E . A . Hayes et al .: J Extra Corpor Technol 2023 , 55 , 189 – 193 191
Figure 2 . Centrifuged-based plasmapheresis results . A – Reduction in titers of anti-A and anti-B IgG and IgM . B – Reduction in HLA antibodies by average mean fluorescence intensity ( MFI ) at the DQ locus .
AB + donors wase used for the plasma exchange volume . The study was set to complete once 1.5 – 2 plasma exchange occurred or 2 h , whichever came first . Two hours was set as the average transplant time to simulate a true clinical scenario .
Baseline blood samples were analyzed for isohemagglutinin titers ( IT ), Panel Reactive Antibody ( PRA ) panel , complete blood count ( CBC ), and plasma hemoglobin . IT and a PRA panel were performed at 30-minute increments throughout the study . After the study , samples were again sent for final IT , PRA , CBC , and plasma hemoglobin . All samples were stored at four degrees Celsius until completion of the study , at which time they were delivered to the clinical laboratory for analysis .
Results
There was a decrease in anti-A and anti-B IgM and IgG titers as well as a decrease in anti-HLA antibodies with both membrane-based and centrifuge-based plasmapheresis . Both demonstrated similar hemolytic and thrombotic profiles .
Centrifuge-based plasmapheresis
The mean baseline IT was 1:256 for anti-A IgM and 1:512 for anti-A IgG . Anti-B titers were lower for both IgM and IgG starting at 1:128 and 1:192 , respectively . All four antibodies showed a decrease in titers with the first two passes and continued decrease or stable titers with the following two passes as demonstrated in Figure 2A . After the fourth pass , anti-A titers decreased to a mean of 1:20 for IgM and 1:48 for IgG , representing a reduction of 50 % and 39 %, respectively . Anti-B titers decreased to a mean of 1:2 for IgM and 1:12 for IgG , representing a reduction of 86 % and 53 %, respectively . The overall mean anti-A and anti-B titer reduction was 4.375 titers
( 93.8 % change ) with 62.5 % of titers 1:4 at the end of the run at 2 h .
There were also high baseline class II anti-HLA antibody levels with all samples demonstrating a mean fluorescence intensity ( MFI ) > 3,000 . The cumulative MFIs prior to the runs were 12,106 and 14,615 . Both CP circuits demonstrated a rapid decrease in MFI with a reduction to < 3000 by the second pass at the 60-minute mark as demonstrated by Figure 2B . After the fourth pass , the cumulative MFI was reduced to 6,133 and 4,133 corresponding to a 2.0 – 3.5-fold decrease at the end of the two-hour run .
Membrane-based plasmapheresis
The mean baseline IT was 1:256 for anti-A IgM and 1:768 for anti-A IgG . Baseline anti-B titers were again lower for both IgM and IgG starting at 1:128 and 1:192 , respectively . Similar to CP , all four antibodies showed a decrease in titers with the first two passes . The following two passes demonstrated continued decrease or stable IT as demonstrated in Figure 3A . After the fourth pass , anti-A titers decreased to a mean of 1:18 for IgM and 1:72 for IgG , representing a reduction of 56 % and 42 %, respectively . Anti-B titers decreased to a mean of 1:1.5 for IgM and 1:20 for IgG , representing a reduction of 93 % and 47 %, respectively . The overall mean anti-A and anti-B titer reduction was 4.625 titers ( 93.7 % change ) with 50 % of the titers 1:4 at the end of the run at two hours .
Furthermore , there were high baseline class II anti-HLA antibody levels with all samples demonstrating an MFI > 3,000 . The cumulative MFIs prior to the runs were 14,324 and 17,110 . Both MP circuits demonstrated a rapid decrease in MFI with a reduction to < 3,000 by the third pass at the 90-minute mark as demonstrated in Figure 3B . After the fourth pass , the cumulative MFI was reduced to 8,176 and 6,756 ,