Jos Jansen

5 119 Screening for abnormal glycosylation in a cohort of adult liver disease patients and presence of an additional isoform (mass 78976, corresponding with loss of 2 sialic acids). There were no signs of other glycosylation abnormalities. The second patient was a male liver transplant recipient diagnosed with alpha-1 anti-trypsin deficiency. At age of sampling he was 28 years old. His QTOF-MS profile showed an increase in the trisialo TF isoform of 12,4% (median for the LTx group is 1.9%) and also an increased loss of 2 sialic acids (mass 78976). For both patients, we could not detect transferrin glycoforms with missing galactose residues, as for example seen in the V-ATPase assembly defects. tIEF but not QTOF-MS shows that loss of one sialic acid is more frequent and more severe in LTx candidates compared to CLD patients and HC To see what the effect is of liver disease on desialylation we compared the tIEF screening results between LTx and CLD samples. Table 2 shows the medians for all isoforms. The prevalence of several isoforms was statistically significantly different between these groups, but medians where within the normal range. Only the LTx group had a median of the trisialo TF isoform above the upper limit of normal and significantly higher than in the chronic liver disease group (11.8% vs 10.4%, p < 0.001). An abnormal tIEF pattern was more frequently seen in LTx candidates compared to CLD patients (175/511=34% vs. 72/450=16%, Chi square p-value =0.000). Table 2. medians of the different tiEF TF isoforms Abnormal samples (n=247) CLD (n=72) LTx (n=175) MWU TF Isoform Range (%) Median (%) SD Median (%) SD p-value Asialo 0.0-3.2 0.94 1.02 1.24 0.79 0.001 Mono 0.0-5.0 4.84 2.52 2.02 1.74 0.000 Di 3.3-7.6 5.25 1.21 5.27 1.39 0.588 Tri 4.9-10.6 10.40 3.07 11.84 2.25 < 0.001 Tetra 47.3 – 62.7 52.63 6.71 52.67 5.72 0.476 Penta 18.7 - 31.5 20.78 3.94 19.95 3.44 0.038 TF=Transferrin, CLD=chronic liver disease, LTx=liver transplantation, MWU: Mann Whitney U test, SD=standard deviation