Clinical characteristics and incidence of toxoplasmosis after autologous hematopoietic stem cell transplantation: A retrospective study and literature review

Background Toxoplasmosis is a rare but life‐threatening infection occurring in immunocompromised hosts, including allogeneic hematopoietic stem cell transplantation (allo‐HSCT) recipients. However, thus far, the clinical features and incidence of toxoplasmosis in autologous HSCT (auto‐HSCT) recipients remain unknown. This retrospective survey aimed to analyze 152 patients who received auto‐HSCT between 1998 and 2017. Methods Serological tests for Toxoplasma gondii‐specific IgG were performed on 109 (71.7%) recipients, and 12 pre‐HSCT recipients (11%) were Toxoplasma seropositive. Among the 12 recipients, three who did not receive trimethoprim‐sulfamethoxazole (TMP/SMX) prophylaxis developed cerebral, pulmonary or disseminated toxoplasmosis due to reactivation after auto‐HSCT and died despite treatment. Results The incidences of toxoplasmosis were 2% and 25% among 152 auto‐HSCT recipients (five recipients received auto‐HSCT two times) and 12 pre‐HSCT Toxoplasma seropositive recipients, respectively. Further, we conducted a literature review and identified 21 cases of toxoplasmosis following auto‐HSCT. In these previous cases, the mortality rate was high, especially for pulmonary and disseminated toxoplasmosis. Our findings suggest that, similar to toxoplasmosis after allo‐HSCT, toxoplasmosis after auto‐HSCT is a fatal complication. Conclusions Serial screening of T. gondii‐specific IgG before HSCT could contribute to the detection of Toxoplasma reactivation and allow for prompt diagnosis and treatment. The present study is the first to reveal the incidence of toxoplasmosis after auto‐HSCT among seropositive patients in Japan.