Two patients with spontaneous HIT syndrome
| Patient no. (age in years, gender) . | Day of blood sample . | SRA % serotonin release at different UFH concentrations (IU/mL) . | PF4-dependent EIAs, absorbance, OD units (absorbance at high heparin) . | |||||
|---|---|---|---|---|---|---|---|---|
| 0 . | 0.1 . | 0.3* . | 100 . | EIA-IgG, McMaster (negative < 0.45) . | EIA-IgG, Immucor GTI (negative < 0.40) . | EIA-IgG/A/M Immucor GTI (negative < 0.40) . | ||
| 1 (62, M) | Day 0 † | 100‡ | 100‡ | 100 | 0 | 1.83 (0.29) | 1.06 (0.07) | 0.95 (0.130) |
| Day 14 | 0 | 12 | 61 | 0 | 1.14 (0.30) | 0.47 (ND) | 0.54 (ND) | |
| 2 (54, F) | Day 0 † | 81§ | 100§ | 100 | 0 | 2.89 (0.48) | 2.87 (0.125) | 2.80 (0.23) |
| Day 28 | 2 | 81 | 100 | 0 | 2.58 (0.46) | 2.98 (ND) | 2.73 (ND)¶ | |
| Patient no. (age in years, gender) . | Day of blood sample . | SRA % serotonin release at different UFH concentrations (IU/mL) . | PF4-dependent EIAs, absorbance, OD units (absorbance at high heparin) . | |||||
|---|---|---|---|---|---|---|---|---|
| 0 . | 0.1 . | 0.3* . | 100 . | EIA-IgG, McMaster (negative < 0.45) . | EIA-IgG, Immucor GTI (negative < 0.40) . | EIA-IgG/A/M Immucor GTI (negative < 0.40) . | ||
| 1 (62, M) | Day 0 † | 100‡ | 100‡ | 100 | 0 | 1.83 (0.29) | 1.06 (0.07) | 0.95 (0.130) |
| Day 14 | 0 | 12 | 61 | 0 | 1.14 (0.30) | 0.47 (ND) | 0.54 (ND) | |
| 2 (54, F) | Day 0 † | 81§ | 100§ | 100 | 0 | 2.89 (0.48) | 2.87 (0.125) | 2.80 (0.23) |
| Day 28 | 2 | 81 | 100 | 0 | 2.58 (0.46) | 2.98 (ND) | 2.73 (ND)¶ | |
Neither patient had laboratory evidence for microangiopathic hemolysis, vasculitis, or antiphospholipid antibodies (negative anticardiolipin and β2-glycoprotein-1 immunoassays, and normal dilute Russell viper venom time).
ND, not done.
For both patients, % serotonin release was inhibited to 0% at 0.3 IU/mL UFH with Fc receptor-blocking monoclonal antibody (data not shown).
Day 0 represents day of admission, with blood sample obtained before any administration of heparin.
Heparin-dependent platelet activation was evident using one-quarter diluted serum: 37% serotonin release at 0.1 IU/mL UFH vs 0% release at 0 IU/mL heparin (insufficient serum was available to test at one-half diluted serum).
Heparin-dependent platelet activation was evident using one-eighth diluted serum (94% serotonin release at 0.1 IU/mL UFH vs 18% serotonin release at 0 IU/mL heparin) and using one-sixteenth diluted serum (85% serotonin release at 0.1 IU/mL UFH vs 3% release at 0 IU/mL UFH).
For patient 2, subsequent results in the EIA-IgG/A/M (Immucor GTI) were as follows: 0.95 (day 100) and 0.25 (day 240).