In vitro and in vivo persistence of reticulocytes from donor red cells

BACKGROUND: Reticulocytes are important in the phenotyping of transfused patients. Reticulocytes can persist in blood units for the shelf life of the unit. STUDY DESIGN AND METHODS: Temperature dependence of reticulocyte persistence was examined in vitro at 4, 24, and 37 degrees C by using thiazole orange staining and flow cytometric analysis. Two-color flow cytometric analysis was used to evaluate the persistence of donor reticulocytes in transfused patients. RESULTS: Flow cytometric analysis using thiazole orange demonstrated that persistence of reticulocytes in units of stored CPDA-1 blood was temperature-dependent. Reticulocytes disappeared over 13 and 6 days at 24 degrees C and 37 degrees C, respectively, but at 4 degrees C the reticulocyte count changed little over 35 days. Two-color flow cytometric analysis of reticulocyte antigens was used to follow donor reticulocytes in 14 transfusion events in nine different patients. Donor reticulocytes persisted through 24 hours in 75 percent of the patients and were detectable at 48 hours in three patients. CONCLUSION: This study demonstrates that reticulocytes persist during refrigerated storage; they are detectable in the circulation of most recipients for the first 24 hours after transfusion and in the circulation of a few recipients after 48 hours. These findings may have relevance for separation techniques based on reticulocyte density in samples drawn shortly after transfusion and for evaluation of reticulocyte counts in patients with hematologic abnormalities.     

Eradication of minimal disease in severe combined immunodeficient mice with disseminated Daudi lymphoma using chemotherapy and an immunotoxin cocktail

Severe combined immunodeficient (SCID) mice injected intravenously with a human Burkitt's lymphoma cell line (Daudi) develop disseminated lymphoma (SCID/Daudi), which is fatal in 100% of the mice. Early treatment of these mice with either an immunotoxin (IT) cocktail (consisting of anti-CD19-ricin A chain plus anti-CD22-ricin A chain) or chemotherapy significantly prolonged survival but was not curative. Combination therapy with the IT cocktail and any one of three chemotherapeutic drugs (doxorubicin, cytoxan, or camptothecin) cured the mice. Cure was demonstrated by both histopathologic examination of treated mice and, more importantly, by adoptive transfer of cells from organs of the cured mice to naive SCID mice where 100 tumor cells would have caused disease in the recipients. These results provide a strong rationale for combining IT therapy with conventional chemotherapy in the treatment of B-cell neoplasia.     

Improved Survival and Reduced Phenotypic Severity Following AAV9/MECP2 Gene Transfer to Neonatal and Juvenile Male Mecp2 Knockout Mice

Typical Rett syndrome (RTT) is a pediatric disorder caused by loss-of-function mutations in the methyl-CpG binding protein 2 (MECP2) gene. The demonstrated reversibility of RTT-like phenotypes in mice suggests that MECP2 gene replacement is a potential therapeutic option in patients. We report improvements in survival and phenotypic severity in Mecp2-null male mice after neonatal intracranial delivery of a single-stranded (ss) AAV9/chicken β-actin (CBA)-MECP2 vector. Median survival was 16.6 weeks for MECP2-treated versus 9.3 weeks for green fluorescent protein (GFP)-treated mice. ssAAV9/CBA-MECP2–treated mice also showed significant improvement in the phenotype severity score, in locomotor function, and in exploratory activity, as well as a normalization of neuronal nuclear volume in transduced cells. Wild-type (WT) mice receiving neonatal injections of the same ssAAV9/CBA-MECP2 vector did not show any significant deficits, suggesting a tolerance for modest MeCP2 overexpression. To test a MECP2 gene replacement approach in a manner more relevant for human translation, a self-complementary (sc) adeno-associated virus (AAV) vector designed to drive MeCP2 expression from a fragment of the Mecp2 promoter was injected intravenously (IV) into juvenile (4–5 weeks old) Mecp2-null mice. While the brain transduction efficiency in juvenile mice was low (~2–4% of neurons), modest improvements in survival were still observed. These results support the concept of MECP2 gene therapy for RTT.     

Assessment of microalbuminuria and glycated hemoglobin in type 2 diabetes mellitus complications

ObjectiveTo relate microalbuminuria with the degree of glycaemic control in type 2 diabetic patients and determine the prevalence of poor glycemic control amongst the normotensive diabetes mellitus (NDM) and hypertensive diabetes mellitus (HDM) with or without microalbuminuria.MethodsA total of 95 type 2 diabetes mellitus patients and 30 healthy controls were randomly selected and studied. 17 of the 95 patients were normotensive diabetic with microalbuminuria, 40 of them were HDM presenting with microalbuminuria and 38 were NDM without microalbuminuria. Their blood was obtained for fasting plasma glucose and glycated haemoglobin while their urine was obtained for albumin and creatinine estimation and the ratio was calculated.ResultsOut of the 95 diabetic patients studied, 57 (60%) of them had microalbuminuria while 38 (40%) had normoalbuminuria. The mean ages in the diabetics with microalbuminuria were higher than those without microalbuminuria (P=0.054 6). The mean glycated haemoglobin was the highest (5.95±2.06)% in NDM with microalbuminuria when compared with HDM with microalbuminuria (5.83±1.62)% and that in (5.66±2.49)% in NDM without microalbuminuria (P=0.000 9). Similarly, fasting plasma glucose was the highest (9.09±4.31) mmol/L in NDM with microalbuminuria than those without microalbuminuria (7.70±3.33) mmol/L (P=0.000 1). The prevalence of poor glycaemic control was the highest (29%) in NDM with microalbuminuria while the least (21%) in NDM without microalbuminuria.ConclusionsThe risk of microalbuminuria increases with poor glycemic control. Persistent increase in glycated haemoglobin may be an indicator of worsening albumin creatinine ratio and diabetic nephropathy. Therefore, regular screening for microalbuminuria in addition to continuous (3-monthly) glycated HbA1c estimation is advised.     

T lymphocytes control microbial composition by regulating the abundance of Vibrio in the zebrafish gut

Dysbiosis of the intestinal microbial community is considered a risk factor for development of chronic intestinal inflammation as well as other diseases such as diabetes, obesity and even cancer. Study of the innate and adaptive immune pathways controlling bacterial colonization has however proven difficult in rodents, considering the extensive cross-talk between bacteria and innate and adaptive immunity. Here, we used the zebrafish to study innate and adaptive immune processes controlling the microbial community. Zebrafish lack a functional adaptive immune system in the first weeks of life, enabling study of the innate immune system in the absence of adaptive immunity. We show that in wild type zebrafish, the initial lack of adaptive immunity associates with overgrowth of Vibrio species (a group encompassing fish and human pathogens), which is overcome upon adaptive immune development. In Rag1-deficient zebrafish (lacking adaptive immunity) Vibrio abundance remains high, suggesting that adaptive immune processes indeed control Vibrio species. Using cell transfer experiments, we confirm that adoptive transfer of T lymphocytes, but not B lymphocytes into Rag1-deficient recipients suppresses outgrowth of Vibrio. In addition, ex vivo exposure of intestinal T lymphocytes to Rag1-deficient microbiota results in increased interferon-gamma expression by these T lymphocytes, compared to exposure to wild type microbiota. In conclusion, we show that T lymphocytes control microbial composition by effectively suppressing the outgrowth of Vibrio species in the zebrafish intestine.