Comparison of CDC-AHG, C1q-AHG, and standard single antigen bead testing in patients refractory to platelet transfusion

详细信息    查看全文

• 作者：Anne Halpin ; Amiah Klein ; Luis Hidalgo ; Patricia Campbell ; Susan Nahirniak
• 刊名：Human Immunology
• 出版年：2015
• 出版时间：October 2015
• 年：2015
• 卷：76
• 期：supp_S
• 页码：51
• 全文大小：179 K

文摘

Patients refractory to platelet transfusion are tested for class I HLA antibody (Ab). CDC-AHG has been used due to cost, turnaround time (TAT) and clinically appropriate sensitivity for this indication. This study compares CDC-AHG, standard single antigen bead (SAB) testing and C1q-AHG SAB testing to determine if more efficient and clinically relevant methods are available for refractory patients.

Methods

Patients were tested for class I HLA Ab by CDC-AHG (Lambda Cell Tray™), SAB (LABScreen® Single Antigen), and C1q-AHG (C1qScreen™ + wash and AHG); sera were EDTA treated prior to SAB/C1q testing. Sera were also tested by SAB at 1/8 dilution (n = 6) .36 samples were tested from 35 patients.

Results

CDC results were 0% PRA (n = 6), 17–74% (n = 15), and >$>$80% (n = 15). If Ab specificity could be assigned by CDC, these Ab were detected by SAB and C1q but additional specificities were present including in 2 of the patients with CDC 0% PRA. Also, 2 sera had Ab missed by CDC due to difficult tail analysis. There is no clear SAB MFI threshold where Ab is detected by CDC. MFI values of 8000–10,000 consistently result in a CDC positive result although lower values may also do so. Similar Ab were detected by SAB and C1q but there is often a lack of agreement between most reactive beads. The diluted sera suggest better agreement with C1q results; dilution may detect Ab NOT detected by SAB testing as shown in Patient 1. Patient 2 shows no prozone.

Conclusion

It is hard to compare SAB and CDC as cells are phenotypic, readout is subjective, and Ab specificity can’t be assigned if PRA is high. The few diluted samples tested appear to be comparable to C1q but further dilution studies are ongoing. Dilution testing involves less change to current practice of SAB testing and fits easily in work flow, enabling faster TAT. These results represent SAB and C1q-AHG testing in platelet refractory patients, but may be extended to solid organ transplant to investigate the strength of Ab. Platelet transfusion outcomes are available for 10 patients but relevance review is ongoing.