 | |
| Recipient | 11:01, 24:02 | 35:03, 51:01 | 04:04, 13:01 | 03:02, 06:03 | 01:03, 03:01 | |
| XM | T cells | B Cells | ||||
| CDC XM | Positive | Positive | ||||
| Flow XM | Positive | Positive | ||||
| Single Antigen Bead SAB Report 1 – Click to view |
Class I : Multiple anti HLA Abs | Class II: Multiple Anti HLA Abs. |
Questions & Answers
Q1. Which of the class I HLA antibodies are donor specific?
Ans: B*8:01 is positive, B52:01 is negative.
Q2. As we cant find the HLA A*24:07 and A*02:11 in the single antigen bead panel, how do we know if the Anti-HLA antibodies present in the recipient are going to react with this HLA allele?
Ans: A:02:11 is likely positive, A24*07 is likely negative. Can use HLA matchmaker or HLA lab to assess for whether it is Donor specific or not.
Q3. How can we know if the single antigen bead report is valid and not due to some random cross reactivity with the beads?
Ans: Look for self antigens, they should be negative. If they are positive, usually will be due to some background cross-reactivity, and can either repeat or if only for one antigen like C then can use those as negative threshold.
Q4. Are HLA C antibodies, important or can we ignore those antibodies? Do I really need to get HLA C typing?
Ans: Yes, important if present and then will need HLA C typing. If no HLA C antibodies then typing at present not important, but may be important later and so would consider typing all loci as price now same for 3 and 6 loci.
