A case report of multiple-transfused aplastic anemia complicated by hemolysis and delayed neutrophil recovery after bone marrow transplantation]

The authors report an 18-year-old female who developed severe hemolytic reaction and delayed neutrophil recovery after bone marrow transplantation (BMT) for aplastic anemia from her HLA-identical sibling. She had received much transfusion (61 units of red blood cells including 4 units of fresh whole blood from her parents and 350 units of platelets) for 12 years before BMT. To prevent graft rejection, she received an intensified preparative regimen consisted of cyclophosphamide 200 mg/kg followed by 5 Gy total body irradiation and 5 Gy total lymphoid irradiation. Prophylaxis for GVHD was short term methotrexate and cyclosporin-A. Despite of the removal of the red cells from the marrow, marked hemolytic reaction caused by antibodies directed to rh" (E) and hr' (c) red cell antigens was observed when rh" (E) and hr' (c) positive donor erythroid began to recover. The recovery of neutrophils, especially the fraction of segmented cells was also delayed. Flow cytometry showed that the serially collected patient's sera reacted to neutrophils derived from both patient's blood on the 64th post-transplant day and the donor's blood. The reactivity was strongest in pre-BMT sera. We conclude that residual antibodies sensitized before BMT are a major cause of these hematological problems.     

Pivotal function for cytoplasmic protein FROUNT in CCR2-mediated monocyte chemotaxis

Ligation of the chemokine receptor CCR2 on monocytes and macrophages with its ligand CCL2 results in activation of the cascade consisting of phosphatidylinositol-3-OH kinase (PI(3)K), the small G protein Rac and lamellipodium protrusion. We show here that a unique clathrin heavy-chain repeat homology protein, FROUNT, directly bound activated CCR2 and formed clusters at the cell front during chemotaxis. Overexpression of FROUNT amplified the chemokine-elicited PI(3)K-Rac-lamellipodium protrusion cascade and subsequent chemotaxis. Blocking FROUNT function by using a truncated mutant or antisense strategy substantially diminished signaling via CCR2. In a mouse peritonitis model, suppression of endogenous FROUNT markedly prevented macrophage infiltration. Thus, FROUNT links activated CCR2 to the PI(3)K-Rac-lamellipodium protrusion cascade and could be a therapeutic target in chronic inflammatory immune diseases associated with macrophage infiltration.     

Increased susceptibility to HIV-1 of peripheral blood lymphocytes in acute infection with Epstein-Barr virus

Epstein-Barr virus (EBV) is an important pathogen in human immunodeficiency virus (HIV)-infected individuals that causes lymphoma and other lymphoproliferative disorders upon disease progression; however, interaction between the two viruses during acute infection is not well known. Expression of CCR5, a major coreceptor for HIV, was enhanced on CD4+ T cells from patients with acute EBV infection. Furthermore, susceptibility of those cells to R5-HIV-1, but not X4-HIV-1, was increased. EBV effects on CCR5 expression on or susceptibility to R5-HIV-1 of CD4+ T cells did not require coinfection of the same cell with the two viruses, because CD4+ T cells from patients with acute EBV infection were not infected with EBV. Considering that both HIV and EBV are transmitted by intimate contact, such possible interaction between the two viruses may have implications for viral transmission and the pathogenesis of HIV disease.     

Anti-idiotypes to oxidized LDL antibodies in intravenous immunoglobulin preparations--possible immunomodulation of atherosclerosis

OBJECTIVE: The aim of this study was to examine whether intravenous immunoglobulin (IVIg) preparations contain anti-oxLDL and anti-anti-oxLDL antibodies. BACKGROUND: Oxidized low-density lipoprotein (oxLDL) is one of the major players in atherogenesis. IVIg can reduce atherosclerosis in experimental animal models. METHODS: Six commercial IVIg preparations were tested for the presence of anti-oxLDL antibodies by EIA. Inhibition studies were performed with the different IVIg preparations and IgGs purified from a pool of sera from patients with high anti-oxLDL antibody levels. Absorption assays were carried out to evaluate the presence of anti-idiotypes against anti-oxLDL antibodies in IVIg preparations. RESULTS: IVIg preparations tested had various degrees of reactivity towards oxLDL. Absorption experiments suggested that the reactivity was specific because it could be effectively absorbed by oxLDL and not by an irrelevant antigen PPD. The reactivity was smaller than that observed with the IgG from the pool with high anti-oxLDL antibody levels. Inhibition studies with IVIg demonstrated 20-45% inhibition of anti-oxLDL binding to oxLDL, compared to 76% inhibition by the pool with high anti-oxLDL levels. To investigate the presence of anti-idiotypes against anti-oxLDL antibodies within IVIg, F(ab')2 fragments of IVIg IgG were used to absorb IgG F(ab')2 fragments from the pool of sera with high anti-oxLDL levels. The decreased binding to oxLDL of the absorbed supernatants shows that IgG F(ab')2 fragments of the IVIg preparations had high inhibitory capacities ranging from 65 to 90%. CONCLUSIONS: IVIg preparations contain both anti-oxLDL and anti-anti-oxLDL activity. This finding may explain the immunomodulating effect of IVIg in atherosclerosis.     

Role of P-Selectin in the Migration of Neutrophils to Chemoattractant-Induced Cutaneous Inflammation in Mice

The role of P-selectin in the accumulation of neutrophils at acute dermal inflammatory sites induced by chemoattractants, LTB4 and IL-8 was investigated in the mouse. A mouse P-selectin-human IgG chimera bound to mouse neutrophils in vitro in a calcium-dependent manner, as detected by flow cytometry. A rat monoclonal antibody (mAb) against mouse P-selectin, RB40.34 abolished P-selectin-IgG chimera binding to mouse neutrophils, but a control antibody did not. Intradermal injection of LTB4 at a dose of 100 ng/site caused neutrophil accumulation to increase by 3-4 fold, as detected by measuring myeloperoxidase activity. Neutrophil extravasation to perivascular tissue was detected by histochemical observation. The intravenous injection of RB40.34 or the specific LTB4 antagonist, SM-15178, at doses at 5 mg/kg attenuated the accumulation of neutrophils by 55.6% and 70.3%, respectively, but a control antibody showed no effect. Similarly, intradermal administration of IL-8 at a dose of 5 g/site induced significant neutrophil migration into the interstitial tissue of the skin, as followed by measuring myeloperoxidase activity and histopathologic analysis. The intravenous injection of RB40.34 at a dose of 5 mg/kg reduced the neutrophil accumulation by 59.2%; in contrast, a control antibody showed no effect. To our knowledge, this is the first direct demonstration that P-selectin plays a substantial role in LTB4and IL-8-induced neutrophil accumulation in mouse skin.     

Ossifying fibromyxoid tumor of soft parts. Cytogenetic findings

Ossifying fibromyxoid tumor (OFMT) of soft parts is a recently described, rare but morphologically distinctive soft tissue tumor. The histogenesis of this lesion remains uncertain, although several immunohistochemical and ultrastructural features suggest that it is an unusual neural tumor, possibly of Schwann cell origin. We report here a case of a malignant variant of OFMT that occurred in the foot of a 52-year-old man. The karyotype of a pulmonary metastasis exhibited the following complex numeric and structural aberrations:72 approximately 74,XXY,-5,+6,+del(8)(p21),del(9)(p22),+10,der(11)t(3;11)(p21;p15),del(12) (q13),der(13)t(5;13)(q13;q34),+18,+19,+20,-22 [cp10]. A kidney metastasis exhibited the following karyotypic abnormalities: 46,XY,add(3)(p11),+der(3)t(3;?;11)(3qter-->3p11::?::11q13-->11qter), -5,del(8)(p21),add(9)(q22),del(9)(p22),der(11)t(3;11)(p21;p15),del(12)(q13),+der(13)t(5;13) (q13;q34),-22. To our knowledge, this is the first reported case of OFMT in which clonal chromosomal aberrations have been shown.     

Renal primitive neuroectodermal tumor: An immunohistochemical and cytogenetic analysis

The cytogenetic and morphologic characteristics of a case with a primitive neuroectodermal tumor (PNET) arising from the left kidney in a 22 year old man are presented. The patient was detected as having a left renal mass with a tumor embolus In the inferior vena cava and multiple pulmonary metastases. A radical nephrectomy with tumor embolectomy of the Inferior vena cava, along with a resection of the pulmonary nodules were performed. Histologic examination revealed a dense proliferation of small round cells with many Homer-Wright type rosettes and perlvascular pseudo-rosettes. Immunohlstochemically, the tumor cells stained strongly positive for HBA71(p30/32^{M IC2}), a surface glycopro-teln specific to PNET and Ewlng's sarcoma. In addition, the tumor cells expressed several neural markers (neuron specific enolase, neurofilament, synaptophysin, and Leu-7) and vimentin, while the epithelial, muscular, and lymphocytlc markers were negative in the tumor cells. Cytogenetic analysis of cultured tumor cells showed a reciprocal translocation t(11; 22)(q24; q12) that is considered to be specific to PNET and Ewing's sarcoma. In conclusion, this case suggested that a karyotyping analysis is a useful diagnostic tool for renal PNET, and it may therefore be utilized to help distinguish between difficult cases of small round cell tumors and Wilms' tumor of the kidney.