To analyze the proportion change of CD19⁺ CD24^hiCD38^hi B cells to mononuclear cells in peripheral blood of liver transplant recipients and its relationship with acute cellular rejection (ACR) after liver transplantation.

The clinical data of 80 adult recipients of liver transplantation after cardiac death donation in the First Affiliated Hospital of Zhejiang University School of Medicine from 2013 to 2015 were retrospectively analyzed. According to the occurrence of ACR, the recipients were divided into ACR group (25 cases) and non-ACR group (55 cases). The venous blood of the participants was collected and the peripheral blood mononuclear cells were isolated. FITC-monoclonal mouse anti-human CD19 antibody, PE-monoclonal mouse anti-human CD24 antibody and APC-monoclonal mouse anti-human CD38 antibody were added. The percentage of CD19⁺ CD24^hiCD38^hi B cells in each group was detected by flow cytometry. The measurement data conforming to normal distribution were compared by group t test or one-way ANOVA, the counting data were compared by chi-square test, and Kaplan-Meier method was used to draw the receiver operating characteristic curve. A P<0.05 was considered statistically significant.

The pre-operative average proportion of CD19⁺ CD24^hiCD38^hi B cells in peripheral blood of ACR group [(3.13±0.91)%] and non-ACR group [(3.49±0.83)%] had no significantly difference (t=1.636, P>0.05). The average proportion of CD19⁺ CD24^hiCD38^hi B cells in peripheral blood before ACR was (1.87±0.70)% in ACR group. The percentages of CD19⁺ CD24^hiCD38^hi B cells in non-ACR group were (1.64±0.52)%, (1.63±0.56)% and (2.04±1.24)% respectively at 3, 6 months and 1 year after liver transplantation, and the mean values at 3 and 6 months after liver transplantation were lower than those before surgery and 1 year after liver transplantation (P<0.05). The average proportion of CD19⁺ CD24^hiCD38^hi B cells in peripheral blood of ACR group was (0.8±0.5)% on the time of ACR, which lower than the average level before ACR (t=5.752, P<0.05), and also lower than the average level of 3, 6 months and 1 year after operation of non-ACR group ( P<0.05). In addition, the proportion of CD19⁺ CD24^hiCD38^hi B cells was increased in the ACR group after receiving anti-rejection treatment. The average proportion of CD19⁺ CD24^hiCD38^hi B cells was (0.84±0.08)% at 7 days after treatment, which had no statistical significance with the level when the ACR occurred (P>0.05), but the difference between 30 days after treatment [(1.65±0.18)%] and the level when the ACR occurred had statistical significance (P<0.05). When the cut-off value was 1.015%, the sensitivity and specificity of CD19⁺ CD24^hiCD38^hi B cells frequency for predicting the occurrence of ACR were 0.786 and 0.702, respectively. The area under the curve was 0.775 (95%CI: 0.671-0.879, P<0.05).

The decreased frequency of CD19⁺ CD24^hiCD38^hi B cells is associated with the occurrence of ACR after liver transplantation, and could be served as a cellular marker for predicting the occurrence of ACR.