Immune modulation to prevent antibody-mediated rejection after allogeneic hematopoietic stem cell transplantation.

It has been shown that antibodies to donor CD34+/VEGFR-2+ stem cells or antibodies against mismatched HLA are associated with graft rejection after hematopoietic stem cell transplantation (HSCT). CD34/VEGFR-2 positive stem cells have been implicated to play a major role in engraftment after HSCT. In this study we treated four patients with an imminent risk of antibody-mediated rejection with immune modulation, i.e. plasma exchange, intravenous immunoglobulin (IVIG), and rituximab before HSCT. Three of the patients had been previously transplanted and rejected their initial grafts after 12 months, 1 month, and less than 1 month, respectively. The fourth patient was not transplanted previously but had HLA directed antibodies present against the graft. During the immune modulatory treatment we followed the pattern of antibodies in sera using FACS and microcytotoxicity assay. We could show that two patients had antibodies against donor CD34+/VEGFR-2+ cells while the other two had antibodies directed against HLA. All four patients tolerated the immune modulatory regimen without any side effects. In this preliminary study we show that immune modulatory treatment may be used to reduce antibody levels and to prevent rejection after HSCT. In two of the three patients which experienced previous rejections and had detectable anti-HLA or anti-CD34+/VEGFR-2+ antibodies, immune modulation resulted in engraftment. In the fourth patient with known anti-HLA-class I antibodies, the treatment also resulted in engraftment. Our results encourage further studies regarding this treatment regimen.

Improved survival after allogeneic hematopoietic stem cell transplantation in recent years. A single-center study.

We analyzed the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) over the past 2 decades. Between 1992 and 2009, 953 patients were treated with HSCT, mainly for a hematologic malignancy. They were divided according to 4 different time periods of treatment: 1992 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009. Over the years, many factors have changed considerably regarding patient age, diagnosis, disease stage, type of donor, stem cell source, genomic HLA typing, cell dose, type of conditioning, treatment of infections, use of granulocyte-colony stimulating factor (G-CSF), use of mesenchymal stem cells, use of cytotoxic T cells, and home care. When we compared the last period (2006-2009) with earlier periods, we found slower neutrophil engraftment, a higher incidence of acute graft-versus-host disease (aGVHD) of grades II-IV, and less chronic GVHD (cGHVD). The incidence of relapse was unchanged over the 4 periods (22%-25%). Overall survival (OS) and transplant-related mortality (TRM) improved significantly in the more recent periods, with the best results during the last period (2006-2009) and a 100-day TRM of 5.5%. This improvement was also apparent in a multivariate analysis. When correcting for differences between the 4 groups, the hazard ratio for mortality in the last period was 0.59 (95% confidence interval [CI]: 0.44-0.79; P < .001) and for TRM it was 0.63 (CI: 0.43-0.92; P = .02). This study shows that the combined efforts to improve outcome after HSCT have been very effective. Even though we now treat older patients with more advanced disease and use more alternative HLA nonidentical donors, OS and TRM have improved. The problem of relapse still has to be remedied. Thus, several different developments together have resulted in significantly lower TRM and improved survival after HSCT over the last few years.

Clinical experience with a new apheresis filter that specifically depletes ABO blood group antibodies.

BACKGROUND: Although living kidney donors are increasingly being used, in most centers, 30 to 40 percent of potential donors are being turned down due to ABO mismatch. A protocol for ABO-mismatched kidney transplantation without splenectomy and with antigen-specific adsorption of ABO antibodies instead of nonspecific plasmapheresis was therefore designed. STUDY DESIGN AND METHODS: The immunosuppressive protocol used at the Department of Transplantation Surgery, Karolinska University Hospital, Stockholm, Sweden, together with relevant clinical data for 11 of the studied patients, have been described previously. The protocol called for immunoadsorption of ABO antibodies on Days -6, -5, -2, and -1 and on Days +2, +5, and +8. Patient plasma was recirculated through a new apheresis filter, the Glycosorb ABO column (Glycorex Transplantation AB), containing synthetic terminal trisaccharide A or B blood group antigen linked to a Sepharose matrix. RESULTS: Since 2001, 15 patients, including 2 infants, have been successfully transplanted with ABO-mismatched kidneys from living donors. The donor-recipient blood groups were A1-O (n = 5), A2-O (n = 2), B-O (n = 4), B-A (n = 2), and A1B-B (n = 2). ABO antibody titers at transplantation did not exceed immunoglobulin G 4 or immunoglobulin M 4 levels. No humoral rejections and no late rebound of ABO antibodies were observed. No adverse effects related to immunoadsorption treatment have been recorded. CONCLUSION: It is concluded that ABO-mismatched kidney transplantations can be successfully performed without splenectomy and that ABO antibodies can be effectively and safely depleted with the Glycosorb ABO column.

The Stockholm experience with ABO-incompatible kidney transplantations without splenectomy.

BACKGROUND: ABO-incompatible kidney transplantations have previously only been performed after several pre-operative sessions of plasmapheresis followed by splenectomy, and with the conventional triple-drug immunosuppressive protocol being reinforced with anti-lymphocyte globulin and B-cell-specific drugs. We have designed a protocol without splenectomy, based on antigen-specific immunoadsorption, rituximab and a conventional triple-drug immunosuppressive protocol. METHODS: The protocol called for a 1-month pre-transplantation conditioning period, starting with one dosage of rituximab and followed by full-dose tacrolimus, mycophenolate mofetil and prednisolone. Antigen-specific immunoadsorption was performed on pre-transplantation days -6, -5, -2 and -1. After the last session, 0.5 g/kg of intravenous immunoglobulin (IVIG) was administered. Postoperatively, three more apheresis sessions were given every third day. RESULTS: Twenty-one patients have received transplants with this protocol. The ABO-antibodies (Abs) were readily removed by the antigen-specific immunoadsorption and were kept at a low level post-transplantation by further adsorptions. There were no side effects, and all but one patient have normal renal transplant function. CONCLUSIONS: We conclude that after one infusion each of rituximab and IVIG, and antigen-specific immunoadsorption, blood-group incompatible renal transplantations can be performed with standard immunosuppression and without splenectomy, and with excellent short- and long-term results.

Photopheresis for the treatment of refractory renal graft rejection.

Acute rejection episodes still occur after kidney transplantation in spite of modern immunosuppressive protocols including combined tacrolimus, mycophenolate mofetil, and prednisolone. The authors present seven cases of biopsy-proven acute rejection after kidney transplantation refractory to conventional rejection therapy with repeated pulses of high-dose steroids followed by polyclonal or monoclonal antibodies that responded well to photopheresis treatment. Photopheresis is an atoxic immunomodulatory apheresis-based treatment with no generalized immunosuppressive action; rather, it is directed at suppressing donor-specific T-cell clones. At the last follow-up, 9 to 43 months after transplantation, all patients had functioning grafts, with serum creatinine levels ranging from 105 to 312 microM. The authors conclude that photopheresis treatment contributed to the favorable outcome. Therefore, the authors are presently designing a prospective, randomized trial to evaluate the effect of photopheresis as an adjuvant prophylactic treatment after renal transplantation.

ABO incompatible kidney transplantations without splenectomy, using antigen-specific immunoadsorption and rituximab.

ABO incompatible kidney transplantations have previously only been performed after several preoperative sessions of plasmapheresis and splenectomy, with the conventional triple-drug immunosuppressive protocol being reinforced with antilymphocyte globulin and B-cell-specific drugs, such as cyclophosphamide or deoxyspergualine. We have designed a protocol without splenectomy, based on antigen-specific immunoadsorption, rituximab and a conventional triple-drug immunosuppressive protocol. The protocol calls for a 10-day pretransplantation conditioning period, starting with one dosage of rituximab and followed by full dose tacrolimus, mycophenolate mofetil and prednisolone. Antigen-specific immunoadsorption was performed on pretransplantation days -6, -5, -2 and -1. After the last session, 0.5 g/kg of intravenous immunoglobulin (IVIG) was administered. Postoperatively, three more apheresis sessions were given every third day. Furthermore, if there was a significant increase in the antibody titers, extra sessions were considered. Eleven patients have received transplants with this protocol. The ABO antibodies were readily removed by the antigen-specific immunoadsorption and were kept at a low level post-transplantation by further adsorptions. There were no side effects and all patients have normal renal transplant function. We conclude that after an infusion each of rituximab and IVIG, and antigen-specific immunoadsorption; blood group-incompatible renal transplantations can be performed with excellent results using standard immunosuppression and no splenectomy.

Successful ABO-incompatible kidney transplantations without splenectomy using antigen-specific immunoadsorption and rituximab.

BACKGROUND: Historically, ABO-incompatible kidney transplantations have only been undertaken after splenectomy and unspecific plasmapheresis and with quadruple drug immunosuppression plus B-cell specific drugs. We have evaluated a protocol for ABO-incompatible kidney transplantation without splenectomy using antigen-specific immunoadsorption, rituximab, and a conventional triple-drug immunosuppressive regimen. METHODS: The protocol called for a 10-day pretransplant conditioning period starting with one dosage of rituximab and followed by full dose tacrolimus, mycophenolate mofetil, and prednisolone. Antigen-specific immunoadsorption was performed on pretransplant days -6, -5, -4, and -1. After the last session, 0.5 g/kg of intravenous immunoglobulin was administered. Postoperatively, three more apheresis sessions were given every third day. Furthermore, if there was a significant increase in the antibody titers, extra sessions were considered. RESULTS: Four patients have received transplants with this protocol. The donor-recipient blood groups were A2/O, B/O, B/A, and A1/O. The ABO-antibodies were readily removed by the antigen-specific immunoadsorption and were kept at a low level posttransplantation by further adsorptions. There were no side effects, and all patients have normal renal-transplant function. CONCLUSIONS: We conclude that after one infusion each of rituximab and intravenous immunoglobulin and antigen-specific immunoadsorption, blood-group-incompatible renal transplantations can be performed with standard immunosuppression and without splenectomy.

Leukocyte depleted, unscreened blood products give a low risk for CMV infection and disease in CMV seronegative allogeneic stem cell transplant recipients with seronegative stem cell donors.

Leukocyte depletion (LD) by blood product filtration has been shown to be similarly effective to the use of screened, CMV seronegative blood products to prevent CMV disease in CMV seronegative allogeneic stem cell transplant (SCT) patients with CMV seronegative donors. The aim of this retrospective study was to determine the risk for development of CMV infection requiring preemptive therapy and for CMV disease if unscreened products treated by prestorage LD is used. Forty-nine consecutive patients transplanted after June 1995 were included. As a control group, 33 patients transplanted from January 1992 to June 1995 in whom a combination of CMV seronegative and LD blood products were given. All patients were monitored weekly by a leukocyte-based PCR for CMV DNA detection. Preemptive therapy was initiated after two consecutively positive tests. No patient developed CMV disease in either group. CMV DNA was detected in 6/49 (p = NS) in the study group and in 3/33 patients in the historical control group. Two patients in the study group were given preemptive therapy compared to one patient in the control group. This study suggests that the risk for CMV disease and the need for preemptive therapy against CMV is low in CMV seronegative allogeneic SCT patients receiving grafts from CMV seronegative stem cell donors receiving LD blood products. Thus, this strategy can be safely used together with PCR monitoring and preemptive therapy.

Risk factors for moderate-to-severe chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

Among 810 consecutive hematopoietic stem cell transplantation (HSCT) patients, 679 survived more than 3 months and were evaluated for chronic GVHD. The aim of this study was to find predisposing factors increasing the risk of development of moderate-to-severe chronic GVHD. Many of the donors were HLA-identical siblings or related (n = 435), 185 were HLA-matched unrelated, and 59 were mismatched related or unrelated donors. Most of the patients had a hematological malignancy (n = 568), but 111 patients with a nonmalignant disease were included. Two hundred twenty-three patients (33%) developed mild, 41 (6%) moderate, and 15 (2.2%) severe chronic GVHD. The 5-year probability of development of moderate-to-severe chronic GVHD was 10%. We analyzed 30 potential risk factors for chronic GVHD. In the multivariate analysis, acute GVHD) grades II to IV (relative hazard [RH], 2.30; 95% CI, 1.29-4.10; P = .005), CML diagnosis (RH, 2.37; CI, 1.38-4.08; P = .002) and transplantation from an immunized female donor to a male recipient (RH, 2.16; CI, 1.14-4.11; P = .02) were independent risk factors for moderate-to-severe chronic GVHD. Recipient age also was significant (RH, 2.42; CI, 1.23-4.77; P = .01) if CML was not included in the analysis. In patients with no risk factors, the 5-year probability of development of moderate-to-severe chronic GVHD was 5%. In patients with 1 risk factor, the probability was 13%; 2 risk factors, 23%; and 3 risk factors, 45%. Among patients who developed chronic GVHD (n = 279), acute GVHD grades II to IV (RH, 2.18; CI, 1.23-3.86; P < .01) was the only predictive factor for moderate-to-severe chronic GVHD versus mild disease. Patients with previous acute GVHD grades II to IV may benefit from more aggressive initial treatment. This possibility would have to be examined in clinical trials.