Table 1:
Patient Characteristics
| Cohort (N=25) | |
|---|---|
| Age (Years) at Transplant, Median (IQR) | 8.6 (4.2–15.5) |
| Age (Years) at 1st Tocilizumab, Median (IQR) | 17.9 (12.9–19.9) |
| Sex (Male) | 14 (56.0%) |
| Ethnicity (Hispanic) | 12 (48.0%) |
| Race | |
| White | 15 (60.0%) |
| Black | 3 (12.0%) |
| Asian | 1 (4.0%) |
| Other | 6 (24.0%) |
| First Transplant | 22 (88.0%) |
| Panel Reactive Antibody >20%*** | 2 (8%) |
| Deceased Donor | 18 (72.0%) |
| Induction Immunosuppression | |
| IL-2 Inhibitor | 20 (80.0%) |
| ATG | 3 (12.0%) |
| Alemtuzumab | 2 (8.0%) |
| Maintenance Immunosuppression | |
| FK, MMF, Prednisone | 24 (96.0%) |
| FK, Sirolimus, Prednisone | 1 (4.0%) |
| Immunosuppression Risk Prior to AMR Diagnosis | |
| Medication Nonadherence Suspected/Reported | 6 (25%) |
| Physician Directed Medication Reduction | 6 (25%) |
| Pharmacy Error | 1 (4%) |
| Unknown | 12 (48%) |
| Time from transplant to AMR (Months), Median (IQR) | 41.4 (24.3–67.7) |
| Time from AMR to 1st Tocilizumab (Months), Median (IQR) | 10.6 (8.3–17.6) |
| Time from Transplant to Pre-Tocilizumab Biopsy (Months), Median (IQR) | 58.2 (31.5–109.9) |
| Time from Pre-Tocilizumab Biopsy to Tocilizumab Initiation (Months), Median (IQR) | 1.2 (0.6–2.8) |
| Time from Tocilizumab to Last Follow-up (Months), Median (IQR) | 15.8 (8.4–35.7) |
| Number of Doses of Tocilizumab, Median (IQR) | 12.0 (6.0–19.0) |
| Last Follow-up Description | |
| Tocilizumab Ongoing | 15 (60.0%) |
| At time of last dose of Tocilizumab (no adverse event) | 5 (20.0%) |
| At time of last dose of Tocilizumab (due to adverse event) | 3 (12%) |
| Tocilizumab Ongoing but on hold | 1 (4.0%) |
| Graft Loss | 1 (4.0%) |
| eGFR at 1st Tocilizumab, Median (IQR) (ml/min/1.73m2) | 67.3 (55.0–78.0) |
| HLA DSA Positive at diagnosis of AMR * | 23 (92.0%) |
| Pre-Tocilizumab pulse steroids | 21 (84%) |
| Pre-Tocilizumab IVIG | 25 (100%) |
| Pre-Tocilizumab Rituximab | 24 (96.0%) |
| Pre-Tocilizumab Bortezomib | 8 (32%) |
| Pre-Tocilizumab Plasmapheresis | 12 (48%) |
| HLA DSA at 1st Tocilizumab | |
| DQ | 13 (52.0%) |
| DR | 4 (16.0%) |
| A1 | 1 (4.0%) |
| None** | 7 (28.0%) |
| AMR Type at Time of 1st Tocilizumab | |
| Active AMR | 16 (64.0%) |
| Chronic Active AMR | 9 (36.0%) |
| C4d Positive at Time of 1st Tocilizumab*** | 13 (52%) |
| Concurrent ACR at Time of 1st Tocilizumab*** | |
| None | 14 (56.0%) |
| borderline | 5 (20.0%) |
| 1A | 3 (12.0%) |
| 2A | 2 (8.0%) |
| Concurrent IVIG during Tocilizumab therapy | 11 (44%) |
*
The 2 patients negative for HLA DSA had high AT1R-Ab (>17 units/mL)
**
Of these patients, 5 had high AT1R-Ab (>17 units/mL), 1 had AT1R-Ab in the “at risk” range (12 units/mL), and 1 was not tested for non-HLA
***
1 patient missing PRA data. 2 patients missing full biopsy scoring and 1 missing ACR evaluation
AMR: antibody mediated rejection, IL-2: interleukin 2, ATG: anti-thymocyte globulin, FK: tacrolimus, MMF: mycophenolate mofetil, eGFR: estimated glomerular filtration rate, HLA DSA: human leukocyte antigen donor specific antibody, ACR: acute cellular rejection