Latin America: the next region for haematopoietic transplant progress.

Haematopoietic cell transplant activity in the 28 countries comprising Latin America is poorly defined. We conducted a voluntary survey of members of the Latin American Bone Marrow Transplantation Group regarding transplant activity 2009-2012. Collated responses were compared with data of transplant rates from the Worldwide Network for Blood and Marrow Transplantation for other geographic regions. Several socio-economic variables were analysed to determine correlations with transplant rates. In total, 94 teams from 12 countries reported 11 519 transplants including 7033 autotransplants and 4486 allotransplants. Annual activity increased from 2517 transplants in 2009 to 3263 in 2012, a 30% increase. Median transplants rate (transplant per million inhabitants) in 2012 was 64 (autotransplants, median 40; allotransplants, median 24). This rate is substantially lower than that in North America and European regions (482 and 378) but higher than that in the Eastern Mediterranean and Asia Pacific regions (30 and 45). However, the Latin America transplant rate is 5-8-fold lower than that in America and Europe, suggesting a need to increase transplant availability. Transplant team density in Latin America (teams per million population; 1.8) is 3-4-fold lower than that in North America (6.2) or Europe (7.6). Within Latin America, there is substantial diversity in transplant rates by country partially explained by diverse socio-economic variables including per capita gross national income, health expenditure and physician density. These data should help inform future health-care policy in Latin America.

Natural killer (NK) cells inhibit human umbilical cord blood erythropoiesis.

To examine the role of NK cells on in vitro human umbilical cord (HUC) blood erythropoietic progenitor growth, 25 normal HUC blood samples were depleted of CD56+ cells by using immunomagnetic beads coated with CD56 monoclonal antibodies (mAb). When stimulated by erythropoietin (Epo) to form colonies in plasma clot medium, the CD(56+)-depleted preparations demonstrated a two-fold increase in the number of early erythropoietic progenitors (BFU-E) over nondepleted preparations. This stimulatory effect of CD56+ depletion on BFU-E growth was not due to artifactual stimulations of other accessory cells by the mAb or the dynabeads used in the depletion procedure, since separate addition of these materials to culture did not exert any stimulatory effect on BFU-E growth. Direct co-culture of purified NK and autologous cord blood mononuclear cells (MNC) in plasma clot medium resulted in a dose-dependent decrease in BFU-E population. In addition, when NK and MNC were cocultured separately in double-layer cultures, the expansion of BFU-E was significantly decreased. Because direct cell-to-cell contact is prohibited in double-layer cultures, the observed inhibition of BFU-E proliferation could be mediated at least in part through soluble factors. To test this hypothesis, NK cell supernatant fluid obtained 24 hours after NK cell incubation was added to plasma clot culture medium. A significant decrease in BFU-E number was again observed. In conclusion, our results indicate that HUC blood BFU-E proliferation is inhibited by NK cells, and that the mechanism of this inhibition is mediated, at least in part, by one or more humoral factors.

African histoplasmosis in a Belgian AIDS patient.

We describe an African histoplasmosis case in a 65-year-old Belgian living in Zaire for 46 years. Microscopic bone marrow examination showed Histoplasma. It was confirmed by cultures and hamster inoculation. Autopsy revealed a fungal dissemination by Histoplasma duboisii.