ALBERT

Description: Hereditary Persistence of Fetal Hemoglobin (HPFH) is a clinically benign condition characterized by continuous synthesis of fetal hemoglobin (Hb F) in adult life without major related hematological changes. The nondeletional HPFH is characterized by hemoglobin F level between 5% and 30%, in heterozygotes state. This condition has been observed among Blacks, Italians, Greeks, English and Chinese. Two different forms are known, characterized by the type of chain involve, either Gγ or Aγ. Several point mutations in the promoter region of the Aγ globin gene have been identified in ndHPFH: −202, −198, −196, −195, −117, −114, deletion 4pb (−222 −225) and −158. The propositus is a 36 year old black female with a moderate increased level of Hb F, also her sister and her sibling had the same condition. She was discovered during studies due to the presence of splenomegaly and gastroesophageal reflux. The Hbs A, A2 and F were eluted and quantified by cation exchange high-performance liquid chromatography (HPLC-CE), using Beta Tal short program, Variant BioRad (Hercules, California, USA). DNA was isolated from peripheral blood leukocytes by a salting-out extraction procedure. The Aγ and Gγ promoters globins gene were amplified independently by PCR and the presence of the HPFH mutation was determined by denaturing gradient gel electrophoresis technique (DGGE) as previously described Gottardi et al., (1992). The Aγ promoter globin gene was sequenced in three members of the family using the BigDyeTM Terminator Cycler Sequencing Kit and the ABI PRISMTM 310 Genetic Analyzer (PE Applied Biosystems, Foster City, CQ, USA). Her hematological studies revealed Hb: 14.2 g/dl, Hcto: 41.1 %, MCV: 94.4 fl, MCHC: 34.5 fl, Hb A: 81.9 %, Hb A2: 2.1 % and Hb F: 6.3 %. The sibling hematological finding was Hb: 13.1 g/dl, Hcto: 41.8 %, MCV: 83.7 fl, MCHC: 31.3 fl, Hb A: 83.2 %, Hb A2: 3.2 % and Hb F: 5.1. The sister was Hb: 14.3 g/dl, Hcto: 46.4 %, MCV: 105.9 fl, MCHC: 30.8 fl, Hb A: 83.7 %, Hb A2: 3.3 % and Hb F: 2.7 %. No spleen enlargement was seen in the other two affected members of the family. The DGGE results in the Aγ promoter, suggested the presence of a non-deletion form of HPFH in heterozygotes state. The Aγ promoter region revealed the presence of a substitution C→T at position −211. This mutation does not modify any restriction site. To our knowledge the −211 (C→T) mutation in the Aγ promoter have not been reported previously. Since modulation of g-globin gene expression in adults could provide a therapeutic intervention in hemoglobinopathy, the study of the molecular mechanisms generating HPFH is medically relevant.

Description: The monocyte capacity to differentiate into dendritic cells (DCs) was originally demonstrated by human in vitro DC differentiation assays that have subsequently become the essential methodologic approach for the production of DCs to be used in DC-mediated cancer immunotherapy protocols. In addition, in vitro DC generation from monocytes is a powerful tool to study DC differentiation and maturation. However, whether DC differentiation from monocytes occurs in vivo remains controversial, and the physiologic counterparts of in vitro monocyte-derived DCs are unknown. In addition, information on murine monocytes and monocyte-derived DCs is scarce. Here we show that mouse bone marrow monocytes can be differentiated in vitro into DCs using similar conditions as those defined in humans, including in vitro cultures with granulocyte-macrophage colony-stimulating factor and interleukin 4 and reverse transendothelial migration assays. Importantly, we demonstrate that after in vivo transfer monocytes generate CD8- and CD8+ DCs in the spleen, but differentiate into macrophages on migration to the thoracic cavity. In conclusion, we support the hypothesis that monocytes generate DCs not only on entry into the lymph and migration to the lymph nodes as proposed, but also on extravasation from blood and homing to the spleen, suggesting that monocytes represent immediate precursors of lymphoid organ DCs. (Blood. 2004;103:2668-2676)

Description: Despite the information dealing with the differential phenotype and function of the main mouse dendritic cell (DC) subpopulations, namely, CD8α− and CD8α+ DCs, their origin and involvement in antiviral immune responses in vivo are still largely unknown. To address these issues, this study used the changes occurring in DC subpopulations during the experimental infection by the Swiss (SW) strain of the mouse mammary tumor virus (MMTV). MMTV(SW) induced an 18-fold increase in lymph node DCs, which can be blocked by anti-CD62L treatment, concomitant with the presence of high numbers of DCs in the outer cortex, in close association with high endothelial venules. These data suggest that the DC increase caused by MMTV(SW) infection results from the recruitment of blood-borne DCs via high endothelial venules, by a CD62L-dependent mechanism. In addition, skin sensitization assays indicate that MMTV(SW) infection inhibits epidermal Langerhans cell migration to the draining lymph node. Moreover, data on the kinetics of MMTV(SW)-induced expansion of the different DC subsets support the hypothesis that CD8− and CD8+ DCs represent different maturation stages of the same DC population, rather than myeloid- and lymphoid-derived DCs, respectively, as previously proposed. Finally, the fact that DCs were infected by MMTV(SW) suggests their participation in the early phases of infection.