L-carnitine improves pH and decreases surface phosphatidylserine expression in extended stored apheresis platelets.

Extension of the storage period of apheresis platelets to seven or ten days may be possible with the implementation of screening for bacteria. This, however, may impair platelet quality, and additive compounds that improve storage parameters would be desirable. Apheresis platelets were harvested using the Cobe LRS device. Part of the product was aliquoted into two CLX bags, 60 ml into each, on day 0. L-carnitine (LC) to a final concentration of 5 mM was added to one container and saline to the other. pH, morphology score, and surface expression of phosphatidylserine were measured on day 1, and, in addition, hypotonic shock response (HSR) and the extent of shape change (ESC) on days 5, 10, and 13. Differences between test and controls were analyzed using paired t-tests. The addition of LC improved pH by day 5, but was more evident by days 10 and 13. By day 10, significant differences (<0.01) were observed in pH (6.54 +/- 0.3 vs. 6.75 +/- 0.3), lactate (176 +/- 31 vs. 150 +/- 24 mg %), morphology score (213 +/- 27 vs. 229 +/- 35) and ESC (7 +/- 6 vs. 11 +/- 6). Percent surface phosphatidylserine expression was less in the LC treated platelets (16 +/- 7 vs. 12 +/- 4, P<0.03). Much of the benefit observed was attributable to improved parameters in some donors. LC improves the quality of extended stored apheresis platelets.

Prestorage pooled whole-blood-derived leukoreduced platelets stored for seven days, preserve acceptable quality and do not show evidence of a mixed lymphocyte reaction.

BACKGROUND: Prestorage pooling of whole-blood-derived PCs (WBD-PCs) would be advantageous to transfusion services in that it would make the product available in a more timely manner, reduce wastage of untransfused pools, and simplify bacterial screening by allowing testing of the pool rather than each single PLT concentrate (PC). STUDY DESIGN AND METHODS: Four to six individual leukoreduced PCs were pooled into a 1.5-L CLX-HP PLT storage bag using a sterile connecting device. Controls were individual prestorage leukoreduced PCs that were stored as single products. Products were sampled on Days 5 and 7 for measures of PLT quality; coagulation, fibrinolytic and complement activation; and for evidence of a mixed lymphocyte reaction. RESULTS: The pH level was well maintained to Day 7 with no prestorage pool having a pH below 6.7. Day 7 studies showed no evidence of coagulation or difference in complement activation. F1.2 levels did not differ between Days 5 and 7, but a 10- to 15-percent increase in C3a des-Arg was observed between these days in all product types. Day 7 activated lymphocyte surface markers (CD69, CD71, HLA-DR) were all at lower limits of detection in the prestorage pooled products, and levels of supernatant cytokines were either not different between product types on either study day or, if different, were lower in the prestorage pooled products. CONCLUSION: There is no evidence of a deterioration in quality, activation of coagulation or complement, or a mixed lymphocyte reaction attributable to the prestorage pooling process with up to 7 days of storage.

Redirected T-cell cytotoxicity to epithelial cell adhesion molecule-overexpressing adenocarcinomas by a novel recombinant antibody, E3Bi, in vitro and in an animal model.

BACKGROUND: To redirect cytotoxic T cells to target a broad range of adenocarcinomas, the authors constructed a novel, recombinant, bispecific antibody, E3Bi, directed at the tumor-associated antigen, epithelial cell adhesion molecule (EpCAM), and the CD3 receptor on T cells. METHODS: T cells were prepared from healthy blood donors. The cytotoxicity of activated T cells (ATC) redirected to tumor cells by E3Bi was measured with in vitro (51)Cr release assays. In vivo studies were performed in a severe combined immunodeficient (SCID)/Beige mouse xenograft model. Tumor-bearing mice were treated with low doses (1 mg/kg) or high doses (10 mg/kg) of E3Bi along with ATC (2 x 10(9) cells/kg), and treatment efficacy was evaluated both by ex vivo tumor cell survival assay after in vivo treatments and by in vivo tumor growth delay studies. RESULTS: In vitro, targeting the EpCAM-overexpressing human tumor cell lines with E3Bi increased specific cytotoxicity of ATC by > 70% at an effector-to-target ratio of 2.5 (P < 0.001); this cytotoxicity was abolished competitively in the presence of an anti-EpCAM monoclonal antibody. In contrast, E3Bi did not enhance ATC cytotoxicity toward the low EpCAM-expressing tumor cell line. In ex vivo tumor cytotoxicity assays, a significant reduction in tumor cell survival (40% with low-dose E3Bi; 90% with high-dose E3Bi) was observed in E3Bi/ATC-treated mice compared with control mice that were treated with ATC only. In addition, SCID/Beige mice xenografted with LS174T tumors demonstrated a significant tumor growth delay (P = 0.0139) after receiving E3Bi/ATC/interleukin 2 (IL-2) compared with mice that received ATC/IL-2 alone. CONCLUSIONS: E3Bi specifically and very efficiently redirected T cells to destroy EpCAM-overexpressing tumors both in vitro and in an animal model. These results suggest a therapeutic utility for E3Bi in the treatment of adenocarcinomas.