Contributions
Abstract: EP814
Type: E-Poster Presentation
Session title: Infections in hematology (incl. supportive care/therapy)
Background
Vaccination against hepatitis B virus (HBV) is highly recommended for hematopoietic stem cell transplantation (HSCT) recipients who have no protective antibody titers against the surface antigen (anti-HBs). The effectiveness of vaccination, reflecting the immune system functionality, represents a reliable marker for the qualitative immune reconstitution post HSCT. However, it is subjected to several factors (pre-immunization, HSCT type, conditioning regimen, graft source, etc.) thus complicating the drawing of secure conclusions as for the efficacy of vaccination programs post HSCT. With regard to autologous HSCT (AHSCT), the general aspect is that the immune system recovers soon after AHSCT therefore patients (pts) after a period of approximately 6 months post AHSCT are considered to be as immunocompetent as healthy individuals.
Aims
We evaluated the HBV vaccination responses in pts autografted for malignant diseases who had anti-Hbs titers <10 IU/ml both before AHSCT as well as the time of vaccination and were in remission and off chemotherapy post-transplant.
Methods
Twenty seven pts aged 51,6 (22-67) years (ys), autografted for lymphoma (n=19), multiple myeloma (n=9) and leukemia (n=1) were included in the study. The median CD34+ infused cells were 6,4×106/kg. The engraftment was successful and regarding the lymphocytes recovery, the median absolute count at +100 day was 1740 (450-4090)/mm3. After a median of 4,3 (0,6–8,5) ys post AHSCT, the recombinant HBV vaccine Genevac-B® (Serum Institute of India Pvt. Ltd) was given monthly, in a 3 doses schedule (20 mg/injection). The median lymphocytes count during the vaccination period were 374/mm3, 1643/mm3, 628/mm3, 844/mm3, and 301/mm3 for the B, CD3+, CD4+, CD8+ and NK cells respectively; all within normal ranges. We considered as effective response the presence of >10 IU/ml anti-HBs titers and the ultimate response rates of pts who successfully completed the 3 vaccine doses, were compared with an internal group of healthy individuals (control group) who were also vaccinated in our centre with the same product during the study period.
Results
After the 1st dose the response rate was 11% (3/27 pts), reaching to 81% (21/26 pts) after the 2nd and to 88% (23/26 pts) after the 3rd dose. In univariate (student’s T-test) and multivariate (logistic regression) analysis, no factor significantly affected the achievement of protective anti-HBV responses after vaccination completion, probably due to the size of our study group. The observed response rates after each dose were lower compared to the reported ones based on the reported product’s efficacy profile (19%, 86% and 100% after the 1st, 2nd and 3rd dose respectively). In the direct comparative analysis with our control group, a strong trend for inferior responses was noticed for the autografted pts (88% vs 100%, p=0,07).
Conclusion
This study on a relatively homogenous group of pts is, to our knowledge, the only one that directly compares the HBV vaccine responses in autografted pts with healthy individuals who were vaccinated in the same area, similar period with the same product, thus providing an accurate comparative analysis. Although the intervention was offered late post AHSCT and pts had already adequate lymphocytes subpopulations counts at the time of vaccination, the response rates were lower compared to healthy individuals. Our results, in agreement with others, are indicative of a long lasting immune impairment post AHSCT highlighting the necessity of prolonged surveillance and intensified vaccination programs for autografted pts.
Keyword(s): Antibody response, Autologous hematopoietic stem cell transplantation, Hepatitis B virus, Vaccination
Abstract: EP814
Type: E-Poster Presentation
Session title: Infections in hematology (incl. supportive care/therapy)
Background
Vaccination against hepatitis B virus (HBV) is highly recommended for hematopoietic stem cell transplantation (HSCT) recipients who have no protective antibody titers against the surface antigen (anti-HBs). The effectiveness of vaccination, reflecting the immune system functionality, represents a reliable marker for the qualitative immune reconstitution post HSCT. However, it is subjected to several factors (pre-immunization, HSCT type, conditioning regimen, graft source, etc.) thus complicating the drawing of secure conclusions as for the efficacy of vaccination programs post HSCT. With regard to autologous HSCT (AHSCT), the general aspect is that the immune system recovers soon after AHSCT therefore patients (pts) after a period of approximately 6 months post AHSCT are considered to be as immunocompetent as healthy individuals.
Aims
We evaluated the HBV vaccination responses in pts autografted for malignant diseases who had anti-Hbs titers <10 IU/ml both before AHSCT as well as the time of vaccination and were in remission and off chemotherapy post-transplant.
Methods
Twenty seven pts aged 51,6 (22-67) years (ys), autografted for lymphoma (n=19), multiple myeloma (n=9) and leukemia (n=1) were included in the study. The median CD34+ infused cells were 6,4×106/kg. The engraftment was successful and regarding the lymphocytes recovery, the median absolute count at +100 day was 1740 (450-4090)/mm3. After a median of 4,3 (0,6–8,5) ys post AHSCT, the recombinant HBV vaccine Genevac-B® (Serum Institute of India Pvt. Ltd) was given monthly, in a 3 doses schedule (20 mg/injection). The median lymphocytes count during the vaccination period were 374/mm3, 1643/mm3, 628/mm3, 844/mm3, and 301/mm3 for the B, CD3+, CD4+, CD8+ and NK cells respectively; all within normal ranges. We considered as effective response the presence of >10 IU/ml anti-HBs titers and the ultimate response rates of pts who successfully completed the 3 vaccine doses, were compared with an internal group of healthy individuals (control group) who were also vaccinated in our centre with the same product during the study period.
Results
After the 1st dose the response rate was 11% (3/27 pts), reaching to 81% (21/26 pts) after the 2nd and to 88% (23/26 pts) after the 3rd dose. In univariate (student’s T-test) and multivariate (logistic regression) analysis, no factor significantly affected the achievement of protective anti-HBV responses after vaccination completion, probably due to the size of our study group. The observed response rates after each dose were lower compared to the reported ones based on the reported product’s efficacy profile (19%, 86% and 100% after the 1st, 2nd and 3rd dose respectively). In the direct comparative analysis with our control group, a strong trend for inferior responses was noticed for the autografted pts (88% vs 100%, p=0,07).
Conclusion
This study on a relatively homogenous group of pts is, to our knowledge, the only one that directly compares the HBV vaccine responses in autografted pts with healthy individuals who were vaccinated in the same area, similar period with the same product, thus providing an accurate comparative analysis. Although the intervention was offered late post AHSCT and pts had already adequate lymphocytes subpopulations counts at the time of vaccination, the response rates were lower compared to healthy individuals. Our results, in agreement with others, are indicative of a long lasting immune impairment post AHSCT highlighting the necessity of prolonged surveillance and intensified vaccination programs for autografted pts.
Keyword(s): Antibody response, Autologous hematopoietic stem cell transplantation, Hepatitis B virus, Vaccination