Prevalência e fatores de risco para hemólise imune nos pacientes submetidos a transplante hepático

Abstract

Liver transplant (LT) anemia is multifactorial. Immune hemolysis occurs due to auto-antibodies, drug induced or not, or due to allo-antibodies, formed by transfusion or passenger lymphocyte syndrome (PLS). The aim of this study was to evaluate the prevalence and risk factors for immune hemolysis in LT. Between September 2014 and April 2016, 175 patients submitted to 178 LT were included. Multi-organ recipients were excluded. Samples from before, seven consecutive days and weekly for four weeks were analyzed for complete blood cound, reticulocyte count, lactate dehydrogenase (LDH), indirect bilirrubin (IB) and imummohematological tests. SPSS 24 was used for statistical analysis, p<0.05 was considered significant. The mean age was 52.1 ± 14.6 years old, with 105 male patients (60%). The most frequent causes of cirrhosis were hepatitis C virus (HCV, 59 – 33.7%) and alcohol (44 – 25.1%). Anemia before LT was present in 140 patients (74.2%), with lower hemoglobin (Hb) concentration in those with positive direct antiglobulin test (DAT, p=0.014). Nine patients (5.1%) presented positive antibody screen (AS) before transplant, with 2.3% of clinical significance. This finding was more frequent in RhD negative patients (p=0.017). Positive DAT occurred in 53 patients (30.3%) and was related to high MELD score (p=0,048), HCV (p=0.005) and furosemide use (p=0.001). These patients presented higher levels of IB (p<0.001). Ninety six patients (55%) were transfused in the studied period. One hundred and fourty five patients (87.8%) were still anemic on the fourth week. Twenty two patients (12.5%) presented positive AS after LT, with nine patients (5.7%) presenting clinically significant antibodies. Positive AS occurred more frequently in RhD negative (p=0.021) and in those transfused with red blood cells units (RBCU, p=0.022). Sixteen patients received grafts with minor ABO incompatibility. Post-transplant positive DAT was associated with higher levels of LDH (p=0.006), piperacillin-tazobactam use (p=0.021) and was more frequent in the non identical ABO group (p=0.0038). In this group, five of eleven positive DAT patients presented anti-A (2) or anti-B (3) on the eluate, representing PLS. All PLS patients received liver graft O and were using mycofenolate, tacrolimus and steroids. Four patients presented hemolysis and three were transfused due to PLS. These patients, compared to all the other patients, presented lower Hb concentration (p=0.043) and higher LDH levels (p=0.008) and reticulocyte counts (p=0.008). The presence of auto and allo-antibodies against red blood cell antigens is frequent in LT, but clinical significant hemolysis occurred in only 2.8%. Antibodies are more frequent in patients with higher MELD scores, with HCV, in use of pre-transplant furosemide, in those transfused patients with RBCU, RhD negative and piperacillin-tazobactam use after LT. The only risk factor for PLS is minor ABO mismatch between donor and recipient.