Generalized crystal-storing histiocytosis associated with monoclonal gammopathy: molecular analysis of a disorder with rapid clinical course and review of the literature

Crystal-storing histiocytosis (CSH) is a rare event in disorders associated with monoclonal gammopathy. The intracellular crystal formation is almost always accompanied by the expression of κ light chains. However, the exact mechanism for the storage has not been clarified until now. We report a case of generalized CSH in a 73-year-old man who presented with IgA κ paraproteinemia and paraproteinuria. The initially observed CSH in the bone marrow biopsy was associated with the clinical and pathomorphologic features of a monoclonal gammopathy of undetermined significance. The progression of disease could not be affected by steroid therapy and the patient died of septic shock 7 months after detection of CSH. At the time of autopsy there was evidence for multiple myeloma and generalized CSH. Two-dimensional gel electrophoresis of liver tissue combined with immunoblotting revealed the massive storage of heavy chains of {alpha} type and light chains of {kappa} type, each in a monoclonal pattern. Analysis of the stored {kappa} light chain by nanoelectrospray-ionization mass spectrometry indicated that it belongs to the variable KI variability subgroup. We identified some unusual amino acid substitutions including Leu59, usually Important for hydrophobic interactions within a protein, at a position where it has never been previously described in plasma cell disorders. In conclusion, we present the first case of CSH with molecular identification of the stored {kappa} subgroup and detection of unusual amino acid substitutions. Our results suggest that conformational alterations induced by amino acid exchanges represent a crucial pathogenic factor in CSH

Granulocyte-colony stimulating factor response is superior to neutropenia duration in predicting the risk of infection after high-dose chemotherapy for myeloma and lymphoma

The patient granulocyte-colony stimulating factor (G-CSF) response is represented by the leukocyte peak in the blood induced by a single dose of G-CSF after chemotherapy, and is correlated with subsequent neutropenic infection risk. General patterns for a meaningful risk group stratification, have not yet been determined. Two independent data sets including a total of 306 cases with myeloma or lymphoma and autologous blood stem cell transplant were available. An infection susceptibility curve plotted according to ranked G-CSF responses from a multicenter study reproduced and validated a curve from the previous single center. Two trend changes were seen within these curves at around 11 000 and 22 000 leukocytes/mu L, which separated three groups with a high, medium and low risk of infection. While G-CSF response is related to the consecutive duration of neutropenia, it retains additional independent predictive information for infection risk (p < 0.0001) and, more important, is a tool available before the onset of the critical period

Selective induction of apoptosis in leukemic B-lymphoid cells by a CD19-specific TRAIL fusion protein

Although the treatment outcome of lymphoid malignancies has improved in recent years by the introduction of transplantation and antibody-based therapeutics, relapse remains a major problem. Therefore, new therapeutic options are urgently needed. One promising approach is the selective activation of apoptosis in tumor cells by the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). This study investigated the pro-apoptotic potential of a novel TRAIL fusion protein designated scFvCD19:sTRAIL, consisting of a CD19-specific single-chain Fv antibody fragment (scFv) fused to the soluble extracellular domain of TRAIL (sTRAIL). Potent apoptosis was induced by scFvCD19:sTRAIL in several CD19-positive tumor cell lines, whereas normal blood cells remained unaffected. In mixed culture experiments, selective binding of scFvCD19:sTRAIL to CD19-positive cells resulted in strong induction of apoptosis in CD19-negative bystander tumor cells. Simultaneous treatment of CD19-positive cell lines with scFvCD19:sTRAIL and valproic acid (VPA) or Cyclosporin A induced strongly synergistic apoptosis. Treatment of patient-derived acute B-lymphoblastic leukemia (B-ALL) and chronic B-lymphocytic leukemia (B-CLL) cells resulted in strong tumoricidal activity that was further enhanced by combination with VPA. In addition, scFvCD19:sTRAIL prevented engraftment of human Nalm-6 cells in xenotransplanted NOD/Scid mice. The pre-clinical data presented here warrant further investigation of scFvCD19:sTRAIL as a potential new therapeutic agent for CD19-positive B-lineage malignancies