Background: Autologous stem cell transplantation (HSCT) is an evidence-based medical approach to treat systemic sclerosis patients with rapidly progressing disease state.

Objectives: To further understand the efficacy of HSCT, the analysis of the process of immune reconstitution after HSCT is elementary. Here, we focused on B cell (memory), namely titers of standard vaccinations against various infectious diseases at different timepoints prior and after HSCT. Besides the titers, we included serum immunoglobulins in our analysis. Consequently, the aim is to investigate the immunological effects particularly in the first two years after HSCT.

Methods: To give an overview of the immune reconstitution, we here show the data of 31 patients (11 females, 20 males) with a median age of 43 at the time of the HSCT. The data of the vaccination titers were collected at certain time points during HSCT; before transplantation, as well as 6, 12 and 24 months after HSCT. Before transplantation it was recommended to boost missing vaccinations following to the determined titers. Most of the patients showed a sufficient amount of antibodies before the transplantation. Below, we show the individual values at the different timepoints with the course of the medium value. As well, we focused on reference range which most of the patients stayed above during this two-year-time-period.

To further understand the immune process after an autologous stem cell transplantation, we evaluated the amount of the serum immunoglobulins IgG, IgM and IgA. The majority of the patients showed normal IgG, IgM and IgA before transplantation. As well, we point out the development of the serum immunoglobulins before and in this two-year-time period after HSCT.

Results: Mainly, a decrease of the titer was evaluated especially in the first six months after the transplantation. For example, the diphtheria antitoxin titer significantly decreased from month 0 to month 6, t(13)=3.62, p=0.004. Equally the tetanus antitoxin titer t(13)=3.62, p=0.004 and the measles IgG antibodies t(13)=2.84, p=0.015. Some titer significantly decreased within the first year after HSCT which is shown by the mumps IgG antibodies which also significantly dropped t(16)=2.55, p=0.022. Similarly to the vaccination titer, the titer of the IgM serum immunoglobulins decreased in the first 6 months after HSCT t(12)=3.19, p=0.009 as well as the titer of IgG serum immunoglobulins in the first 12 months after HSCT t(11)=2.52, p=0.030. Despite the decrease most of the patients stayed on a low to adequate level of protecting titers, recommend by the Standing Committee on Vaccination (STIKO). Past this two-year-time-period after HSCT the immune reconstitution was perceived by recreation of the titers or remaining on a sufficient level.

Conclusion: In the majority of the patients a decrease of the vaccination titers and serum immunoglobulins, particularly in the first six to twelve months after autologous stem cell transplantation, has been recognized. Consequently, it allows to give special vaccination recommendations for patients individually before and after autologous stem cell transplantation.

REFERENCES NIL. Acknowledgements: NIL.

Disclosure of Interests: Sofie Endres: None declared, Ann-Christin Pecher: None declared, Reinhild Klein: None declared, Jörg Henes ABBVIE, Astra-Zeneca, BMS, Boehringer-Ingelheim, GSK, Pfizer, UCB.