How do we translate gaps and unmet needs of blood management for thalassemia into a collaborative implementation framework?

BACKGROUND AND OBJECTIVE

The mainstay of management for thalassemia is regular blood transfusions. However, gaps and unmet needs of blood services for thalassemia are still not clearly identified and addressed in Thailand, a country prevalent with thalassemia. What can be a collaborative implementation framework that helps advance practices and policies relating to blood management for thalassemia?

METHODS

The first Blood & Beyond Roundtable Discussion was held in July 2022 to gather the current situation, gaps, and unmet needs of blood services for thalassemia from multidisciplinary experts and thalassemic patients. The Implementation Guide as suggested by the Centre for Effective Services was applied as a tool to consolidate information from the discussions and construct the collaborative implementation framework.

RESULTS

The National Blood Center and hospitals in Thailand followed the missions specified in the National Blood Policy and the standard guidelines to ensure the best practice of blood management for thalassemia. However, there were six gaps and unmet needs identified from the discussions. After all discussion points were mapped onto the framework, an implementation plan comprised of five specific activities became clear and actionable.

CONCLUSION

Without the complete information from both experts and patients, the implementation plan would not have been successfully constructed. The method that we employed to translate all information into the framework can be adapted by other countries to develop their own specific framework efficiently.

Seroprevalence of leptospirosis among blood donors in an endemic area

Thailand is known to be endemic for leptospirosis. This bacterium may pose a potential risk to transfusion safety. This study was a cross-sectional study examining the seroprevalence of leptospirosis among Thai blood donors. A total of 1053 serum specimens collected from blood donors residing in 5 regions of Thailand during March to September 2020 were included in this study. All samples were tested for the presence of antibodies to 22 leptospiral serovars using the microscopic agglutination test (MAT) and anti-Leptospira IgG antibodies using commercially available enzyme immunoassay. We found no evidence of recent exposure to Leptospira spp. in sera of healthy Thai blood donors by MAT, including those in higher-risk areas. However, in this same group, we did find small numbers of past exposure (1.7%) to Leptospira spp. by IgG ELISA. According to the findings of this study, there is currently no evidence for implementing new blood banking procedures to identify possible carriers in Thailand, however these should be continually monitored and revised according to the infectious disease burden in each country. It should be noted that there was a difference in the occupation rate between the general population reported in Thailand and blood donors in this study; it may not reflect the actual situation in the country.

Prognostic factors and impact of CMV reactivation on acute myeloid leukemia patients after HLA-matched myeloablative allogeneic stem cell transplantation in a high CMV prevalence country

INTRODUCTION

Relapse of acute myeloid leukemia (AML) after allogeneic stem cell transplantation (allo-SCT) leads to dismal outcomes. This study aimed to identify high-risk patients and explore the effects of cytomegalovirus (CMV) reactivation in a high CMV-seropositive population.

METHODS

The study involved a single-center retrospective cohort in Thailand, analyzing clinical risk factors and CMV-mediated immune responses, correlated with transplant outcomes in AML patients.

RESULTS

Eighty-five patients with AML in complete remission (CR) undergoing HLA-matched myeloablative allo-SCT between 2011 and February 2021 were enrolled. The relapse rate was 27.1% with the median time of 7 months after transplantation. The 3-year relapse-free-survival (RFS) and overall-survival (OS) were 72.2% and 80.8%, respectively. The disease status (>CR1) and absence of chronic graft-versus-host disease (cGVHD) were independently significant adverse prognostic factors of RFS and OS. Ninety-two percent of recipient-donor pairs were both CMV seropositive. The CMV reactivation occurred in 54.1% of the patients. The clinically significant CMV infection rate was 49.4%. No CMV syndrome/disease or CMV-related mortality occurred. One-year cumulative incidence of relapse among CMV-reactivation and non-reactivation groups were 14.3% and 25.6%, respectively, without a statistically significant difference. Transplantation-related mortality was 11.1%.

CONCLUSIONS

The transplantation beyond CR1 and absence of cGVHD are powerful prognostic factors associated with inferior RFS and OS. In a high CMV prevalence country, there appears to be no impact of CMV reactivation on relapse in AML patients undergoing an allo-SCT.

Randomised controlled trial of glucose-6-phosphate dehydrogenase deficient versus non-deficient red blood cell transfusion in patients with hypoproliferative anaemia

BACKGROUND

Recent studies revealed the glucose-6-phosphate dehydrogenase (G-6-PD) deficiency prevalence of 7.7-10% among Thai blood donors. Transfusion of red blood cells (RBCs) from these subjects potentially causes haemolysis in recipients.

METHODS

RBC units from the National Blood Centre were sampled to assess G-6-PD levels using spectrophotometry. Patients with pure underproduction anaemia requiring blood transfusion were randomised to receive G-6-PD-deficient versus normal ABO-matched RBCs. Pre- and 48-h post-transfusion indirect bilirubin, haemoglobin, haematocrit, lactate dehydrogenase (LDH) and haptoglobin were measured.

RESULTS

From April 2020 to March 2021, 374 RBC units were tested for G-6-PD, and that 25 were found to be G-6-PD deficient. Twelve units of G-6-PD-deficient RBCs and 14 units of normal RBCs were given to patients who met the inclusion criteria. The median (interquartile range) increases of indirect bilirubin in G-6-PD-deficient (N = 11) versus normal RBCs (N = 13) were + 0.12 (0.27) versus + 0.01 (1.3) mg/dl, p = 0.030), respectively. The median increases of haemoglobin were 1.00 (0.50) versus + 0.80 (0.95), p = 0.910, respectively. The increases in haematocrit were 2.59 (1.9) versus 2.29 (2.1), p = 0.733, respectively. There were no significant differences in changes of LDH and haptoglobin levels and no transfusion reactions.

DISCUSSION

G-6-PD-deficient packed red cells were associated with mildly elevated indirect bilirubin after transfusion, but there was no observed clinical symptoms.

ChAdOx1 nCoV-19 vaccine-associated thrombocytopenia: three cases of immune thrombocytopenia after 107 720 doses of ChAdOx1 vaccination in Thailand

We reported three cases of immune thrombocytopenia (ITP) that developed within 6 weeks after ChAdOx1 nCoV-19 vaccination. Antiplatelet factor 4 antibodies were undetectable in all three cases. Therefore, vaccine-induced immune thrombotic thrombocytopenia was very unlikely. Other potential causes of thrombocytopenia were excluded. Their clinical presentations, severity of thrombocytopenia and outcomes were varied. Only one ITP case, an 80-year-old man, received ITP treatments and achieved complete response after 2 weeks of eltrombopag. An 84-year-old man had spontaneous complete remission, and a 55-year-old woman had partial platelet recovery without ITP treatments. Among 107 720 Thais administered the ChAdOx1 vaccine between 16 March and 10 May 2021, these three ITP cases resulted in an estimated risk of ITP of at least one per 36 000 doses, which was approximately similar to the risk of ITP after measles-mumps-rubella immunization. This raises the concern of an increased risk of ITP after ChAdOx1 vaccination.

High B-cell activating factor levels in multi-transfused thalassemia patients

OBJECTIVES

To assess the associations between B-cell activating factor (BAFF) and alloimmunisation in multi-transfused thalassemia.

BACKGROUND

Red blood cell (RBC) alloimmunisation is a complication of multi-transfused thalassemia. BAFF is promoting B cells that produce alloantibodies.

METHODS/MATERIALS

Multi-transfused thalassemia, 15 years or older, were recruited in the cohort study. Alloantibodies and BAFF levels were analysed.

RESULTS

Of 114 patients, the overall prevalence of RBC alloimmunisation was 29.8%. The most common alloantibodies were anti-E, anti-Mi^a and anti-c. BAFF levels were different among the three groups; the patients with baseline alloantibodies (median ± interquartile range 1251 ± 474 pg/ml), without alloantibodies (1098 ± 453) and healthy controls (719 ± 306), p < 0.001. The BAFF level was elevated in the >25 years old patients (vs. the <25, p = 0.011) and the buffy-coat-reduced blood recipients (vs. the pre-storage leukocyte-depletion, p = 0.005). Absolute lymphocyte count was higher in the patients without baseline alloantibodies (vs. with baseline alloantibodies, p = 0.049) and the splenectomised patients (vs. the non-splenectomised patients, p < 0.001). Of the 72 patients without baseline antibodies, four who developed new antibodies showed no statistically different BAFF levels compared with those without new antibodies after 40-month follow-up (1296 ± 734 vs. 1062 ± 460, p = 0.491). In multivariate analysis, BAFF to absolute lymphocyte ratio was independently associated with RBC alloimmunisation (odds ratio 3.07, 95% confidence interval 1.124-8.369, p = 0.029).

CONCLUSION

B-cell activating factor (BAFF) levels were elevated in multi-transfused thalassemia and the BAFF to absolute lymphocyte ratio was associated with red blood cell (RBC) alloimmunisation.

Prevalence of thrombocytopenia, anti-platelet factor 4 antibodies and D-dimer elevation in Thai people After ChAdOx1 nCoV-19 vaccination

BACKGROUND

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare distinctive syndrome characterized by unusual site thrombosis accompanied by thrombocytopenia after ChAdOx1 nCoV-19 vaccination. Platelet-activating anti-platelet factor 4-dependent antibodies (anti-PF4 Abs) were detected in most cases of VITT. To date, data from Asian countries are lacking.

OBJECTIVES

To determine the prevalence of thrombocytopenia, anti-PF4 Abs, and D-dimer elevation in Thai people administered the ChAdOx1 vaccine.

PATIENTS/METHODS

A total of 521 vaccinated and 146 nonvaccinated subjects were enrolled. Blood samples were collected to determine platelet counts, anti-PF4 Abs using ELISA and D-dimer levels 5 to 30 days after the first vaccination.

RESULTS

None of the participants developed thrombocytopenia or had significantly decreased platelet counts from baseline after ChAdOx1 vaccination. The frequencies of anti-PF4 Abs between vaccinated (16/521; 3.1%; 95% confidence interval [CI], 1.8-4.9) and nonvaccinated Thai people (6/146; 4.1%; 95% CI, 1.5-8.7) were similar. None of the detectable anti-PF4 Abs activated platelets in vitro. The average D-dimer levels between vaccinated and control groups were similar (282.2 ± 286.3 vs 267.8 ± 219.3 ng/mL; P = 0.58). Four vaccinated and one nonvaccinated participants had markedly elevated D-dimer levels >2000 ng/mL without detectable anti-PF4 Abs. Imaging studies of these asymptomatic subjects revealed incidental pulmonary embolism in a vaccinated elderly woman.

CONCLUSIONS

This study demonstrated a low prevalence of thrombocytopenia and pathogenic anti-PF4 Abs after ChAdOx1 vaccination. D-dimer testing revealed no significant coagulation activation. Routine tests for platelet counts, anti-PF4 Abs, and D-dimer levels are not recommended for VITT screening without clinical suspicion.

Clinical impacts of DNA-based typing and provision of antigen-matched red blood cell units for chronically transfused patients with thalassemia

Blood transfusion, the main therapy for patients with severe thalassemia, is challenged by alloantibodies that can lead to hemolytic transfusion reactions. The use of prophylactic antigen-matched units is recommended, but serologic typing, before the first transfusion, is rarely performed and is not reliable after chronic transfusion. Patient DNA-based typing is a promising strategy, but clinical outcome data are lacking. The aim of this study was to determine the benefits of antigenmatched transfusion guided by DNA-based typing in terms of new alloantibody formation and increases in mean pretransfusion hemoglobin (Hb) levels. We performed DNA-based typing on samples from 24 transfusion-dependent patients with thalassemia who had no serologic phenotyping performed before the first transfusion. These patients were then transfused with antigen-matched donor RBC units that were typed serologically. New alloantibody formation and mean pre-transfusion Hb levels were evaluated after implementing this extended common antigen-matching transfusion protocol. Sixty-three percent of the patients in this study were diagnosed as having beta-thalassemia Hb E. Alloantibodies were already present in 87.5 percent (21/24) of these patients, and most of these antibodies were multiple and/ or unidentified. After the enrollment, there were 717 transfusion episodes comprising 1209 RBC units. The number of RBC units transfused to each patient ranged from 22 to 119 units. At the median duration of 25.5 months (range 10-34 months), no new alloantibodies were detected since the beginning of the protocol. Seventy-four transfusion episodes in six patients were crossmatch-positive due to autoantibodies (patients 2, 4, 8, 9, and 14) or anti-Chido (patient 18) that had been identified before the study. There were no hemolytic transfusion reactions in this study. Five patients (patients 1, 2, 12, 15, and 20) showed increased mean pre-transfusion Hb levels (≥1 g/dL) and one patient (patient 16) had longer intervals between transfusions (compared with those before the protocol), suggesting longer RBC survival, although there was no statistical difference in the whole group. Our study highlights the benefits of DNA-based typing in chronically transfused patients with thalassemia who had no phenotyping data before the first transfusion. Patient DNA-based typing for antigen-matched transfusion is safe in thalassemia and allows us to obtain better-matched blood units for complicated patients.

Cold agglutinin disease following SARS-CoV-2 and Mycoplasma pneumoniae co-infections

SARS‐CoV‐2 and other respiratory co‐infections may occur. As Mycoplasma pneumoniae and various viruses can cause cold agglutinin disease (CAD), the presence of CAD in COVID‐19 patients should indicate the need of investigations for those pathogens.

A case of nearly mistaken AB para-Bombay blood group donor transplanted to a group 'O' recipient

Unintentional ABO mismatch kidney transplantation can cause detrimental hyperacute rejection. We report the first successful ABO incompatible kidney transplantation from an AB para-Bombay donor to O recipient. At the initial evaluation, the donor's ABO type was discordance on the cell typing and serum typing, which typed to be 'O' as cell typing and 'AB' as serum typing. At the second investigation, it was confirmed that the donor had a unique, rare but not uncommon blood type AB para-Bombay which was incompatible with the recipient's blood group. The kidney transplantation was successfully performed by an ABO incompatible preconditioning, double filtration plasmapheresis (DFPP) and rituximab. The serum creatinine at 12 months post-transplantation was 1.3 mg/dL. The pathology of the kidney biopsy showed no signs of rejection.

Interferon-α is not elevated in idiopathic thrombotic thrombocytopenic purpura patients

Idiopathic thrombotic thrombocytopenic purpura (TTP) patients have ADAMTS13 deficiency, which is usually caused by ADAMTS13 autoantibodies. However, the triggering factors for the autoantibody production remain unclear. Interferon-α (IFN-α) is a cytokine involved with many autoimmune processes such as inducing the activation of peripheral dendritic cells and stimulating T cells and B cells. It also plays an important role in some autoimmune diseases. Elevated IFN-α levels have been observed in some TTP patients and previous case reports have shown the occurrence of TTP after IFN-α treatment. Thus, we hypothesized that high levels of IFN-α would correlate with presence of ADAMTS13 autoantibodies. However, we did not observe elevated IFN-α levels in 36 TTP patients (mean 5.29 pg/ml, standard deviation (SD) 26.56 pg/ml) compared to healthy controls (mean 0 pg/ml, SD 0 pg/ml), P = 0.59. IFN-α levels of most patients (94%) were undetectable. Only two patients had increased IFN-α levels and ADAMTS13 autoantibodies were detected in these two patients. Interestingly, both the patients had an underlying autoimmune disease. Although there have been cases of secondary TTP following IFN-α treatment, no evidence supports a role of IFN-α in the development of idiopathic TTP in our patient population.

Rapid increases in parasitemia following red cell exchange for malaria

Exchange transfusion is frequently used as an adjunctive treatment of severe malaria, although the efficacy of exchange transfusion as therapy for severe malaria remains controversial. The major perceived benefit of exchange transfusion is the rapid reduction of parasite load. However, no previous report has shown the dynamic change in parasitemia shortly following an acute load reduction. We report a 20-year-female who developed cerebral malaria and 30% parasitemia after traveling to Africa. In addition to antimalarial treatment, red cell exchange (RCX) was begun emergently with an automated blood-cell separator. Parasitemia dropped from 30 to 15% immediately after the procedure but rapidly increased to 25% after 50 min. The second procedure was performed 12 h after the first procedure. Her neurologic status returned to baseline on Day 2, and she was discharged on Day 6. Rapid increases in parasitemia can be observed after mechanical load reduction following RCX.