Immunoglobulin G from patients with heparin-induced thrombocytopenia binds to a complex of heparin and platelet factor 4

Heparin-induced thrombocytopenia (HIT) is an important complication of heparin therapy. Although there is general agreement that platelet activation in vitro by the HIT IgG is mediated by the platelet Fc receptor, the interaction among the antibody, heparin, and platelet membrane components is uncertain and debated. In this report, we describe studies designed to address these interactions. We found, as others have noted, that a variety of other sulfated polysaccharides could substitute for heparin in the reaction. Using polysaccharides selected for both size and charge, we found that reactivity depended on two independent factors: a certain minimum degree of sulfation per saccharide unit and a certain minimum size. Hence, highly sulfated but small (< 1,000 daltons) polysaccharides were not reactive nor were large but poorly sulfated polysaccharides. The ability of HIT IgG to recognize heparin by itself was tested by Ouchterlony gel diffusion, ammonium sulfate and polyethylene glycol precipitation, and equilibrium dialysis. No technique demonstrated reactivity. However, when platelet releasate was added to heparin and HIT IgG, a 50-fold increase in binding of radio-labeled heparin to HIT IgG was observed. The releasate was then depleted of proteins capable of binding to heparin by immunoaffinity chromatography. Only platelet factor 4-immunodepleted releasate lost its reactivity with HIT IgG and heparin. Finally, to determine whether the reaction occurred on the surface of platelets or in the fluid phase, washed platelets were incubated with HIT IgG or heparin and after a wash step, heparin or HIT IgG was added, respectively. Reactivity was only noted when platelets were preincubated with heparin. Consistent with these observations was the demonstration of the presence of PF4 on platelets using flow cytometry. These studies indicate that heparin and other large, highly sulfated polysaccharides bind to PF4 to form a reactive antigen on the platelet surface. HIT IgG then binds to this complex with activation of platelets through the platelet Fc receptors.     

Accuracy of supplementary serologic testing for human T-lymphotropic virus types I and II in US blood donors. Retrovirus Epidemiology Donor Study

Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II.     

A novel de novo point mutation of the OCT‐binding site in the IGF2/H19‐imprinting control region in a Beckwith–Wiedemann syndrome patient

The IGF2/H19‐imprinting control region (ICR1) functions as an insulator to methylation‐sensitive binding of CTCF protein, and regulates imprinted expression of IGF2 and H19 in a parental origin‐specific manner. ICR1 methylation defects cause abnormal expression of imprinted genes, leading to Beckwith–Wiedemann syndrome (BWS) or Silver–Russell syndrome (SRS). Not only ICR1 microdeletions involving the CTCF‐binding site, but also point mutations and a small deletion of the OCT‐binding site have been shown to trigger methylation defects in BWS. Here, mutational analysis of ICR1 in 11 BWS and 12 SRS patients with ICR1 methylation defects revealed a novel de novo point mutation of the OCT‐binding site on the maternal allele in one BWS patient. In BWS, all reported mutations and the small deletion of the OCT‐binding site, including our case, have occurred within repeat A2. These findings indicate that the OCT‐binding site is important for maintaining an unmethylated status of maternal ICR1 in early embryogenesis.     

Searching for the initiating site of the major capsid protein to generate virus-like particles for a novel laboratory mouse papillomavirus

Correctly folded virus-like particles (VLPs) of papillomavirus (PV) display conformationally dependent epitopes that are type specific, maintained on authentic virions, and induce neutralizing antibodies. Alignment of the L1 amino acid (aa) sequences of 84 PVs revealed that the lengths of their N-termini are diverse and that multiple, possible initiation methionine (met) codons exist. The L1 gene of MusPV (MmuPV1), that naturally infects immunodeficient laboratory mouse strain (NMRI-Foxn1^nu/Foxn1^nu), has four met codons at the 1st, 2nd, 28th, and 30th aas from its N-terminus. Of these, the 3rd and 4th mets, that are at the 28th and 30th aa position from the N-termius, respectively, are located at the position where most PVs have their first met. These two mets, located at the 9th and 11th from the YLPP conserved aas of most PVs, should be considered as consensus initiation codons of PV L1s. Three L1 proteins of MusPV, starting from the 2nd, 3rd, and 4th mets, were expressed using a baculovirus expression system and characterized for their ability to self-assemble into VLPs. While MusPV L1 proteins starting from the 2nd met expressed an L1 protein that did not fold into VLPs, the L1s starting from the 3rd and 4th mets generated correct VLPs in abundant quantities. We now conclude that the highest quantity and best quality VLPs are made from the consensus L1 met of MusPV.     

Questionnaire-Based Survey Conducted in 2011 concerning Endoscopic Management of Barrett's Esophagus in East Asian Countries

Background/Aims: Endoscopic definitions and management of Barrett's esophagus vary widely among countries. To examine the current situation regarding diagnosis, epidemiology, management and treatment of Barrett's esophagus in East Asian countries using a questionnaire-based survey. Methods: Representative members of the Committee of the International Gastrointestinal Consensus Symposium developed and sent a questionnaire to major institutions in China, South Korea, Japan, Thailand, Indonesia, and the Philippines. Results: A total of 56 institutions in the 6 countries participated in the survey. We found that the presence of specialized columnar metaplasia is considered to be important for diagnosing Barrett's esophagus in East Asian countries except for Japan. C&M criteria have not been well accepted in East Asia. The palisade vessels are mainly used as a landmark for the esophagogastric junction in Japan. The prevalence of long segment Barrett's esophagus is extremely low in East Asia, while the prevalence of short segment Barrett's esophagus is very high only in Japan, likely due to different diagnostic criteria. Conclusion: Among East Asian countries, we found both similarities and differences regarding diagnosis and management of Barrett's esophagus. The findings in the present survey are helpful to understand the current situation of Barrett's esophagus in East Asian countries.     

Results of a phase 4 trial of tacrobell® in liver transplantation patients: a multicenter study in South Korea

Background/Aims: This 26-week pilot study was performed in de novo liver transplant recipients to evaluate the efficacy of tacrobell capsule as an immunosuppressant drug after living donor liver transplant patients by determining the rate of acute cellular rejection after its use and evaluating its safety after transplantation. Methodology: From October 2005 to July 2007, 57 patients from four major medical centers in Seoul, South Korea were enrolled in the study. This open-label, noncomparative, multicenter pilot study lasted 26 weeks and assigned patients to receive tacrobell and corticosteroid after liver transplantation. Tacrobell (0.05mg/ kg/day, bid) and methylprednisolone were injected either on the day of the operation or on postoperative day one. A retrospective matched control group consisting of living donor liver transplant recipients at one center (Asan medical center) was used for comparison. Results: The rate of acute cellular rejection with tacrobell after 26 weeks of administration was 0.0% (95% CI, 0.0%-6.27%), which was below our hypothesized 36%. The most common drug-related adverse events included endocrine/nutritional disorders followed by gastrointestinal and hepatobiliary disorders. No patients died during the study period. The side effect profile of this drug was no different than other tacrolimus based immunosuppressants. Conclusions: Although our study was based on a low risk population and had a shortterm follow up, we conclude that tacrobell, as a generic tacrolimus, can be considered safe and effective in liver transplant patients.     

The impact of periodontitis on oral health‐related quality of life: a review of the evidence from observational studies

Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries.     

Monitoring and Treatment for BK Virus After Kidney Transplantation

Background

The BK nephropathy (BKN) shows a 10% prevalence among cases of kidney transplantation (KT). We assessed the incidence of BK replication in KT recipients as well as our updated screening strategy and the impact of interventions on BK virus infections.

Methods

Since September 2007, our screening protocol for BK virus included examination of urine cytology or BK virus DNA real-time polymerase chain reaction (PCR) detection on postoperative days 1, 5, 9, 16, 24, 36, 48 weeks up to 1 year. IR present, we tested urine BK virus DNA PCR quantitation. We applied the updated screening protocol from August 2010. It urine BK DNA PCR quantification was above 10⁷ copies/mL, we checked regularly blood the BK virus DNA PCR quantification. In addition, if the blood BK virus DNA load was above 10⁴ copies/mL and the serum creatinine elevated, we was performed an allograft biopsy. Between September 2007 and December 2011, the 58 recipients who showed BK viremia were enrolled in the present study in 2 groups according to the period of screening protocol (era I, era II).

Results

The time between kidney transplantation and BK viremia detection of era II was shorter than that of era I (16 vs 29 weeks; P = .001). Viremia clearance rate at 6 months in era II was significant higher than that of era I (82% vs 36.8%; P = .001) as well as at 12 months (100% vs 61.1%, P < .001) after intervention. Interestingly, viremia clearance at 12 months after intervention was 100% in era II.

Conclusion

An updated screening protocol for BK virus allowed early detection and accurate diagnosis of BKN. Early detection of BK virus infection enabled early intervention and improved viral clearance rate.     

Comparison of the Incidence of De Novo Malignancy in Liver or Kidney Transplant Recipients: Analysis of 2673 Consecutive Cases in a Single Center

Purpose

An increased incidence of de novo malignancy (dM) is an established complication among solid organ transplant (SOT) recipients compared with the general population. The aims of this study were to describe the incidence and cumulative risk for development of dM among our transplanted population, depending on various clinical and pathologic variables.

Methods

We retrospectively reviewed the medical records and pathologic data of SOT recipients performed from February 1995 to December 2010.

Results

Among 2673 consecutive SOT recipients, the dM that developed in 66 (2.5%) patients included, 16 (0.6%; 24.2% of overall dM) lymphoid dM and 50 (1.9%; 75.8% of overall dM) nonlymphoid dM. Cumulative incidence of dM in liver was significantly higher than that in kidney transplant recipients. A significantly higher cumulative incidence of dM was observed among living donor versus deceased donor SOT. Although the more frequent development of lymphoid dM was observed during the first year posttransplantation, the cumulative risk of nonlymphoid dM increased year by year, reaching a substantially higher incidence than that of lymphoid dM beyond 5 years after SOT. Comparing the various immunosuppressive regimens, the cumulative incidence was greater among the group with basiliximab induction. However, the hazard of occurrence was unaffected by whether tacrolimus or cyclosporine was used for maintenance immunosuppression. The increased risk of dM was not dependent on recipient age or gender.

Conclusion

This study demonstrated distinctive cumulative incidences of dM in different clinical and pathologic settings.