Characterization of the anti-factor VIII immunoglobulin profile in patients with hemophilia A by use of a fluorescence-based immunoassay.

BACKGROUND: The development of neutralizing antibodies, referred to as inhibitors, against factor VIII is a major complication associated with FVIII infusion therapy for the treatment of hemophilia A (HA). Previous studies have shown that a subset of HA patients and a low percentage of healthy individuals harbor non-neutralizing anti-FVIII antibodies that do not elicit the clinical manifestations associated with inhibitor development. OBJECTIVE: To assess HA patients' anti-FVIII antibody profiles as potential predictors of clinical outcomes. METHODS: A fluorescence immunoassay (FLI) was used to detect anti-FVIII antibodies in 491 samples from 371 HA patients. RESULTS: Assessments of antibody profiles showed that the presence of anti-FVIII IgG1 , IgG2 or IgG4 correlated qualitatively and quantitatively with the presence of an FVIII inhibitor as determined with the Nijmegen-Bethesda assay (NBA). Forty-eight patients with a negative inhibitor history contributed serial samples to the study, including seven patients who had negative NBA titers initially and later converted to being NBA-positive. The FLI detected anti-FVIII IgG1 in five of those seven patients prior to their conversion to NBA-positive. Five of 15 serial-sample patients who had a negative inhibitor history and had anti-FVIII IgG1 later developed an inhibitor, as compared with two of 33 patients with a negative inhibitor history without anti-FVIII IgG1 . CONCLUSIONS: These data provide a rationale for future studies designed both to monitor the dynamics of anti-FVIII antibody profiles in HA patients as a potential predictor of future inhibitor development and to assess the value of the anti-FVIII FLI as a supplement to traditional inhibitor testing.

Home-based factor infusion therapy and hospitalization for bleeding complications among males with haemophilia.

Information from the medical records of 2650 US males with haemophilia living in six states was used to examine the influence of infusing factor concentrate at home (home therapy) and other variables on rates of hospitalization for a haemorrhagic bleeding complication (HBC) over a 4-year period. Bleeding complications included actual and suspected haemorrhagic events but excluded elective admissions for procedures necessitated by haemorrhage (e.g. joint synovectomy). Other risk determinants considered in the analyses included age, race, employment status, health insurance type, care received in federally funded haemophilia treatment centres (HTCs), factor deficiency type and severity, amount of factor prescribed, prophylactic treatment, and presence of inhibitors at baseline. Survival analysis methods were used to evaluate relationships between baseline risk factors and subsequent hospitalization rates. During 8708 person years (PYs) of follow-up, 808 subjects (30.5%) had a total of 1847 bleeding-related hospitalizations; an overall rate of 21.2 admissions per 100 PYs. Using proportional hazards regression to adjust for all of the studied factors, we found that home therapy use (among residents of four of the states) and care in HTCs were independently associated with a decreased risk for a first HBC. Patients who had government-sponsored health insurance or who had no insurance, those of minority race or ethnicity, those with higher levels of factor use, and those with inhibitors were at increased HBC risk. We conclude that the use of home therapy and receipt of care in HTCs are each associated with a substantially lower risk for HBC among males with haemophilia.

Long-term nonprogressive infection with human immunodeficiency virus type 1 in a hemophilia cohort.

Seven long-term nonprogressors (LTNPs) have been identified in a cohort of 128 human immunodeficiency virus (HIV)-1 infected individuals with hemophilia. Studies included quantitation of virus by polymerase chain reaction, characterization of primary virus isolates in vitro, analysis of lymphocyte surface markers, and measurement of virus-specific cytotoxic T lymphocytes (CTLs). Viruses of LTNPs exhibited slow growth in vivo and in vitro. LTNPs had expansion of CD8 T cells with increased expression of HLA-DR. Intermittent HIV-1-specific CTL effector activity was detected in freshly isolated peripheral blood mononuclear cells of most LTNPs. CTL precursor frequencies were higher in LTNPs than in patients with progressive disease. Virus antigen-specific lymphoproliferation was vigorous in some LTNPs. Thus, LTNPs in this cohort have maintained remarkably low virus burdens and vigorous HIV-1-specific cell-mediated immunity over a 15-year period. The presence of expanded, activated CD8 T cells with cytotoxic effector function in the peripheral blood suggests ongoing viral replication.

Human immunodeficiency virus in semen arises from a genetically distinct virus reservoir.

The reservoir of human immunodeficiency virus (HIV) in semen is unknown. Several lines of evidence suggest that semen HIV may not arise from the same reservoir of infection as peripheral blood. If true, the viral burden in the two compartments could be qualitatively and quantitatively different, a scenario of potentially profound significance for the design of effective strategies of treatment, disease monitoring, and infection containment. We report here that the ratio of infected to uninfected leukocytes in ejaculated semen specimens is highly discordant with paired blood samples, demonstrating that they derive from distinct populations of infected cells. In addition, infectious HIV was isolated from semen cells, but not from blood cells, of an individual on triple antiretroviral therapy; the absence of major resistance-conferring mutations in the semen virus indicates that it was replicating in isolation from the antiviral agents. The compartmentalization of blood and semen infection was further supported by genetic analysis of several infectious HIV clones isolated from semen cells and peripheral blood cells of another donor not on antiretroviral therapy. Protease gene sequence analyses revealed significant divergence of the two viral populations. These findings confirm the distinct compartmentalization of HIV in the semen of this study cohort, and support the concept that semen HIV arises from an isolated reservoir of infection that may function independently in the pathobiology of HIV disease.

Human immunodeficiency virus type 1-specific cytotoxic T lymphocytes (CTL), virus load, and CD4 T cell loss: evidence supporting a protective role for CTL in vivo.

The relationships between primary human immunodeficiency virus type 1 (HIV-1) Gag-specific cytotoxic T lymphocyte (CTL) frequency, virus load, and CD4 T cell loss were evaluated in a group of 46 HIV-1-infected persons with hemophilia. Freshly isolated peripheral blood mononuclear cells in limiting dilution assays were used to measure HIV-1 Gag-specific CTL frequencies. Concurrent measurements of virus load and lymphocyte surface markers were obtained. No correlation between Gag-specific CTL frequency and concurrent CD4 cell count was observed. A significant inverse relationship was observed between HIV-1 Gag-specific CTL frequency and provirus load as measured by polymerase chain reaction. Subjects with higher CTL frequencies were found to have more stable CD4 cell counts over time. These results provide additional evidence to support the concept that the predominant role of this virus-specific cellular immune response is to limit viral replication and CD4 cell loss in HIV-1 infection.

DDI and liver tests in HIV-1 seropositive haemophiliacs.

Many patients with haemophilia who are HIV-1 seropositive are co-infected with the hepatitis C virus with variable degrees of underlying liver disease. To evaluate whether the use of the antiretroviral agent Dideoxyinosine (DDI) causes worsening of hepatic dysfunction as measured by liver enzyme tests, we reviewed our cohort of patients previously treated with monotherapy with Zidovudine (AZT) and subsequently changed to DDI. Seventeen patients (median age: 34 years, median absolute CD4 lymphocyte cell count: 86 cells µL(-1) ) were included in this study. None had coincident use of other hepatotoxic agents. The median duration of treatment with AZT and DDI was 18 and 15 months, respectively. There was no significant change in liver function tests with the use of DDI and no development of clinical signs of hepatotoxicity. Neither duration of treatment, absolute CD4 lymphocyte cell count, pre-existing elevation of baseline aminotransferase levels nor the use of Pneumocystis carinii prophylaxis therapy resulted in further elevation of liver function tests. Monotherapy with DDI was well tolerated in this cohort of HIV-1-seropositive haemophiliacs with coincident hepatitis C infection.

AIDS-associated non-Hodgkin's lymphomas as primary and secondary AIDS diagnoses in hemophiliacs. Hemophilia Malignancy Study Group.

We studied the characteristics and temporal trends of AIDS- associated non-Hodgkin's lymphoma (AIDS-NHL) in individuals with hemophilia. Prospective data were collected on 33 HIV-positive hemophiliacs with AIDS-NHL enrolled in the Hemophilia Malignancy Study (HMS), of whom 21 had primary and 12 had secondary or subsequent AIDS-defining illnesses, and analyzed for frequency and temporal trends. As compared with primary AIDS- NHL, secondary AIDS-NHL occurred at an older mean age, 37 versus 29 years (p = 0.12); at a lower mean CD4 count, 46 versus 154 (p = 0.07); after a longer period of immunosuppression (CD4 < 200/microl), 41 versus 16 months (p = 0.03); and with shorter median survival, 2 versus 7 months (p = 0.09). The presence of EBV in tumor tissue was associated with shorter survival, 1 versus 7 months (p = 0.17). Between 1981 and 1988 and 1989 and 1994, the proportion of primary AIDS diagnoses that were AIDS-NHL changed minimally, 4.6 versus 6.1%, whereas there were significant decreases in Pneumocystis carinii pneumonia (PCP, p = 0.02) and wasting (p = 0.07), and an increase in Candida (p = 0.004). These findings confirm that an increasing proportion of AIDS-NHL in hemophiliacs are occurring as secondary or later AIDS diagnoses, and they are associated with prolonged duration of immunosuppression.

Hemostasis: a practical review of conservative and operative care.

Progress in the treatment of persons with hemophilia has improved quality of life and made surgical intervention in these patients possible. Optimum management should include a facility equipped with a special coagulation laboratory, a hematologist proficient in the management of coagulation disorders, a surgeon with experience operating on persons with a clotting disorder, and a blood bank with experienced personnel. Persons with inhibitors should undergo elective procedures only after consultation between surgeon and hematologist. Replacement of deficient factor protein by the intravenous infusion of factor concentrates allows normal hemostasis. The manufacture of factor concentrates includes purification and viral attenuation procedures to limit exposure to other proteins and decrease the risk of transmission of viral infection. These concentrates may be delivered by bolus intravenous infusion or as a continuous intravenous infusion which allows for less total units of factor to be administered. In patients with mild hemophilia A, intravenous or intranasal desmopressin acetate may be used to increase the Factor VIII: coagulant level and eliminate exposure to blood products. With careful perioperative management, patients with hemophilia may undergo surgery safely without excessive bleeding. In the future because of prophylactic therapy, the need for orthopaedic procedures may be decreased substantially.

Inhibitors in congenital haemophilia.

Inhibitor formation is a serious complication, occurring in 24-52% of patients with haemophilia A and in 1.5-3% of patients with haemophilia B. Low-titre inhibitors can easily be overcome and do not represent a treatment challenge. They are treated with increased doses of factor concentrate. However, high-titre inhibitors may still cause death from haemorrhage in this population. Optimal treatment of acute, life-threatening haemorrhage in patients with factor VIII inhibitors includes either porcine factor VIII or human factor VIII in high doses since, with both modalities, circulating factor levels are achievable. If the inhibitor titres are too high, plasmapheresis may be warranted. For routine joint bleeds, PCC or aPCC can be administered at home with variable success. For patients with factor IX inhibitors treatment options are more limited. If the haemorrhage is life-threatening, plasmapheresis should be done to decrease the inhibitor and high doses of pure factor IX administered either by continuous infusion or bolus. Attainment of levels of > 20% should be attempted. New clinical options, such as rFVIIa, may emerge. For both groups of patients, IT should be started as soon as the inhibitor is discovered and its behaviour characterized. Unfortunately, no standard regimen for IT exists and the treater will have to choose whichever schedule he/she feels is the most appropriate.

Anaphylaxis after treatment with recombinant factor VIII.

BACKGROUND: Treatment of hemophilia patients with recombinant factor VIII concentrates has not previously been associated with anaphylaxis. STUDY DESIGN AND METHODS: A 5-week-old boy with severe hemophilia A developed dyspnea, cyanosis, hypotension, and a diffuse urticarial rash following treatment with a recombinant factor VIII (Recombinate). To identify the cause of anaphylaxis in this patient, the vial lot was examined for the presence of endotoxin, and a checkerboard immunoblotting technique was used to test serum and/or plasma samples from the patient and mother for the presence of antibodies (IgA, IgG, IgE, and IgM) to Recombinate-related antigens (recombinant factor VIII, von Willebrand factor, human serum albumin, Chinese hamster ovary proteins, bovine serum albumin, mouse monoclonal anti-human factor VIII, polyethylene glycol 3350), and to ethylene oxide, the agent used to sterilize the infusion equipment. RESULTS: No immune response directed against the Recombinate-related antigens or ethylene oxide that could be associated with the anaphylactic reaction was identified. Endotoxin was not present upon rabbit pyrogen testing of the therapeutic product. CONCLUSION: These studies failed to show any association between Recombinate and the onset of the allergic reaction. This seems to be the first reported case of anaphylaxis following the infusion of a recombinant form of factor VIII concentrate.

Hepatitis C seropositivity in HIV-negative children with severe haemophilia.

With the advent of new viral inactivation and purification methods for factor concentrates in the 1980s, transmission of both HIV-1 and hepatitis viruses has been significantly decreased. However, on routine annual testing of the paediatric population at the New England Hemophilia Center (NEHC), several children were noted to be hepatitis C (HCV) seropositive. Thus, a retrospective review of children with severe haemophilia was undertaken. Twenty-six children (median age: 7.5 years) under the age of 12 were identified. All were HIV-1 seronegative and had received hepatitis B immunization. Of these, 22 had received factor concentrate. Four children had no documented HCV serostatus, and seven were HCV seropositive using a second-generation ELISA. Transfusion products were reviewed and stored serum samples were evaluated using a second-generation ELISA to identify the approximate date of seroconversion with positive tests confirmed by RIBA analysis. Three children became seropositive before 1989 using factor concentrates with early viral attenuation procedures. Two children who seroconverted after 1991 received only monoclonal affinity purified factor concentrate that was either pasteurized or solvent/detergent treated. There was no evidence of horizontal or nosocomial viral transmission. We are unable to prove causality with the factor concentrates used by these children. Continued surveillance with sensitive measures for detection of HCV in persons with haemophilia using plasma-derived factor concentrate is necessary.

Tibial bone plug resorption with extra-articular cyst: a rare complication of anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction failure resulted in tibial bone plug resorption and the formation of a large extra-articular cyst. To our knowledge, this is the first report of this kind of ACL failure. The relationship to known factors is discussed.

Modern treatment of haemophilia.

Many rapid advances have been made in the diagnosis and therapy of haemophilia. Nevertheless, the condition still poses problems and challenges (e.g., joint disease, transfusion-transmitted diseases, inhibitors, provision of care in developing countries, and education and cost issues). WHO and the World Federation of Hemophilia held a joint meeting in Geneva, on 21-23 March 1994, to discuss and review current and future approaches to the management of haemophilia and its complications, including prospects for genetic technology and gene therapy in developed and developing countries. The present review article summarizes the discussions and recommendations made by the participants.