Margarita Ivanova

Persistent immune alterations and comorbidities in splenectomized patients with Gaucher disease.

Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the gene encoding acid-β-glucosidase, resulting in functional disruptions in degradation of glycosphingolipids and lysosomal accumulation of the substrates. The most frequent clinical presentations of GD are thrombocytopenia, splenomegaly and bone pain. Prior to advent of enzyme replacement therapy, splenectomy was performed for complications of hypersplenism such as severe thrombocytopenia and transfusion dependency. Though there is evidence about worsening bone disease after splenectomy, there is no systematic study to assess its effects on the immune system in GD patients. In order to investigate the long-term immunological effects of splenectomy, we used flow cytometry to compare the immunophenotypes of GD patients who had undergone splenectomy (SGD) to those with intact spleen. The results show that SGD patients have significantly fewer CD27(+)/IgM(+) B-cells but more CD4(+)/CD45RO(+) and CD8(+)/CD45RO(+) T-cells. The most surprising finding was an almost complete absence of circulating dendritic cells in SGD patients. In addition, splenectomized subjects had comorbidities, the most common being monoclonal gammopathy of undetermined significance (MGUS). Taken together, these results highlight the persistence of multiple immune alterations and comorbidities coexisting in higher frequency in the SGD group and they are not affected by GD specific therapy.

Gaucheromas: When macrophages promote tumor formation and dissemination

Deficiency of the lysosomal enzyme, β-glucocerebrosidase, and accumulation of its substrate in cells of the reticuloendothelial system affects multiple organ systems in patients with Gaucher disease (GD). Lipid laden macrophages turn into Gaucher cells (GC) which are the pathological characteristic of GD. GC focally accumulate in the liver, spleen and at extraosseous sites to form benign lesions called Gaucheromas. Gaucheromas pose diagnostic and therapeutic challenges. We studied the pathophysiology of extraosseous Gaucheroma formation in a cohort of patients with GD. Among 63 patients followed at a single center, 3 patients with genotypes L444P/L444P and N370S/N370S, were diagnosed with extraosseous Gaucheromas. Flow cytometry revealed a higher expression of CD16+/CCR4+ non-classical monocytes in blood of GD patients who have developed Gaucheromas. A biopsy showed infiltration of GC, which reactivity against CD163, CD68 and VEGF. The cell proliferative marker Ki67 and CCL2, a factor anti-tumor activity, were negative. Our study indicates that extraosseous Gaucheromas are comprised of cellular elements with characteristics of tumor-associated macrophages, the major players in cancer related inflammation. The occurrence of non-classical CD16+/CCR4+ monocytes reflect the underlying cause for the accumulation of the macrophages capable of migrating to distant sites outside the reticuloendotheial system, and giving rise to tumor-like Gaucheromas.