Autologous hematopoietic stem cell transplantation in systemic sclerosis induces long-lasting changes in B cell homeostasis toward an anti-inflammatory B cell cytokine pattern

BackgroundAutologous hematopoietic stem cell transplantation (aHSCT) is performed in patients with aggressive forms of systemic sclerosis (SSc). The profile of B cell reconstitution after aHSCT is not fully understood. The aim of this study was to investigate changes of B cell subsets and cytokine production of B cells in patients with SSc after aHSCT.MethodsPeripheral blood of six patients with SSc was collected at defined intervals up to 16months after aHSCT. Immunophenotyping was performed, and B cell function was determined by measuring cytokine secretion in supernatants of stimulated B cell cultures.ResultsWithin 1month after aHSCT, a peak in the percentage of CD38(++)/CD10(+)/IgD(+) transitional B cells and CD38(++)/CD27(++)/IgD(-) plasmablasts was detected. Long-term changes persisted up to 14months after aHSCT and showed an increased percentage of total B cells; the absolute B cell number did not change significantly. Within the B cell compartment, an increased CD27/IgD(+) naive B cell percentage was found whereas decreased percentages of CD27(+)/IgD(+) pre-switched memory, CD27(+)/IgD(-) post-switched memory, and CD27(-)/IgD(-) double-negative B cells were seen after aHSCT. Cytokine secretion in B cell cultures showed significantly increased IL-10 concentrations 13 to 16months after aHSCT.ConclusionA changed composition of the B cell compartment is present for up to 14months after aHSCT indicating positive persisting effects of aHSCT on B cell homeostasis. The cytokine secretion profile of B cells changes in the long term and shows an increased production of the immune regulatory cytokine IL-10 after aHSCT. These findings might promote the clinical improvements after aHSCT in SSc patients.