Case Scenario: Crossmatch Is Positive, What to do?
Case Study: 50 y/o male with ADPKD presents with ESRD and progressive renal failure and has a creatinine of 5, after your counselling he is planning a pre-emptive transplant with his wife as donor. Rest of his workup is normal. Immunological workup is below.
| Sensitization History | None | |||||
| HLA Typing | A | B | C | DR | DQ | DP |
| Donor (O-) | 02:03, 24:02 | 38:02, 49:01 | 07:01, 07:02 | 13:01, 15:02 | 05:01, 06:03 | 02:01, 04:01 |
| Recipient (A+) | 02:01, 02:03 | 13:01, 15:02 | 04:03, 08:01 | 12:02, 12:02 | 03:01, 03:01 | 13:01, 13:01 |
| XM | T cells | B Cells | ||||
| CDC XM | Negative | Negative | ||||
| Flow XM | Negative | Positive | ||||
| Single Antigen Bead | Class I : No anti HLA Abs | Class II: No Anti HLA Abs. |
Questions & Answers
Q1. How is a Flow XM done?
Ans: Donor cells incubated with recipient sera, then anti-IgG flouroescent tag added. Then placed in flow cytometry. If anti-donor cells IgG antibodies present then fluorescence noted and mean channel shift notes the degree of positivity. T for class I, B for class I and II.
Q2. Why is this Flow XM positive?
Ans: “Sticky” B cell
Q3. What may be causes of false positive Flow XM?
Ans: Sticky B cell, IgG autoantibodies
Q4. What may be causes of false negative Flow XM?
Ans: Low level antibody, poor technique.
Q5. What does a positive Flow XM predict?
Ans: Predicts AMR during transplant
Q6. What will you do for this transplant pair?
Ans: Move forward for transplant.
