Does a febrile reaction to platelets predispose recipients to red blood cell alloimmunization?

BACKGROUND: A variable effect of inflammation on alloimmunization to transfused red blood cells (RBCs) in mice has been recently reported. We investigated whether RBC alloimmunization in humans was affected by transfusion of blood products in temporal proximity to experiencing a febrile transfusion reaction (FTR) to platelets (PLTs), an event predominantly mediated by inflammatory cytokines.
STUDY DESIGN AND METHODS: Blood bank databases were used to identify patients who experienced an FTR or possible FTR to PLTs from August 2000 to March 2008 (FTR group). The control group of patients received a PLT transfusion on randomly selected dates without experiencing an FTR. The "event" was defined as the PLT transfusion that caused the FTR in the FTR group or the index PLT transfusion in the control group. The number of transfused blood products and their proximity to the event were recorded along with other recipient data. The primary endpoint was the rate of RBC alloimmunization between the two groups.
RESULTS: There were 190 recipients in the FTR group and 245 in the control group. Overall, the recipients in the control group were younger and received more blood products on the day of their event and over the subsequent 10 days. The alloimmunization rate among recipients in the FTR group was higher than in the control group (8% vs. 3%, respectively; p = 0.026).
CONCLUSIONS: These preliminary data support our hypothesis that recipient inflammation may affect RBC alloimmunization in humans; however, a more detailed understanding of the pathophysiologic association between inflammation and alloimmunization is required before definitive conclusions can be reached.     

The natural history of ticks

Ticks have evolved to become one of the most important groups of arthropod vectors of human pathogens. One or more of the approximately 840 known species of ticks are found in most terrestrial regions of the earth. Ticks are a highly specialized group of obligate, bloodsucking, nonpermanent ectoparasitic arthropods that feed on mammals, birds, and reptiles. They are classified into two major families, Ixodidae (hard-bodies ticks) and Argasidae (soft-bodied ticks). The Ixodidae is the largest and most important family. There are many taxonomic keys for identifying ticks to assist the serious investigator. Their life cycles are often complex, and even though ticks are associated with their parasitic habits, ticks spend most of their life off hosts and in vegetation or soil. Maintenance of water balance during periods of overhydration while feeding and periods of dehydration while fasting is significant in the distribution, survival, activity, and transmission of disease-causing pathogens to humans and animals. Ticks attach to skin of the host by using their hypostome as an anchor and create a feeding lesion to ingest blood or tissue fluids. Soft-bodied ticks feed relatively rapidly (hours or less) and ingest only blood. Hard-bodied ticks take days to complete feeding and feed on blood, lymph, and lysed tissues from a pool that forms around the mouthparts. Feeding causes direct damage to the skin of the host. Disease-causing organisms may be ingested or expelled during feeding. Ingestion of relatively enormous quantities of blood is characteristic of ticks.     

The natural history of asthma from childhood to adulthood

Medical Practitioners are often questioned regarding the prognosis of a child with asthma. We have performed a literature review of the natural history of childhood asthmatics. Factors which affect the natural history and prognosis of childhood asthma are discussed. Current evidence suggests that evolution of asthma severity is fairly predictable. Features of childhood asthma such as severity, duration, atopy, bronchial hyperresponsiveness and exposure to smoking can predict the course of asthma into adulthood. Most children with mild intermittent asthma will outgrow their asthma, or have mild episodic asthma. Early commencement of anti-inflammatory therapy, such as inhaled corticosteroids may prevent the progression of the disease. Most patients with mild asthma have good functional outcome and low healthcare utilisation.     

Post-transfusion alloimmunization to granulocytes and platelets in Japanese patients as determined by the MPHA method

The current occurrence of alloimmunization to granulocytes and platelets after blood transfusion is unclear due to the fact that antibody assays are cumbersome. Using the MPHA method with extracted granulocyte and platelet antigens, a randomized, blinded trial was conducted to investigate three types of alloantibodies in 431 Japanese patients receiving leukocyte-depleted blood transfusions prepared with or without our latest leukocyte-reduction filter. The frequency of granulocyte, platelet and HLA class I alloantibodies was 0.44%, 0.44% and 16.74%, respectively, in patients receiving non-filtered products and 0%, 0% and 0.49%, respectively, in patients receiving filtered products. The granulocyte antibody reacted with an antigen approximately of 51 KDa. The platelet-specific alloantibody was associated with GPIIb/IIIa and GPIa/IIa. The important factors affecting alloimmunization were the transfusion dose and the use of unfiltered platelet products.     

The natural history of idiopathic scoliosis

Background. The natural history of idiopathic scoliosis is a crucial issue in the planning and assessment of different treatment methods. This article presents the evaluation of scoliotic deformity in immature patients who have been in observation without any treatment. Material and methods. 159 patients (128 girls, 31 boys) were examined between 1971 and 2002. Skoliosis was diagnosed at a mean age of 6 years 4 months (range 2.1-8.10), and observation was concluded at a mean age of 16 years 11 months (range 14.6-20.3). The mean follow-up was 10 years 5 months. The prognostic factors analyzed were: age, sex, Cobb angle, Mehta angle, apical vertebral rotation, specific rotation, Risser test. The progression and regression of curvature was analyzed in different biological age periods, and was measured by calculating the difference in the Cobb angle on successive x-rays divided by the interval between x-rays. Results. The mean progression of curvature before age 5 was 5.7 degrees per year; in the 6-10 age bracket, 2.3 degrees per year; in the 11-15 age bracket, 7.4 degrees per year; in the >15 age bracket, 0.3 degrees per year. The mean progression for patients with Risser 1 was 8.8 degrees per year; Risser 2, 7.3 degrees per year; Risser 3, 5.1 per year; Risser 4, 2.1 degrees per year; Risser 5, 0.3 degrees per year. Conclusions. The progression of curvature in idiopathic scoliosis is variable, and is influenced by age. Knowledge of the natural history of idiopathic scoliosis is a crucial tool in predicting the development of spinal curvature. The Risser test and biological age are the only effective predictors of progression.     

Absence of D alloimmunization in D- pediatric oncology patients receiving D-incompatible single-donor platelets

BACKGROUND: Guidelines are lacking for prophylaxis against D alloimmunization after D-incompatible platelet transfusion. A rational basis for the application of prophylaxis would be beneficial for institutions in which inventory constraints demand the administration of large numbers of D-incompatible platelets. STUDY DESIGN AND METHODS: A retrospective analysis was performed of all D-incompatible platelet transfusions administered at a pediatric research hospital over a 1.5-year period. Patients exclusively received single-donor WBC-reduced platelets and did not receive RhIg immunoprophylaxis. Numbers, source, ABO type, duration of serologic follow-up, and level of RBC contamination of D-incompatible transfusions were analyzed. All positive D serologies in the institution over a 3.5-year period were examined to determine cause and potential association with platelet transfusion. RESULTS: Thirty-five patients not receiving bone marrow transplant and seven bone marrow transplant patients received 490 and 255 D-incompatible transfusions, respectively, over 1.5 years. Patients had various diagnoses, predominantly malignancies. Seventy-nine percent of D-incompatible transfusions were ABO compatible. An estimated 2300 incompatible transfusions were performed over 3.5 years. No case of D alloimmunization was detected. CONCLUSIONS: D immunoprophylaxis is generally unnecessary in pediatric oncology patients receiving D-incompatible, WBC-reduced, single-donor platelets not visibly contaminated by RBCs. Further studies to validate these observations in the pediatric population and to extend them to other population groups are warranted.     

The known unknowns of HPV natural history

The discovery that certain high-risk strains of human papillomavirus (HR-HPV) cause nearly 100% of invasive cervical cancer has spurred a revolution in cervical cancer prevention by promoting the development of viral vaccines. Although the efficacy of these vaccines has already been demonstrated, a complete understanding of viral latency and natural immunity is lacking, and solving these mysteries could help guide policies of cervical cancer screening and vaccine use. Here, we examine the epidemiological and biological understanding of the natural history of HPV infection, with an eye toward using these studies to guide the implementation of cervical cancer prevention strategies.     

Persistence of lymphocytotoxic antibodies in patients in the trial to reduce alloimmunization to platelets: implications for using modified blood products

Patients with acute myelogenous leukemia undergoing induction chemotherapy have significant decreases in alloimmune platelet refractoriness if they receive filter-leukoreduced or UV-B-irradiated vs standard platelet transfusions (3%-5% vs 13%, respectively; P ≤ .03) with no differences among the treated platelet arms (Trial to Reduce Alloimmunization to Platelets). Therefore, measuring antibody persistence might identify the best platelets for transfusion. Lymphocytotoxic (LCT) antibody duration was evaluated for association with patient age, sex, prior transfusion and pregnancy history, study-assigned platelet transfusions, and percentage LCT panel reactive antibodies. During the Trial to Reduce Alloimmunization to Platelets, 145 patients became antibody positive; and 81 (56%) of them subsequently became antibody negative. Using Kaplan-Meier estimates, projected antibody loss was 73% at 1 year. Major factors associated with antibody persistence were prior pregnancy and percentage panel reactive antibody positivity, whereas neither the assigned type of platelets transfused during the 8 weeks of the trial nor prior transfusion history was predictive. After 5 to 8 weeks, the number and type of blood products transfused had no effect on either antibody development or loss. A majority of patients with acute myelogenous leukemia who develop LCT antibodies during induction chemotherapy will lose their antibodies within 4 months regardless of the type or number of blood products they receive.