Autologous transfusion recovery of WBC-reduced high-concentration platelet concentrates

In vivo recovery and survival of apheresis and whole blood-derived platelets: a paired comparison in healthy volunteers

BACKGROUND

Methods of platelet preparation may alter the recovery and survival characteristics of platelets following transfusion. As suggested by a recent clinical trial, platelet recovery may be better preserved with apheresis platelet preparations than with platelets prepared from whole blood by the platelet-rich plasma (PRP) method.

STUDY DESIGN AND METHODS

In vivo platelet recovery and survival of autologous leukoreduced (LR) apheresis platelets and autologous filter-LR PRP platelets were compared in 22 healthy volunteers using a paired crossover design. On the same day, each participant gave one apheresis platelet donation and one whole blood donation from which platelets were recovered from the PRP. The sequence of donations was randomly assigned for each participant. Following 5 days of storage and bacterial screening, a sample from each platelet product was labeled with either (51)chromium or (111)indium (randomly assigned) and both samples were simultaneously re-infused into the original donor. Recovery and gamma-function platelet survival were calculated for each platelet product using the multiple hit mathematical model.

RESULTS

Five day stored LR-apheresis platelets had 18.8 percent better recovery, and 32.9 percent longer gamma-survival than filter-LR PRP platelets. Stored apheresis platelets had lower p-selectin expression and higher morphology scores than stored PRP platelets.

CONCLUSIONS

Filter-LR PRP platelet preparation appears to adversely affect platelet recovery and survival characteristics. The reasons for this effect are not clear. These results may not apply to all apheresis and PRP methods of platelet preparation.

Platelet activation and residual activation potential during storage of hyperconcentrated platelet products in two different platelet additive solutions

BACKGROUND

To improve platelet (PLT) quality, hyperconcentrated PLT concentrates (hcPCs) were compared to standard PLT concentrates (stdPCs) in two different PLT additive solutions, T-Sol and PAS-27a. PAS-27a differs from T-Sol by containing glucose, phosphate, potassium, magnesium, and bicarbonate.

STUDY DESIGN AND METHODS

PLTs were harvested by apheresis twice from 14 donors; each unit was divided into two. Four units from each donor were produced: hcPCs, 2000 x 10(9) per L in T-Sol or PAS-27a; and stdPCs, 1400 x 10(9) per L in 65 percent T-Sol or PAS-27a and 35 percent acid citrate dextrose-plasma. On Days 1 through 4, swirling was scored and PLT count, mean PLT volume, pH, blood gas, glucose, and lactate were measured. Expression of CD42a, CD62P, CD63, and PAC-1 was analyzed by flow cytometry on resting PLTs and PLTs stimulated with thrombin receptor agonist peptide (TRAP).

RESULTS

Glucose consumption and lactate production were significantly higher in hcPCs stored in PAS-27a than in T-Sol. Both stdPC and hcPC PLTs in T-Sol expressed CD62P and PAC-1 significantly higher than in PAS-27a. Over time the T-Sol hcPCs revealed highest expression of CD62P and CD63. A significantly higher capacity for up regulation of CD62P, CD63, and PAC-1 upon TRAP stimulation was found for stdPCs and hcPCs in PAS-27a compared to PLTs in T-Sol. TRAP-stimulated PLTs in stdPCs and hcPCs suspended in PAS-27a showed significantly higher potential for down regulation of CD42a than the T-Sol concentrates.

CONCLUSIONS

PLTs appear better preserved in vitro in PAS-27a than in T-Sol, and this suggests that storage of hcPCs in PAS-27a could be extended beyond 24 hours.

Recovery and life span of 111 indium-radiolabeled platelets treated with pathogen inactivation with amotosalen HCl (S-59) and ultraviolet A light

BACKGROUND

A photochemical treatment (PCT) method to inactivate pathogens in platelet concentrates has been developed. The system uses a psoralen, amotosalen HCl, coupled with ultraviolet A (UVA) illumination.

STUDY DESIGN AND METHODS

Three sequential clinical trials evaluated viability of PCT platelets prepared with a prototype device. Posttransfusion recovery and lifespan of (111)Indium-labeled autologous 5 day-old platelets in healthy subjects was assessed. In the first study, 23 subjects received transfusions of autologous PCT and/or control platelets. In a second study, 16 of these subjects received PCT platelets processed with a Compound Adsorption Device (CAD) (PCT-CAD) to reduce patient exposure to residual amotosalen. In the third study, the effect of gamma-irradiation on PCT platelets was studied. Data from control transfusions from Study A were used for paired comparisons in the latter 2 studies.

RESULTS

Mean PCT-CAD platelet recovery for the 16 subjects with paired data was 42.5 +/- 8.7% versus 50.3 +/- 7.7% for control platelets, mean difference of 7.8% (p < 0.01). Mean lifespan for PCT-CAD platelets was 4.8 days (+/-1.3) versus 6.0 days (+/-1.2) for control platelets, mean difference of 1.3 days (p < 0.01). Platelet recovery and lifespan were similar to PCT-CAD for PCT without CAD treatment and PCT-CAD with gamma-irradiation.

CONCLUSION

Viability of 5 day-old PCT platelets was less than for control platelets. However, both were within ranges reported for 5 day-old platelets.