Adult T-cell leukemia/lymphoma in HTLV-1 non-endemic regions

Area of Science:

• Virology
• Hematology
• Epidemiology

Background:

• Human T-lymphotropic virus type 1 (HTLV-1) is a neglected virus causing severe neurological and lymphoproliferative diseases.
• Adult T-cell leukemia/lymphoma (ATLL), a highly aggressive hematological malignancy, develops in approximately 5% of HTLV-1 carriers worldwide.
• Spain, a non-endemic country, has a significant migrant population from HTLV-1 endemic regions in Latin America and Africa.

Purpose of the Study:

• To report the main features of all patients diagnosed with ATLL in Spain.
• To analyze the incidence and characteristics of ATLL in a non-endemic country with a high migrant flow.

Main Methods:

• Utilized a national HTLV-1 register established in Spain in 1989.
• Collected and analyzed data on all diagnosed ATLL patients in Spain up to December 2022.

Main Results:

• A total of 451 HTLV-1 infections were reported in Spain by end of 2022, with 35 (7.8%) diagnosed with ATLL.
• The average incidence of ATLL in Spain is two cases per year, with a mean age at diagnosis of 47; 57% of patients were female, and a majority were migrants (57% Latin American, 26% African).
• ATLL patients exhibited significantly higher HTLV-1 proviral loads compared to asymptomatic carriers, and survival was generally less than one year.

Conclusions:

• ATLL incidence in Spain is low and predominantly associated with migrants from HTLV-1 endemic regions.
• Due to the poor prognosis of ATLL, screening is recommended for migrants from endemic countries and natives with relevant exposure history.
• HTLV-1 testing is crucial for early detection and management, especially in at-risk populations within non-endemic settings.