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We study heavy-flavor hadron production in high-energy pp collisions, assuming the formation of a small, deconfined and expanding fireball where charm quarks can undergo rescattering and hadronization. We adopt the same in-medium hadronization mechanism developed for heavy-ion collisions, which involves Local Color-Neutralization (LCN) through recombination of charm quarks with nearby opposite color charges from the background fireball. Diquark excitations in the hot medium favor the formation of charmed baryons. The recombination process, involving closely aligned partons from the same fluid cell, effectively transfers the collective flow of the system to the final charmed hadrons. This framework can qualitatively reproduce the observed experimental findings in heavy-flavor particle-yield ratios, pT -spectra and ellipticflow coefficients. Our results provide new, complementary support to the idea that the collective phenomena observed in small systems have the same origin as those observed in heavy-ion collisions.

A multi-step setup for heavy-flavor studies in high-energy nucleus-nucleus (AA) and proton-nucleus (pA) collisions is presented. The propagation of the heavy quarks in the medium is described in a framework provided by the relativistic Langevin equation, here solved using weak-coupling transport coefficients. Successively, the heavy quarks hadronize in the medium. We compute the nuclear modification factor and the elliptic flow parameter of the final Dmesons both in AA and in pA collisions and compare our results to experimental data.

A multi-step setup for heavy-flavor studies in high-energy nucleus-nucleus (AA) collisions — addressing within a comprehensive framework the initial QQ¯$Q\overline Q $ production, the propagation in the hot medium until decoupling and the final hadronization and decays — is presented. The propagation of the heavy quarks in the medium is described in a framework provided by the relativistic Langevin equation and the corresponding numerical results are compared to experimental data from RHIC and the LHC. In particular, outcomes for the nuclear modification factor RAA and for the elliptic flow υ2 of D/B mesons, heavy-flavor electrons and non-prompt J/ψ’s are displayed.

Abstract Background Carboplatin/paclitaxel is the chemotherapy of choice for advanced ovarian cancer, both in first line and in platinum-sensitive recurrence. Although a significant proportion of patients have some neurotoxicity during treatment, the long-term outcome of chemotherapy-induced neuropathy has been scantly studied. We retrospectively assessed the prevalence of residual neuropathy in a cohort of patients in clinical remission after first-line carboplatin/paclitaxel for advanced ovarian cancer. Methods 120 patients have been included in this study (101 participating in a multicentre phase III trial evaluating the efficacy of consolidation treatment with topotecan, and 19 treated at the National Cancer Institute of Naples after the end of the trial). All patients received carboplatin (AUC 5) plus paclitaxel (175 mg/m2) every 3 weeks for 6 cycles, completing treatment between 1998 and 2003. Data were collected between May and September 2004. Residual sensory and motor neurotoxicity were coded according to the National Cancer Institute – Common Toxicity Criteria. Results 55 patients (46%) did not experience any grade of neurological toxicity during chemotherapy and of these none had signs of neuropathy during follow-up. The other 65 patients (54%) had chemotherapy-induced neurotoxicity during treatment and follow-up data are available for 60 of them. Fourteen out of 60 patients (23%) referred residual neuropathy at the most recent follow-up visit, after a median follow up of 18 months (range, 7–58 months): 12 patients had grade 1 and 2 patients grade 2 peripheral sensory neuropathy; 3 patients also had grade 1 motor neuropathy. The remaining 46/60 patients (77%) had no residual neuropathy at the moment of interview: recovery from neurotoxicity had occurred in the first 2 months after the end of chemotherapy in 22 (37%), between 2 and 6 months in 15 (25%), or after more than 6 months in 9 patients (15%). Considering all 120 treated patients, there was a 15% probability of persistent neurological toxicity 6 months after the end of chemotherapy. Conclusion A significant proportion of patients with advanced ovarian cancer treated with first-line carboplatin/paclitaxel suffer long-term residual neuropathy. This issue should be carefully taken into account before considering re-treatment with the same agents in sensitive recurrent disease.

Verifies the applicability to research on indexers' reading strategies of the process observing technique known as Verbal Protocol or Thinking Aloud. This interpretative-qualitative data collecting technique allows the observation of different kinds of process during the progress of different kinds of tasks. Presents a theoretical investigation into "reading" and into formal methodological procedures to observe reading processes. Describes details of the methodological procedures adopted in five case studies with analysis of samples of data. The project adopted three kinds of parameters for data analysis: theoretical, normative, empirical (derived from observations made in the first case study). The results are compared, and important conclusions regarding documentary reading are drawn.

Postoperative venous thromboembolism (VTE) is a common and costly complication following total joint arthroplasty (TJA). Development of a refined thrombophilic screening panel will better equip clinicians to identify patients at high-est risk for developing VTEs. In this pilot study, 62 high-risk TJA recipients who had developed pulmonary emboli (PE) within 90-days of surgery were eligible to participate. Of these patients, 14 were enrolled and subsequently adminis-tered a pre-determined panel of 18 hematologic tests with the aim of identifying markers that are consistently elevated or deficient in patients developing PE. A separate cohort of seven high-risk TJA recipients who did not report a symp-tomatic VTE within 90-days of surgery were then enrolled and Factor VIII and lipoprotein(a) levels were assessed. The most common aberrance was noted in 10 patients (71.4%) who had elevated levels of Factor VIII followed by five patients (35.7%) who had elevated levels of lipoprotein(a). Factor VIII was significantly prevalent (p < 0.001) while lipoprotein(a) failed to achieve statistical significance (p = 0.0708). Of the patients who were within normal limits of Factor VIII, three-fourths were "high-normal" with Fac-tor VIII levels within 5% of the upper limit of normal. This study demonstrates the potential utility of this hematologic panel as part of a perioperative screening protocol aimed at identifying patients at risk for developing VTEs. However, future larger scale studies assessing the capabilities and limitations of our findings are warranted.

Background: within the frame of reference of any medical specialty, having a consensus list of the type and number of practices characterizing its professional work is key. Thus, the goal of this study was to define a list of minimum procedures to ensure competence in gastrointestinal endoscopy based on a structured consensus process, and to explore the views of leading experts in gastrointestinal endoscopy regarding endoscopist training in Argentina and the need for competence certification., Materials and Methods: this research entailed a mixed-methods prospective study including using the Delphi method as focus group qualitative research technique, followed by a structured survey., Results: the final consolidated list included 17 procedures deemed essential for competence certification in gastrointestinal endoscopy. Given the dispersion found in the range of minimum numbers required for competence a decision was made to use the median value. For upper gastrointestinal endoscopy the minimum number of procedures was set at 200, whereas 150 was established for videocolonoscopy., Conclusion: this list is a key item in the development of a gastrointestinal endoscopy training framework and competence certification program.

Hemophilia A is an X-linked recessive bleeding disorder characterized by absent or ineffective coagulation factor VIII, a condition that could result in a severe and potentially life-threatening bleed. Although the current standard of care involves prophylactic replacement therapy of factor VIII, the development of neutralizing anti-factor VIII alloantibody inhibitors often complicates such therapeutic treatment. Emicizumab (Hemlibra®), a novel recombinant therapeutic agent for patients with hemophilia A, is a humanized asymmetric bispecific IgG4 monoclonal antibody designed to mimic activated factor VIII by bridging factor IXa and factor X thus effecting hemostasis. Importantly, this drug eliminates the need for factor VIII and complications associated with inhibitor generation. Emicizumab has been approved for use in several countries including the United States and Japan for prophylaxis of bleeding episodes in hemophilia A with and without FVIII inhibitors. Therapy is also approved in the European Union for routine prophylaxis of bleeds in hemophilia A with inhibitors or severe hemophilia A without inhibitors. Unfortunately, emicizumab therapy presents unique challenges for routine and specialty coagulation tests currently used to monitor hemophilia A. In this review, hemophilia A is presented, the biochemistry of factor VIII is discussed, and the impact of the therapeutic agent emicizumab is highlighted., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Aim: The objective of this work was to define a value for the 99th percentile of high-sensitive troponin T and to evaluate the prognostic value of this biomarker in a population of patients with type 2 diabetes without a history of cardiovascular disease., Methods: In this prospective, observational and analytic study, 482 patients with type 2 diabetes were enrolled. The patients were asymptomatic, with no history of cardiovascular events, renal insufficiency, or inflammatory or systemic disease. As events we considered a combined end point of major adverse cardiovascular events (MACE)., Results: 94.9% of the patients had detectable troponin values, 20.7% of the patients had troponin values above the healthy population reference upper threshold (14pg/mL). The 99th percentile value for this patient population was 48pg/mL. Age, sex, the glomerular filtration rate and hypertension were associated with troponin values>14pg/mL. The incidence of MACE was 3.96 per 100 patients/year (p/y) between those with hs-TnT>14pg/mL and 1.07 per 100 p/y between those with hs-TnT≤14pg/mL (HR=3.78 CI95 1.49-9.58; p=0.005)., Conclusions: The 99th percentile value of troponin T in a population of patients with type 2 diabetes is 3-fold higher than the value proposed by the manufacturer for a healthy population. We also observed a significant difference in the distribution of troponin T values between men and women. This biomarker may be a valuable prognostic factor, since troponin T values above the reference upper threshold were associated with an increase in the risk of cardiovascular events in these patients., (Copyright © 2020 SEEN and SED. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction: The chief resident plays a strategic role in terms of leadership and cohesion among residents., Objective: To characterize the activities developed by chief residents and identify their achievements and difficulties., Methods: A survey about demographic outcome measures, activities performed, most and least gratifying situations, and training needs was completed., Results: In total, 88 % of chief residents completed the survey; 46 % were females. Activities were related to health care (26 %), academic management (25 %), teaching (24 %), administration (16 %), and research (10 %). The most gratifying situation was playing a teaching role, and the least gratifying one were difficulties in the management of interpersonal relations. A lack of training was recognized by 57 %, whereas 95 % would recommend becoming a chief resident., Conclusion: The most gratifying situation was playing a teaching role, and the least gratifying one were difficulties in the management of interpersonal relations., Competing Interests: None, (Sociedad Argentina de Pediatría.)

Introduction: Von Willebrand disease (VWD) is the most prevalent inherited bleeding disorder. Diagnosis requires measurement of VWF-platelet binding function, for which VWF ristocetin cofactor activity (VWF:RCo) is the reference method. Recently, an automated latex particle-enhanced immunoturbidimetric von Willebrand factor activity assay (VWF:Ab) has been validated showing superior characteristics. We further validate VWF:Ab in a prospective study including post-treatment patient samples., Methods: A total of 1151 samples were collected from patients tested for VWD, including 119 samples from patients treated with desmopressin or VWF replacement product. All samples were tested for VWF:Ab and VWF:RCo, and the methods were compared using linear regression. Imprecision, linearity and lower detection limit were determined for both assays., Results: VWF:Ab showed improved precision compared to VWF:RCo. Linear regression of VWF:Ab and VWF:RCo across all samples exhibited good agreement (R 2 = 0.89) with statistical significance (P < 0.001) and bias of -8.7. Concordance was high in classifying samples as normal or abnormal. Analysis of treated samples showed excellent agreement (R 2 = 0.91) with statistical significance (P < 0.001) and bias of -4.3., Conclusions: Our analysis validates the VWF:Ab assay in a prospective study of a large cohort of patient samples and extends these results to post-treatment patient samples., (© 2017 John Wiley & Sons Ltd.)

Platelet markers [soluble CD40 ligand (sCD40L) and soluble p selectin (sPselectin)] are associated with platelet activation and cardiovascular events. We sought to investigate the reproducibility of these markers over time and the effect of low-dose aspirin on sCD40L and sPselectin in plasma and serum. Following an overnight fast, 40 healthy volunteers had weekly phlebotomy and were administered aspirin 81 mg/day between weeks 3 and 4. Reproducibility over time was assessed by coefficient of variation (CV) and inter-class correlation coefficient. Correlation between markers was assessed using Pearson r statistic. Difference between levels pre- and post-aspirin was measured with Wilcoxon signed-rank test. Data are presented as median (interquartile range). sCD40L and sPselectin measurements were reproducible over time in plasma and serum (CV < 10 %). Measurement of sCD40L and sPselectin in plasma correlated with levels in serum before aspirin and after aspirin. There was no significant correlation between sCD40L and sPselectin. After 1-week of aspirin 81 mg/day, there was a reduction in sCD40L and sPselectin in serum and plasma, respectively. Soluble CD40L and sPselectin are independent markers that are reproducible over time in both plasma and sera and are reduced by 1-week of low-dose aspirin.

Purpose: This review aimed at presenting the benefits regarding the speech perception in noise shown by children who wear hearing aid devices and/or cochlear implants with the Frequency Modulation (FM) System at school., Research Strategy: A bibliographic survey was conducted in an electronic database with standardized search until the year 2012, and a manual search was performed by using specific keywords., Selection Criteria: For the selection and evaluation of the scientific studies chosen in the search, criteria were established covering the following aspects: type of study, participants, adopted intervention, and evaluation of results., Data Analysis: The FM system was verified to improve speech perception and speech threshold in noise in all studies., Results: Regarding the performance as to type, the best results were obtained when children used the personal FM system, followed by the table and the sound field systems., Conclusion: After extensive review of national and international literature, it was concluded that the studies indicate the need for further research concerning mainly the impact of the FM system on the school performance of children who have sensory devices coupled to the FM system. Findings in the literature with relation to the publications focused on speech perception in noise did not relate educational and auditory aspects.

Hemostasis is a major concern during the perioperative period. Changes in platelet aggregation and coagulation factors may contribute to the delicate balance between thrombosis and bleeding. We sought to better understand perioperative hemostasis by investigating the changes in platelet aggregation and coagulation factors during the perioperative period. We performed a prospective cohort analysis of 70 subjects undergoing non-emergent orthopedic surgery of the knee (n = 28), hip (n = 35), or spine (n = 7) between August 2011 and November 2011. Plasma was collected preoperatively (T1), 1-h intraoperatively (T2), 1-h (T3), 24-h (T4) and 48-h (T5) postoperatively. Platelet function testing was performed using whole blood impedance aggregometry. Coagulation assays were performed for factor VII, factor VIII, von Willebrand Factor (vWF), and fibrinogen. Of the 70 patients, mean age was 64.1 ± 9.8 years, 61% were female, and 74% were Caucasian. Platelet activity decreased until 1 h postoperatively and then significantly increased above baseline at 24- and 48-h postoperatively. Compared to baseline, coagulation factors decreased intraoperatively. Factor VII activity continued to decrease, while FVIII, vWF, and fibrinogen all increased above baseline postoperatively. The results of our study indicate significant changes in platelet activity and coagulation factors during the perioperative period. Both platelet activity and markers of coagulation decrease during the intraoperative period and then some increase postoperatively. These changes may contribute to the hypercoagulabity and/or bleeding risk that occurs in the perioperative period. Future prospective studies aimed at correlating hemostatic changes with perioperative outcomes are warranted.

Some studies suggest that mean platelet volume (MPV) correlates with increased risk for cardiovascular morbidity and mortality. In this study, we aim to assess reproducibility, need for standardized measurements, effect of aspirin, and association with other established markers of platelet activity. Following an overnight fast, 48 healthy volunteers had weekly assessment of platelet activity and were administered aspirin 81 mg daily for 7 d between weeks 3 and 4. We investigated the influence of time between phlebotomy and MPV measurement (n=10). Reproducibility was assessed by coefficient of variation (CV) and intraclass correlation coefficient (ICC). MPV measurements were reproducible (Week 1: 10.6 fL [9.9-11], Week 2: 10.6 fL [10.0-10.9], Week 3: 10.6 fL [9.8-11]). CV was ≤ 4% and ICC>0.85 (p<0.001) for each comparison, indicating excellent reproducibility. There was no effect of aspirin on MPV (10.6 fL [9.8-11] versus 10.5 fL [9.9-11]; p=0.81). MPV significantly increased as time between phlebotomy and MPV measurement increased (Spearman's rho=0.94, p=0.001). Increasing MPV tertiles was associated with collagen- and thrombin receptor-activated peptide-induced platelet aggregation but not with ADP- or arachidonic acid-induced or spontaneous platelet aggregation. In conclusion, when standardized, MPV is a reproducible marker of platelet size and not affected by low-dose aspirin. MPV is modestly associated with some, but not all, markers of platelet activity.

Background: Mechanisms for increased cardiovascular risk in HIV-1-infected adults are incompletely understood, but platelet activation and immune activation leading to a prothrombotic state have been proposed as significant contributors. Aspirin has antiplatelet and immunomodulatory properties. We explored whether 1 week of low-dose aspirin attenuates platelet activation and immune activation in HIV-1-infected and virologically suppressed adults on antiretroviral therapy., Methods: Platelet activation and immune activation were measured in HIV-1-infected subjects virologically suppressed on antiretroviral therapy and controls before and after 1 week of low-dose aspirin., Results: Compared with control subjects, HIV-1-infected subjects had increased platelet activation, as measured by spontaneous platelet aggregation and aggregation in response to adenosine diphosphate, collagen, and arachidonic acid. After aspirin therapy, percent aggregation decreased similarly in both HIV-1-infected and control subjects to all platelet agonists tested except aggregation in response to arachidonic acid, which remained elevated in the HIV-1-infected group. HIV-1-infected subjects exhibited increased markers of T-cell activation (CD38 and HLA-DR) and monocyte activation (sCD14), which decreased after 1 week of aspirin therapy. Moreover, leukocyte responses to Toll-like receptor stimulation were enhanced after 1 week of aspirin therapy. In vitro studies showed that HIV-1 plasma could activate healthy platelets, which in turn activated monocytes, implicating a direct role for activated platelets in immune activation., Conclusions: Our data demonstrate that heightened platelet activation and immune activation in treated HIV-1 disease are attenuated by 1 week of aspirin therapy. Aspirin should be further studied for its antithrombotic and immunomodulatory benefits in treated HIV-1 disease.

Purpose: To validate a monitoring questionnaire about hearing and language development applied by community health agents in the first year of life., Methods: Seventy six community health agents, previously trained on infant hearing health, administered a questionnaire to the families of 304 children with ages from 0 to 1 year. The questionnaire contains questions regarding hearing and language development and, for all age groups, the question "Does your child hear well?" was presented. The validity of the questionnaire was assessed by analyzing false positive and false negative rates of the identified children. A double-blind study was conducted so that all children assessed by the questionnaire were submitted to hearing evaluation performed by audiologists., Results: Four children (1.32%) were diagnosed with sensorineural hearing loss (two unilateral), and 69 (22.7%) with conductive hearing loss. The monitoring questionnaire showed specificity of 96% and sensitivity of 67%, with a false-negative rate of 33% for not identifying the unilateral hearing loss, and a false-positive rate of 4%., Conclusion: The questionnaire used has shown to be feasible and relevant to actions of the community health agents of the Family Health Strategy program, with high specificity and moderate sensitivity. The use of the validated instrument should be considered to complement Newborn Hearing Screening Programs, in order to identify late onset or acquired hearing loss.

Background: Light transmission aggregometry (LTA) is considered the gold standard for investigating platelet activity ex vivo. However, LTA protocols are not standardized, and differences in LTA procedure are a potential source of variance in results. Centrifugation speed is an essential component of platelet preparation in LTA, has yet to be standardized, and may affect platelet aggregation results. We sought to investigate the effect of relative centrifugal force (RCF) intensity on LTA results., Methods: Ten healthy controls had venous blood drawn and centrifuged at 150, 200, 300, and 500 g for 10 min. Cell counts in whole blood and platelet-rich plasma (PRP) were measured using a hematology analyzer. LTA was performed using 1.0 μm adenosine diphosphate (ADP) and 0.4 μm epinephrine as an agonist. Aggregation (%) was compared at 60, 120, 180, and 300 s and at maximum aggregation., Results: Centrifugation speed was associated with decreasing platelet count (P < 0.001) and decreasing mean platelet volume (P < 0.001) in PRP. Maximum aggregation decreased with increasing speeds for ADP 1.0 μm (150 g- 89%, 200 g- 93%, 300 g- 71%, 500 g- 17%; P < 0.001). Similar findings were noted at 120 s (150 g- 69%, 200 g- 50%, 300 g- 35%, 500 g- 12%; P < 0.001), 180 s (150 g- 82%, 200 g- 74%, 300 g- 44%, 500 g- 13%; P < 0.001), and 300 s (150 g- 85%, 200 g- 88%, 300 g- 55%, 500 g- 14%; P < 0.001). Consistently, platelet aggregation in response to epinephrine 0.4 μm decreased significantly with increasing centrifuge RCF at 60, 120, 180, 300 s and at maximum aggregation (P < 0.05 for each comparison)., Conclusion: Our data demonstrate the importance of centrifugation speed in the interpretation of LTA results, supporting the need for standardization of centrifugation RCF in LTA protocols., (© 2011 Blackwell Publishing Ltd.)

We previously reported that patients with early-onset HIV-1 ITP developed a unique anti-platelet integrin GPIIIa antibody against the GPIIIa49-66 epitope. Anti-GPIIIa49-66 antibody-induced platelet fragmentation requires sequential activation of the platelet 12-lipoxygenase (12-LO) and NADPH oxidase to release reactive oxygen species (ROS). 12-LO is upstream of the NADPH oxidase pathway and 12(S)-HETE, the product of 12-LO, induces the same oxidative platelet fragmentation as anti-GPIIIa49-66. Since the megakaryocyte (MK) is the progenitor cell for platelets, we have investigated the effect of anti-GPIIIa49-66 on MK differentiation and, in particular, the potential role of anti-GPIIIa49-66 induced ROS in this process. We first show that polyclonal anti-GPIIIa49-66 antibody isolated from HIV-1 ITP patients inhibits MK proliferation 2.5-fold in in vitro culture of human cord blood CD34+ cells driven by thrombopoietin (TPO). We also observe a three-fold decrease in the number of MK colony-forming units in the presence of a human monoclonal anti-GPIIIa49-66 antibody. However, we could not detect ROS release in DCFH-loaded mouse megakaryoblastic cells L8057 treated with anti-GPIIIa49-66 antibody. In addition, 12(S)-HETE does not inhibit the in vitro differentiation of L8057 cells induced by TPO. In fact, we found a dose dependent increase in the percentage of CD41 positive cells (from 17.1% to 48.7%) in in vitro culture of L8057 cells treated with various concentrations of H2O2 (from 5 to 20 μM). We therefore conclude that the anti-GPIIIa49-66 antibody inhibits MK differentiation through β3 integrin signalling independent of ROS release.

Background: Enhanced platelet activation in human immunodeficiency virus (HIV)-1-infected patients has been reported and shown to strongly correlate with plasma viral load. Activated platelets are known to express and to release a variety of proteins that can modulate the immune system. Specifically, platelet-derived CD154 has been shown to be directly involved in the development of autoimmune thrombocytopenia (ITP). The mechanism by which HIV-1 infection leads to platelet activation and the effect of this activation on the development of HIV-1 ITP, however, is not fully understood., Objective: We have investigated the effect of HIV-1 Trans activating factor (Tat) on platelet activation., Results: We report that HIV-1 Tat directly interacts with platelets and induces platelet activation resulting in platelet micro-particle release. This activation by Tat requires the chemokine receptor CCR3 and β3-integrin expression on platelets, as well as calcium flux. Tat-induced activation of platelets releases platelet CD154, an immune modulator. Enhanced B-cell activity is found in mouse spleen B cells co-cultured with platelets treated with Tat in vitro. An early antibody response against adenovirus is found in Tat-injected mouse immunized with adenovirus, suggesting an enhanced immune response in vivo., Conclusions: We have described a role of Tat-induced platelet activation in the modulation of the immune system, with implications for the development of HIV-1-associated thrombocytopenia., (© 2011 International Society on Thrombosis and Haemostasis.)

A 2½-year-old male child and a 23-year-old woman with no clinical symptoms were investigated during routine consultations. Cation exchange high performance liquid chromatography (HPLC) revealed an additional peak eluting before Hb A. DNA sequencing showed a novel heterozygous mutation at codon 20 of the α1-globin gene. The hemoglobin (Hb) variant was named Hb Brugg. Analysis of oxygen affinity Hb and Hb stability did not show any changes compared to normal Hb constellation.

Anti-platelet autoantibodies are frequently found in systemic lupus erythematosus (SLE) patients and contribute to the development of SLE-associated immunologic thrombocytopenia (SLE-ITP). Although the correlation of anti-dsDNA autoantibody with platelet-associated antibody has been reported, the potential mechanism underlying such a correlation is incompletely understood. We have reported that anti-platelet integrin GPIIIa49-66 (CAPESIEFPVSEARVLED) autoantibodies play a major role in the development of HIV-1-related thrombocytopenia (HIV-1-ITP). The strong negative charge of GPIIIa49-66 prompts us to investigate whether GPIIIa49-66 can be an epitope mimicking dsDNA. We report here that anti-GPIIIa49-66 antibodies are found in three out of nine SLE-ITP patients. Double-stranded (ds) DNA competitively inhibited the binding of purified patient anti-dsDNA antibodies to GPIIIa49-66 peptide. Both polyclonal and monoclonal anti-GPIIIa49-66 antibodies are able to cross-react with dsDNA. Consistent with previous reports, the DNA binding activities of anti-GPIIIa49-66 antibodies are mainly dependent on the positively charged amino acid in the heavy-chain complementarity-determining region 3 (HCDR3). The HCDR3 of human SLE anti-dsDNA monoclonal antibody (mAb) 412.67 demonstrates a similar positively charged amino acid chain orientation compared with that of anti-GPIIIa49-66 mAb A11, and it cross-reacts with GPIIIa49-66 peptide. Purified anti-GPIIIa49-66 antibodies from SLE-ITP patients are able to induce platelet fragmentation in vitro and to induce thrombocytopenia in vivo. Thus, our data suggest that specific epitope cross-reaction between GPIIIa49-66 and dsDNA could be a mechanism involved in the development of SLE-associated thrombocytopenia.

Patients with HIV-1 immune-related thrombocytopenia have a unique antibody (Ab) against integrin GPIIIa49-66 capable of inducing oxidative platelet fragmentation via Ab activation of platelet nicotinamide adenine dinucleotide phosphate oxidase and 12-lipoxygenase releasing reactive oxygen species. Using a phage display single-chain antibody (scFv) library, we developed a novel human monoclonal scFv Ab against GPIIIa49-66 (named A11) capable of inducing fragmentation of activated platelets. In this study, we investigated the in vivo use of A11. We show that A11 does not induce significant thrombocytopenia or inhibit platelet function. A11 can prevent the cessation of carotid artery flow produced by induced artery injury and dissolve the induced thrombus 2 hours after cessation of blood flow. In addition, A11 can prevent, as well as ameliorate, murine middle cerebral artery stroke, without thrombocytopenia or brain hemorrhage. To further optimize the antithrombotic activity of A11, we produced a bifunctional A11-plasminogen first kringle agent (SLK), which homes to newly deposited fibrin strands within and surrounding the platelet thrombus, reducing effects on nonactivated circulating platelets. Indeed, SLK is able to completely reopen occluded carotid vessels 4 hours after cessation of blood flow, whereas A11 had no effect at 4 hours. Thus, a new antithrombotic agent was developed for platelet thrombus clearance.

A kindred with inherited macrothrombocytopenia (MTCP) and sensorineural hearing loss (SNHL) from Ghent, Belgium was identified. Currently, joint expression of MTCP and hearing loss are linked to mutations within MYH9 only. Thus, we tested the hypothesis that a mutation within MYH9 is responsible for the autosomal dominant inheritance of MTCP and hearing loss in the Ghent family. A mutation screen of MYH9 coding region including its intron-exon junctions, as well as common hearing loss genes GJB2, GJB3, and GJB6, was performed. However, no pathogenic sequence alteration was identified. Patients' leukocytes were determined to be normal for NMMHC-A distribution via immunofluorescence analysis and free of Döhle body-like inclusions, identified as aggregates of mutant NMHC-IIA in MYH9 disorders. Also, western blot analysis with anti-NMHC-IIA antibody identified a single 220 kDa immunoreactive band with normal expression level of NMHC-IIA within the platelets and leukocytes of the affected family members. The immunoblot analysis eliminates the possibility of a large deletion within MYH9 that can escape detection by direct sequencing. Collectively, these results suggest that molecular genetic etiology of the Ghent family disorder may be due to as yet unidentified gene whose mutation(s) yields a phenocopy of the MYH9-related disease.

Background: having knowledge about the validity of procedures for newborn hearing screening (NHS) is fundamental, once the purpose of these programs is to identify all newborns with hearing loss at an acceptable cost., Aim: to estimate the specificity and the false-positive rate of NHS protocols using transient evoked otoacoustic emissions (TEOAE) and automated auditory brainstem response (AABR)., Method: participants were 200 newborns who were submitted to a hearing screening test between March and July 2006. Three protocols were analyzed: protocol 1, NHS was carried out in two steps using TEOAE; protocol 2, NHS was carried out in two steps using AABR; and protocol 3, NHS was carried out in one step, using the two procedures - testing with TEOAE followed by a retest with AABR for all the newborns who did not pass the TEOAE testing., Results: although there was no statistically significant difference when comparing the referral rates to audiological diagnosis obtained in protocols using TEOAE and AABR, the protocol using TEOAE referred four times more newborns. Protocol 3 presented the highest referral rate, with a statistically significant difference when compared to protocols 1 and 2., Conclusions: the false-positive rate and consequently specificity were better for the protocol using AABR, followed respectively by the protocol using TEOAE and using both TEOAE and AABR.

Anti-platelet integrin GPIIIa49-66 antibody (Ab) induces complement-independent platelet oxidative fragmentation and death by generation of platelet peroxide following NADPH oxidase activation. A C-terminal 385-amino acid fragment of ADAMTS-18 (a disintegrin metalloproteinase with thrombospondin motifs produced in endothelial cells) induces oxidative platelet fragmentation in an identical kinetic fashion as anti-GPIIIa49-66 Ab. Endothelial cell ADAMTS-18 secretion is enhanced by thrombin and activated by thrombin cleavage to fragment platelets. Platelet aggregates produced ex vivo with ADP or collagen and fibrinogen are destroyed by the C-terminal ADAMTS-18 fragment. Anti-ADAMTS-18 Ab shortens the tail vein bleeding time. The C-terminal fragment protects against FeCI3-induced carotid artery thrombosis as well as cerebral infarction in a postischemic stroke model. Thus, a new mechanism is proposed for platelet thrombus clearance, via platelet oxidative fragmentation induced by thrombin cleavage of ADAMTS-18.

Patients with HIV-1 immune-related thrombocytopenia (HIV-1-ITP) have a unique Ab against platelet GPIIIa49-66 capable of inducing oxidative platelet fragmentation in the absence of complement. HIV-1-seropositive drug abusers are more prone to develop immune thrombocytopenia than non-drug abusers and have a higher coinfection with hepatitis C virus (HCV) than non-drug abusers (90% vs 30%). Molecular mimicry was sought by screening a phage peptide library with anti-GPIIIa49-66 antibody as bait for peptides sharing homology sequences with HCV. Several phage peptide clones had 70% homology with HCV protein. Sera from dually infected thrombocytopenic patients with HCV and HIV-ITP reacted strongly with 4 nonconserved peptides from HCV core envelope 1. Reactivity correlated inversely with platelet count (r(2) = 0.7, P < .01). Ab raised against peptide PHC09 in GPIIIa(-/-) mice induced thrombocytopenia in wild-type mice. Affinity-purified IgG against PHC09 induced oxidative platelet fragmentation in vitro. Drug abusers dually infected with HCV and HIV-1 had a greater incidence and severity of thrombocytopenia as well as titer of anti-GPIIIa49-66/PHC09 Ab. NZB/W F1 mice injected with recombinant core envelope 1 developed Ab versus PHC09 and significantly decreased their platelet count (P < .001). Thus, HCV core envelope 1 can induce thrombocytopenia by molecular mimicry with GPIIIa49-66.

We have described an autoantibody against beta3 (GPIIIa49-66), a region of platelet integrin alphaIIbbeta3 that is unique. It induces platelet fragmentation in the absence of complement via antibody activation of platelet NADPH oxidase and 12-lipoxygenase to release reactive oxygen species, which destroy platelets. To study the mechanism of anti-GPIIIa antibody-induced platelet fragmentation, we screened a human single chain Fv antibody library with the GPIIIa49-66 peptide. Nine monoclonal antibodies were identified that were capable of binding to GPIIIa49-66. Surprisingly, binding avidity for GPIIIa49-66 did not correlate with activity of induction of platelet fragmentation. We therefore investigated the requirements for platelet fragmentation. Mutations were introduced into the heavy chain complementary-determining region-3 of clones 11, 43, and 54 by site-directed mutagenesis. The capability of these clones to induce platelet fragmentation or bind to GPIIIa49-66 subsequently changed. Molecular modeling of these clones with their mutants revealed that the ability to induce platelet fragmentation is affected by the side chain orientation of positively charged amino acids in the heavy chain of residues 99-102. Thus, a structural change in the conformation of anti-GPIIIa49-66 antibody contributes to its binding to the beta3 integrin and subsequent antibody-induced platelet fragmentation and aggregate dissolution.

An HIV antibody (Ab) against platelet integrin GPIIIa49-66 induces complement-independent platelet particle formation by the elaboration of reactive oxygen species (ROS) downstream of the activation of the platelet NADPH oxidase by the 12-lipoxygenase (12-LO) product 12(S)-HETE. To determine whether other inducers of platelet particle formation also function via the induction of ROS, we examined the effects of the Ca(2+) ionophore A23187 and phorbol myristate acetate (PMA). Both agents induced oxidative platelet particle formation in an identical fashion as Ab, requiring Ca(2+) flux and 12(S)-HETE production as well as intact NADPH oxidase and 12-LO pathways. Since HIV-ITP patients with this Ab correct their platelet counts with dexamethasone (Dex), we examined the role of this steroid in this unique autoimmune disorder. Dex at therapeutic concentrations inhibited Ab-, A23187-, or PMA-induced platelet particle formation by inhibiting platelet PLA(2), 12-LO, and NADPH oxidase. The operational requirement of translocation of PLA(2), 12-LO, and NADPH oxidase components (p67 phox) from cytosol to membrane for induction of ROS was both inhibited and partially reversed by Dex in platelets. We conclude that (1) platelet particle formation can be induced by the generation of ROS; and (2) platelet PLA(2), 12-LO, NADPH oxidase, and cytosol membrane translocation, requirements for ROS production, are inhibited by Dex.

Patients with early HIV-1 infection develop an autoimmune thrombocytopenia in which antibody is directed against an immunodominant epitope of the beta3 (glycoprotein IIIa [GPIIIa]) integrin, GPIIIa49-66. This antibody induces thrombocytopenia by a novel complement-independent mechanism in which platelets are fragmented by antibody-induced generation of H2O2 derived from the interaction of platelet nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and 12-lipoxygenase. To examine whether sharing of epitope between host and parasite may be responsible for this immunodominant epitope, we screened for antibody-reactive peptides capable of inhibiting platelet lysis and oxidation in vitro, using a filamentous phage display 7-mer peptide library. Fourteen of these phage-peptide clones were identified. Five shared close sequence similarity with GPIIIa49-66, as expected. Ten were molecular mimics with close sequence similarity to HIV-1 proteins nef, gag, env, and pol. Seven were synthesized as 10-mers from their known HIV-1 sequence and found to inhibit anti-GPIIIa49-66-induced platelet oxidation/fragmentation in vitro. Three rabbit antibodies raised against these peptides induced platelet oxidation/fragmentation in vitro and thrombocytopenia in vivo when passively transferred into mice. One of the peptides shared a known epitope region with HIV-1 protein nef and was derived from a variant region of the protein. These data provide strong support for molecular mimicry in HIV-1-immunologic thrombocytopenia within polymorphic regions of HIV-1 proteins. A known epitope of nef is particularly incriminated.

Background: Previous evaluations of HPLC as a tool for detection of hemoglobin variants have done so within newborn-screening programs and/or by use of stored samples. We describe a 32-month prospective study in a clinical diagnostic laboratory in which we evaluated the imprecision of HPLC retention times and determined the retention times for hemoglobin variants seen in a multiethnic setting., Methods: We analyzed all samples on the Bio-Rad Variant II HPLC system. For normal hemoglobin fractions and hemoglobin variants, we recorded and analyzed their retention times, their proportion of the total hemoglobin (%), and the peak characteristics. We compared the imprecision of retention time with the imprecision of retention time normalized to the retention time of hemoglobin A0 (Hb A0) and to the retention time of Hb A2. Alkaline and acid hemoglobin electrophoresis, and in certain cases globin chain electrophoresis, isoelectric focusing, and DNA analysis, were performed to document the identities of the hemoglobin variants., Results: The mean (SD) imprecision (CV) of the retention time was 1.0 (0.7)% with no statistical difference compared with the imprecision for normalized retention times. Among 60,293 samples tested, we encountered 34 unique hemoglobin variants and 2 tetramers. Eighteen variants and 2 tetramers could be identified solely by retention time and 3 variants by retention time and proportion of total hemoglobin. Four variants could be identified by retention time and peak characteristics and eight variants by retention time and electrophoretic mobility. One variant (Hb New York) was missed on HPLC. Retention time on HPLC was superior to electrophoresis for the differentiation and identification of six members of the Hb J family, four members of the Hb D family, and three variants with electrophoretic mobilities identical or similar to that of Hb C. Six variants with electrophoretic mobilities identical or similar to that of Hb S could be differentiated and identified by retention time and proportion of total hemoglobin. HPLC detected two variants (Hb Ty Gard and Hb Twin Peaks) missed on electrophoresis., Conclusions: The retention time on HPLC is reliable, reproducible, and in many cases superior to conventional hemoglobin electrophoresis for the detection and identification of hemoglobin variants. Confirmatory testing by electrophoresis can be eliminated in the majority of cases by use of retention time, proportion of total hemoglobin, and peak characteristics of HPLC.

High-affinity (Kd = 1 x 10(-9) M) anti-platelet GPIIIa has been isolated from serum immune complexes of immunologic thrombocytopenic HIV-1-infected patients (HIV-1-ITP). Affinity-purified anti-platelet antibody reacted with a recombinant GPIIIa-(1-200) and -(1-66) fusion peptide and with an 18-mer GPIIIa-(49-66) peptide but not with seven other GPIIIa peptides spanning the length of GPIIIa. Most of the anti-platelet antibody ( approximately 85%) could be adsorbed to and eluted from a GPIIIa-(49-66) affinity column. Binding of antibody to platelets could be inhibited by GPIIIa-(49-66) or an equimolar peptide-albumin conjugate (IC50 = 2 microM). Sera from 7 control subjects and 10 classic autoimmune thrombocytopenic patients gave background reactivity with GPIIIa-(49-66). HIV-1-ITP sera from 16 patients reacted with a mean OD 6-fold greater than background (range, 4- to 9-fold). Serum anti-GPIIIa-(49-66) concentration correlated inversely with platelet count, R2 = 0.51, n = 31, P < 0. 0001. Because mouse platelet GPIIIa-(49-66) has 83% homology with human GPIIIa and mouse monocytes contain Fc receptors for the human IgG1-kappa/lambda antibody, we determined the in vivo effect of human anti-GPIIIa on mouse platelets. Affinity-purified antibody, 25-50 microg given i.p., resulted in a precipitous drop in platelet count to 30% of baseline, with nadir at 4 hr and return to normal in 36 hr. No effect was noted with control IgG. Acute thrombocytopenia could be prevented or reversed by the injection of the GPIIIa-(49-66) albumin conjugate at zero time or 2 hr after antibody, respectively, but not with a scrambled peptide-albumin conjugate. Thus HIV-1-ITP patients have high-affinity anti-platelet GPIIIa against a major antigenic determinant, GPIIIa-(49-66), which correlates inversely with platelet count and induces thrombocytopenia in mice.

Acquired inhibitors of coagulation causing bleeding manifestations are rare in children, particularly without an associated underlying disorder such as autoimmune disease. We describe an otherwise healthy 1 1/2-year-old girl who had extensive spontaneous bruising and prolonged bleeding from venipuncture sites. Prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged, with evidence of an immediate-acting inhibitor. Thrombin clotting time, fibrinogen, and platelets were normal. Biologic assay of factors II, V, VII, and X were all low, with increasing values at higher dilutions. However, by immunoassay and/or chromogenic assays, only factor II was reduced. An antibody which failed to neutralize prothrombin activity in vitro was detected against radiolabeled prothrombin. Coagulation studies normalized in parallel with clinical recovery and disappearance of the antibody. This case demonstrates acute hypoprothrombinemia-lupus anticoagulant syndrome as a rare presentation of bleeding diathesis in a healthy young child.

Six monoclonal IgG1-k antibodies (LK2, LK3r, LK4-55, LK5, LK6-55, LK7r) were raised against platelet membrane GPIIIa in order to study the structure-function relationship of this molecule. Antibodies were selected on their ability to react with GPIIIa by ELISA on adherent platelets, by immunoblot on platelet lysates and by fluorescence flow cytometry on intact platelets. Fluorescence reactivity varied from 3- to 202-fold greater than isotype control fluorescence. Two MoAbs reacted on immunoblot under reduced conditions (LK7r and LK3r). Two reacted with a 55 kD chymotrypsin/subtilisin digest of GPIIIa which is likely to exclude amino acids 121-348 (LK4-55 and LK6-55). Four of the MoAbs (LK5, LK3r, LK2 and LK4-55) inhibited tyrosine phosphorylation of one to four distinct bands on immunoblot. LK4-55 reacted with an N-terminal 66 amino acid fusion protein of GPIIIa near the PLA epitope (Leu 33). LK7r reacted with a 212-222 peptide reported to be an RGD fibrinogen binding site. LK2 reacted near a disintegrin-RGD binding site. Except for LK5, all inhibited ADP, collagen and thrombin-induced platelet aggregation in a heterogeneous fashion. Percentage inhibition of 125I-fibrinogen binding to platelets varied from 18% to 98%. No correlation was noted between inhibition of fibrinogen binding, location of MoAb binding on GPIIIa, reactivity of MoAb binding with GPIIIa, inhibition of thrombin-induced tyrosine phosphorylation or inhibition of platelet aggregation induced by ADP, collagen or thrombin. Thus MoAbs, binding to platelet GPIIIa at different sites, inhibit platelet aggregation in a heterogeneous manner.

Human anti-CD4 IgG antibodies from 3 HIV-1-infected patients were affinity purified and shown to inhibit HIV-1 binding and infection of HBP-T cells. Lymphocytes from patient A, whose anti-CD4 inhibited HIV-1 binding by 68% and infection by 72%, were cultured and transformed with EBV. A human monoclonal antiidiotype antibody against anti-HIV-1 gp120 (2B) was produced, which inhibited infection of HBP-T cells by 68% at 1 microgram/ml. Mice were immunized with 2B to determine whether this anti-CD4 could be an internal image antiidiotype against anti-HIV-1 gp 120 (Ab1). Two mice produced antisera reactive with rgp120 on ELISA, whereas immunization with normal IgG produced minimal reactivity compared to unreactive normal mouse sera. However, immunoblot competition studies in which affinity-purified anti-HIV-1 gp120 (Ab1) bound to the gp120 band on nitrocellulose strips in the presence of 2B demonstrated enhancement of signal (i.e., binding of Ab2 to Ab1), rather than inhibition of Ab1 binding. Thus 2B is not an internal image of the paratope of anti-HIV-1 gp120 but yet it is capable of inducing an antibody against rgp120. This indicates that the anti-CD4 (Ab2) does bind to the binding site of Ab1, but not as a complete internal image. These data indicate the production of a human monoclonal antiidiotype antibody that inhibits binding of HIV-1 to CD4 and induces the production of antibody against HIV-1 gp120, without being an internal image antiidiotype (Ab2 beta).

Human immunodeficiency virus 1-related idiopathic thrombocytopenic purpura (HIV-1-ITP) patients have a 4-fold increased percentage of CD5+ B cells and a 4.8-fold increased percentage of serum immune complexes precipitated by polyethylene glycol (PEG-ICs) compared to control subjects, as reported previously. Since CD5+ B cells produce predominantly IgM rheumatoid factor (RF) vs. Fc of IgG and PEG-ICs contain high levels of IgM, we looked for the presence of RF in the immune complexes of HIV-1-ITP patients. PEG-ICs were adsorbed to protein A and dissociated with acid, and IgM and IgG were purified by gel filtration and affinity chromatography. Solid-phase ELISA was used to measure antibody specificity vs. platelets, Fc, and HIV-1 gp120, p24, and CD4. Dissociated IgG antibody reacted with platelets, HIV-1 gp120, p24, and CD4, but not with Fc. Serum IgG did not react with platelets or Fc but did react with HIV-1 gp120, p24, and CD4. Both PEG-IC IgM and serum IgM reacted with Fc as well as the other four antigens. Control IgM and IgG were unreactive. Isolated IgM from PEG-ICs relocated approximately 50% of the IgG preincubated with IgM to the Vo region of a G200 gel-filtration column. Anti-platelet IgG but not IgM could be affinity-purified from fixed platelets. Both F(ab')2 fragments of anti-platelet IgG and the total PEG-IC bound to platelets in a saturation-dependent manner. F(ab')2 of anti-platelet IgG inhibited 50% binding of PEG-IC to platelets at an F(ab')2/complex ratio of 3:1 (wt/wt). Scatchard analysis revealed two classes of binding sites: high-affinity Kd values of 0.8-1.8 nM and lower-affinity Kd values of 6.6-12.3 nM with respective numbers of binding sites of 44,000-57,000 and 122,000-256,000 (n = 4). Anti-platelet IgG of 6/6 patients precipitated GPIIIa from platelet lysates of surface 125I-labeled platelets. Platelet count correlated inversely with anti-platelet IgG (r = -0.73; P < 0.01; n = 27). Thus, PEG-ICs of HIV-1-ITP patients contain IgM RF, which sequesters serum anti-platelet IgG containing anti-GPIIIa. Anti-platelet IgG contributes to binding of immune complexes to platelets and correlates with thrombocytopenia.

A unique murine monoclonal antibody (LK-4) is described which differentiates PLA1/PLA1 platelet extracts from PLA2/PLA2 and PLA1/PLA2 platelet extracts on solid phase ELISA and immunoblot at the 100kD GPIIIa location, but not on intact platelets. LK-4 reacts equally with intact PLA1/PLA2 and PLA2/PLA2 platelets. Adsorbtion of LK-4 with PLA1/PLA1 platelets results in loss of reactivity for intact platelets as well as platelet extracts on ELISA or immunoblot. LK-4 inhibits platelet aggregation induced by ADP, epinephrine, collagen and thrombin, suggesting reactivity at or near the fibrinogen binding site on GPIIIa. It is suggested the LK-4 reacts with a conformation-induced common epitope for PLA1 and PLA2 on GPIIIa, with loss of this conformation for PLA2 GPIIIa following solubilization with Triton X-100.

Anti-CD4 antibody was found in 30% of human immunodeficiency virus (HIV-1)-seropositive thrombocytopenic patients compared with 5% of nonthrombocytopenic seropositive patients (chi 2 = 21.7, P less than 0.001) and was shown by the following observations to contain internal-image anti-idiotype antibody (Ab2) directed against the antibody (Ab1) to gp120, the HIV-1 envelope glycoprotein that binds to CD4: (i) affinity-purified anti-CD4 (Ab2) bound to affinity-purified anti-HIV-1gp120 (Ab1) on solid-phase radioimmunoassay, and binding could be blocked by recombinant CD4 (rCD4) as well as recombinant gp120 (rgp120); (ii) F(ab')2 fragments of Ab1 inhibited the binding of Ab2 to rCD4; (iii) Ab2 inhibited the binding of Ab1 to HIV-1 beads; (iv) Ab2 inhibited the binding of Ab1 to gp120 on immunoblot; (v) Ab2 bound to the CD4 receptor on a CD4-bearing T-cell line, H9; (vi) Ab3 (anti-rgp120) could be produced in vivo by immunizing mice with Ab2, and binding of Ab3 to rgp120 could be blocked with rCD4; and (vii) three different Ab2 preparations bound to two different homologous Ab1 preparations. Ab1 or Ab2 alone did not bind to platelets, whereas the idiotype-anti-idiotype complex did bind to platelets in a concentration-dependent manner. Binding of the internal-image complex was 10-fold greater than that of a non-internal-image Ab1-Ab2 complex composed of anti-HIV-1gp120 and anti-anti-HIV-1gp120. Thus, patients with HIV-1 thrombocytopenia contain internal-image idiotype-anti-idiotype complexes that could be affecting CD4 cell number or function, inhibiting HIV-1 binding to CD4 cells or contributing to HIV-1 thrombocytopenia.

We report four cases of immunologic thrombocytopenic purpura related to human immunodeficiency virus (HIV) transmitted through heterosexual contact in persons who were not homosexual, addicted to intravenous narcotic drugs, or hemophilic. Each transmission occurred in a different setting. A 23-year-old white woman had immunologic thrombocytopenic purpura in July 1985, with a platelet count of 11 X 10(9)/L. In January 1987, she had prominent submandibular and posterior cervical adenopathy. A careful social-sexual history revealed several sexual contacts with a male narcotic addict before July 1985. A 27-year-old heterosexual white man had a platelet count of 8 X 10(9)/L in December 1986. A social-sexual history revealed that his fiancée had been an intravenous narcotic addict 6 years ago. A 64-year-old white woman had a platelet count of 75 X 10(9)/L in May 1986, approximately 2 years after she had resumed having sexual intercourse with her husband who had had a triple coronary bypass in October 1983. The husband had received HIV-seropositive blood. A 42-year-old white man had a platelet count of 45 X 10(9)/L, which was associated with a cutaneous eruption refractory to antibiotics and antifungal agents. He had had sexual contacts with several women, who, to the best of his knowledge, were neither prostitutes nor intravenous narcotic addicts. He denied homosexuality or drug abuse. All four patients were HIV-seropositive and had circulating immune complexes and platelet-associated IgG, C3C4, and IgM values that were considerably higher than those usually measured in patients with classic autoimmune thrombocytopenia, averaging 2.4-, 2.2-, 6.5- and 5.2-fold higher, respectively. Thus, HIV-related immunologic thrombocytopenic purpura can be heterosexually spread and should become part of the differential diagnosis of unexplained thrombocytopenia. Obtaining a careful social-sexual history is mandatory in such patients.

The immunologic platelet profile of 29 patients with hemophilia who had received multiple transfusions (14 had thrombocytopenia) was compared with profiles of 15 patients with classic autoimmune thrombocytopenia. Thrombocytopenic hemophiliacs who were seropositive for the human immunodeficiency virus (13 out of 14) had platelet-bound immunoglobulin G and C3C4 levels as well as circulating immune complexes that were 15.1-, 4.0-, and 2.4-fold greater, respectively, than normal control subjects' platelets and 3.4-, 2.6-, and 2.4-fold greater, respectively, than autoimmune thrombocytopenic patients' platelets. Hemophiliacs with normal platelet counts (nine out of 13 seropositive) had elevated values that were intermediate in level between those of thrombocytopenic hemophiliacs and those of classic autoimmune thrombocytopenic patients. The four seronegative hemophiliacs had normal values (except for one platelet-bound IgG measurement). An inverse correlation was noted between platelet count and platelet-bound IgG, r = -0.838, P less than 0.001. Serum antiplatelet reactivity (1:256 mean titer compared with control sera) resided predominantly in the 7S IgG fraction, and bound to autologous as well as homologous platelets at concentrations as low as 0.06 to 0.13 mg/ml. F(ab')2 fragments of the 7S IgG fraction inhibited binding of hemophilic IgG to normal platelets and bound to normal platelets at concentrations as low as 0.06 mg/ml. Antiplatelet IgG could be eluted from six of six hemophilic and eight of eight classic autoimmune thrombocytopenic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Thrombocytopenic purpura has recently been noted in sexually active homosexual men. To elucidate the pathogenesis of thrombocytopenic purpura in this population, we compared the disorder in 33 homosexual men with that in 23 patients (15 women and 8 men) thought to have classic autoimmune thrombocytopenic purpura. The homosexual group had 3.8-fold higher levels of platelet-bound IgG and 4.2-fold higher levels of platelet-bound complement than the patients with autoimmune thrombocytopenic purpura. Eluates from the platelets of only 1 of 10 homosexual patients reacted in vitro with normal platelets, as compared with those from the platelets of 12 of 15 patients with autoimmune thrombocytopenic purpura. Twenty-one of 24 homosexual patients (88 per cent) had elevated serum levels of immune complexes that were capable of binding to platelets, whereas none of 5 patients with autoimmune thrombocytopenic purpura had circulating immune complexes. The IgG fraction of positive serum samples from three homosexual patients did not bind to normal platelets, whereas that from the positive serum of two patients with autoimmune thrombocytopenic purpura and one woman in whom isoimmune antiplatelet antibody developed during pregnancy (studied as a positive control) did bind to normal platelets. We conclude that, whereas classic autoimmune thrombocytopenic purpura involves antiplatelet IgG directed against platelet antigenic determinants, the thrombocytopenic purpura that occurs in sexually active homosexual men is usually caused not by antiplatelet IgG but probably by the nonspecific deposition of complement and immune complexes on platelets.

Since November 1982 we have seen an association of thrombocytopenic purpura with chronic narcotic addiction in 70 patients with a mean platelet count of 53000 +/- 4000 (SE); 33 had stopped taking intravenous drugs for an average of 21.2 +/- 4.7 months; 13 of 15 had elevated antibody titers for a virus related to the acquired immunodeficiency syndrome. Platelet-bound IgG, IgM, and complement levels were 16.7-, 5.6-, and 3.1-fold greater than control values, respectively, and 2.6-, 1.9-, and 2.4-fold greater than values in 25 patients with classic autoimmune thrombocytopenic purpura studied at the same time. Thirty-three of thirty-six addicts had elevated circulating immune complexes, whereas 8 patients with autoimmune thrombocytopenia had no elevation. Eleven of eighteen addicts had positive serum platelet-reactive IgG titers, compared to 5 of 19 patients with classic autoimmune thrombocytopenia. The platelet-reactive IgG in sera of addicts was composed of 7S IgG antibody as well as high molecular weight (immune complex) IgG. Thus, chronic addicts appear to have a new immunologic platelet disorder associated with the presence of 7S IgG antiplatelet antibody, like patients with classic autoimmune thrombocytopenic purpura, and immune complex associated nonspecific platelet IgG, like male homosexual patients with thrombocytopenia.