A possible case of Chagas disease reactivation after a bone marrow transplant

Dear Sir,

We would like to contribute to the article by Angheben and co-workers which was recently published in Blood Transfusion¹. The Authors described a case of reactivation of Chagas disease in a paediatric patient who underwent a bone marrow transplant (BMT) in a non-endemic country.

To our understanding, since no data related to the patient’s infection status prior to the BMT were clearly provided by the Authors, it is very difficult to concur that this was truly a case of Chagas disease reactivation after a BMT.

Chagas disease in transplant recipients may occur in one of the following ways: (i) via the blood transfusion given during the BMT. Blood transfusions from donors with asymptomatic parasitaemia represent a major form of transmission in some endemic areas, and have also been described in non-endemic countries²; (ii) through reactivation of a latent infection which could have previously been acquired by vector-borne transmission, blood transfusion or congenital transmission; and (iii) de novo acquisition of the infection via the graft which, in this case, could have been caused by the transplanted bone marrow itself.

With respect to the first point, if the patient had been transfused in Italy, the possibility of transfusion-transmitted T. cruzi infection during the BMT period would also have to be considered. In this event, the blood component most likely to be implicated in the transmission would be platelets, as recently reported by some Authors². However, in the text the Authors stated that the patient was transfused in Argentina during her treatment for leukaemia, but not in Italy while undergoing the allogeneic BMT. As a result, this possibility can reasonably be ruled out.

With respect to reactivation of a latent infection, the information indicating a possible Chagas disease reactivation was that the patient had major risk factors for prior infection, i.e. having lived in and/or being born in an area in which T. cruzi is endemic, having been transfused in Argentina and, in addition, having a mother who was also from an endemic area. However, some essential data are missing: i.e. the recipient’s infection status prior to the BMT, information regarding the proposed route of transmission, such as the blood donors, and investigations into her mother’s T.cruzi infection status. In addition, the article did not specify which region of Argentina the patient came from, which could have been valuable information since not all regions in Argentina are equally affected and certain areas are currently free of T. cruzi transmission, such as the Provinces of Buenos Aires, Chubut and Santa Cruz³.

On the other hand, this case could possibly have been example of BMT-transmitted T. cruzi. It would have been helpful to investigate the donor to exclude this route of transmission, especially considering that he or she was from California which, in fact, is among the regions with the greatest number of Latin-American immigrants in the United States and, consequently, has the highest proportion of Latin-American donors. In addition, this population has been increasing over the years and performing a recipient tracing study could have helped to identify an infected BMT donor.

Cases of transplant-related Chagas disease have mainly been described in organ transplant recipients in Latin America. Transplants from infected donors whose status is unknown at the time of the transplantation can result in the recipient acquiring severe acute Chagas disease⁴. However, all blood components from infected donors have the potential to transmit the infection. In fact, T. cruzi can survive in platelet components with anticoagulant solution for up to 5 days when stored at room temperature², for 18 days in red blood cells at 4 ºC, and can also survive cryopreservation and thawing⁵. Theoretically, bone marrow may also transmit T. cruzi infection.

There are various factors that support the belief that this case was a reactivation of Chagas disease (the patient’s clinical features, the major risk factors for a previous, although unconfirmed, infection by Chagas disease prior to the BMT) but, equally, there were also factors to support a BMT-transmitted Chagas’ disease (the donor was from California, no proof that the patient was infected prior to the BMT). Since both these options are possible, we suggest that this report should be considered as a possible case of Chagas disease reactivation after a BMT; it is certainly a very interesting report concerning a case of this disease in an immunosuppressed patient. Given that Chagas disease can be fatal in such patients, as demonstrated in the case described, the recommendation to implement measures to prevent the transmission or reactivation of Chagas disease in transplant recipients is in itself an outstanding contribution already made by the Authors. We totally agree with the Authors on this point since this recommendation could be of vital future importance for patients with similar conditions, and because it has also been successfully proven in BMT patients with Chagas disease in Latin America.