![Figure 1. Four MM patients with HIT complicating heparin flush exposure associated with stem cell harvesting for planned aSCT. (A) Platelet counts for 101 MM patients undergoing stem cell harvesting (without cyclophosphamide stem cell mobilization) pre-aSCT; box and whisker plots indicate the platelet count values (median, interquartile range [IQR], 1.5 × IQR, and outliers [open circles]) for 97 non-HIT MM controls at 3 time points: (1) apheresis catheter placement (start of heparin flushes), (2) immediately prior to stem cell harvesting, and (3) and time of scheduled aSCT. The corresponding platelet count values for the 4 patients with HIT are shown as colored solid circles (green, patient 1; purple, patient 2; red, patient 3; and blue, patient 4). The outlier data point indicated by an asterisk (*) represents a control patient whose platelet count was only 40 × 109/L at time of stem cell harvesting; the thrombocytopenia, which was attributed to possible line infection, had resolved by the time of aSCT 2 weeks later (platelet count, 369 × 109/L). For the 97 controls, there was a median (IQR) interval of 6 (5, 9) days between apheresis catheter insertion and stem cell harvesting and a median (IQR) interval of 23 (22, 29) days between catheter insertion and admission for subsequent aSCT. (B) Clinical courses of 4 MM patients who developed HIT. Shown for each patient are the sequential platelet counts (including nadir values), thrombosis occurrence (3 of 4 patients developed right upper-limb deep vein thrombosis [DVT]), and anticoagulants given. Patient age (in years) is given prior to designation of patient sex (F, female; M, male). (C) Summary of HIT assay results. The 4 patients had strongly positive results in all 4 HIT assays: (1) SRA (maximal percent serotonin release at 0.1 and/or 0.3 IU/mL UFH; for all patients, serotonin release was <10% at 100 IU/mL UFH and in the presence of the Fc receptor–blocking monoclonal antibody IV.3), (2) in-house IgG-specific enzyme immunoassay (EIA-IgG), (3) commercial polyspecific enzyme immunoassay that detects antibodies of IgG, IgA, and/or IgM istotypes (EIA-GAM), and (4) latex immunoturbidimetric assay (LIA). AL amyl., amyloid light-chain amyloidosis; F, female; Fx, fondaparinux; LMWH, low-molecular-weight heparin; M, male; OD, optical density; Pos, positive; RUL DVT, right upper-limb deep-vein thrombosis.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/130/14/10.1182_blood-2017-06-788679/4/blood788679f1.jpeg?Expires=1735506038&Signature=fVh~t8yClzVFQr6spHAP9Z6k~bhuTrxa0W5CB~OFzCF32O022REBFO8LkwZ3W0fNCbO9muefS-TRch3YDuxoIRygTSDXhubiYz3K1E06FxUdnMClyiZWsLS5Kc86zwYwf24oUvTAJ51QSd9tPnYQ3REmAfL4ayg1LmdAmKnadsb6v-ECM~9I2SU6cH6DYM71Hjfj5oa5wAjL2b~EPmztIJCCLutr3H~ga9cUKULoaE3lnFzykf9CQi1YAdtzfUkL4ZI0mg1cH7BkzctdSNzEwd7MZ~W6rEQB1uTVRjSn8JbcmLvMd88t9ocq5l0YkO9zYVTU~4vqxFuKoMAXk2Hm9Q__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Four MM patients with HIT complicating heparin flush exposure associated with stem cell harvesting for planned aSCT. (A) Platelet counts for 101 MM patients undergoing stem cell harvesting (without cyclophosphamide stem cell mobilization) pre-aSCT; box and whisker plots indicate the platelet count values (median, interquartile range [IQR], 1.5 × IQR, and outliers [open circles]) for 97 non-HIT MM controls at 3 time points: (1) apheresis catheter placement (start of heparin flushes), (2) immediately prior to stem cell harvesting, and (3) and time of scheduled aSCT. The corresponding platelet count values for the 4 patients with HIT are shown as colored solid circles (green, patient 1; purple, patient 2; red, patient 3; and blue, patient 4). The outlier data point indicated by an asterisk (*) represents a control patient whose platelet count was only 40 × 109/L at time of stem cell harvesting; the thrombocytopenia, which was attributed to possible line infection, had resolved by the time of aSCT 2 weeks later (platelet count, 369 × 109/L). For the 97 controls, there was a median (IQR) interval of 6 (5, 9) days between apheresis catheter insertion and stem cell harvesting and a median (IQR) interval of 23 (22, 29) days between catheter insertion and admission for subsequent aSCT. (B) Clinical courses of 4 MM patients who developed HIT. Shown for each patient are the sequential platelet counts (including nadir values), thrombosis occurrence (3 of 4 patients developed right upper-limb deep vein thrombosis [DVT]), and anticoagulants given. Patient age (in years) is given prior to designation of patient sex (F, female; M, male). (C) Summary of HIT assay results. The 4 patients had strongly positive results in all 4 HIT assays: (1) SRA (maximal percent serotonin release at 0.1 and/or 0.3 IU/mL UFH; for all patients, serotonin release was <10% at 100 IU/mL UFH and in the presence of the Fc receptor–blocking monoclonal antibody IV.3), (2) in-house IgG-specific enzyme immunoassay (EIA-IgG), (3) commercial polyspecific enzyme immunoassay that detects antibodies of IgG, IgA, and/or IgM istotypes (EIA-GAM), and (4) latex immunoturbidimetric assay (LIA). AL amyl., amyloid light-chain amyloidosis; F, female; Fx, fondaparinux; LMWH, low-molecular-weight heparin; M, male; OD, optical density; Pos, positive; RUL DVT, right upper-limb deep-vein thrombosis.
