Immunohistochemistry analysis of bone marrow biopsies in multiple sclerosis patients undergoing autologous haematopoietic stem cells transplantation.

OBJECTIVE: Recently autologous haematopoietic stem cell transplantation (AHSCT) has been introduced for the treatment of severe forms of multiple sclerosis (MS). As little data are available on bone marrow (BM) of MS patients undergoing AHSCT, we investigated the morphological and phenotypic characteristics of MS BM.
METHODS: BM biopsies of 14 MS patients screened for AHSCT and 10 control patients were evaluated to assess cellularity, morphology, immunological profile and bone marrow microenvironment. Immunohistochemistry analysis was performed to evaluate the expression of CD3, CD4, CD8, CD20, CD68, CD45, MMP-9.
RESULTS: 8 out of 14 MS (57%) patients showed a reduction of age-related bone marrow cellularity, possibly due to previous immunosuppressive therapies. There were no differences in the T CD3+ lymphocyte expression rate amongst MS and the control patients, the CD4/CD8 ratio (2:1) was maintained as was the rate of B lymphocytes. We found an increased, although not significant, MMP-9 expression (9.2%) in the bone marrow of MS patients, when compared to the control patients (6.3%).
CONCLUSION: The BM of MS patients showed a reduced cellularity and CD45+ cells content in comparison to the controls. A slightly increased expression of MMP-9 was also shown, possibly confirming an involvement of this compartment in the pathogenesis of the disease.