Hyaline-vascular type unicentric Castleman disease with dysplastic follicular dendritic cell proliferative lesions: a case report.

Castleman disease (CD) is a rare lymphoproliferative disease. Hyaline-vascular type unicentric CD has a good prognosis if completely resected during surgery. However, follicular dendritic cell proliferative lesions have the potential for recurrence and metastasis. A 22-year-old man was referred to our hospital with the chief complaint of nausea and vomiting. These symptoms were caused by a right mesocolonic tumor pushing the duodenum. The patient underwent laparoscopic tumorectomy and complete surgical excision. The postoperative course was uneventful, with no complications. Pathological examination confirmed that the tumor was an enlarged lymph node, typical of hyaline vascular-type CD; however, follicular dendritic cell proliferative lesions were noted. We report a rare case of hyaline-vascular-type CD with follicular dendritic cell proliferative lesions associated with malignancy, as limited case reports exist on this particular disease.

Post-transplant donor-specific anti-HLA antibodies with a higher mean fluorescence intensity are associated with graft fibrosis in pediatric living donor liver transplantation.

The roles of post-transplant anti-HLA donor specific antibody (DSA) in pediatric liver transplantation (LT), including therapeutic strategies, remain controversial. This study aimed to identify the risks of post-transplant DSA for graft fibrosis progression in pediatric living donor LT (LDLT). We retrospectively evaluated 88 LDLT pediatric cases between December 1995 and November 2019. DSAs were assessed with single antigen bead test. Graft fibrosis was histopathologically scored with METAVIR and the centrilobular sinusoidal fibrosis system. Post-transplant DSAs were detected in 37 (52.9%) cases at 10.8 (1.3-26.9) years post-LDLT. The histopathological examination of 32 pediatric cases with post-transplant DSA revealed that 7 (21.9%) with a high DSA-MFI (≥9,378) showed graft fibrosis progression (≥F2). No graft fibrosis was observed in the subjects with a low DSA-MFI. The risk factors for developing graft fibrosis in pediatric cases with post-transplant DSA were an older graft age (>46.5 years old), lower platelet count (<10.7 × 104/ml) and higher Fib4 index (>0.7807, recipient age; >1.8952, donor age). Limited efficacy of additional immunosuppressants was observed in DSA positive pediatric cases. In conclusion, pediatric cases with a high DSA-MFI and risk factors should undergo a histological examination. The appropriate treatment for post-transplant DSA in pediatric LT needs to be determined.

Functional roles of graft-infiltrating lymphocytes during early-phase post-transplantation in mouse cardiac transplantation models.

Immunological behavior of graft-infiltrating lymphocytes (GILs) determines the graft fate (i.e., rejection or acceptance). Nevertheless, the functional alloreactivity and the phenotype of GILs at various times during the early post-transplantation phase have not been fully elucidated. We examined the immunological activities of early-phase GILs using a murine model of cardiac transplantation. GILs from 120-h allografts, but not 72-h allografts, showed robust activation and produced proinflammatory cytokines. In particular, a significant increase in CD69+ T-bet+ Nur77+ T cells was detected in 120-h allografts. Furthermore, isolated GILs were used to reconstitute BALB/c Rag2-/- γc-/- (BRG) mice. BRG mice reconstituted with 120-h GILs displayed donor-specific immune reactivity and rejected donor strain cardiac allografts; conversely, 72-h GILs exhibited weak anti-donor reactivity and did not reject allografts. These findings were confirmed by re-transplantation of cardiac allografts into BRG mice at 72-h post-transplantation. Re-transplanted allografts continued to function for >100 days, despite the presence of CD3+ GILs. In conclusion, the immunological behavior of GILs considerably differs over time during the early post-transplantation phase. A better understanding of the functional role of early-phase GILs may clarify the fate determination process in the graft-site microenvironment.

Triazolopyrimidine derivative NK026680 and donor-specific transfusion induces CD4+CD25+Foxp3+ T cells and ameliorates allograft rejection in an antigen-specific manner.

We have previously demonstrated the unique properties of a new triazolopyrimidine derivative, NK026680, which exerts immunosuppressive effects in rat heart transplant model and confers tolerogeneic properties on ex vivo-conditioned dendritic cells in mice. We herein demonstrate that NK026680 promotes the expansion of regulatory T cells (Tregs) with potent immunoregulatory effects when used in combination with donor-specific transfusion (DST). BALB/c (H-2d) heart graft were transplanted into C57BL/6 (H-2b) mice following intravenous injection of donor splenocytes (DST) and oral administration of NK026680. The NK026680 plus DST treatment markedly prolonged the survival time of the donor-graft, but not that of the 3rd party-graft (C3H; H-2k). Treg cells in the recipient spleen on day 0 expanded when stimulated with donor-antigens in vivo and in vitro. After heart transplantation, Treg cells accumulated into the graft and increased in the spleen. NK026680 plus DST also decreased activated CD8+ T cells in the spleen and inhibited infiltration of CD8+ T cells into the graft. Depletion of CD25+ cells inhibited the graft prolonging effect of the NK026680 plus DST treatment. NK026680 administration together with DST induces potent immunoregulatory effects in an antigen-specific manner, likely due to the in vivo generation of donor-specific Tregs.

Novel immunological approach to asses donor reactivity of transplant recipients using a humanized mouse model.

In organ transplantation, a reproducible and robust immune-monitoring assay has not been established to determine individually tailored immunosuppressants (IS). We applied humanized mice reconstituted with human (hu-) peripheral blood mononuclear cells (PBMCs) obtained from living donor liver transplant recipients to evaluate their immune status. Engraftment of 2.5 × 106 hu-PBMCs from healthy volunteers and recipients in the NSG mice was achieved successfully. The reconstituted lymphocytes consisted mainly of hu-CD3+ lymphocytes with predominant CD45RA-CD62Llo TEM and CCR6-CXCR3+CD4+ Th1 cells in hu-PBMC-NSG mice. Interestingly, T cell allo-reactivity of hu-PBMC-NSG mice was amplified significantly compared with that of freshly isolated PBMCs (p < 0.05). Furthermore, magnified hu-T cell responses to donor antigens (Ag) were observed in 2/10 immunosuppressed recipients with multiple acute rejection (AR) experiences, suggesting that the immunological assay in hu-PBMC-NSG mice revealed hidden risks of allograft rejection by IS. Furthermore, donor Ag-specific hyporesponsiveness was maintained in recipients who had been completely weaned off IS (n = 4), despite homeostatic proliferation of hu-T cells in the hu-PBMC-NSG mice. The immunological assay in humanized mice provides a new tool to assess recipient immunity in the absence of IS and explore the underlying mechanisms to maintaining operational tolerance.

Proficiency Level of Novice Technically Qualified Surgeons in Laparoscopic Rectal Resection.

The actual proficiency levels of surgeons after their qualification by the Endoscopic Surgical Skill Qualification System have not been established. This study aimed to investigate whether technically qualified surgeons could safely perform laparoscopic low anterior resection and to evaluate the proficiency level at the time of certification acquisition. A total of 46 patients (mean age, 63.3 y; male to female ratio, 29:17) who underwent low anterior resection were included. Outcomes of 46 low anterior resections for rectal cancer performed by 3 novice surgeons certified by the Endoscopic Surgical Skill Qualification System from 2013 to 2018 at 2 hospitals were retrospectively assessed. The mean operative time and blood loss were 201 minutes and 12.9 mL, respectively. One patient (2.2%) required conversion to open surgery, and major postoperative complications occurred in 4 patients (8.6%), including anastomotic leakage in 2 patients (4.3%). Histologic R0 resection was achieved in all cases. The operative time moving average for the 3 surgeons gradually decreased from 233 to 158 minutes. In cumulative sum charts, the operative time values continuously decreased after the 12th case compared with the target operative time (180 min). In conclusion, surgeons can safely perform laparoscopic low anterior resection just after their qualification but have the potential to further attain proficiency.