Haemolysis, pure red cell aplasia and red cell antibody formation associated with major and bidirectional ABO incompatible haematopoietic stem cell transplantation

Prevalence of Pure Red Cell Aplasia Following Major ABO-Incompatible Hematopoietic Stem Cell Transplantation

Background

Pure red cell aplasia (PRCA) is one of the important complications in major ABO-incompatible allogeneic hematopoietic stem cell transplantation (HSCT). The established pathogenic factor of PRCA is the persistence of high anti-donor isohemagglutinins. As previously verified, the conditioning regimen and donor type were the factors associated with the development of PRCA in the small-sized studies. Currently, the prevalence, risk factors, and prognosis of PRCA are still worth studying to provide evidence.

Methods

We conducted a prospective nested case-control study to determine the prevalence, donor-related factors, and the outcomes of PRCA following major ABO-incompatible transplantation. A total of 469 patients who underwent ABO-incompatible grafts were observed.

Results

None of the patients were diagnosed with PRCA with minor or bidirectional ABO-incompatible HSCT. Thirteen of the187 patients (7%; 95% confidence interval [CI], 3.9%–11.9%) developed PRCA following major ABO-incompatible HSCT. Eleven of the 13 patients with PRCA recovered entirely. Donor type was an independent factor associated with post-HSCT PRCA (odds ratio [OR]=0.030; 95% CI, 0.003–0.321; P=0.004). The cumulative incidence rates of post-HSCT PRCA in the context of major ABO-incompatible HSCT were 0.8%, 13.1%, and 27.2% for the haploidentical donor (HID), unrelated donor, and matched related donor, respectively. No significant influence of PRCA on transplantation outcomes was observed.

In conclusion, post-HSCT PRCA is a rare and less threatening complication in major ABO-incompatible HSCT. The majority of patients with PRCA could recover. Additionally, HIDs for recipients may have a low risk of post-HSCT PRCA. This trial was registered at www.chictr.org.cn (#ChiCTR2000041412).

Pure red cell aplasia after major or bidirectional ABO incompatible hematopoietic stem cell transplantation: to treat or not to treat, that is the question

Pure red cell aplasia (PRCA) is a complication related to major or bidirectional ABO mismatched hematopoietic stem cell transplantation. This disorder is characterized by anemia, reticulocytopenia, and the absence or virtual absence of erythroid progenitors, other causes such as infections, hemolysis, disease relapse, or drug toxicity having been excluded. Patients with PRCA may become RBC transfusion dependent for long periods, suffering an important long-term iron overload, alloimmunization, and transfusion reactions. The persistence of recipient isoagglutinins against donor ABO antigens produced by host residual plasmatic cells has been considered as the immunological cause of the prolonged erythroid aplasia. PRCA behaves in many cases as a self-limited condition and resolution may occur spontaneously within weeks, months, and even years. Many different therapeutic approaches have been reported for posttransplant PRCA as plasmapheresis, high doses of erythropoietin, donor lymphocyte infusions, anti-thymocyte globulin, Rituximab and steroids, among others. However, to date there is no standard of care and the question if patients with PRCA should be treated and at which point remains. The objective of this article is to review the natural evolution of PRCA, and the treatments that have been used over time focusing on their suitability and efficacy.

[Clinical analysis of 67 cases of pure red cell aplastic anemia]

Objective: To investigate secondary factors, laboratory features, treatment options, and prognosis of pure red cell aplastic anemia (PRCA) . Methods: This was a multicenter retrospective clinical study. Patients aged above 18 years newly diagnosed with PRCA between June 1, 2010, and June 1, 2019, were recruited as the main study object. A comparative analysis of remission rate and overall survival rate was made according to different treatment schemes adopted by patients and different drug reduction rates. Results: A total of 67 patients with PRCA were included in this study and the secondary PRCA group accounted for 44.8% (30/67) . The most common secondary factors were thymoma (n=10) and T-cell large lymphocytic leukemia (T-LGLL) (n=6) . The overall response rate of PRCA was 85.7% and the 3-year overall survival rate of PRCA was (74.3±7.5) %. The remission rate of cyclosporine A alone was slightly higher than that of oral glucocorticoid alone or combined with glucocorticoid[90.0% (36/40) vs 75.0% (12/16) , P=0.147]. After patients applied with cyclosporine A treatment reached CR/PR and remained stable for 3-6 months, the dose of cyclosporine A was reduced by 25 mg each time. The cyclosporine A reduction interval of a 25 mg/d reduction in more than 1 month significantly prolonged the median disease-free survival compared with a 25 mg/d reduction in less than 1 month [not reached vs 15 (95% CI 7-23) months, P<0.001]. There were 62.5% (10/16) of patients who responded to the initial or incremental treatment regimen after relapse. Conclusion: PRCA has features of various secondary factors, high overall survival rate, and high remission rate. Treatment with cyclosporine A alone is preferred, and cyclosporine A should be slowly tapered to reduce the risk of later relapse after it takes effect and patients reach a steady state.