Dr. Niranjan N. Rathod
Associate Director & Head
of Department of HaematoOncology
& Bone Marrow
Transplant
Nanavati Super Speciality
Hospital, Mumbai

Dr. Nimish Kulkarni
Associate Consultant
Department of
Haemato-Oncology &
Bone Marrow Transplant
Nanavati Super Speciality
Hospital, Mumbai

Dr. Prathamesh Kulkarni
Associate Consultant
Department of
Haemato-Oncology &
Bone Marrow Transplant
Nanavati Super Speciality
Hospital, Mumbai

Thalassemia Major is a substantial burden for a country like India. Approximately 1,00,000 Thalassemic children are born every year worldwide of which around 10,000 are born in India. Haematopoietic Stem Cell Transplant (HSCT) is the only curative treatment option currently available for Thalassemia. Outcomes of Haematopoietic Stem Cell Transplant for Thalassemia Major have substantially improved over the past three decades. Worldwide, more than 90% of its patients have now survived Haematopoietic Stem Cell Transplantation, and the disease-free survival rate has been recorded to be around 80%.

The ABO incompatibility between donor and recipient is not an absolute barrier for a successful Allogeneic Haematopoietic Stem Cell Transplant. Conflicting data however still exists about the influence of ABO incompatibility on transplant outcome with a few cases also reporting transplant failure. One way to overcome this incompatibility and minimise its impact on a transplant is to reduce the titres of the mismatched antigen / antibody. Various methods have been described for red cell and plasma depletion of the Stem Cell concentrate on Major ABO mismatch / bi-directional mismatch Haematopoietic Stem Cell Transplant.

THE CASE

A 6-year old boy with a case of Thalassemia Major, diagnosed at the age of 6 months, required regular PRBC transfusions every 18-20 days. Chelation was started when he was just 2 years old. His condition





was assessed as Class II by Lucarelli staging. Investigations revealed HLA 10/10 match with his younger sister; however, they were a bidirectional ABO mismatch. The recipient’s blood group was A Rh while donor’s was B Rh Positive. The Anti B titres in recipient was 1:512 (directed toward red cells in the harvested product) and Anti A titres in donor – 1:64 (directed towards the recipient red cells).

THE PROCEDURE

The patient was transplanted with stem cells harvested from his sister’s bone marrow. Post harvest, red cell depletion was done with 6% HES and plasma reduction was done by plasma expressor. He also received neutrophil engraftment on day 24 and platelet engraftment on day 28. Titration of immunosuppression was done on OPD basis.

THE RESULT

3 months post-transplant, mixed chimerism is at 85.3%. The patient has been transfusion free and is now leading a normal healthy life.

Red cell depletion by 6% HES is a comparatively simple procedure with good yield. Stem cell loss post red cell depletion was comparable to the literature available and almost similar to the loss expected with other machine oriented methods. No variation in the clinical course of transplant was noted apart from delayed engraftment which correlates with the literature on ABO mismatched Haematopoietic Stem Cell Transplant, irrespective of the procedure employed for red cell depletion.

DISCUSSION

Children who are transplanted early, with less number of transfusions and less iron accumulation, have the best success rate of up to 90% with Haematopoietic Stem Cell Transplant. ABO mismatch is no more a major hindrance for Haematopoietic Stem Cell Transplant. Red cell depletion by 6% HES is a cost-effective and efficient method with no major drawbacks and can be implemented as a substitute for costly and sophisticated machinery.