BMT: Bone Marrow Transplant Associated Thrombotic Microangiopathy

Remission of microangiopathy in transplanted thalassemic child

Transplant associated thrombotic microangiopathy is a severe complication of Hematopoeitic stem cell transplantation. Although there is agreement in terms of diagnostic criteria, treatment options are not clarified yet. We present a patient aged 2.6 years who developed transplant associated thrombotic microangiopathy after allogeneic bone marrow transplantation and to discuss both risk factors and possible spontaneous remission of transplant associated thrombotic microangiopathy.

Renal thrombotic microangiopathy associated with chronic humoral graft versus host disease after hematopoietic stem cell transplantation

Thrombotic microangiopathy (TMA) is a known complication of hematopoietic stem cell transplantation (HSCT). The pathogenesis of TMA is controversial but considered to involve various factors such as total body irradiation, use of calcineurin inhibitors for prophylaxis against graft versus host disease (GVHD), viral infection, and GVHD. Herein we describe a case with renal TMA after HSCT, which was probably associated with antibody-mediated endothelial cell injury from chronic GVHD (termed here 'chronic humoral GVHD'). A 49-year-old man presented two years after HSCT with renal dysfunction and proteinuria but without the clinical features of TMA. Histopathological examination of renal biopsy showed chronic glomerular endothelial cell injury with double contour of the glomerular basement membrane, microthrombi and the deposition of complement split product C4d along the glomerular capillaries. Renal tubulitis and peritubular capillaritis were also noted with a multilayered basement membrane and patchy C4d deposition on peritubular capillaries. These findings resemble those of chronic antibody-mediated rejection after kidney transplantation. Furthermore, C4d deposition suggests complement activation. Although circulating anti-blood type and anti-human leukocyte antigen antibodies were not detected, the renal TMA in this case was probably associated with chronic humoral GVHD.

Replacement of calcineurin inhibitors with daclizumab in patients with transplantation-associated microangiopathy or renal insufficiency associated with graft-versus-host disease

Transplantation-associated microangiopathy (TAM) or renal insufficiency (RI) after allogeneic hematopoietic stem cell transplantation is associated with a high mortality. As calcineurin inhibitors (CI) may contribute to TAM or RI, we evaluated the efficacy of replacing CI by daclizumab in patients with graft-versus-host disease (GVHD). Thirteen patients with GVHD-associated TAM and five patients with RI were treated with daclizumab 1 mg/kg intravenous (i.v.)/week, discontinuation of the CI and continuation of the remaining GVHD treatment. All patients had acute GVHD (steroid-sensitive (n=4), steroid-refractory (n=10)) or chronic GVHD (n=4) and were treated with CI before the start of daclizumab. Nine of 13 patients with TAM treated with daclizumab and discontinuation of CI achieved complete remission of TAM, two had stable disease, and one patient did not respond. Patients receiving daclizumab for RI without TAM showed stabilization (2/5) or improvement (3/5) of renal function. Four of 14 patients with acute GVHD achieved CR, two partial remission, eight patients did not respond and 11/14 died at a median of 39 days after start of the daclizumab. Our data demonstrate that replacement of CI by daclizumab can improve TAM and RI. However, mortality remains high in patients with acute GVHD.

Risk Factors and Severe Outcome in Thrombotic Microangiopathy After Allogeneic Hematopoietic Stem Cell Transplantation

BACKGROUND

Thrombotic microangiopathy (TMA) has been described as severe complication after hematopoietic stem cell transplantation (HSCT). The principal aim of this study was to focus the incidence and the outcome of TMA in the era of more complex HSCTs.

METHODS

We analyzed the role of some predicting factors for the incidence and the outcome of TMA after HSCT. We enrolled 539 consecutive patients (307 males, median age 31 years) undergoing HSCT from match or mismatch human leukocyte antigen family donor (314) or match/mismatch unrelated (195) and haploidentical donor (30) for malignant or nonmalignant diseases. TMA diagnosis was performed by homogeneous clinical and laboratory criteria.

RESULTS

Sixty-four of 539 patients presented TMA (11,87%) and the five-year cumulative incidence of TMA was 14% (HR=0.13). Fifty nine of 64 patients were affected by malignant and 5/64 by non-malignant diseases. On multivariate analysis, TMA occurrence was influenced by graft versus host disease >grade II (P=0.0001), donor type (P=0.029), gender (P=0.0233), total body irradiation based conditioning regimen (P=0.0041). Three factors for TMA outcome proved to be statistically significant by multivariate analysis: age (P=0.009), donor type (P=0.0187) and TMA index (P=0.029). The TMA mortality rate was 50%. The outcome was influenced by defibrotide (P=0.02 in univariate analysis).

CONCLUSIONS

The study underlines the possibility of finding out which patients are more prone to developing post-HSCT TMA, and identifies which risk factors are more frequently associated with a dismal outcome after TMA.

High Titer of ADAMTS13 Inhibitor Associated with Thrombotic Microangiopathy of the Gut and Skeletal Muscle after Allogeneic Hematopoietic Stem Cell Transplantation

Transplantation-associated thrombotic microangiopathy (TMA) is one of the main complications after hematopoietic stem cell transplantation (HSCT). At the time of onset of gut TMA, a patient developed a high titer of an inhibitor of the non-immunoglobulin G type to ADAMTS13, which physiologically hydrolyzes von Willebrand factor to control spontaneous intravascular thrombus formation. The patient developed symptoms of myositis, a disorder that has occasionally been reported to manifest after HSCT and to resemble some idiopathic autoimmune diseases. However, a muscle biopsy specimen presented pathologic findings of TMA, including microvascular platelet thrombus formation, without inflammatory lymphocyte infiltration. ADAMTS13 activities returned to normal after steroid treatment, and the improvement of TMA symptoms followed. This patient appears to represent a rare case of post-HSCT TMA associated with the development of an ADAMTS13 inhibitor.

Therapeutic plasma exchange in patients with grade 2-3 hematopoietic stem cell transplantation-associated thrombotic thrombocytopenic purpura: a ten-year experience

In the present retrospective study we report our 10-year experience with therapeutic plasma exchange (TPE) in 18 patients with grade 2-3 hematopoietic stem cell transplantation (HSCT)-associated thrombotic thrombocytopenic purpura (TTP). During TPE a mean total quantity of 26.5 +/- 15.1 L of plasma was exchanged. Five patients (27.7%) had a complete response eight patients (44.4%) had a partial response while five patients (27.7%) died during TPE treatment. Among the survivors, relapse of TTP occured in three patients (23%) and although these patients were treated again with TPE, all died. First-year survival rate was 41.2%. Our results indicate that TPE may be effective in the treatment of some patients with grade 2-3 HSCT-associated TTP.

Thrombotic microangiopathy in blood and marrow transplant patients receiving tacrolimus or cyclosporine A

BACKGROUND

Cyclosporine A (CSA) and tacrolimus (FK-506) are both associated with thrombotic microangiopathy (TMA) in allogeneic BMT recipients, although it is not known which drug is more likely to cause the syndrome. The optimal treatment of BMT-associated TMA is also not known.

STUDY DESIGN AND METHODS

To estimate the risks, predisposing factors, and outcomes of TMA, data were analyzed from two cohorts of BMT patients who had received CSA or FK-506 in our institution with the same clinical definition for TMA. TMA was diagnosed in 11 of 55 patients (CSA, 3 of 24; FK-506, 8 of 31).

RESULTS

The daily risk of developing TMA was 0.12 percent for patients receiving CSA and 0.26 percent for those receiving FK-506 (p = 0.16, chi-square). Among patients receiving FK-506, sibling donor BMT recipients were as likely to develop TMA as matched unrelated donor recipients. Serum CSA and FK-506 concentrations were not elevated above the therapeutic range in most patients with TMA. The blood urea nitrogen to serum creatinine ratio was elevated in patients with TMA. Despite daily plasmapheresis, 9 of 11 patients died without resolution of TMA; however, the causes of death were multifactorial, including GVHD. Histologic evidence for TMA was absent in 1 patient who died with persistent clinical signs attributed to microangiopathy.

CONCLUSIONS

In this study, a high incidence of TMA was found in patients receiving either CSA or FK-506 following BMT, with uniform diagnostic criteria and strict monitoring. Neither drug showed elevated levels in most patients with TMA. Plasmapheresis was unsuccessful in reversing most cases of TMA.

Impact of thrombotic thrombocytopenic purpura on leukemic children undergoing bone marrow transplantation

Thrombotic thrombocytopenic purpura (TTP) has emerged as one of the main transplant-related complications over the last 15 years. The current study defines the incidence and the risk factors for the occurrence of TTP in 131 consecutive leukemic children who were transplanted between January 1994 and December 1997 at four Italian pediatric centers. Patients with ALL (101), AML (21), MDS (9), underwent an HLA-identical sibling BMT (82) or an HLA-identical unrelated BMT (49), receiving a conditioning regimen consisting of high-dose chemotherapy in 24 patients and of F-TBI combined with high-dose chemotherapy in 107 patients. The diagnosis of TTP was retrospectively evaluated on the basis of parallel criteria. TTP treatment varied according to the protocol of each treatment center. Twenty-eight of 131 patients (21.4%) developed TTP at a median of 46 days (range 21-80) after BMT. Multivariate analysis demonstrated that the risk of TTP was higher in patients who underwent unrelated BMT (P value = 0.02). Acute GVHD, stage of disease at BMT, conditioning with TBI, gender, age, did not appear to be associated with the occurrence of TTP. As to the outcome, TTP resolved in 19 patients while in nine it was the principal cause of death (32.1%). In patients with TTP, LDH peak value was the only statistically significant factor (P = 0.001) related to severe TTP. In conclusion, our experience demonstrates that leukemic children undergoing BMT, especially from an unrelated donor, should be carefully assessed for TTP which appears to be a severe and relatively common transplant-related complication when strict diagnostic criteria are applied.