Wolfgang Zieger

Proliferative merkel cells were not detected in human skin

The fetal development of Merkel cells-neuroendocrine cells of the skin—has been a matter of debate for a long time. Recent results have helped to confirm their intraepidermal development in humans. Simple epithelial cytokeratins (CK) nos. 8, 18, 19 and 20 are well established markers at the light microscopic level. These cells could be detected from fetal week 8 within the epidermis with an enormous increase during the following weeks. This gives rise to the question as to whether Merkel cells are undergoing mitoses or whether they are derived from basal keratinocytes. We studied fetal and adult skin using antibodies to simple epithelial CK and to Ki67, a human nuclear cell proliferation-associated antigen in an attempt to answer these questions. In human adult and fetal skin of various stages we could not detect any Merkel cells undergoing cell division. These results suggest that Merkel cells are postmitotic cells to be renewed from undifferentiated keratinocytes with stem cell characteristics.

Cord blood as a source of autologous RBCs for transfusion to preterm infants.

BACKGROUND: This prospective study was conducted to gain experience as to whether it is technically possible to produce autologous RBCs in additive solution from cord blood (CB), to optimize the blood supply for preterm infants.

Engraftment capacity of umbilical cord blood cells processed by either whole blood preparation or filtration.

Umbilical cord blood (UCB) preparation needs to be optimized in order to develop more simplified procedures for volume reduction, as well as to reduce the amount of contaminating cells within the final stem cell transplant. We evaluated a novel filter device (StemQuick™E) and compared it with our routine buffy coat (BC) preparation procedure for the enrichment of hematopoietic progenitor cells (HPCs). Two groups of single or pooled UCB units were filtered (each n = 6), or equally divided in two halves and processed by filtration and BC preparation in parallel (n = 10). The engraftment capacity of UCB samples processed by whole blood (WB) preparation was compared with paired samples processed by filtration in the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse animal model. Filtration of UCB units in the two groups with a mean volume of 87.8 and 120.7 ml, respectively, and nucleated cell (NC) content of 9.7 and 23.8 × 108 resulted in a sufficient mean cell recovery for mononucleated cells ([MNCs] 74.2%‐77.5%), CD34+ cells (76.3%‐79.0%), and colony‐forming cells (64.1%‐86.3%). Moreover, we detected a relevant depletion of the transplants for RBCs (89.2%‐90.0%) and platelets ([PLTs] 77.5%‐86.1%). In contrast, the mean depletion rate using BC processing proved to be significantly different for PLTs (10%, p = 0.03) and RBCs (39.6%, p < 0.01). The NC composition showed a highly significant increase in MNCs and a decrease in granulocytes after filtration (p < 0.01), compared with a less significant MNC increase in the BC group (p < 0.05). For mice transplanted with WB‐derived progenitors, we observed a mean of 15.3% ± 15.5% of human CD45+ cells within the BM compared with 19.9% ± 16.8% for mice transplanted with filter samples (p = 0.03). The mean percentage of human CD34+ cells was 4.2% ± 3.1% for WB samples and 4.5% ± 3.2% for filter samples (p = 0.68). As the data of NOD/SCID mice transplantation demonstrated a significant engraftment capacity of HPCs processed by filtration, no negative effect on the engraftment potential of filtered UCB cells versus non‐volume‐reduced cells from WB transplants was found. The StemQuick™E filter devices proved to be a useful tool for Good Manufacturing Practices conform enrichment of HPCs and MNCs out of UCB. Filtration enables a quick and standardized preparation of a volume‐reduced UCB transplant, including a partial depletion of granulocytes, RBCs, and PLTs without the need for centrifugation. Therefore, it seems very probable that filter‐processed UCB transplants will also result in sufficient hematopoietic reconstitution in humans.

Mild Course of Fetal Rh D Haemolytic Disease due to Maternal Alloimmunisation to Paternal HLA Class I and II Antigens

The patient is a pregnant women of African origin with a prior history of spontaneous abortion and newborn dystrophy. The investigation showed an anti‐Rh D antibody (IgG isotypes 1 and 3) with an indirect antiglobulin tube test (IAT) titre of 1:512. The monocyte monolayer assay (MMA) proved clearly the interaction of Fc receptors with the maternal anti‐D, and so a clinical significance was expected. In spite of this, no signs of severe haemolysis in the Rh‐D‐positive and direct antiglobulin test‐positive fetus could be observed. Furthermore, two HLA class I and II alloantibodies (anti‐A10, anti‐DR13) directed against paternal and fetal antigens were detected in the serum of the gravida. Both antibodies showed an inhibitory effect on the in vitro phagocytosis capacity of mononuclear cells expressing at least one of the corresponding HLA antigens (immunophagocytosis inhibition (IPI) test). Thus, the mild course of haemolytic disease may be explained by an effective inhibition of the fetal mononuclear phagocyte system by maternal HLA class I and/or class II antibodies resulting in a diminished destruction of anti‐D‐coated fetal red blood cells.

Water birth: microbiological colonisation of the newborn, neonatal and maternal infection rate in comparison to conventional bed deliveries

IntroductionThe risk of infectious complications after water birth which might be due to water contaminated by faecal bacteria or environmental microbes from the water supply system is still in discussion.Materials and methodsWe performed a microbiological study comparing neonatal bacterial colonisation after water birth to conventional bed deliveries with or without relaxation bath. In all three groups (96 deliveries) we isolated most frequently from ear and palate of the newborns Staphylococcus epidermidis, E. coli and enterococci, which belong to the normal vaginal flora.ResultsNeonatal outcome, infants´ and maternal infection rate did not differ between the three groups