Abstract 2038

Introduction:

Anti-HLA antibodies are associated with several complications in solid organ transplantations but their impact after allogeneic hematopoietic stem cell transplantation (HSCT) is not very well defined yet.

Patients and methods:

To evaluate the relevance of anti-HLA antibodies, we have retrospectively analyzed 107 peripheral blood allogeneic HSCT after reduced-intensity conditioning (RIC) regimen between 2005 and 2010. Acute myeloid leukaemia (n=52,48.5%) and multiple myeloma (n=18,17%) were the most common diagnosis in the cohort. The detection of anti-HLA antibodies was systematically performed in all patients before transplantation.

Results:

We found in 24 patients (22%) the presence of anti-HLA antibodies. There was no association between the presence of anti-HLA antibodies and engraftment, incidence of relapse or acute GvHD. The presence of anti-HLA antibodies was associated with worse survival in univariate analysis (HR 2.04; [95%CI,1.21–3.44], p=0.0056) and in multivariate analysis (HR 2.63; [95%CI, 1.32–5.25], p=0.006). The 3-year probability of OS was 34% (95%CI, 24–49) without anti-HLA antibodies and 16% (95%CI, 6–41) in their presence (Figure 1). The other significant factors on survival were the disease status at transplantation, the age, minor and major ABO incompatibilities between donor and recipient, the sex-mismatching and the CMV status. Moreover, the positive anti-HLA antibodies group showed a trend of higher TRM in univariate analysis (p=0.07) and in multivariate analysis (HR= 1.9; [95%CI, 0.94 – 3.9], p=0.076). The TRM at 3 years after transplantation were 31% (95%CI, 26–37) without anti-HLA antibodies and 46% (95%CI, 36–57) in their presence (figure 2). The causes of the pejorative effect of the anti-HLA antibodies were not defined yet but we observed microangiopathy associated with vascular endothelium damage which could be related to the presence of anti-HLA antibodies.

Conclusion:

Our study suggests that anti-HLA antibodies should be tested and considered as an important prognostic factor for transplant outcomes after RIC HSCT.

Disclosures:

No relevant conflicts of interest to declare.

Author notes

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Asterisk with author names denotes non-ASH members.

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