HIV antibody status and immunological abnormalities in Polish haemophiliacs

Sera of 520 multitransfused haemophiliacs were examined for antibody to HIV; 447 patients had haemophilia A and 73 had haemophilia B. In 382 patients with haemophilia A and in 62 with haemophilia B solely Polish-made blood products were used for replacement therapy. The remaining haemophiliacs had also received imported clotting factor concentrates prior to the investigation. Only 8 patients (haemophilia A - 7, haemophilia B - 1) developed anti-HIV and all of them had been exposed to commercial concentrates. The analysis of T-cell subsets demonstrated an inverted T4/T8 ratio (less than 1.0) in 7 (30%) of the 23 haemophiliacs treated solely with domestic cryoprecipitate and in 3 (37%) of the 8 seropositive recipients of commercial concentrates. The most frequent alteration in both subgroups was a reduced ratio with either normal absolute numbers or an increase in T8 cells. Increased serum IgG levels were found in 82% of the users of cryoprecipitate and in 75% of the seropositive patients. Serum beta-2-microglobulin level was elevated in 69 and 62% of each subgroup, respectively. The observed immunological abnormalities, at least in the cryoprecipitate treated subgroup, may be causally related to factors other than HIV infection.     

Hepatitis C in haemophiliacs

Virtually all haemophiliacs who received non-virucidally treated, large-pool clotting factor concentrates before 1986 became infected with hepatitis C virus (HCV). Although approximately one-tenth of HCV-infected people have been shown to clear the infection naturally, in the remaining cases the infection slowly progresses. Unfortunately, a significant percentage of HCV-infected hemophilic patients were also co-infected with human immunodeficiency virus (HIV), which can accelerate the progression to cirrhosis and liver failure. As regards treatment, combination therapy with interferon (IFN) and ribavirin has improved the poor results obtained with IFN monotherapy and has become the standard treatment of chronic hepatitis C. Given the positive results obtained with pegylated interferon in non-haemophiliacs, ongoing trials are evaluating this promising therapy in HCV-chronically infected haemophilic patients. Finally, anti-HCV treatment should also be considered for those haemophiliacs co-infected with HIV in whom anti-retroviral treatment has stabilized the HIV infection.     

Effect of clotting factors concentrates on lymphocyte and neutrophil function in vitro

Immunological abnormalities have been reported in haemophiliacs. Although infections with HIV, hepatitis and other viruses may contribute to these abnormalities, immune defects are detectable also in HIV seronegative haemophiliacs. It is likely that chronic exposure to extraneous proteins in clotting factor concentrates (CFCs) may play a role in immunomodulation, but the underlying mechanisms remain unclear. The results of the present paper show that: a) soluble HLA class I (sHLA-I), soluble Fas-ligand (sFas-L) and transforming growth factor beta 1 (TGF-beta1) are detectable in plasma derived but not in recombinant CFCs; b) the level of sHLA-I and sFas-L is proportional to the grade of CFCs purity whereas TGF-beta1 showed very variable levels; c) soluble molecules detected in CFCs exert immunomodulatory effects in vitro like apoptosis induction in Jurkat cells and inhibition of mixed lymphocyte reaction response, antigen-specific lymphocyte cytotoxic activity and neutrophil chemotaxis.     

Factor IX concentrate therapy and thrombosis: relation to changes in plasma antithrombin III

Commercial factor IX (fIX) concentrate therapy has been associated with thrombogenic complications, the cause of which is uncertain. We have previously reported that infusion of these fIX concentrates led to a decrease in antithrombin III (ATIII) functional activity, but not antigen, from pre-infusion levels. The patient plasmas also showed a cathodal shift in ATIII antigen by crossed immunoelectrophoresis (CIEP). We chose to characterize these ATIII changes more extensively in additional patients, by functional assays, radial immunodiffusion (RID), and CIEP. The effects of commercial fIX concentrate therapy on plasma ATIII levels appear to be dose-related, with most pronounced effects at 100 U/Kg; the effects are also cumulative, with a persistence of ATIII changes 24 hours after infusion in patients on daily therapy. We also studied pre- and post-infusion ATIII levels in patients who received 100 U/Kg of a more purified fIX concentrate (American Red Cross), which contains little or no activated clotting factors and has been shown to be non-thrombogenic in animal models. These patients showed no change post-infusion in ATIII levels by clotting, amidolytic, or RID assays, nor any significant change by CIEP. These data suggest that the ATIII changes that occur predictably after commercial fIX concentrate therapy are caused by a contaminating protein or proteins other than fIX and that the ATIII changes observed are related to the thrombotic complications of these commercial concentrates.     

In vivo characteristics of thaw siphon cryoprecipitate compared to other factor VIII preparations

5 severe haemophiliacs were infused with cryoprecipitate prepared by the continuous thaw-siphon technique, with cryoprecipitate prepared by overnight thawing and with intermediate-purity factor VIII concentrate. All 3 preparations gave a similar mean half-life for coagulant factor VIII of approximately 10 hours. The immediate recovery of this activity was similar for the 2 cryoprecipitates, but higher for the purified concentrate.     

Altered serum factor VIII-related antigen (VIII : AGN)/von Willebrand factor (VIII : vWf) in haemophiliacs with inhibitors to factor VIII procoagulant activity (VIII : C)

Inhibitors to factor VIII (anti-F VIII) developing in patients with classic haemophilia have apparent specificity for the factor VIII procoagulant activity (VIII : C), rather than the factor VIII-related antigen (VIII : AGN) and von Willebrand factor (VIII : vWf) regions of the factor VIII complex. Since procoagulant function is absent following in vitro clotting, but serum retains VIII : AGN/vWf properties, we searched for differences in VIII : AGN and VIII : vWf of inhibitor serum that might relate to the presence of anti-F VIII. Rocket immunoelectrophoresis and the washed platelet ristocetin assay were performed on the plasma and serum of nine haemophiliacs with inhibitors, 23 non-inhibitor haemophiliacs and six normal subjects. Unlike normal and non-inhibitor haemophilic sera, that from five of nine inhibitor patients demonstrated absent VIII : vWf and significantly lower VIII : AGN (p less than 0.05). Furthermore, VIII : AGN of faster mobility was detected on crossed immunoelectrophoresis of the sera of three inhibitor patients. Thrombin clotting of plasma from haemophiliacs with high titer anti-F VIII was associated with a greater loss of VIII : vWf than seen with non-inhibitor haemophilic plasma. This effect was independent of the presence of platelets. These data indicate that in vitro clotting is associated with alteration in the serum VIII : AGN/vWf of some haemophiliacs with anti-F VIII.     

Recombinant clotting factors

The recombinant era for haemophilia began in the early 1980s with the cloning and subsequent expression of functional proteins for both factors VIII and IX. Efficient production of recombinant clotting factors in mammalian cell culture systems required overcoming significant challenges due to the complex post-translational modifications that were integral to their pro-coagulant function. The quick development and commercialization of recombinant clotting factors was, in part, facilitated by the catastrophic impact of viral contamination of plasma-derived clotting factor concentrates at the time. Since their transition into the clinic, the recombinant versions of both factor VIII and IX have proven to be remarkable facsimiles of their plasma-derived counterparts. The broad adoption of recombinant therapy throughout the developed world has significantly increased the supply of clotting factor concentrates and helped advance aggressive therapeutic interventions such as prophylaxis. The development of recombinant VIIa was a further advance bringing a recombinant option to haemophilia patients with inhibitors. Recombinant DNA technology remains the platform to address ongoing challenges in haemophilia care such as reducing the costs of therapy, increasing the availability to the developing world, and improving the functional properties of these proteins. In turn, the ongoing development of new recombinant clotting factor concentrates is providing alternatives for patients with other inherited bleeding disorders.     

Antibody to hepatitis C virus after a vapour-heated factor VIII concentrate. The Study Group of the Fondazione dell'Emofilia

To evaluate whether or not clotting factor concentrates exposed to virucidal procedures transmitted hepatitis C, sera obtained in 1984-1986 from 27 previously untreated hemophiliacs infused with a vapour-heated factor VIII concentrate were tested retrospectively for the antibody to the hepatitis C virus (anti-HCV). A 2-year-old hemophiliac, negative for anti-HCV before administration of concentrate, seroconverted at week 12 and remained anti-HCV positive thereafter. Both his parents were anti-HCV negative and he had no other household contact. The patient had also become HBsAg positive at week 8 and had at the same time a marked elevation of alanine aminotransferase. His double infection with the hepatitis B and C viruses indicates that hot vapour was not completely effective in inactivating these viruses.     

Clinical application of a chromogenic substrate method for determination of factor VIII activity

A chromogenic substrate kit for the determination of factor VIII activity (COATEST Factor VIII) has been evaluated in five different laboratories, one of them using a semi-automated procedure. This chromogenic method was compared to one-stage clotting assays for factor VIII determination in plasmas from healthy subjects, carriers of hemophilia A, severe, mild and moderate hemophilia A as well as von Willebrand's patients. In all these cases, a high correlation between these two methods was obtained (r = 0.96-0.99, n = 385) with a good agreement of the assigned potencies at all levels of factor VIII. A good correlation (r = 0.94) was also obtained for the levels of factor VIII after infusion of concentrates in six severe hemophiliacs or after administration of DDAVP to von Willebrand's patients. The chromogenic method is insensitive to preactivation of factor VIII by thrombin, thus yielding valid potency assignments also in these situations. The precision was higher with the chromogenic method than with the one-stage clotting assays (C.V. = 2-5% vs 4-15%). Altogether, the new chromogenic substrate method has proven itself suitable for determination of factor VIII in plasma and concentrates.     

Protein content and factor VIII complex in untreated, treated and monoclonal factor VIII concentrates

Replacement therapy with clotting factor concentrates may expose the recipients not only to virus contamination but also to continuous stimulation of the immune system by repeated infusions of allogenic proteins. Concentrate purity is now a very important prerequisite to be taken into account in choosing what product can better meet the patient's needs. We compared protein content (albumin, fibrinogen, fibronectin, immunoglobulins) and factor VIII:C/vWF:Ag complex in untreated, treated and monoclonal factor VIII concentrates. Protein content is dramatically decreased in new treated ultrapure concentrates. Improved traditional fractionation methods allowed to obtain very high Factor VIII specific activity. New fractionation methods with immunoaffinity chromatography by means of monoclonal antibodies can give highly pure concentrates even if deliberately added albumin decreases factor VIII specific activity in final formulation. Otherwise monoclonal concentrates show a very high specific activity in terms of fibrinogen and immunoglobulin content, which, unlike albumin, are affecting the immune system in hemophiliacs.     

Assessment for evidence of non a-non b hepatitis in patients given n-heptane-suspended heat-treated clotting factor concentrates

Nineteen patients, (2 adults, 17 children) with inherited bleeding disorders were infused with n-heptane-suspended-heated clotting factor concentrates. Twelve of the nineteen were previously untreated. Six patients were infused with Profilnine Heat-Treated® and 13 with Profilate Heat-Treated. Five separate centers participated and were given various lots of concentrates for use. Blood from the seventeen children was sampled prior to entry, at infusion, 2 weeks, 6 weeks, 12 weeks and 6 months after the first infusion. The two adults were sampled every 2 weeks. Twelve of the 19 patients were followed beyond six months. Three patients demonstrated a rise in ALT during the first six months of observation with levels above 2.5 times the upper limit of normal. One of these patients showed a parallel increment in a-CMV IgM titer and a second patient, an adult, had previously received many units of single donor blood components. During the second 6 month observation interval, two patients showed a rise in ALT. One of these patients had been exposed to only one lot of concentrate with no other viral cause being determined. Two additional patients had a moderate increase in ALT up to 98 U/L (normal <50). No patients were clinically ill or showed jaundice during these episodes. The hepatitis episode at 11 months in the patient using one lot of concentrate, might suggest a non-viral mechanism in this instance. This study indicates that these concentrates may be associated with episodes of ALT above 2.5 times the upper limit of normal in approximately 20% of the patients treated, but the etiology of the raised ALT may not always be Non A-Non B hepatitis.     

Manufacture and composition of fresh frozen plasma and virus-inactivated therapeutic plasma preparations: correlation between composition and therapeutic efficacy

The clinical efficacy of the therapeutic plasma used in the treatment of congenital and acquired severe coagulopathy depends on the potency of clotting factor and inhibitor activities. The composition of plasma strongly depends on the conditions under which it is produced. A low citrate anticoagulant-to-blood ratio, short intervals between donation and plasma separation and rapid freezing markedly improve the preservation of unstable coagulation factors. The influence of different leukocyte reduction filters on plasma quality still requires clarification. Recent trials on long-term storage conditions suggest that keeping plasma at -30 degrees C or colder over a period of 24-36 months prevents substantial decrease in clotting factor activities including factor VIII (FVIII). Three types of therapeutic plasma are currently available. Quarantine-stored fresh frozen plasma (FFP) contains physiological activities of therapeutically relevant plasma proteins, but carries a risk of transmitting blood-borne viruses that cannot be detected by human immunodeficiency virus (HIV) and hepatitis B and C screening. In contrast, solvent/detergent-treated plasma (SDP) and methylene blue/light-treated plasma (MBP) is virtually free of HIV and hepatitis C virus (HCV) subtypes. Virus inactivation procedures can have the consequence of reducing several clotting factors and inhibitors in SDP and MBP to varying degrees. However, pooling of plasma units before solvent/detergent (SD) treatment results in well-standardized protein levels of SDP. At least five prospective trials and four observational studies covering different clinical settings suggest that SDP and FFP do not substantially differ in their clinical efficacy or in their tolerance. By way of contrast, there is a lack of data about the clinical efficacy and tolerance of MBP compared to FFP.     

Heterogeneity of factor IX in therapeutic factor IX concentrates

Rabbit antibody to human factor IX was used to investigate the factor IX antigenic content and electrophoretic mobility of commercial products as well as experimental “activated products”. Rocket immunoelectrophoresis of all concentrates showed a 1.2–3 fold increased antigenic content/unit factor IX clotting activity when compared to plasma. Two dimensional crossed immunoelectrophoresis of standard Factor IX concentrates produced a single sharp peak whether electrophoresed in Ca²⁺ or EDTA containing buffer. “Activated” concentrates produced a dome shaped precipitin arc. The addition of plasma to standard factor IX concentrates yielded a marked shoulder only when the electrophoresis was run in EDTA. This effect could not be reproduced by the addition of antithrombin III (AT-III). The addition of plasma to some “activated” products revealed an even more pronounced heterogeneity whether in Ca²⁺ or EDTA and the addition of AT-III in the same products produced a second precipitin peak. These results indicate that at least three forms of factor IX exist in Factor IX concentrates. The absence of detectable AT-III reacting material in the standard concentrates is $\text{a priori}$ evidence of the absence of major amounts of IXa, whereas the presence of AT-III reacting material in the “activated” concentrates is evidence of biologically active material.     

Treatment of von Willebrand disease

In von Willebrand disease, there are two main options for the treatment of spontaneous bleeding episodes and for bleeding prophylaxis: desmopressin and transfusional therapy with plasma products. Desmopressin is the treatment of choice for most patients with type 1, who account for approximately 70 to 80 per cent of all cases with the disease. This non-transfusional hemostatic agent raises endogenous factor VIII and von Willebrand factor three- to fivefold and thereby transiently corrects both the intrinsic coagulation and primary hemostasis defects. In patients with the more severe type 3 and in the majority of those with type 2 desmopressin is not effective or is contraindicated, so that it is usually necessary to resort to plasma concentrates containing factor VIII and von Willebrand factor. Concentrates treated with virus inactivation methods should be preferred to cryoprecipitate because they are equally effective and perceived as safer.     

Contamination of coagulation factor concentrates with human parvovirus B19 genotype 1 and 2

Human parvovirus B19 (B19) DNA has frequently been detected in plasma-derived coagulation factor concentrates. Furthermore, transmission of B19 infection was observed, indicating presence of the infectious virus despite routine viral inactivation/removal procedures during the manufacturing process. Recently, human parvovirus DNA isolates, variant from B19, have been identified resulting in classification of B19 virus into three distinct genotypes, with all viruses previously classified as B19 belonging to genotype 1. So far, there is no information available on contamination of clotting factor concentrates with genotype 2. Therefore, we analysed 202 different factor concentrate lots for genotype 1 and 2 DNA by PCR. Analysis of one hundred eighty-one lots representing 13 different products, administered over the last three years, was compared to 21 lots (8 products) used until the early 1980s which had not been treated by viral inactivation procedures. Genotype 1 DNA was detected in 77/181 (42.5%) currently administered lots, and 17/21 (81%) previously used lots. The level of genotype 1 DNA contamination was similar in currently and previously administered concentrates. Genotype 2 DNA was found in 5/202 (2.5%) lots, all of which were co-contaminated with genotype 1 DNA. DNA sequence analysis showed that the PCR-double positive concentrates contained typical genotype 1 and genotype 2 DNA. Because genotype 2 appears to cause a similar spectrum of diseases as genotype 1, simultaneous detection of genotype 2 by nucleic acid amplification testing (NAT), now widely applied to plasma pools for genotype 1, would give an added level of safety to blood products.     

B cell dysfunction in haemophilia in the absence and presence of HIV-1 infection

56 haemophiliacs selected on the basis of HIV-1 antibody status, liver disease grade and mean annual dose of clotting factor concentrate used were studied. Spontaneous and stimulated IgG and IgM production in vitro were measured. HIV-1 infection was associated with increased spontaneous immunoglobulin production and an impaired response to pokeweed mitogen and Staph Aureus protein A. Implying a shift in the proportions of partially and fully activated B cells. In the absence of HIV-1 infection there was a shift to a greater proportion of partially activated B cells in patients with severe liver disease. The remainder had in vitro immunoglobulin production comparable to controls. B cell abnormalities occur early in the course of HIV-1 infection. Liver disease and not clotting factor concentrate treatment cause B cell abnormalities in the absence of HIV-1 infection in haemophilia.     

In vitro characterization of various heat-treated prothrombin complex concentrates (PCC)

All of 6 heat-treated prothrombin complex concentrates (PCC) tested contained adequate levels of factor IX but factor VII content was low. Levels of factors II, X, protein C and protein S were variable and antigen levels were always greater than those of functional activities. On crossed-immunoelectrophoresis factor IX showed variable anodal shift in all concentrates tested and in some activated factor IX was demonstrated by immunoblotting technique. These findings suggested some activation and/or denaturation during production and/or heating. Modest amount of factor VIII clotting activity by solid-phase amidolytic method and of factor VIII antigen was demonstrated in some concentrates but none contained more than a trace factor VIII inhibitor bypassing activity. The results suggested that heat-treated PCC should provide safe therapeutic products for hemophilia B.     

Detection and characterisation of two missense mutations at a cleavage site in the factor VIII light chain.

Haemophilia A is an X-linked bleeding disorder caused by a deficiency of factor VIII. As an essential cofactor in the intrinsic clotting cascade, factor VIII is activated and subsequently inactivated by proteolytic cleavages involving factor IIa (thrombin), factor Xa and activated protein C (APC). Investigation of the thrombin cleavage sites at amino acids 372 and 1689 of the factor VIII protein by oligonucleotide screening, DNA amplification and direct sequencing, enabled us to identify two missense mutations in 441 unrelated haemophiliacs. A C-to-T transition, which leads to the substitution of cysteine for arginine at position 1689, was found in a severely affected patient and a previously undescribed G-to-A substitution, causing replacement of arginine1689 with histidine, was found in a patient with mild disease.     

Recombinant factor VIIa does not induce hypercoagulability in vitro

Recombinant factor VIIa (rVIIa) has been reported to be clinically effective and safe in haemophilic patients with inhibitor antibodies. Compared to activated prothrombin complex concentrates the risk of thrombotic complications seems to be very low after rVIIa administration. Determination of free thrombin generation has been shown to identify hypercoagulability. Therefore, free thrombin and prothrombinase activity (Xa generation) were assessed after extrinsic activation of rVIIa supplemented factor VIII and factor IX deficient plasma. Free thrombin generation was also determined after supplementation of (activated) prothrombin complex concentrates. Addition of 150 U rVIIa/ml shortened the clotting times markedly in control, factor VIII, and factor IX deficient plasma. In contrast, free thrombin and Xa generation were not different in the absence or presence of 150 U rVIIa/ml. Addition of (activated) prothrombin complex concentrates resulted in a marked increase of free thrombin generation in all investigated plasmas. Although in vitro studies cannot reflect specific clinical circumstances our results support the notion that rVIIa does not induce a hypercoagulable state as sporadically observed after administration of (activated) prothrombin complex concentrates.     

Age at first treatment and immune tolerance to factor VIII in severe hemophilia

Findings from a recent study suggest that earlier start of treatment with factor VIII in patients with severe hemophilia is associated with a higher risk to develop inhibitors. We set out to assess the association between age of first administration of clotting factor VIII and the risk to develop inhibitors in infants with severe hemophilia A. This work was a cohort study, carried out in the national hemophilia treatment center. The study included eighty-one consecutive patients with severe hemophilia A who received their first dose of factor VIII between 1975 and 1998. Patients were followed until their last visit in 2001 or 2002. The average follow-up was 16 years (range 3-26). Persistent inhibitory antibodies developed in 12 of 81 patients (15%). Cumulative incidence at 100 exposure days was 34% (95% confidence interval 7-61%) in patients starting therapy before the age of 6 months, 20% (4-36%) in patients starting therapy between 6 months and 1 year, 13% (0-27%) in those starting therapy between 1 and 1.5 years, and 0% in those who started therapy beyond 1.5 years of age (p for trend 0.03). Our findings confirm that age of first factor VIII administration in children with severe hemophilia A is inversely associated with the risk to develop antibodies against factor VIII. The role of confounding factors such as the type of factor VIII mutation and environmental factors needs to be evaluated.