Compared to patients with Hurler Syndrome (HS), children with severe combined immunodeficiency (SCID) often suffer from infections that might affect outcome following hematopoietic stem cell transplantation (HSCT).
A retrospective chart review was conducted among 31 SCID and 16 HS patients who received HSCT at <2 years of age at The Hospital for Sick Children between 2000-2012. Data was collected regarding pre-HSCT infections, donor source and HLA disparity, conditioning and GvHD prophylaxis as well as post-HSCT donor engraftment, infections, development of acute and chronic GvHD and 2-year survival. Comparison between groups was conducted by Fisher’s exact test with p<0.05 considered as statistically significant.
Infections, particularly pneumonia and bacteremia, were more common (p=0.038) pre-HSCT among patients with SCID than with HS (87% versus 56%, respectively). Other pre-HSCT characteristics were similar, apart from the more common conditioning with anti-thymocyte globulin and/or irradiation among patients with HS (p<0.001). After HSCT, neutrophil engraftment occurred by day 14 in 71.4% of patients with SCID but none of the patients with HS (p<0.001). The incidence of infections post-HSCT was similar between groups. Acute GvHD was detected among 61% and 56% of patients with SCID and HS, respectively, while chronic GvHD occurred in 45% and 38%, respectively; differences that were not significant. Two-year survival post-HSCT among patients with SCID was 22/31 (71%), similar to that among HS patients (75%).
Our study indicates that the presence of infections and other pre-HSCT characteristics do not have significant effects on the outcome of HSCT in patients with SCID.