Initial steroid bolus injection promotes vigorous CD8+ alloreactive responses toward early graft acceptance immediately after liver transplantation in humans

Advantage of tacrolimus/mycophenolate mofetil regimen for cytotoxic T cell-mediated defence and its inhibition by additive steroid administration in high-risk liver transplant recipients

Our previous work revealed that the recipients with the highest pre-existing numbers of CD8(+) effector T cells (TE ) [hyperparathyroidism (HPT)E recipients] occupied approximately 30% of adult transplant recipients performed in our hospital. HPTE recipients demonstrated very poor clinical outcome compared with the remaining 70% of recipients with the lowest pre-existing TE (LPTE recipient). This study aimed to clarify the best combined immunosuppressive regimen related to function of cytotoxic T lymphocytes (CTLs) for HPTE recipients. Eighty-one HPTE recipients were classified into three types, according to the immunosuppressive regimens: type 1, tacrolimus (Tac)/glucocorticoid (GC); type 2, Tac/mycophenolate mofetil (MMF)/GC; and type 3, Tac/MMF. Frequencies of severe infection, rejection and hospital death were the highest in types 1 and 2, whereas the lowest occurred in type 3. The survival rate in type 3 was the highest (100%) during follow-up until post-operative day 2000. Regarding the immunological mechanism, in type 1 TE perforin and interferon (IFN)-γ were generated through the self-renewal of CD8(+) central memory T cells (TCM ), but decreased in the early post-transplant period due to marked down-regulation of interleukin (IL)-12 receptor beta-1 of TCM. In type 2, the self-renewal TCM did not develop, and the effector function could not be increased. In type 3, in contrast, the effectors and cytotoxicity were correlated inversely with IL-12Rβ1(+) TCM levels, and increased at the highest level around the pre-transplant levels of IL-12Rβ1(+) TCM . However, the immunological advantage of Tac/MMF therapy was inhibited strongly by additive steroid administration.

Early coupled up-regulation of interleukin-12 receptor beta-1 in CD8+ central memory and effector T cells for better clinical outcomes in liver transplant recipients

This study aimed to investigate the role of initial priming of interleukin (IL)-12 receptor beta-1 in CD8(+) central memory T cells (initial IL-12RTCM priming) and CCR7-negative subsets (CNS) in effector cell expansion and clinical outcome after living donor liver transplantation (LDLT). One hundred and six patients who underwent LDLT were classified into the following three groups according to hierarchical clustering of CD8(+) CD45 isoforms before LDLT: I, naive-dominant; II, effector memory-dominant; and III, effector-dominant. The pre-existing CD8(+) effector cells (TE ) and activated immune status increased progressively from group I to group II to group III. Groups I, II and III received tacrolimus (Tac)/glucocorticoid (GC) regimens. Eighteen group III recipients received Tac/mycophenolate mofetil (MMF) and were defined as group IV. Initial IL-12RTCM priming was slightly, moderately and markedly decreased in droups I, II, and III, respectively. Initial priming of IL-12Rβ1 in CNS was decreased markedly in the three groups with marked decreases of TE , perforin and interferon (IFN)-γ; all parameters were restored by up-regulation of IL-12Rβ1(+) TCM through the self-renewal of TCM . The lag time required until coupled up-regulation of IL-12Rβ1 of TCM and CNS to above baseline was 12, 20 and 32 days in groups I, II and III, respectively. Inferior clinical outcomes were associated with increasing lag time. In contrast, the initial priming of IL-12Rβ1 in TCM and CNS remained above baseline in group IV due to MMF-mediated increase of IL-12Rβ1. Early coupled up-regulation of TCM and CNS leads to efficient TE differentiation and optimal clinical outcomes.

Significance of semiquantitative assessment of preformed donor-specific antibody using luminex single bead assay in living related liver transplantation

Aim. To analyze the risks of preoperatively produced donor-specific antibody (DSA) in liver transplantation. Methods. DSA was assessed using direct complement-dependent cytotoxicity (CDC) and anti-human globulin- (AHG-) CDC tests, as well as the Luminex Single Antigen assay. Among 616 patients undergoing blood type identical or compatible living donor liver transplantation (LDLT), 21 patients were positive for CDC or AHG-CDC tests, and the preserved serum from 18 patients was examined to determine targeted Class I and II antigens. The relationships between the mean fluorescence intensity (MFI) of DSA and the clinical outcomes were analyzed. Results. Patients were divided into 3 groups according to the MFI of anti-Class I DSA: high (11 patients with MFI > 10,000), low (2 patients with MFI < 10,000), and negative (5 patients) MFI groups. Six of 11 patients with high Class-I DSA showed positive Class-II DSA. Hospital death occurred in 7 patients of the high MFI group. High MFI was a significant risk factor for mortality (P = 0.0155). Univariate analysis showed a significant correlation between MFI strength and C4d deposition (P = 0.0498). Conclusions. HLA Class I DSA with MFI > 10,000 had a significant negative effect on the clinical outcome of patients with preformed DSA in LDLT.

Non-inflammatory centrilobular sinusoidal fibrosis in pediatric liver transplant recipients under tacrolimus withdrawal

AIM

  We hypothesized that non-inflammatory central sinusoidal fibrosis (NICSF) is a sign of inadequate immunosuppression in children after living-donor liver transplantation.

METHODS

  In study 1, liver biopsy specimens of 158 patients who had undergone liver transplantation 10 years before or earlier were examined to study the relationship between NICSF and tacrolimus withdrawal. In study 2, tacrolimus was resumed in 18 patients with NICSF in follow-up biopsies after tacrolimus withdrawal and the subsequent histological changes were analyzed.

RESULTS

  In study 1, after excluding 95 patients with ongoing vascular, biliary and immunological complications, 47 of 63 patients (75%) had NICSF and significant (P = 0.0285) contributing factors were found to be episodes of tacrolimus withdrawal. In study 2, during withdrawal, tacrolimus administration had been discontinued in nine, reduced to once per month in three, twice per month in two, once a week in two and twice a week in two patients, and then finally resumed to daily administration in all. NICSF was scored as 4 in one, 3 in seven, 2 in four and 1 in six patients using modified Dixon's criteria (score, 0-4). After resumption, NICSF was improved in six, unchanged in 11 and aggravated in one patient. C4d deposition was improved in all NICSF-improved patients. Incidence of positive C4d prior to resumption was significantly greater in improved patients than non-improved patients (P = 0.0245).

CONCLUSION

  NICSF might be an indicator of inadequate immunosuppression in long-term followed recipients and its mechanism may be due to immune reactions including humoral immunity.

Initial burst of viremia related to CD8 effector memory T cells after living donor liver transplantation in hepatitis C virus-infected recipients

The post-transplant immune responses, viremia, and allograft histology after living donor liver transplantation were studied in 39 hepatitis C virus (HCV)-infected recipients. The recipients were classified into the following groups according to a hierarchical clustering of their preoperative CD8CD45 T-cell isoforms: group I, naive-dominant; group II, effector memory-dominant; and group III, effector-dominant. Plasma HCV-RNA rapidly increased and then peaked as an initial burst around postoperative day (POD) 25 in group I, on POD 40 in group II, and on POD 55 in group III. The initial burst of viremia was suppressed by the high expression of CD8+CD28-CD27- subsets. The progression of fibrosis > or =F2 was significantly more frequent for those patients with the highest viremia levels. Moreover, the initial T-cell immune response became less important throughout time, and new immune responses emerged after 2 months that modified the host-virus interaction. It is suggested that the interferon (IFN)-alpha/ribavirin therapy starting 2 months may be an effective option and now is undertaken.

Coupled regulation of interleukin-12 receptor beta-1 of CD8+ central memory and CCR7-negative memory T cells in an early alloimmunity in liver transplant recipients

This study investigated how CD8(+) T cell subsets respond to allo- and infectious immunity after living donor liver transplantation (LDLT). Early alloimmunity: 56 recipients were classified into three types according to the post-transplant course; type I demonstrated uneventful post-transplant course, type II developed severe sepsis leading to multiple organ dysfunction syndrome or retransplantation and type III with acute rejection. In 23 type I recipients, the interleukin (IL)-12 receptor beta-1 (R beta 1)(+) cells of central memory T cells (Il-12R beta 1(+) T(CM)) were increased above the pretransplant level. In 16 type II recipients, IL-12R beta 1(+) T(CM) was decreased markedly below the pretransplant level on postoperative day (POD) 5. In 17 type III recipients, IL-12R beta 1(+) T(CM) was decreased for a more prolonged period until POD 10. Along with down-regulation of IL-12R beta 1(+) T(CM), the IL-12R beta 1(+) cells of CCR7-negative subsets (CNS) as well as perforin, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha decreased gradually, resulting in the down-regulation of effectors and cytotoxicity. The down-regulation of IL-12R beta 1(+) T(CM) was suggested to be due to the recruitment of alloantigen-primed T cells into the graft, and then their entry into the secondary lymphoid organ, resulting in graft destruction. Infectious immunity: immunocompetent memory T cells with the capacity to enhance effectors and cytotoxicity were generated in response to post-transplant infection along with both up-regulation of the IL-12R beta 1(+) T(CM) and an increase in the CNS showing the highest level of IL-12R beta 1(+) cells. In conclusion, this work demonstrated that the IL-12R beta 1(+) cells of T(CM) and CNS are regulated in a tightly coupled manner and that expression levels of IL-12R beta 1(+) T(CM) play a crucial role in controlling allo- and infectious immunity.

Risk factors for recurrence of primary sclerosing cholangitis after living donor liver transplantation: a single center experience

We retrospectively reviewed our 10-year experience with living donor liver transplantation (LDLT) in 30 consecutive patients with end-stage primary sclerosing cholangitis (PSC) to determine long-term patient and graft survival and risk factors for recurrence of PSC. For strict diagnosis of recurrence, patients with hepatic artery thrombosis (n = 2), ABO blood type incompatible transplantation (n = 3), and postoperative survival shorter than 1 year (n = 5) were excluded from the study, leaving 20 patients for analysis. Recurrence was diagnosed in 11 patients 26-71 months after transplantation. Multivariate analysis showed that cytomegalovirus diseases within 3 months after transplantation and related donors were independent risk factors for recurrence. When the effects on recurrence were compared among donor-recipient relationships, there were significant differences, especially between nonrelated donors and parents. Multivariate analysis showed that age was an independent risk factor for time to graft loss. Cytomegalovirus prophylaxis and avoidance of related donors are important in reducing PSC recurrence, although this is a preliminary report with limitations due to the small number of patients. LDLT for young patients with PSC using grafts from their parents might have to be avoided where deceased donor liver transplantation is available.

Serial assessment of immune status by circulating CD8 effector T cell frequencies for posttransplant infectious complications

To clarify the role of CD8⁺ effector T cells for infectious complications, 92 recipients were classified according to the hierarchical clustering of preoperative CD8⁺CD45 isoforms: Group I was naive, Group II was effector memory, and Group III was effector (E) T cell-dominant. The posttransplant infection rates progressively increased from 29% in Group I to 64.3% in Group III recipients. The posttransplant immune status was compared with the pretransplant status, based on the measure (% difference) and its graphical form (scatter plot). In Groups I and II, both approaches showed a strong upward deviation from pretransplant status upon posttransplant infection, indicating an enhanced clearance of pathogens. In Group III, in contrast, both approaches showed a clear downward deviation from preoperative status, indicating deficient cytotoxicity. The % E difference and scatter plot can be used as a useful indicator of a posttransplant infectious complication.