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EBMT 2020 Annual Meeting - Viruses, parasites and tropical diseases: the impact of infections on HSCT performance worldwide

Global Committee

Global Committee Session - Sunday 30 August, 08:45-10:00H, Auditorium 5

The impact of different types of infection on HSCT performance will be covered in an extended special session on Sunday, featuring five speakers.

The first talk will focus partly on the COVID-19 pandemic that has disrupted HSCT activity. The presentation, titled ‘Impact (known or potential) of community respiratory virus infections (CRVs) on the outcome of recipients of an allogeneic HSCT or CAR T-cell therapy’ will be given by Dr Rodrigo Martino of the Division of Clinical Hematology at Hospital de la Sant Creu i Sant Pau, Barcelona and Universitat Autónoma de Barcelona, Spain.

He will discuss that infections caused by human CRVs (hCRVs) are very common in recipients of a HCT. Until 2020, the hCRVs which most commonly caused severe morbidity in these patients included hRSV, hMPV, hPIV 1-4, endemic hCoV, hADV, hRV, hEV and hBoV, which infect patients during community epidemics, and occur in a relatively predictive manner during certain periods of each year. However, the eruption of the hCoV SARS-CoV-2 and its worldwide pandemic has had a strong impact on HCT programmes worldwide, which include the complete shut-down of HCT activity in many centres around the world for several months, resulting in an unquantifiable number of alloHCT and CAR-T cell candidates who will never receive their otherwise planned treatment.

Dr Martino will also discuss the sudden enormous complexities in the procurement of matched unrelated donor HSCs, their transportation and the sudden shift from their fresh infusion to their universal cryopreservation, and also the need to implement very strict infection-control policies and continuous screening for this single viral pathogen.

He says: “There have also been very high levels of stress in healthcare workers, especially nurses in clinical HCT units, and a shortage of attending physicians. We will face potentially high rates of mortality and morbidity if we are unable to avoid high rates of COVID-19 in our patients. Of course, at the time of this special online EMBT congress in August 2020, there is no effective prophylactic nor therapeutic anti-viral treatment. The HCT community worldwide, like all of society, is being forced to react to COVID-19’s continuously changing behaviour. And most of the challenges still lie ahead.”

The issues around tropical diseases will then be addressed by Dr. Francesca F. Norman, National Referral Unit for Tropical Diseases, Infectious Diseases Department, Ramón y Cajal University Hospital, Madrid, Spain.

She will discuss that travel and migration contribute to the emergence of certain geographically-restricted infectious diseases which may cause considerable morbidity and mortality worldwide. Although in non-endemic areas, transmission may be limited (vectors may be absent, hosts may be non-susceptible or the environment may be unfavourable), transplant patients may develop infrequent exotic infections (transfusion-transmitted cases, transmission via graft, initial de novo infection in endemic areas or reactivation of latent infections).

Dr Norman says: “Cases of dengue, Zika, chikungunya, histoplasmosis, malaria, Chagas disease and Strongyloides infection have been reported in the context of HSCT. Donors and recipients may have been exposed to geographically-restricted infections, and diagnosis in the context of transplantation may be difficult.”

She will explain how donor screening and deferral recommendations for tropical infections may be controversial and vary among endemic and non-endemic regions. “Fever and other non-specific symptoms are frequent in hospitalised patients, and may not alert physicians to the possibility of infrequent/ exotic infections especially in a non-endemic context,” says Dr Norman. “In cases of transmission via the graft, an association may be difficult to establish and specialised diagnostic techniques for infrequent infections may not always be readily available.  A high index of suspicion, specific guidelines, and notification to authorities are necessary for a prompt and adequate response in the context of geographically-restricted infections and transplantation.”

In his talk on parasitic infections in bone marrow transplant (BMT) patients, Professor Gregorio Jaimovich of Favaloro University Hospital, Buenos Aires, Argentina, will explain that although parasitic diseases affect a huge part of the population, mainly in developing countries, they are understudied. There are few prospective trials on parasitic infections in BMT patients, and management recommendations are based on expert opinions.

He will discuss several examples, including toxoplasmosis, the opportunistic infection caused by Toxoplasma Gondii. Endemic regions include France, Latin America and sub-Saharan Africa with 2 to 3% of the population affected. “The reactivation of latent cyst in the central nervous system has been described in highly immunosuppressed hosts like those receiving an allogeneic transplant, recipients without exposure to the Toxoplasma Gondii with a toxoplasmosis positive donor, those under GvHD treatment and those not receiving cotrimoxazole. Diagnosis using PCR and early treatment with cotrimoxazole is the backbone to control the disease,” explains Professor Jaimovich. 

He will also highlight Chagas disease, caused by Trypanosoma Cruzi, transmitted by the large insect vinchuca to humans, or vertically from mother to the fetus, and by unscreened blood transfusions and organ donations. Although it is only endemic in Latin America, large migration movements have spread the disease to North America and Europe. The disease is silent in 70% of infected people. As in other parasitic infections, reactivation occurs in most BMT patients. Parasite circulation can be detected by a PCR test, and benznidazole is an effective drug treating the disease both in patients and infected donors.

He will also discuss other less well-known parasitic diseases, including Strongiloides Stercolaris, a soil-transmitted parasite that penetrates the skin of people walking barefoot, migrating throughout the circulatory system to the lungs and then to the digestive tract where it stays in the duodenum. “Parasites can be silent or cause bloody diarrhoea and abdominal pain. Eosinophilia could be an alert. Treatment with ivermectin ensures parasite eradication,” says Professor Jaimovich.

In the other talks in this session, the impact of infections in Asia will be addressed by Alok Srivastava, Professor in the Department of Haematology, Christian Medical College (CMC), Vellore, India and Head of the Centre for Stem Cell Research, a unit of Institute of Stem Cell Research and Regenerative Medicine (inStem), Bengaluru, at Vellore, Tamil Nadu, India, while the features of infections in resource-limited countries will be presented by Dr Asma Quessar, Head of Hematology and Pediatric Oncology Department, University Hospital Ibn Rochd, Casablanca, Morocco.