Clinical observation on hemophilia A treatment by cadaveric spleen transplantation

Can the spleen be divided into two functional parts?

Solid evidence has revealed unsuspected functions of the spleen. Asplenic or hyposplenic patients bear an increased susceptibility to overwhelming postsplenectomy infection. We, for the first time, performed the split splenic transplantation to redress hemophilia A. We also resected the middle part of the spleen completely and anatomically for the first time. Our findings illustrate that the spleen can be divided into 2 functional parts, and may shed a new light on the understanding and practice in splenic surgery.

Technical refinements in small bowel transplantation

PURPOSE OF REVIEW

This review focuses on the recently described or revised refinements or innovations in small bowel transplantation.

RECENT FINDINGS

Changes in donor selection criteria; cadaveric procurement techniques; organ preservation solutions; management of the recipient abdominal wall; technical modifications, pitfalls and recommendations to be applied during the engraftment as well as intestinal living donation will be covered.

SUMMARY

Intestinal transplantation has evolved over time to become a clinically accepted therapy for patients with intestinal failure. Short- and long-term results have improved. The surgical procedures have been standardized and the applications broaden, but there have been recently published refinements that might affect the future results of clinical intestinal transplantation and guide research.

Gene transfer of antisense B7.1 attenuates acute rejection against splenic allografts in rats

Blockade of CD80-CD28 costimulatory pathway induces unresponsiveness of T cells to alloantigens and protects allografts against immune rejection in numerous animal models. The aim of this study was to investigate whether blocking expression of B7.1 (CD80) on donor splenocytes by an antisense technique protected splenic allografts against immune rejection. Splenic grafts from Wistar-Furth rats were intra-arterially transfused with an antisense B7.1 expression vector, before they were transplanted into Sprague-Dawley rats. The rats were sacrificed at scheduled times, and the splenic allografts histologically examined. Antisense gene transfer resulted in marked down-regulation of B7.1 in donor spleens, hyporesponsiveness of recipient T cells, and attenuated acute immune rejection against splenic allografts. No obvious damage to skin, liver, or gut due to graft-versus-host disease was detected in the recipients. In conclusion, blocking expression of B7.1 in donor spleens by antisense gene therapy represented a potential alloantigen-specific immunosuppressive strategy to inhibit acute rejection against splenic allografts.

Transplantation of the spleen: effect of splenic allograft in human multivisceral transplantation

OBJECTIVES

To describe the effect of the splenic allograft in human multivisceral transplantation.

SUMMARY BACKGROUND DATA

We performed transplants of the spleen as part of a multivisceral graft in an attempt to decrease both the risk of infection from an asplenic state and the risk of rejection by a possible tolerogenic effect. To our knowledge, this is the first report of human splenic transplantation in a large series.

METHODS

All primary multivisceral recipients who received a donor spleen (N = 60) were compared with those who did not receive a spleen (N = 81).

RESULTS

Thirty-five of 60 (58%) are alive in the spleen group, and 39 of 81 (48%) are alive in control group (P = 0.98). In univariate analysis, splenic recipients showed superiority in freedom-from-any rejection (P = 0.02) and freedom-from-moderate or severe rejection (P = 0.007). No significant differences were observed in analyses of infectious complications between the spleen and control groups. Both platelet and leukocyte counts became normal in splenic patients, whereas these counts were significantly increased in nonsplenic recipients. Observed incidence of graft versus host disease (GVHD) was 8.25% (5 of 60) in the spleen group and 6.2% (5 of 81) in the control group (P = 0.70). Increased incidence of autoimmune hemolysis was observed in the spleen group.

CONCLUSIONS

Allograft spleen can be transplanted within a multivisceral graft without significantly increasing the risk of GVHD. The allogenic spleen seems to show a protective effect on small bowel rejection. Further investigation with longitudinal follow-up is required to precisely determine the immunologic and hematologic effects of the allograft spleen.

Correction of hemophilia as a proof of concept for treatment of monogenic diseases by fetal spleen transplantation

Previous clinical attempts to correct genetic deficiencies such as hemophilia or Gaucher disease by transplantation of allogeneic spleen were associated with aggressive graft versus host disease, mediated by mature T cells derived from the donor spleen. We show that a fetal pig spleen harvested at the embryonic day 42 stage, before the appearance of T cells, exhibited optimal growth potential upon transplantation into SCID mice, and the growing tissue expressed factor VIII. Transplantation of embryonic day 42 spleen tissue into hemophilic SCID mice led to complete alleviation of hemophilia within 2-3 months after transplant, as demonstrated by tail bleeding and by assays for factor VIII blood levels. These results provide a proof of principle to the concept that transplantation of a fetal spleen, obtained from a developmental stage before the appearance of T cells, could provide a novel treatment modality for genetic deficiencies of an enzyme or a factor that can be replaced by the growing spleen tissue.

Opposite effects of donor apoptotic versus necrotic splenocytes on splenic allograft tolerance

BACKGROUND

Apoptotic cells have immunosuppressive activity, whereas necrotic cells activate immune response, indicating they might have different effects on immune rejection against splenic allografts. The aim of this study was to determine whether administration of apoptotic or necrotic splenocytes of donor origin could impact the acute rejection of splenic allografts.

MATERIALS AND METHODS

Apoptotic or necrotic splenocytes derived from donor rats were induced by irradiation or freeze thaw, respectively. Heterotopic vascularized spleen transplantation was performed from Wistar-Furth (donor) to Sprague-Dawley (recipient) rats, and splenocytes were intravenously injected into the recipients. At different time points, the recipients were sacrificed and the splenic allografts underwent histological examination. The interferon-gamma (IFN-gamma) and transforming growth factor-beta1 (TGF-beta1) in sera, spleens of recipients, and donor splenocytes before administration were measured. Mixed leukocyte reaction (MLR) was detected with recipient splenocytes as effectors and donor splenocytes as stimulators.

RESULTS

Exposure to gamma-irradiation at dose of 10,000 rad caused over 80% splenocytes to become apoptotic. The levels of TGF-beta1 released by apoptotic splenocytes in vitro were significantly higher than that by untreated splenocytes, whereas there was almost no TGF-beta1 detected in necrotic splenocytes culture medium. Administration of apoptotic splenocytes significantly attenuated acute rejection of splenic allografts, evidenced by less severe splenic histological alteration and reduction of histological scores compared with control; whereas necrotic splenocytes exacerbated the acute rejection. Apoptotic splenocytes inhibited production of IFN-gamma but increased the levels of TGF-beta1, whereas necrotic splenocytes showed opposite activity in production of those cytokines. Administration of apoptotic splenocytes inhibited MLR, and necrotic splenocytes promoted MLR.

CONCLUSIONS

The apoptotic and necrotic splenocytes exhibited opposite effects on acute rejection against splenic allografts, and IFN-gamma and TGF-beta1 have been involved in the effects.

Ten-year experience with living related donated splenic transplantation for the treatment of hemophilia A

AIM

Six cases of hemophilia A treated with living related donated splenic transplantation (LRDST) were performed over 10 years.

METHODS

We reviewed the six consecutive cases of LRDST from 1992 to 2002. Three patients received whole spleen allografts and the other three, partial spleen allografts. All allografts were transplanted to the extraperitoneal space in the right iliac fossa by an end-to-end anastomosis between the splenic artery and the internal iliac artery and an end-to-side anastomosis between the splenic vein and the external (or common) iliac vein. After the operation, a combined regimen with cyclosporine, azathioprine, anti-lymphocyte globulin, OKT3, was administered to suppress the immune reaction.

RESULTS

The functional period of the allografts varied between 30 days to 4 years. Patient factor-VIII (F-VIII) levels rose from less than 5% before operation to 15% to 56% postoperatively. One patient died from central nervous system complications. Another lost his graft because exogenous F-VIII was not supplemented in timely fashion at the onset of rejection. And the third could no longer afford the expensive immunosuppressive drugs at 2 years after the operation and eventually lost the spleen. The remaining three patients presently have regained self-support, among whom one has survived for 4 years.

CONCLUSION

Though the sample pool is relatively small, our clinical observations tend to confirm LRDST as a feasible, effective treatment for hemophilia A.

Administration of tolerogenic dendritic cells induced by interleukin-10 prolongs rat splenic allograft survival

The risk and intensity in splenic graft rejection are greater than in other types of transplants, because the spleen is the largest peripheral lymphoid organ and the immunosuppressive drugs administered can cause splenic dysfunction. In this study, we demonstrate that intravenous injection of interleukin-10-treated donor-type dendritic cells into recipient rats prolongs the survival of splenic allografts. Although the mechanisms are not clear, the induction of tolerance to grafted spleens seems to rely mainly on blockage of expression of the costimulatory molecule CD86, by interleukin-10, leading to enhanced apoptosis of allospecific T cells by immature and tolerogenic dendritic cells. Administration of tolerogenic cells induced by interleukin-10 may thus represent a useful approach for protection of splenic allografts. Further study is required to investigate the operative pathways and to optimize the strategy targeting dendritic cells to induce tolerance in splenic allografts.

Laparoscopic hand-assisted spleen autotransplantation

BACKGROUND

Only recently has the spleen been perceived as an organ with a major immune function. This raised an interest in spleen salvage after spleen trauma and pancreatic tail resection, for the treatment of hematologic disorders and inducement tolerance for allogenic transplants. The purpose of this study was to evaluate the feasibility of a new technique for spleen transplantation: laparoscopic spleen autotransplantation in a large animal model.

METHODS

Ten 35-kg pigs were used for this study. A laparoscopic hand-assisted splenectomy was first performed. The spleen was extracted through the handport to be flushed with a 4 degrees C saline solution and prepared extracorporeally. The graft was then reintroduced into the same animal's abdominal cavity, and a splenic-to-common iliac artery and vein bypass was performed laparoscopically using a 7-0 polytetrafluoroethylene running suture. The animal was killed 1 week postoperatively for histologic examination.

RESULTS

All 10 animals tolerated the procedure well. No conversion to open surgery was required. The mean operative time was 253 +/- 45 min. The mean time needed to create the artery and vein anastomoses was 116 +/- 165 min, and the mean blood loss was 190 +/- 120 ml. There was no intra- or postoperative death. Intraoperative complications included two stenosed vascular anastomoses, which were taken down and revised. Seven of the 10 spleens were histologically viable 1 week after surgery. The nonviable transplantations were attributable to a thrombosis of the common iliac artery (n = 1) or the transplant artery (n = 2).

CONCLUSIONS

Hand-assisted laparoscopic spleen autotransplantation is feasible in an animal model. This procedure could constitute an option when spleen resection is necessary for pancreatic tail resection, or when spleen preservation is important to the maintenance or restoration of an immune function.

Gene transfer of interleukin-4 delays acute rejection of splenic allografts in rats

Spleen transplantation is the treatment of choice for some diseases, such as hemophilia A. However, the risk and intensity of rejection after spleen transplantation is greater and more difficult to control than other types of transplant. In the present study, we demonstrated that perfusion of IL-4 expression plasmids into donor spleens pretransplantation led to overexpression of IL-4 and downregulation of IFN-gamma in situ, associated with delayed acute rejection of the allograft. Gene transfer of IL-4 may represent a potential therapeutic approach to induce tolerance to splenic allografts.