Gray platelet syndrome (GPS) is a rare recessive disorder caused by biallelic variants in NBEAL2 and characterized by bleeding symptoms, the absence of platelet ɑ-granules, splenomegaly and bone marrow (BM) fibrosis. Due to its rarity, it has been difficult to fully understand the pathogenic processes that lead to these clinical sequelae. To discern the spectrum of pathological features, we performed a detailed clinical genotypic and phenotypic study of 47 GPS patients. We identified 32 new etiological variants in NBEAL2. Our GPS patient cohort exhibited known phenotypes, including macrothrombocytopenia, BM fibrosis, megakaryocyte emperipolesis of neutrophils, splenomegaly, and elevated serum vitamin B12 levels. We also observed novel clinical phenotypes; these include reduced leukocyte counts and increased presence of autoimmune disease and positive autoantibodies. There were widespread differences in the transcriptome and proteome of GPS platelets, neutrophils, monocytes, and CD4-lymphocytes. Proteins less abundant in these cells were enriched for constituents of granules, supporting a role for Nbeal2 in the function of these organelles across a wide range of blood cells. Proteomic analysis of GPS plasma showed increased levels of proteins associated with inflammation and immune response. One quarter of plasma proteins increased in GPS are known to be synthesized outside of hematopoietic cells, predominantly in the liver. In summary, our data demonstrate that, in addition to the well-described platelet defects in GPS, there are also immune defects. The abnormal immune cells may be the drivers of systemic abnormalities, such as autoimmune disease.

Purpose Our aim was to clarify the effective decrease in blood transfusion after primary total knee arthroplasty (TKA) from a multimodal blood-loss prevention approach (MBLPA) and the related risk factors of blood transfusion. Methods We retrospectively compared the rate of postoperative blood transfusion in 418 cases of primary TKA during 2010 from a single institution with two different groups of patients, allocating cases to the group with MBLPA (group 1, study group, N =71) and controls to the group without MBLPA (group 2, standard group, N =347). MBLPA procedure included pre-operative haemoglobin (Hb) optimisation; femoral canal obturation; limited incision and release; periand intra-articular use of saline with adrenalin, morpheic chloride, tobramycin, betamethasone and ropivacaine; tourniquet release after skin closure; 24 hour drain under atmospheric pressure; and two doses of tranexamic acid (TXA) IV. In the control group, surgeons followed the standard procedure without blood-saving techniques. Case-control comparison and blood transfusion risk factors were analysed. Results Group 1 had a zero transfusion rate (0/71), whereas 27.4 % of patients (95/347) in group 2 received allogenic blood transfusion. Significant transfusion risk factors were pre-operative Hb <12 g/dl), American Society of Anesthesiologists (ASA) status III and nonobese body mass index (BMI); Age and gender were not significant risk factors. Conclusions MBLPA in primary TKA was highly effective, with a zero transfusion rate. Risk factors for transfusion were determined, and eliminating them contributed to the avoidance of allogeneic blood transfusion in our study series.

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