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BACKGROUND Determination of blood donor hemoglobin (Hb) levels is a pre‐requisite to ensure donor safety and blood product quality. We aimed to identify Hb measurement practices across blood donation services and to what extent differences associate with low‐Hb deferral rates. METHODS An online survey was performed among Biomedical Excellence for Safer Transfusion (BEST) Collaborative members, extended with published data. Multivariable negative‐binomial regression models were built to estimate adjusted associations of minimum donation intervals, Hb cut‐offs (high, ≥13.5 g/dL in men or ≥ 12.5 g/dL in women, vs. lower values), iron monitoring (yes/no), providing or prescribing iron supplementation (yes/no), post‐versus pre‐donation Hb measurement and geographical location (Asian vs. rest), with low‐Hb deferral rates. RESULTS Data were included from 38 blood services. Low‐Hb deferral rates varied from 0.11% to 8.81% among men and 0.84% to 31.85% among women. Services with longer minimum donation intervals had significantly lower deferral rates among both women (rate ratio, RR 0.53, 95%CI 0.33‐0.84) and men (RR 0.53, 95%CI 0.31‐0.90). In women, iron supplementation was associated with lower Hb deferral rates (RR 0.47, 95%CI 0.23‐0.94). Finally, being located in Asia was associated with higher low‐Hb deferral rates; RR 9.10 (95%CI 3.89‐21.27) for women and 6.76 (95%CI 2.45‐18.68) for men. CONCLUSION Differences in Hb measurement and eligibility criteria, particularly longer donation intervals and iron supplementation in women, are associated with variations in low‐Hb deferral rates. These insights could help improve both blood donation service efficiency and donor care.

This communication describes the preparation of antibodies to human interleukin 2 (IL-2), using as immunogens synthetic peptides derived from the predicted amino acid sequence of IL-2. Rabbits and mice were immunized with protein carrier conjugates of eight chemically synthesized IL-2-derived peptides, each consisting of 13-15 amino acids. The immune antisera were screened in a solid-phase ELISA for reactivity to a native human IL-2. Antibodies to four of the eight peptides were found by a variety of biological and immunochemical criteria to react against human IL-2. Furthermore, an affinity-purified antibody to one of the IL-2 peptides (peptide 84) specifically stained the cytoplasm of phytohemagglutinin-stimulated human peripheral blood lymphocytes or T-leukemic cells (Jurkat). Antibodies to synthetic IL-2 peptides should serve as useful probes for studying this lymphokine and for developing quantitative assays for measuring its levels in biological fluids and its association with disease.

Compared to murine models, data on cells responsible for the homeostasis of human epidermis are scarce and often contradictory. Given the conflicting results and the availability of clinical grade protocols to purify CD34 cells from a given tissue, we pursued to phenotypically characterize human epidermal CD34+ population. After magnetic separation of whole skin CD34+ and CD34) cell fractions and selection for cells highly adherent to extracellular matrix, both CD34± fractions retained the ability to form a stratified epidermis in organotypic cultures and presented similar in vitro migratory phenotypes. However CD34) cells showed higher clonogenic potential and in vitro proliferative capacity. These results indicated that CD34) cell fraction contains stem ⁄ early progenitor cells, while CD34+ cells might be a transit-amplifying precursor for hair follicle (HF) sheath cells. The ability to isolate living cells using differential cell adhesion and surface markers provides an opportunity to study cells from different morphological regions of the HF.

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