Remitting-relapsing multiple sclerosis patient refractory to conventional treatments and bone marrow transplantation who responded to natalizumab.

Bone marrow transplantation (BMT) was introduced as a treatment option 15 years ago for severe, drug-resistant multiple sclerosis (MS). Up until now, BMT has been undertaken in relatively few patients worldwide, with moderate success, and recent studies suggest that patients with early, highly aggressive MS benefit most from this treatment. In this work, we determined peripheral blood lymphocyte populations in a patient (patient A) with remitting-relapsing multiple sclerosis (RR-MS), refractory to conventional treatments, and who underwent BMT, relapsed, and has been treated with natalizumab for the last 22 months. Eleven other RR-MS patients in the acute phase of the disease, untreated or treated with interferon-beta, and 20 healthy subjects served as controls. Natalizumab treatment in patient A resulted in lymphocytosis and increased levels of CD20+/CD20+CD5+ B cells and T regulatory cells (Tregs). The patient maintained relatively low levels of T cells, T helper cells, memory T helper cells, and naive cytotoxic T cells, and very low levels of naive T helper cells and natural killer cells throughout. The Tregs of patient A post-treatment with natalizumab responded well in culture to a peptide mapping to a myelin basic protein antigenic epitope (mean 42% increase) compared with Tregs of healthy controls (mean 15% increase) whereas Tregs of the RR-MS controls or patient A prenatalizumab treatment either did not respond or responded adversely to the peptide (mean 3% and 21% decreases, respectively). Since the beginning of natalizumab treatment, patient A has had no relapses, and his Expanded Disability Status Score has improved. From the parameters studied, Treg responsiveness to autoantigens seems to be an important differentiating factor in RR-MS progression.

Expression patterns of leptin receptor (OB-R) isoforms and direct in vitro effects of recombinant leptin on OB-R, leptin expression and cytokine secretion by human hematopoietic malignant cells.

Several studies have implicated leptin in the pathophysiology of neoplasias. We investigated the direct effect of leptin on malignant hematopoietic tissue that included: primary acute myeloid leukemia (AML) cells, leukemic cell lines and bone marrow biopsies from multiple myeloma (MM) patients. PBMC, T-cells, B-cells and monocytes from healthy subjects served as controls. We defined the patterns of OB-R isoform expression in AML cells and leukemic cell lines in comparison to control cells by RT-PCR. rLeptin upregulated the expression of OB-R and endogenous leptin in AML blasts and certain cell lines but not in control cells. Cytometric Bead Array analysis of pro- and anti-inflammatory cytokines showed that rleptin upregulates IL-6 secretion by AML cells, various cytokines by the leukemic cell lines tested and IL-10 secretion by control PBMC, contributed by monocytes. Western immunoblotting revealed that the effect of rleptin was independent of JAK-2/phospho-JAK-2 protein levels. Finally, MM biopsies stained positive for leptin and, to a lesser extend, OB-R. Immunoreactivity was confined mostly to the nucleus of the myeloma cells. Normal myelocytes, promyelocytes and megakaryocytes stained weakly positive, and erythroid cells were constantly negative. We propose that the leptin/OB-R system is strongly and directly involved in supporting the growth of hematopoietic malignancies.