Protein S and HIV infection. The role of anticardiolipin and anti-protein S antibodies

[Human immunodeficiency virus and venous thromboembolism: Role of direct oral anticoagulants]

Nowadays, thanks to highly active antiretroviral therapy (HAART), human immunodeficiency virus (HIV) infection is transforming into a chronic disease. The life expectancy of people living with HIV (PWH) has increased, as well as their risk of developing several co-morbidities, in particular cardiovascular diseases. In addition, the incidence of venous thromboembolism (VTE) is increased in PWH with a 2 to 10 times higher incidence when compared to the general population. Over the last decade, direct oral anticoagulants (DOACs) have been widely used in the treatment and prevention of VTE and non-valvular atrial fibrillation. DOACs are characterized by a rapid onset of activity, a predictable response and a relatively wide therapeutic window. Nevertheless, drug interactions exist between HAART and DOACs, exposing PWH to a theoretically increased bleeding or thrombotic risk. DOACs are substrates of the transport protein P-glycoprotein and/or of isoforms of cytochromes P450 pathway, which can be affected by some antiretroviral drugs. Limited guidelines are available to assist physicians with the complexity of those drug-drug interactions. The aim of this paper is to provide an updated review on the evidence of the high risk of VTE in PWH and the place of DOAC therapy in this population.

The Youngbloods. Get Together. Hypercoagulation, Complement, and NET Formation in HIV/SIV Pathogenesis

Chronic, systemic T-cell immune activation and inflammation (IA/INFL) have been reported to be associated with disease progression in persons with HIV (PWH) since the inception of the AIDS pandemic. IA/INFL persist in PWH on antiretroviral therapy (ART), despite complete viral suppression and increases their susceptibility to serious non-AIDS events (SNAEs). Increased IA/INFL also occur during pathogenic SIV infections of macaques, while natural hosts of SIVs that control chronic IA/INFL do not progress to AIDS, despite having persistent high viral replication and severe acute CD4+ T-cell loss. Moreover, natural hosts of SIVs do not present with SNAEs. Multiple mechanisms drive HIV-associated IA/INFL, including the virus itself, persistent gut dysfunction, coinfections (CMV, HCV, HBV), proinflammatory lipids, ART toxicity, comorbidities, and behavioral factors (diet, smoking, and alcohol). Other mechanisms could also significantly contribute to IA/INFL during HIV/SIV infection, notably, a hypercoagulable state, characterized by elevated coagulation biomarkers, including D-dimer and tissue factor, which can accurately identify patients at risk for thromboembolic events and death. Coagulation biomarkers strongly correlate with INFL and predict the risk of SNAE-induced end-organ damage. Meanwhile, the complement system is also involved in the pathogenesis of HIV comorbidities. Despite prolonged viral suppression, PWH on ART have high plasma levels of C3a. HIV/SIV infections also trigger neutrophil extracellular traps (NETs) formation that contribute to the elimination of viral particles and infected CD4+ T-cells. However, as SIV infection progresses, generation of NETs can become excessive, fueling IA/INFL, destruction of multiple immune cells subsets, and microthrombotic events, contributing to further tissue damages and SNAEs. Tackling residual IA/INFL has the potential to improve the clinical course of HIV infection. Therefore, therapeutics targeting new pathways that can fuel IA/INFL such as hypercoagulation, complement activation and excessive formation of NETs might be beneficial for PWH and should be considered and evaluated.

Derangement of protein S and C4b-binding protein levels as acquired thrombophilia in HIV-infected adult Nigerians

BACKGROUND

HIV is a chronic inflammatory state with the production of many acute-phase-reactant proteins. Some of these proteins have procoagulant activities that predispose HIV-infected patients to thrombosis.

OBJECTIVES

The aim of the study was to evaluate the effects of HIV infection on the serum levels of C4b-binding protein (C4BP) and protein S as markers of predisposition to thrombosis in HIV-infected adults.

METHODS

The study population comprised of 61 HIV-infected adults on antiretroviral treatment (ART) who had achieved virological suppression, 58 HIV-infected adults not yet on ART and 59 HIV-negative healthy controls. The serum levels of free protein S, C4BP and the euglobulin clot lysis time (ECLT) were determined.

RESULTS

The mean plasma-free protein S level of HIV-infected patients on ART (86.9% ± 25.8%) was significantly higher than that of treatment-naïve HIV-infected patients (75.7% ± 27.3%) (p = 0.005). Conversely, there was no statistically significant difference between the protein S levels of the HIV-infected subjects on ART (86.9% ± 25.8%) and those of the controls (94.9% ± 7.9%) (p = 0.119). The mean C4BP was significantly higher in the treatment-naïve HIV-infected subjects (36.7 ± 1.7 ng/dL) than that in those on ART (30.7 ± 2.6 ng/dL) and that in the controls (22.4 ± 2.4 ng/dL) (p < 0.0001). Protein S deficiency was more prevalent among the subjects with elevated C4BP (p = 0.023). The mean ECLT was significantly more prolonged in the treatment-naïve HIV-infected subjects (241.9 ± 34.7 s) than controls (189.5 ± 40.7 s) (p < 0.0001).

CONCLUSION

HIV infection causes elevated levels of C4BP and diminishes the serum levels of free protein S. We infer that the risk of thrombosis (as measured by these biomarkers) decreases with the use of antiretroviral drugs.

Thrombotic antiphospholipid syndrome in a child with human immunodeficiency virus: a rare case report

BACKGROUND

Antiphospholipid syndrome (APS) is a non-inflammatory autoimmune disorder induced by antiphospholipid antibodies, which occurs exceedingly rarely in pediatric population and even more rarely reported in HIV positive children. A case of 11 years old boy had a sudden onset of swelling in his left lower leg along with pain which were worsening gradually. Initially, topical ointment was applied for 1 month which were ineffective in reducing pain and swelling. Instead, the symptoms were aggravated and suddenly spread to the proximal thigh, accompanied by dyskinesia of left lower leg. Both color doppler ultrasonography and vascular CT scan of left lower leg revealed deep venous thrombosis. His serum anti-phospholipid antibodies (aPLs) were tested positive. He was a known case of HIV virological failure with substantial HIV viral load (VL) despite receiving regular antiretroviral therapy (ART). His symptoms improved after giving aggressive antithrombotic and high dose corticosteroid treatments.

CONCLUSION

When pediatric patients develop thrombotic disease, APS also needs to be ruled out. The autoantibodies levels should be routinely tested to look for recurrent thrombosis in children with HIV/AIDS.

Venous thromboembolism in people living with HIV infection (PWH)

The risk of venous thromboembolism (VTE) and of recurrent VTE remain elevated in people living with HIV compared to controls still with contemporary antiretroviral therapy (ART). The pathophysiology of VTE in HIV is multi factorial and includes an interplay among traditional risk factors, HIV-specific factors, behavioral factors, exposure to ART and other therapies, coinfections, and co-morbidities.

Anticoagulant protein S in COVID-19: low activity, and associated with outcome

Introduction. COVID-19 disease was associated with both thrombo-embolic events and in-situ thrombi formation in small vessels. Antiphospholipidic antibodies were found in some studies.Aim. Assessment of protein S activity in patients with COVID-19 as a cause of this prothrombotic state, and of the association of protein S activity with worse outcome.Methods. All patients admitted for COVID-19 disease in a university hospital between 15^th of May and 15^th of July 2020 were prospectively enrolled into this cohort study. Patients treated with antivitamin K anticoagulants and with liver disease were excluded. All patients had protein S activity determined at admission. The main outcome was survival, while secondary outcomes were clinical severity and lung damage.Results. 91 patients were included, of which 21 (23.3%) died. Protein S activity was decreased in 65% of the patients. Death was associated with lower activity of protein S (median 42% vs. 58%, p < 0.001), and the association remained after adjustment for age, inflammation markers and ALAT. There was a dose-response relationship between protein S activity and clinical severity (Kendall_tau coefficient = -0.320, p < 0.001; Jonckheere-Terpstra for trend: p < 0.001) or pulmonary damage on CT scan (Kendall_tau coefficient = -0.290, p < 0.001; Jonckheere-Terpstra for trend: p < 0.001). High neutrophil count was also independently associated with death (p = 0.002).Conclusion. Protein S activity was lower in COVID-19 patients, and its level was associated with survival and disease severity, suggesting that it may have a role in the thrombotic manifestations of the disease.

Risk Factors and Outcomes of Recurrent Pregnancy Loss in Japan

AIM

To clarify the risk factors and pregnancy outcomes for each risk factor of recurrent pregnancy loss (RPL) in Japan.

METHODS

Using a prospective RPL database collected from 16 facilities in Japan, the prevalence of risk factors for RPL, their treatments and pregnancy outcomes were examined.

RESULTS

Of 6663 patients registered in our database, 5708 patients had RPL. All examinations for risk factors were performed for 1340 patients (23.5%). The prevalences of positive antiphospholipid antibodies (aPL), malformation of the uterus, thyroid dysfunction, parental karyotype abnormality, factor XII deficiency, protein S deficiency and unknown risk factors were 8.7%, 7.9%, 9.5%, 3.7%, 7.6%, 4.3% and 65.1%, respectively. Although factor XII deficiency and protein S deficiency are not recognized as risk factors for RPL in general, low-dose aspirin (LDA) or unfractionated heparin + LDA therapy improved live birth rates. In transiently aPL-positive patients, the live birth rate with LDA therapy was similar to that with heparin + LDA. For unknown risk factors of RPL, the live birth rate in normal fetal karyotype in the none treatment group was similar to that in all other treatments group (81.3% vs 86.0%). Of 5708 RPL patients, pregnancy outcomes were known for 2261 patients and 1697 patients (75.1%) had at least one live birth.

CONCLUSION

The risk factors and pregnancy outcomes for each risk factor of RPL are useful for clinicians and patients. Factor XII deficiency and protein S deficiency may be risk factors of RPL.

Prothrombotic state in HIV: A study on protein C, protein S, homocysteine and correlation with CD4 counts

Introduction

Human immunodeficiency virus (HIV) may result in variable haematological manifestations. Thrombotic events are more common among HIV-infected persons than the general population, possibly due to the increased inflammatory/hypercoagulable state and presence of concurrent comorbidities.

Aims and Objectives

(1) Screen for coagulation abnormalities in HIV-infected patients. (2) Detect certain prothrombotic factors such as deficiency of protein C and protein S and elevation of homocysteine as possible precursors of coagulation defects in HIV patients. (3) Correlation of coagulation abnormalities with CD4 counts.

Methods

A pilot study of 1-year duration conducted in the Department of Pathology in collaboration with ART centre, KGMU Lucknow. All diagnosed HIV-seropositive patients (n = 30) who were not taking Vitamin K, antithrombotic and antiplatelet drugs including aspirin, oral contraceptives and not having known protein C/S deficiency were included in the present study as cases. Apart from this, 30 age- and sex-matched healthy individuals were also included in the present study. Assessment of the bleeding time, prothrombin time and activated partial thromboplastin time, complete blood count was done. Protein C and S were measured by calorimetric assay. Serum homocysteine was measured by the semi-automated method. CD4 count was done by flow cytometry.

Results

The findings of the present study suggest a relationship between HIV, its complications and thrombosis. The HIV-seropositive patients have reduced levels of haemoglobin, CD4 counts, platelet counts, mean platelet volume, protein C and S activity as compared to the healthy individuals. Thrombophilic abnormality in the form of hyperhomocysteinaemia is more frequent in HIV-infected patients. All these parameters have a definite correlation with CD4 count.

Antigenic binding sites of anti-protein S autoantibodies in patients with recurrent pregnancy loss

BACKGROUND

Protein S (PS) deficiency is a risk factor for adverse pregnancy outcomes including recurrent pregnancy loss. Several studies have shown that the presence of anti-PS autoantibodies (anti-PS) leads to an acquired PS deficiency. Hence, an epitope mapping study was conducted to know the pathogenesis of anti-PS in patients with recurrent pregnancy loss.

METHODS

PS was treated with thrombin to divide the protein into γ-carboxyglutamic acid (Gla) domain and Gla-domain free PS. For the preparation of fragments of epidermal growth factor (EGF)-like domains (EGF1-4), PS was subjected to proteolysis using lysyl endopeptidase. The epitopes were identified in immunoblot. Whether anti-PS recognized EGF family proteins in anti-PS-positive patients was also examined.

RESULTS

Anti-PS recognized Gla-domain free PS, especially the three fragments of EGF-like domains, EGF1-2, EGF3-4, and EGF1-4. Anti-PS recognized recombinant human EGF. Anti-PS and polyclonal antibodies to recombinant human EGF recognized PS in the absence of Ca2+ but not in the presence of Ca2+. In competitive inhibition studies, polyclonal antibodies to recombinant mouse EGF blocked anti-PS binding to PS in a concentration-dependent manner.

CONCLUSIONS

These results suggest that anti-PS in patients with recurrent pregnancy loss recognize EGF-like domains in PS. Interestingly, anti-PS also recognized EGF family proteins. Anti-PS in patients with recurrent pregnancy loss may be associated with not only thrombophilia but also the disruption of the EGF system.

Risk of developing antiphospholipid antibodies following viral infection: a systematic review and meta-analysis

Objective The objective of this paper is to conduct a systematic review and meta-analysis on the risk of developing elevated antiphospholipid (aPL) antibodies and related thromboembolic and/or pregnancy events following a viral infection. Method We searched Medline, EMBASE, Web of Science, PubMed ePubs, and Cochrane Central Register of Controlled Trials through June 2016. Independent observational studies of elevated aPL antibodies in patients with a viral infection compared with controls or patients with lupus were included. Results We analyzed 73 publications for 60 studies. Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) were most commonly reported. Compared with healthy controls, patients with HIV were more likely to develop elevated anticardiolipin (aCL) antibodies (risk ratio (RR) 10.5, 95% confidence interval (CI) 5.6-19.4), as were those with HCV (RR 6.3, 95% CI 3.9-10.1), hepatitis B virus (HBV) (RR 4.2, 95% CI 1.8-9.5), and Epstein-Barr virus (EBV) (RR 10.9 95% CI 5.4-22.2). The only statistically significant increased risk for anti-β2-glycoprotein I (anti-β2-GPI) antibodies was observed in patients with HCV (RR 4.8 95% CI 1.0-22.3). Compared with patients with lupus, patients with HIV were more likely to develop elevated aCL antibodies (RR 1.8, 95% CI 1.3-2.6), and those with EBV, elevated anti-β2-GPI antibodies (RR 2.2, 95% CI 1.3-3.9). Thromboembolic events were most prevalent in patients with elevated aPL antibodies who had HCV (9.1%, 95% CI 3.0-18.1), and HBV (5.9%, 95% CI 2.0-11.9) infections, and pregnancy events were most prevalent in those with parvovirus B19 (16.3%, 95% CI 0.78-45.7). However, compared to virus-infected patients with negative aPL antibodies, the only statistically significant increased risk was observed in those with HCV and positive aPL. Conclusions Viral infection can increase the risk of developing elevated aPL antibodies and associated thromboembolic events. Results are contingent on the reported information.

HIV infection, hypercoagulability and ischaemic stroke in adults at the University Teaching Hospital in Zambia: a case control study

BACKGROUND

In Zambia, 14.2% of adults have HIV/AIDS. There has been a substantial and significant increase in patients hospitalized for ischaemic stroke with co-existing HIV infection. However, little is known about the mechanism of stroke in these HIV + ve patients let alone studied in our region. The aim of this pilot study was to explore the association of hypercoagulability state in HIV + ve patients with ischaemic stroke. This was achieved by comparing hypercoagulability state markers between HIV + ve ischaemic stroke patients with HIV-ve and HIV + ve patients with and without ischaemic stroke respectively.

METHODS

A matched case control study in which a total of 52 HIV + ve patients with ischaemic stroke were prospectively compared with control groups for the presence of protein S, protein C deficiencies and hyperhomocysteinaemia. The control groups comprised an equal number of consecutively matched for age and sex HIV-ve and HIV + ve patients with and without ischaemic stroke respectively. Data was analysed in contingency tables using Paired t- test, Chi square and conditional logistic regression.

RESULTS

Ischaemic stroke of undetermined aetiology occurred more frequently in HIV + ve compared to HIV-ve patients (p < 0.001). In addition, protein S deficiency and Hyperhomocysteinaemia were more prominent in HIV + ve than HIV-ve ischaemic stroke patients (P = 0.011). There was no difference in the presence of hyperhomocysteinaemia or protein S deficiency in HIV + ve patients with or without ischaemic stroke. Protein C deficiency was not noted to be significantly different between the cases and the two control arms.

CONCLUSION

Protein S deficiency and hyperhomocysteinaemia were associated with HIV infection, but not stroke in our study population. However, this is an area that requires extensive research and one that we cannot afford to ignore as it is an important bridge to all cardiovascular and cerebrovascular diseases.

Markers of coagulation and inflammation often remain elevated in ART-treated HIV-infected patients

PURPOSE OF REVIEW

Current antiretroviral therapies have dramatically changed the disease course of HIV infection. Although antiretroviral therapy is effective at decreasing viral replication and preserving CD4 T-cell numbers, low-level immune activation and inflammation persist in virally suppressed HIV-infected patients. This chronic immune activation/inflammation may contribute to an increased risk for venous and arterial thrombosis.

RECENT FINDINGS

Several markers of coagulation and inflammation are increased in HIV-infected patients. The Strategies for the Management of Antiretroviral Therapy study reported that plasma D-dimer levels, a marker of fibrinolysis, independently predicted morbidity in HIV-infected patients. Increased plasma and cell surface levels of the procoagulant tissue factor have also been reported in patients with HIV disease. Fibrinogen, von Willebrand factor, and P-selectin are likewise increased in plasma samples of HIV-infected patients; all of these markers suggest HIV-infection results in a procoagulant state. Treatment with antiretroviral therapy reduces, but does not always normalize, levels of biomarkers associated with inflammation and coagulation in HIV+ patients.

SUMMARY

HIV-infected patients are at greater risk for both venous and arterial thrombosis. Chronic immune activation and inflammation in these patients appears to contribute to coagulation risk. Antiretroviral therapy reduces viral replication, immune activation, and markers of coagulation, but these indices do not always return to normal, even after several years of viremic control.

Acquired Thrombophilia

Acquired thrombophilia is associated with an increased risk of venous thromboembolism (VTE). Antiphospholipid syndrome (APS) is the most prevalent acquired thrombophilia and is associated with both venous and arterial thromboses. Human immunodeficiency virus (HIV) is another form of acquired thrombophilia. Risk factors associated with VTE in this population include those related to the disease itself, host factors, and the pharmacotherapy for HIV. A significant proportion of VTE events occur in patients with malignancies. There is an increase in mortality associated with patients having cancer who experience VTE when compared to patients having cancer without VTE. Combination oral contraceptive (COC) use infers risk of thromboembolic events. The risk is dependent upon the presence of an underlying inherited thrombophilia, the estrogen dose, and generation of progestin. Patients at highest risk of VTE include those receiving high-dose estrogen and fourth-generation, progesterone-containing contraceptives. With the exception of APS, thrombophilia status does not alter the acute treatment of an initial VTE in nonpregnant patients.

Hepatic decompensation in antiretroviral-treated patients co-infected with HIV and hepatitis C virus compared with hepatitis C virus-monoinfected patients: a cohort study

BACKGROUND

The incidence and determinants of hepatic decompensation have been incompletely examined among patients co-infected with HIV and hepatitis C virus (HCV) in the antiretroviral therapy (ART) era, and few studies have compared outcome rates with those of patients with chronic HCV alone.

OBJECTIVE

To compare the incidence of hepatic decompensation between antiretroviral-treated patients co-infected with HIV and HCV and HCV-monoinfected patients and to evaluate factors associated with decompensation among co-infected patients receiving ART.

DESIGN

Retrospective cohort study.

SETTING

Veterans Health Administration.

PATIENTS

4280 co-infected patients who initiated ART and 6079 HCV-monoinfected patients receiving care between 1997 and 2010. All patients had detectable HCV RNA and were HCV treatment-naive.

MEASUREMENTS

Incident hepatic decompensation, determined by diagnoses of ascites, spontaneous bacterial peritonitis, or esophageal variceal hemorrhage.

RESULTS

The incidence of hepatic decompensation was greater among co-infected than monoinfected patients (7.4% vs. 4.8% at 10 years; P < 0.001). Compared with HCV-monoinfected patients, co-infected patients had a higher rate of hepatic decompensation (hazard ratio [HR] accounting for competing risks, 1.56 [95% CI, 1.31 to 1.86]). Co-infected patients who maintained HIV RNA levels less than 1000 copies/mL still had higher rates of decompensation than HCV-monoinfected patients (HR, 1.44 [CI, 1.05 to 1.99]). Baseline advanced hepatic fibrosis (FIB-4 score >3.25) (HR, 5.45 [CI, 3.79 to 7.84]), baseline hemoglobin level less than 100 g/L (HR, 2.24 [CI, 1.20 to 4.20]), diabetes mellitus (HR, 1.88 [CI, 1.38 to 2.56]), and nonblack race (HR, 2.12 [CI, 1.65 to 2.72]) were each associated with higher rates of decompensation among co-infected patients.

LIMITATION

Observational study of predominantly male patients.

CONCLUSION

Despite receiving ART, patients co-infected with HIV and HCV had higher rates of hepatic decompensation than HCV-monoinfected patients. Rates of decompensation were higher for co-infected patients with advanced liver fibrosis, severe anemia, diabetes, and nonblack race.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Anti-human protein S antibody induces tissue factor expression through a direct interaction with platelet phosphofructokinase

INTRODUCTION

Autoantibodies including anti-human protein S antibody (anti-hPS Ab) and anti-human protein C antibody (anti-hPC Ab) can be detected in patients with autoimmune diseases with hypercoagulability. The objective of the present study was to determine the effects and molecular pathways of these autoantibodies on tissue factor (TF) expression in human coronary artery endothelial cells (HCAECs).

MATERIALS AND METHODS

HCAECs were treated with anti-hPS Ab or anti-hPC Ab for 3 hours. TF expression was measured by real-time PCR and Western blot. TF-mediated procoagulant activity was determined by a commercial kit. MAPK phosphorylation was analyzed by Bio-Plex luminex immunoassay and Western blot. The potential proteins interacting with anti-hPS Ab were studied by immunoprecipitation, mass spectrometry and in vitro pull-down assay.

RESULTS

Anti-hPS Ab, but not anti-hPC Ab, specifically induced TF expression and TF-mediated procoagulant activity in HCAECs in a concentration-dependent manner. This effect was confirmed in human umbilical endothelial cells (HUVECs). ERK1/2 phosphorylation was induced by anti-hPS Ab treatment, while inhibition of ERK1/2 by U0216 partially blocked anti-hPS Ab-induced TF upregulation (P<0.05). In addition, anti-hPS Ab specifically cross-interacted with platelet phosphofructokinase (PFKP) in HCAECs. Anti-hPS Ab was able to directly inhibit PFKP activities in HCAECs. Furthermore, silencing of PFKP by PFKP shRNA resulted in TF upregulation in HCAECs, while activation of PFKP by fructose-6-phosphate partially blocked the effect of anti-hPS Ab on TF upregulation (P<0.05).

CONCLUSIONS

Anti-hPS Ab induces TF expression through a direct interaction with PFKP and ERK1/2 activation in HCAECs. Anti-hPS Ab may directly contribute to vascular thrombosis in the patient with autoimmune disorders.

High prevalence of prothrombotic abnormalities in multifocal osteonecrosis: description of a series and review of the literature

Multifocal or multiple osteonecrosis (ON), defined by the involvement of 3 or more anatomic sites, is unusual, being observed in only 3%-10% of patients diagnosed with ON. We report the clinical characteristics of a cohort of 29 patients with multifocal ON from a single center and evaluate the prevalence of associated prothrombotic abnormalities in 26 of these patients. We conducted a retrospective study of all patients diagnosed with multifocal ON evaluated in our institution during the last 20 years. We recorded clinical manifestations and underlying diagnoses. A wide thrombophilic profile was performed, including antithrombin, protein C, protein S, lupus anticoagulant, anticardiolipin antibodies, activated protein C resistance, factor V Leiden, mutation G-20210-A of the prothrombin gene, and factor VIII. Coagulation test results were compared with those in a healthy control group and a group of patients with history of lower-extremity deep venous thrombosis. The mean age of the patients was 49.2 ± 15 years (range, 28-81 yr). The mean number of ON localizations per patient was 5.2 ± 2.3 (range, 3-11). Hips were the most commonly affected joint (82%), followed by knees (58%), shoulders (37%), and ankles (13%). Most patients had an underlying disease process, and 12 of 25 (48%) patients had coagulation test abnormalities. The most common alterations were high factor VIII levels and antiphospholipid antibody (aPL) positivity in 24% and 20% of cases, respectively. These abnormalities were more prevalent in patients with multifocal ON compared with patients in the control groups. Sixty-one percent of patients had a history of corticosteroid treatment. Patients with coagulation abnormalities had a higher number of ON localizations per patient (6.5 ± 2.7 vs. 3.88 ± 0.8; p = 0.002) and a higher prevalence of atypical ON localizations (25% vs. 0%; p = 0.05). In conclusion, in the present cohort of patients with multifocal ON, 48% of the patients had at least 1 prothrombotic factor, especially high levels of factor VIII and aPL. These findings have major implications for the diagnosis and treatment of multifocal ON and clearly indicate the need to perform a thrombophilic profile in these patients.

Late onset Warfarin induced skin necrosis in human immunodeficiency virus infected patient with pulmonary tuberculosis

The incidence of Warfarin-induced skin necrosis (WISN) is very low 0.01-0.10%. The majority of the WISN cases appear between day 3 and 6 of onset of Warfarin therapy. The cases of late onset WISN are rarely seen. We report a case of late onset WISN in a young human immunodeficiency virus positive female patient with thrombotic pulmonary embolism and reactivation of pulmonary tuberculosis.

Hyperhomocysteinemia in HIV-Infected Individuals: Correlation of a Frequent Prothrombotic Factor with CD4+ Cell Count

OBJECTIVE

This study was aimed at providing an analysis of the correlation between CD4/CD8 counts and some coagulation factors in HIV-Positive Iranian patients.

METHODS

A case-control study on 58 HIV-infected patients and control group (58 healthy individuals). Patients and controls were matched for sex and age. In this study, several blood parameters were measured in 58 HIV-infected patients and the controls. Laboratory data were then measured including hemoglobin, platelets, homocysteine, serum levels of IgM and IgG antiphospholipid antibodies (aPL), IgM and IgG anticardiolipin antibotdies (aCL), and CD4(+) and CD8(+) cell count.

RESULTS

The HIV-infected patients, compared to healthy controls, showed a significant decline in platelets, CD4 count and CD8 count (p<0.0001), and an increase of homocysteine (p<0.0001) and IgG aPL levels (p<0.0001). No statistical difference was found between patients with CD4 count ≤200 and CD4 count >200 in the evaluated variables.

CONCLUSION

The results showed that thrombophilic abnormality in the form of hyperhomocysteinemia is more frequent in HIV-infected patients and should be considered by clinicians in view of an early diagnosis of the hypercoagulability state to prevent thrombotic complications.

HIV-Associated Venous Thromboembolism

HIV infection has been recognized as a prothrombotic condition and this association has now been proven by a large number of studies with a reported VTE frequency among HIV-infected patients ranging from 0.19% to 7,63 %/year. HIV infection is associated with a two to tenfold increased risk of venous thrombosis in comparison with a general population of the same age. Some risk factors demonstrated a strongest association with VTE such as, low CD4⁺ cell count especially in the presence of clinical AIDS, protein S deficiency, and protein C deficiency. Whereas other risk factors are still controversial like protease inhibitor therapy, presence of active opportunistic infections and presence of antiphospholipid antibodies, including anticardiolipin antibodies and lupus anticoagulant. Physicians caring for HIV positive patients should be able to recognize and treat not only the well-known opportunistic infections and malignancies associated with this chronic disease, but also be alert to the less well-known complications such as thromboses. Pulmonary embolism should be included in the differential diagnosis when patients with HIV/AIDS have unexplained dyspnea or hypoxemia. In younger individuals with VTE, especially men, without other identifiable risk factors for VTE, HIV should be considered. Because interactions between warfarin and antiretrovirals is possible, health care providers should also be alert to the potential of dangerously high or low INRs when they are giving anticoagulants to patients with HIV infection who are undergoing antiretroviral therapy.

Venous thromboembolic disease in the HIV-infected patient

OBJECTIVE

Infection with the HIV has developed into a chronic illness, with longer-term complications increasingly being seen. There is increasing evidence that infection with HIV may be associated with a hypercoagulable state. This study examines the association of HIV infection with the incidence of both pulmonary embolism and deep venous thrombosis.

METHODS

This study was a weighted analysis of data from National Hospital Discharge Survey, a national annual probability survey of discharges from short-stay non-Federal hospitals, from 1996-2004. The risk of pulmonary embolism and/or deep venous thrombosis in an HIV+ individual was ascertained for each age group by calculation of an odds ratio (OR) with a 95% confidence interval (CI). A common OR was computed across strata to evaluate the overall association between PE/DVT and HIV while adjusting for effects of age.

RESULTS

The overall age-adjusted OR indicates a statistically significant increase of 43% for PE in HIV+ individuals as opposed to HIV- individuals (OR, 1.43; 95% CI, 1.39-1.46). This increase differs by age group, with age group 21 to 50 years having the highest odds for PE among HIV+ individuals (OR, 1.58; 95% CI, 1.54-1.63).

CONCLUSIONS

The data supports the hypothesis that HIV-infected individuals are more likely to have clinically detected thromboembolic disease as opposed to non-HIV-infected individuals. This study reveals up to a 43% increase in OR of developing a PE, 10% increase in developing a DVT, and 40% increase in developing PE or DVT in an HIV-infected individual over the 9-year study period after adjusting for age.

[Congenital protein S deficiencies; diagnostic difficulties]

Protein S is a physiologic inhibitor of coagulation acting as a cofactor of activated protein C (APC) that inhibits factor Va and VIII. Approximately 60% of PS is bound to C4bBP, a protein of the complement system and only the free PS has a cofactor PCa role. Congenital PS deficiencies are diagnosed by immunologic dosage of free and total PS and functional assay evaluating APC cofactor activity. However, it has been demonstrated a direct anticoagulant activity of free PS, non-dependant of APC on the cascade coagulation and even PS bound to C4bBP seems to have anticoagulant properties. So, it appears that functional assays available estimate only a part of PS anticoagulant activities and, in addition, many interferences are reported with these tests (lupus anticoagulant, factor V Leiden, factor VIII excess...). Immunologic dosages are more reliable in spite of rare qualitative PS deficiencies that could be non-diagnosed. PS deficiencies are often difficult to diagnose because of an overlapping between normal and pathological values. Familial studies are necessary to prove the hereditary origin because there are several causes of acquired and sometimes persistent PS deficiencies (liver insufficiency, vitamin K absence, hormonal therapy in women, PS auto immune deficiency). About 200 different mutations were retrieved and, therefore, molecular studies are not of current practice. It is recommended currently to measure in first intention the free PS, if possible in association with PCa cofactor activity.

Fracture healing in HIV-positive populations

Highly active anti-retroviral therapy has transformed HIV into a chronic disease with a long-term asymptomatic phase. As a result, emphasis is shifting to other effects of the virus, aside from immunosuppression and mortality. We have reviewed the current evidence for an association between HIV infection and poor fracture healing.

The increased prevalence of osteoporosis and fragility fractures in HIV patients is well recognised. The suggestion that this may be purely as a result of highly active anti-retroviral therapy has been largely rejected. Apart from directly impeding cellular function in bone remodelling, HIV infection is known to cause derangement in the levels of those cytokines involved in fracture healing (particularly tumour necrosis factor-α) and appears to impair the blood supply of bone.

Many other factors complicate this issue, including a reduced body mass index, suboptimal nutrition, the effects of anti-retroviral drugs and the avoidance of operative intervention because of high rates of wound infection. However, there are sound molecular and biochemical hypotheses for a direct relationship between HIV infection and impaired fracture healing, and the rewards for further knowledge in this area are extensive in terms of optimised fracture management, reduced patient morbidity and educated resource allocation. Further investigation in this area is overdue.

Current insight into diagnostics and pathophysiology of the antiphospolipid syndrome

The diagnosis of the antiphospholipid syndrome, a non-inflammatory autoimmune disease characterized by thrombosis or pregnancy morbidity in the presence of antiphospholipid antibodies, depends greatly upon laboratory diagnostics. The diagnostic value of all available assays to detect antiphospholipid antibodies and the anticardiolipin assay in particular, is a matter of ongoing debate. Although the presence of lupus anticoagulant correlates best with thrombosis, accurate determination is not always possible due to anticoagulant treatment. Data on the predictive value of alternatives such as the anti-beta2-glycoprotein I and the anti-prothrombin antibody assay are insufficient and prospective cohort studies are needed. Determining antiphospholipid antibody profiles seems to increase diagnostic specificity. Substantial progress has been made in unravelling the pathophysiological mechanisms underlying the antiphospholipid syndrome. Several cellular receptors for antibody-beta2-glycoprotein I complexes have been identified and their roles in cellular activation are being investigated. In vivo data should provide more insight into the importance of the interaction with individual receptors.

Protein S deficiency and lower-extremity arterial thrombosis: complicating a common presentation

A 42-year-old woman presented to the emergency department with progressive painful discoloration of the digits of her right foot and symptoms previously diagnosed as neuroma. She was admitted to the hospital for dorsalis pedis arterial occlusion and ischemic foot pain. Despite attempts to restore perfusion to the right leg, ischemia of the right foot persisted and progressed to digital gangrene. The patient subsequently required right transmetatarsal amputation and eventually below-the-knee amputation. After extensive inpatient vascular and hematologic work-up of this otherwise healthy woman, test results revealed that she had protein S deficiency, hepatitis C, and human immunodeficiency virus type 1. In addition to describing this patient's evaluation and treatment, we review protein S deficiency, including its correlation with human immunodeficiency virus type 1 infection and laboratory diagnosis. This case promotes awareness of protein S deficiency and serves as a reminder to the physician treating patients with vascular compromise and a history of human immunodeficiency virus type 1 to include protein S deficiency in the differential diagnosis.

Progressive Prothrombotic State in Women With Advancing HIV Disease

BACKGROUND

HIV-infected patients are at increased risk for venous thrombotic events (VTEs). We sought to determine if advancing stages of HIV were associated with coagulation abnormalities that could predispose to VTE.

METHODS

Functional protein S, factor VIII activity, and lupus anticoagulant were assayed in 144 participants of the Women's Interagency HIV Study. Women with conditions associated with VTE (cancer, pregnancy, hormone use, acute infection, cancer, and autoimmune disease) were excluded. Subjects included 34 women with history of clinical AIDS, 11 with immunologic AIDS (CD4 count, <200 cells/dL), 49 with asymptomatic HIV, and 50 HIV-negative comparators.

RESULTS

We found progressive decreases in protein S, when comparing HIV-negative women (median, 76%) to women with asymptomatic HIV (median, 67%), immunologic AIDS (median, 62%), or clinical AIDS (median, 46%; P < 0.0001). Similarly, advancing HIV was associated with stepwise increases in factor VIII, from a median of 116% in HIV-negative women to 149% in those with asymptomatic HIV, 196% in those with immunologic AIDS, and 211% in those with clinical AIDS (P < 0.0001). No subject had lupus anticoagulant.

CONCLUSIONS

Advancing HIV is associated with progressive abnormalities of protein S and factor VIII; both of which are associated with increased risk for VTE, thus providing a biologic mechanism for the increased prevalence of VTE in HIV.

Osteonecrosis in patients with acquired immunodeficiency syndrome (AIDS): report of two cases and review of the literature

An increase in the incidence of abnormalities on bone and mineral metabolism (osteopenia/osteoporosis) and the development of osteonecrosis has been observed in patients with acquired immunodeficiency syndrome (AIDS). Two cases of osteonecrosis in patients with AIDS are reported. Both patients were receiving highly active antiretroviral therapy (HAART) and presented with one or more known risk factors for osteonecrosis. We review the literature and discuss the pathogenesis, diagnosis, prevention and treatment of this entity in patients with AIDS.

Portal vein thrombosis in a patient with HIV treated with a protease inhibitor-containing regimen

We report a case of an HIV seropositive female patient treated with a protease inhibitor-containing regimen who developed recurrent severe life-threathening episodes of haematemesis over time, caused by ruptured oesophageal varices as a consequence of a portal vein thrombosis. Coagulation tests revealed a protein S deficiency, an elevated homocysteinemia and a constitutional elevated plasma factor VIII coagulant activity. These coagulopathies and the HIV infection are independent risk factors for developing venous thromboembolic events. The protease inhibitor treatment may have played a role in increasing the thromboembolic risk. The recurrent bleedings only stopped after invasive surgery. The invasive splenorenal shunt operation was in this case a life-saving procedure.

[Spontaneous skin necrosis from acquired protein S deficiency in a renal transplant recipient]

INTRODUCTION

Spontaneous skin necrosis revealed acquired protein S deficiency due to isotype G autoantibodies.

CASE

This 31-year-old male renal transplant recipient, receiving immunosuppressive treatment, was hospitalized for necrotic purpural lesions. We were not able to detect any triggering factor. Sustained anticoagulant therapy remained essential to prevent new skin lesions and perhaps more thrombotic events.

COMMENTS

This condition is rare in adulthood, but is well described in children's purpura fulminans, especially the post-varicella form. Its mechanism remains unclear.

Anti-thrombomodulin antibodies and venous thrombosis

Thrombomodulin (TM) is a cell surface endothelial glycoprotein having anticoagulant properties. It inhibits thrombin, and activates protein C, leading to the inhibition of activated factors V and VIII. TM autoantibodies could theoretically predispose to thrombosis. We have tested 83 unselected patients with deep venous thrombosis, 36 males and 47 females aged from 1 to 70 years [mean +/- standard deviation (SD), 34.2 +/- 14.5 years] for the presence of IgG anti-TM in their plasmas. Tests were performed by enzyme-linked immunosorbent assay (ELISA) using recombinant human TM kindly provided by PAION GmbH (Aachen, Germany). Results are expressed as the optical density (OD) differences between coated and un-coated wells. Plasmas from 83 normal volunteer donors were used to define the cut-off value as the mean of absorbance of the control group + 3 SDs. The median OD of normal controls group was 0.024 (mean, 0.034; SD, 0.066; range, -0.048 to 0.309). The median OD obtained with plasmas from patients was 0.048 (mean, 0.114; SD, 0.215; range, -0.039 to 1.312) and was significantly higher than that of the control group (P < 0.0001). Choosing a cut-off value of 0.232 (mean OD of the control group + 3 SDs), 11 patients are considered as positive for IgG autoantibodies to TM and three normal controls are weakly positive. Selected plasma with IgG anti-TM and purified IgG were further tested by dot blot using recombinant purified TM and were found positive. Purified IgG of positive plasmas inhibits protein C activation by TM and thrombin, suggesting that anti-TM antibodies have a procoagulant effect. Interestingly, in our study, anti-TM antibodies are found in three of six patients with Budd-Chiari syndrome and four of eight patients with cerebral venous thrombosis. In conclusion, thrombomodulin autoantibodies could be a new interesting marker of thrombophilia easily detected by ELISA.

Thrombosis and a hypercoagulable state in HIV-infected patients

Human immunodeficiency virus infection is an illness with protean manifestations including hematological abnormalities. Thromboembolic complications in HIV-infected patients have been described. Recent literature describes an incidence ranging from 0.26% to 7.6%; higher incidence is seen in patients with active opportunistic infections or malignancy, and in patients with the acquired immunodeficiency syndrome. A variety of potential mechanisms have been proposed to account for the observed hypercoagulability in HIV-infected patients. These include the presence of antiphospholipid-anticardiolipin antibodies, decreased activities of natural anticoagulants (especially protein S), and increased platelet activation. Recent epidemiological studies emphasize the increased incidence of thromboembolic events including myocardial infarction in the HIV-infected population after the introduction of highly active antiretroviral therapy. The use of protease inhibitors in particular is implicated. A hypercoagulable state and especially thromboses are emerging as clinical issues in HIV-infected patients. Further studies are in order to more clearly delineate the pathophysiologic mechanism(s) of thromboses in HIV-infected patients.

Acquired protein C and protein S deficiency in HIV-infected patients

Infection with human immunodeficiency virus (HIV) may lead to hemostatic imbalances. Forty-nine consecutive patients with acute opportunistic infections were screened for thrombophilic parameters. A follow-up investigation was performed after 10 +/- 8 weeks in 26 patients. In acutely ill patients, the incidence of protein S deficiency was 67% (33/49) and of protein C deficiency 25% (12/49), while at the follow-up visit the incidences were 54% (14/26) and 8% (2/26), respectively. Protein S and protein C levels increased significantly from initial to follow-up visit (p < 0.05). Lupus anticoagulants were not detected and anticardiolipin IgG antibodies were present in 11.4% (5/44). Three patients presented with deep venous thrombosis on admission; in two, protein S or protein C deficiency was observed. In conclusion, an acquired protein S and protein C deficiency often develop in patients with HIV and acute illness; this may be reversible after treatment for opportunistic infections.

HIV infection and antiphospholipid antibody: literature review and link to the antiphospholipid syndrome

There is a high incidence of antiphospholipid antibodies, detected by assays for anticardiolipin or lupus-like anticoagulant, in HIV disease. However, a link to the antiphospholipid syndrome, with clinical thrombosis, is tenuous. We report a case of a 25-year-old man with undetermined risk factors for HIV presenting with possible antiphospholipid syndrome manifesting as necrotic skin lesions as the initial clinical presentation for HIV. We also review the literature exploring the association between HIV and antiphospholipid syndrome.

Stroke in black South African HIV-positive patients: a prospective analysis

BACKGROUND AND PURPOSE

Stroke associated with HIV infection is poorly characterized. In this study we analyze the association in a black African population.

METHODS

The clinical, laboratory, and radiological characteristics of 35 hospital-based black South African, heterosexual, HIV-infected patients who did not abuse intravenous drugs and presented with strokes were prospectively studied. The patients were antiretroviral therapy naive. Patients with other intracranial space-occupying lesions were excluded from the study.

RESULTS

The age range was 20 to 61 years (mean, 32.1 years). There were 21 female and 14 male patients, with a female to male ratio of 1.5:1. Cerebral infarction occurred in 33 patients (94%) and intracerebral hemorrhage in 2 patients (6%). Underlying causes were identified in 30 of the 35 patients (86%) and included coagulopathies, meningitis, cardioembolism, and hypertension. The most common coagulopathy was protein S deficiency. No cause was found in 5 patients (14%).

CONCLUSIONS

The results are similar to data from studies on young black African stroke patients who are HIV negative.

Which antiphospholipid antibody tests are most useful?

Despite an active international effort to improve diagnosis and treatment of the antiphospholipid syndrome (Hughes syndrome), there remain problems of lack of standardization and lack of prospective and multivariate epidemiologic analysis which restrict the diagnostic and predictive ability of commercially available tests. Nevertheless, current published series provide some data from which strategic approaches can be used to maximize the efficiency and usefulness of available tests. For further updates on new research and developments of interest to physicians and patients with this syndrome, the following web sites may prove helpful: www.slrapls.org, www.hematology.org, www.acforum.org, www.americanheart.org, www.rarediseases.org, www.aarda.org, and www.lupus.org.

Osteonecrosis complicating highly active antiretroviral therapy in patients infected with human immunodeficiency virus

Few patients with osteonecrosis that complicates human immunodeficiency virus (HIV) infection have been reported. We describe 5 patients whose symptoms of osteonecrosis developed with viral suppression and improvement in CD4 lymphocyte counts as a result of antiretroviral therapy. In addition, we review previously reported cases. The mean patient age was 35 years, and HIV was the sole risk factor in only 33%. Eighteen patients (55%) were receiving antiretroviral treatment when osteonecrosis was diagnosed. For 16 patients whose CD4 lymphocyte counts were reported, the mean CD4 count was 350 cells/mm(3). In 10 of these patients, the occurrence or worsening of symptoms of osteonecrosis appeared to be related to successful antiretroviral therapy. We conclude that osteonecrosis is an emerging manifestation of HIV infection and that it may be either a consequence of immunologic and virologic improvement resulting from antiretroviral therapy or a complication caused by the drugs themselves.

Further evidence for the presence of anti-protein S autoantibodies in patients with systemic lupus erythematosus

Acquired protein S (PS) deficiency in systemic lupus erythematosus (SLE) has been previously reported, but its mechanism and its possible thrombotic role have not been established. The aim of our study was to provide further evidence for auto-immune PS deficiency in 27 Tunisian SLE patients, using PS-specific enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance technology (SPR). PS deficiencies for PS activity, free PS or total PS, respectively, were found in 19, 18 and 12 patients. A significant correlation (r= -0.475, P< 0.016) was found between free/total PS ratio and C4bBP levels, suggesting a role of inflammation in free PS deficiency. Immunoglobulin IgG antibodies to PS were detected in four patients by both ELISA and SPR, in six patients only by ELISA, and in two patients only by SPR. Signals for anti-PS IgG by ELISA and SPR were, however, significantly correlated (r = 0.549, P = 0.003). These results suggest that an auto-immune mechanism could account for low PS activity in patients with SLE. Auto-antibodies to PS may form immune complexes, inducing increased clearance of PS or interfering with the protein C-protein S system.

Autoantibodies to leukocyte alphaMbeta2 integrin glycoproteins in HIV infection

HIV infection is often associated with polyclonal B-cell activation, autoantibodies, and clinically evident autoimmune disease. Because neutropenia and anti-neutrophil autoantibodies are common clinical features of HIV disease, we studied a series of HIV+ patients to determine whether anti-alphaMbeta2 integrin (MAC-1) specific anti-neutrophil autoantibodies occur in HIV disease, as we have shown to occur in patients with immune neutropenia not associated with HIV. Two new assays specific for anti-alphaMbeta2 IgG were developed to carry out these studies: an ELISA method using affinity-purified alphaMbeta2 integrin protein, and a flow cytometry method using subclones of the 293 human fetal kidney cell line, stably transfected with cDNAs for the alphaM and/or beta2 integrin subunits. In studies of the sera of 20 untreated HIV+ individuals, anti-alphaMbeta2 activity was detected in 9 (45%) by one or the other of these assays and in 5 (25%) by both assays. Seven of the 20 HIV+ study subjects had unexplained neutropenia, and of these, 6 (86%) were positive for anti-alphaMbeta2 autoantibodies. Our findings indicate that anti-alphaMbeta2 integrin autoantibodies are frequent in HIV+ individuals, particularly when unexplained neutropenia is also present, and raise the possibility that these autoantibodies may have a role in the acquired neutrophil dysfunction and increased risk of nonopportunistic bacterial infections observed in HIV disease.

Anti-CD34+ Fabs generated against hematopoietic stem cells in HIV-derived combinatorial immunoglobulin library suggest antigen-selected autoantibodies

Bone marrow suppression associated with HIV infection does not appear to be solely due to direct viral cytopathic effects. Autoantibodies may play a role in myelosuppression, however it is unclear whether autoantibodies produced in HIV infection represent a primary pathogenic process or merely reflect polyclonal B cell activation. To address these questions, we generated combinatorial immunoglobulin libraries using the pComb3 phagemid from an HIV+ individual with evidence of circulating autoantibodies. From one library, three anti-CD34 Fabs were identified using fresh CD34+ cells as antigenic targets by a method of phage subtraction. The anti-CD34 Fabs are specific by immunoblotting and Elisa and are of high affinity, with calculated Kds in the range of 10(-7) -10(-8) M. Nucleic acid sequencing revealed all three to be of the VH3 family and to have lambda light chains with some gene segments expressing little somatic mutation, while other segments were somatically mutated in patterns suggestive of antigen selection. These findings indicate that (1) A subset of HIV-associated anti-CD34 autoantibodies are monospecific and antigen-selected and are not merely a consequence of polyclonal B cell activation and elevated Ig levels in HIV. Autoreactivity in HIV therefore includes both polyspecific, low affinity antibodies as well as monospecific antigen-selected high affinity antibodies. (2) Although bone marrow suppression in HIV is likely to be multifactorial, autoantibodies to hematopoietic stem cells may contribute to its pathogenesis. (3) Library sampling of VH gene family rearrangements shows no evidence for under-representation of the VH3 family in the immune dysregulation of HIV infection. Phage subtraction is corroborated to be an effective means of identifying, cloning, and characterizing antibodies to hematopoietic differentiation antigens.

Association of viral load in plasma samples of HIV-infected hemophilia patients with autoantibodies and gp120-containing immune complexes on CD4+ lymphocytes

OBJECTIVE

We investigated whether the induction of antilymphocyte autoantibodies and immune complexes is associated with the activity of HIV replication.

METHODS

Viral HIV-1 RNA was measured in the plasma samples of 84 HIV+ hemophilia patients and correlated with the IgM, IgG, IgM/IgG and IgM/IgG/gp120 load of circulating CD4+ lymphocytes, CD4+ and CD8+ cell counts, plasma neopterin levels and in vitro T-cell responses to mitogens and pooled allogeneic stimulator cells.

RESULTS

Compared to patients with no immune complexes, on circulating CD4+ lymphocytes, viral load was increased in patients with IgM, IgM/IgG or IgM/IgG/gp120 complexes. Sequential analysis of HIV+ patients showed that peaks of retroviral activity were associated with the subsequent formation of CD4+ lymphocyte-reactive IgM and IgG autoantibodies and gp120-containing immune complexes.

CONCLUSION

The induction of autoantibodies and immune complexes attached to CD4+ lymphocytes is associated with periods of increased viral activity in HIV-infected patients.

Human immunodeficiency virus rather than hepatitis C virus infection is relevant to the development of an anti-cardiolipin antibody

We have investigated whether or not a relationship exists between anti-cardiolipin antibody (aCL) positivity and human immunodeficiency virus type 1 (HIV) and/or hepatitis C virus (HCV), and we have attempted to clarify which virus has close association with the development of aCL. We found that aCL positivity in HIV-infected patients was significantly higher than in HCV-infected patients. Furthermore, HIV/HCV dual-infected patients exhibited a higher aCL positivity than patients infected by HCV alone. From these results, we conclude that HIV rather than HCV plays an important role in the development of aCL.

Postinfectious purpura fulminans caused by an autoantibody directed against protein S

OBJECTIVE

To determine the mechanism responsible for idiopathic purpura fulminans, we investigated the procoagulant and anticoagulant pathways in five consecutive patients, four after varicella, and the fifth after a nonspecific infection.

METHODS

Procoagulant and anticoagulant factors, including protein C, protein S, and antithrombin III, were measured by quantitative or functional assays. Anti-protein S autoantibodies were identified by dot blotting and Western blotting, and quantified serially by enzyme-linked immunosorbent assay. Clinical and laboratory data were collated retrospectively.

RESULTS

In each case the disease began 7 to 10 days after the onset of the precipitating infection, with rapidly progressive purpura leading to extensive areas of skin necrosis. The illness was complicated by impaired perfusion of limbs or digits (two patients), peripheral gangrene resulting in an above-knee amputation (one patient), and major organ dysfunction caused by thromboembolic phenomena involving the lungs (two patients), the heart (one patient), or the kidneys (one patient). Protein S levels were virtually undetectable at the time of admission and failed to respond to infusions of fresh frozen plasma, despite correction of other procoagulant and anticoagulant factors. All five children had anti-protein S IgM and IgG autoantibodies, which persisted for less than 3 months after admission. Decline in the anti-protein S IgG antibody concentration was associated with normalization of the plasma protein S levels.

CONCLUSIONS

Autoimmune protein S deficiency may be a common mechanism causing postinfectious idiopathic purpura fulminans. Recognition of the pathophysiologic mechanism may provide a rational basis for treatment. Immediate heparinization, infusions of fresh frozen plasma, and, in cases complicated by major vessel thrombosis, the use of tissue-type plasminogen activator may limit thromboembolic complications.