Table 3.
Reduction of DSA through desensitization
| Pt. no. | No. of PP/IVIG | DSA HLA specificity | Additional risk factors | Pretreatment DSA level | % DSA reduction end of PP | % DSA reduction F/U | DSA levelbF/U | Time of DSA F/U (mos.) |
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| 1 | 7 | B7 | Child to mother | vFCXM+ | 93.9 | ND | ND | ND |
| 2 | 5 | DPI | vFCXM+ | 59.5 | 93.8 | Neg | 12 | |
| 3 | 3 | A2 | Child to mother | vFCXM+ | 33.1 | 96.0 | Neg | 6 |
| 4 | 3 | DR13, DR52, DQ6 | Multiple DSA | FCXM+ | 86.0 | 99.1 | Neg | 7 |
| 5 | 5 | DR16 | FCXM+ | 52.1 | 96.9 | Neg | 1 | |
| 6 | 4 | DQ4 | FCXM+ | 44.3 | 73.0 | Neg | 6 | |
| 7 | 7 | A2 | DSA level | CDC XM+ | 64.7 | Not Tx | Neg | 6 |
| 8 | 3 | A3, B27 | Multiple DSA | FCXM+ | 74.0 | 99.9 | Neg | 2 |
| 9 | 11 | DR4, DR53 | Repeat mismatches | FCXM+ | 77.4 | 98.4 | Neg | 1 |
| 10 | 1 | A2, Cw4, B35 | Multiple DSA | FCXM− | 41.2 | 95.1 | Neg | 1 |
| 11 | 4 | A1, B8 | Multiple DSA | FCXM+ | 92.4 | 98.3 | Neg | 1 |
| 12 | 1 | A68 | DSA increasea | FCXM− | 65.1 | 75.6 | Neg | 1 |
| 13 | 10 | A26, DP2 | FCXM+ | 52.4 | 62.7 | Low Level | 3 | |
| 14 | 6 | B51, Cw15 | FCXM+ | 40.2 | 59.0 | Low Level | 2 | |
| 15 | 1 | B37 | DSA increasea | FCXM− | 51.5 | 91.7 | Low Level | 1 |
| Mean | 64.4 | 85.5 | ||||||
| SD | 15.7 | 14.4 | ||||||
Abbreviations: CDC XM=complement-dependent cytotoxicity crossmatch; DSA=donor HLA-specific Ab; FCXM=flow cytometric XM; F/U=follow-up; MFI, median fluorescence values; ND=not done; PP/IVIG=plasmapheresis and i.v. Ig treatments; Tx=transplanted; vFCXM=DSA levels consistent with a positive FCXM; XM=crossmatch.
To control for interassay variation, the MFIs were expressed as a ratio to the positive control value in each assay. The percentage of Ab reduction from the pretreatment level was determined using these normalized values. Patient no. 7 was not transplanted as desensitization did not reduce the DSA below a positive FCXM level.
The DSA increase was before the initiation of desensitization.
The relative DSA level at last follow-up Ab testing is given. Neg= DSA that was undetectable or below the level considered positive; low level=MFI values for DSA were well below a level consistent with a positive FCXM, that is, MFI <3000 for HLA-A, -B and -DR Ags, with higher values for HLA-C, -DQ and -DP.