Treatment of bleeding episodes with recombinant factor VIII Fc fusion protein in A-LONG study subjects with severe haemophilia A

INTRODUCTION

The Phase 3 A-LONG study demonstrated the safety and efficacy of rFVIIIFc for the control and prevention of bleeding episodes in severe haemophilia A.

AIM

To describe the treatment of bleeding episodes with rFVIIIFc in the A-LONG study.

METHODS

A-LONG subjects (<1 IU dL^-1 endogenous FVIII) were treated with individualized prophylaxis (Arm 1), weekly prophylaxis (Arm 2) or episodic treatment (Arm 3). Information recorded for each bleeding episode included type, location and dose to treat the episode.

RESULTS

During A-LONG, 757 bleeding episodes occurred during the efficacy period; the majority [456 (60%)] occurred in Arm 3 (episodic treatment). Of 93 subjects in the prophylaxis arms who entered the study with target joints, 43 (60%) in Arm 1 and 11 (52%) in Arm 2 did not experience a target joint bleed. Overall, 98% of bleeding episodes (and 98% of bleeds involving a target joint) resolved with one or two infusions; the median dose per infusion to treat a bleed was 27 IU kg^-1 (27 IU kg^-1 for target joints). Using population pharmacokinetic simulations, FVIII activity levels were predicted to be below the upper limit of normal (150 IU dL^-1 ) in most patients in the event that rFVIIIFc is used to treat a bleeding episode in close proximity to a prophylactic dose.

CONCLUSIONS

These findings demonstrate the efficacy of rFVIIIFc for the treatment of acute bleeding episodes in subjects with severe haemophilia A, regardless of treatment regimen.

Natural history and clinical characteristics of inhibitors in previously treated haemophilia A patients: a case series

BACKGROUND

Development of inhibitors is the most serious complication in haemophilia A treatment. The assessment of risk for inhibitor formation in new or modified factor concentrates is traditionally performed in previously treated patients (PTPs). However, evidence on risk factors for and natural history of inhibitors has been generated mostly in previously untreated patients (PUPs). The purpose of this study was to examine cases of de novo inhibitors in PTPs reported in the scientific literature and to the EUropean HAemophilia Safety Surveillance (EUHASS) programme, and explore determinants and course of inhibitor development.

METHODS

We used a case series study design and developed a case report form to collect patient level data; including detection, inhibitor course, treatment, factor VIII products used and events that may trigger inhibitor development (surgery, vaccination, immune disorders, malignancy, product switch).

RESULTS

We identified 19 publications that reported 38 inhibitor cases and 45 cases from 31 EUHASS centres. Individual patient data were collected for 55/83 (66%) inhibitor cases out of 12 330 patients. The median (range) peak inhibitor titre was 4.4 (0.5-135.0), the proportion of transient inhibitors was 33% and only two cases of 12 undergoing immune tolerance induction failed this treatment. In the two months before inhibitor development, surgery was reported in nine (22%) cases, and high intensity treatment periods reported in seven (17%) cases.

CONCLUSIONS

By studying the largest cohort of inhibitor development in PTPs assembled to date, we showed that inhibitor development in PTPs, is on average, a milder event than in PUPs.

Recombinant factor VIII Fc fusion protein for the prevention and treatment of bleeding in children with severe hemophilia A

BACKGROUND

Prophylactic factor replacement, which prevents hemarthroses and thereby reduces the musculoskeletal disease burden in children with hemophilia A, requires frequent intravenous infusions (three to four times weekly).

OBJECTIVE

Kids A-LONG was a phase 3 open-label study evaluating the safety, efficacy and pharmacokinetics of a longer-acting factor, recombinant factor VIII Fc fusion protein (rFVIIIFc), in previously treated children with severe hemophilia A (endogenous FVIII level of < 1 IU dL(-1) [< 1%]).

METHODS

The study enrolled 71 subjects. The starting rFVIIIFc regimen was twice-weekly prophylaxis (Day 1, 25 IU kg(-1) ; Day 4, 50 IU kg(-1) ); dose (≤ 80 IU kg(-1) ) and dosing interval (≥ 2 days) were adjusted as needed. A subset of subjects had sequential pharmacokinetic evaluations of FVIII and rFVIIIFc. The primary endpoint was development of inhibitors (neutralizing antibodies). Secondary endpoints included pharmacokinetics, annualized bleeding rate (ABR), and number of infusions required to control a bleed.

RESULTS

No subject developed an inhibitor to rFVIIIFc. Adverse events were typical of a pediatric hemophilic population. The rFVIIIFc half-life was prolonged relative to that of FVIII, consistent with observations in adults and adolescents. The median ABR was 1.96 overall, and 0.00 for spontaneous bleeds; 46.4% of subjects reported no bleeding episodes on study. Ninety-three per cent of bleeding episodes were controlled with one to two infusions. The median average weekly rFVIIIFc prophylactic dose was 88.11 IU kg(-1) . At study end, 62 of 69 subjects (90%) were infusing twice weekly. Among subjects who had been previously receiving FVIII prophylaxis, 74% reduced their dosing frequency with rFVIIIFc.

CONCLUSION

Twice-weekly infusions with rFVIIIFc were well tolerated and yielded low bleeding rates in children with severe hemophilia A.

Detailed von Willebrand factor multimer analysis in patients with von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 von Willebrand disease (MCMDM-1VWD)

BACKGROUND

Type 1 von Willebrand disease (VWD) is a congenital bleeding disorder characterized by a partial quantitative deficiency of plasma von Willebrand factor (VWF) in the absence of structural and/or functional VWF defects. Accurate assessment of the quantity and quality of plasma VWF is difficult but is a prerequisite for correct classification.

OBJECTIVE

To evaluate the proportion of misclassification of patients historically diagnosed with type 1 VWD using detailed analysis of the VWF multimer structure.

PATIENTS AND METHODS

Previously diagnosed type 1 VWD families and healthy controls were recruited by 12 expert centers in nine European countries. Phenotypic characterization comprised plasma VWF parameters and multimer analysis using low- and intermediate-resolution gels combined with an optimized visualization system. VWF genotyping was performed in all index cases (ICs).

RESULTS

Abnormal multimers were present in 57 out of 150 ICs; however, only 29 out of these 57 (51%) had VWF ristocetin cofactor to antigen ratio below 0.7. In most cases multimer abnormalities were subtle, and only two cases had a significant loss of the largest multimers.

CONCLUSIONS

Of the cases previously diagnosed as type 1 VWD, 38% showed abnormal multimers. Depending on the classification criteria used, 22 out of these 57 cases (15% of the total cohort) may be reclassified as type 2, emphasizing the requirement for multimer analysis compared with a mere ratio of VWF functional parameters and VWF:Ag. This is further supported by the finding that even slightly aberrant multimers are highly predictive for the presence of VWF mutations.

Impact of plasma von Willebrand factor levels in the diagnosis of type 1 von Willebrand disease: results from a multicenter European study (MCMDM-1VWD)

BACKGROUND

Presence of bleeding symptoms, inheritance and reduced von Willebrand factor (VWF) contribute to the diagnosis of type 1 von Willebrand disease (VWD). However, quantitative analysis of the importance of VWF antigen (VWF:Ag) and ristocetin cofactor activity (VWF:RCo) levels in the diagnosis is lacking.

OBJECTIVES

To evaluate the relative contribution of VWF measurement to the diagnosis of VWD.

PATIENTS AND METHODS

From the MCMDM-1VWD study cohort, 204 subjects (considered as affected by VWD based on the enrolling Center diagnoses and the presence of linkage with the VWF locus) were compared with 1155 normal individuals. Sensitivity, specificity and diagnostic positive likelihood ratios (LR) of VWF:Ag and VWF:RCo were computed.

RESULTS

ABO blood group was the variable most influencing VWF levels, but adjustment of the lower reference limit for the ABO group did not improve sensitivity and specificity of VWF:Ag or VWF:RCo. The lower reference limit (2.5th percentile) was 47 IU dL(-1) for both VWF:Ag and VWF:RCo and showed similar diagnostic performance [receiver-operator curve area: 0.962 and 0.961 for VWF:Ag and VWF:RCo, respectively; P = 0.81]. The probability of VWD was markedly increased only for values below 40 IU dL(-1) (positive LR: 95.1 for VWF:Ag), whereas intermediate values (40 to 60 IU dL(-1)) of VWF only marginally indicated the probability of VWD.

CONCLUSIONS

Although the conventional 2.5 lower percentile has good sensitivity and specificity, only VWF:Ag or VWF:RCo values below 40 IU dL(-1) appear to significantly indicate the likelihood of type 1 VWD. The LR profile of VWF level could be used in a diagnostic algorithm.

A quantitative analysis of bleeding symptoms in type 1 von Willebrand disease: results from a multicenter European study (MCMDM-1 VWD)

BACKGROUND

A quantitative description of bleeding symptoms in type 1 von Willebrand disease (VWD) has never been reported.

OBJECTIVES

The aim was to quantitatively evaluate the severity of bleeding symptoms in type 1 VWD and its correlation with clinical and laboratory features.

PATIENTS AND METHODS

Bleeding symptoms were retrospectively recorded in a European cohort of VWD type 1 families, and for each subject a quantitative bleeding score (BS) was obtained together with phenotypic tests.

RESULTS

A total of 712 subjects belonging to 144 families and 195 controls were available for analysis. The BS was higher in index cases than in affected family members (BS 9 vs. 5, P < 0.0001) and in unaffected family members than in controls (BS 0 vs. -1, P < 0.0001). There was no effect of ABO blood group. BS showed a strong significant inverse relation with either von Willebrand ristocetin cofactor (VWF:RCo), von Willebrand antigen (VWF:Ag) or factor VIII procoagulant activity (FVIII:C) measured at time of enrollment, even after adjustment for age, sex and blood group (P < 0.001 for all the four upper quintiles of BS vs. the first quintile, for either VWF:RCo, VWF:Ag or FVIII:C). Higher BS was related with increasing likelihood of VWD, and a mucocutaneous BS (computed from spontaneous, mucocutaneous symptoms) was strongly associated with bleeding after surgery or tooth extraction.

CONCLUSIONS

Quantitative analysis of bleeding symptoms is potentially useful for a more accurate diagnosis of type 1 VWD and to develop guidelines for its optimal treatment.

Linkage analysis in families diagnosed with type 1 von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 VWD

BACKGROUND

von Willebrand disease (VWD) type 1 is a congenital bleeding disorder caused by genetic defects in the von Willebrand factor (VWF) gene and characterized by a reduction of structurally normal VWF. The diagnosis of type 1 VWD is difficult because of clinical and laboratory variability. Furthermore, inconsistency of linkage between type 1 VWD and the VWF locus has been reported.

OBJECTIVES

To estimate the proportion of type 1 VWD that is linked to the VWF gene.

PATIENTS AND METHODS

Type 1 VWD families and healthy control individuals were recruited. An extensive questionnaire on bleeding symptoms was completed and phenotypic tests were performed. Linkage between VWF gene haplotypes and the diagnosis of type 1 VWD, the plasma levels of VWF and the severity of bleeding symptoms was analyzed.

RESULTS

Segregation analysis in 143 families diagnosed with type 1 VWD fitted a model of autosomal dominant inheritance. Linkage analysis under heterogeneity resulted in a summed lod score of 23.2 with an estimated proportion of linkage of 0.70. After exclusion of families with abnormal multimer patterns the linkage proportion was 0.46. LOD scores and linkage proportions were higher in families with more severe phenotypes and with phenotypes suggestive of qualitative VWF defects. About 40% of the total variation of VWF antigen could be attributed to the VWF gene.

CONCLUSIONS

We conclude that the diagnosis of type 1 VWD is linked to the VWF gene in about 70% of families, however after exclusion of qualitative defects this is about 50%.

Correction of both prothrombin time and primary haemostasis by recombinant factor VII during therapeutic alcohol injection of hepatocellular cancer in liver cirrhosis

We evaluated the efficacy of recombinant factor VII to correct impaired haemostasis in a patient with liver cirrhosis requiring an invasive procedure. A test intravenous bolus of 80 microg/kg of recombinant factor VII was given to a Jehovah's Witness, with a solitary 4.4-cm hepatocellular carcinoma and underlying hepatitis C virus cirrhosis, in an attempt to correct his haemostatic disorders and safely inject the tumour with alcohol. An extensive portal block had precluded consideration of liver transplantation. Haemostasis was evaluated by clotting assays, bleeding time and thromboelastography 10 min before and 10 min and 1, 2, 4, 8 and 24 h after factor VII infusion. Parameters of both coagulation (prothrombin time) and platelet function (bleeding time and the alpha and ma parameters of thrombelastography) were improved 10 min after factor VII infusion; improvements lasted 4 to 8 h or more. Platelet count did not change and there was no evidence of disseminated intravascular coagulation. The improvements in haemostatic parameters correlated significantly with the increases in factor VII plasma concentrations (p<0.04). Factor VII clearance was 25.1 U/h/kg and its half-life was 5.8 h. The same dose of recombinant factor VII was given to the patient 1 week later, just before the alcohol injections. The patient had no subsequent bleeding or other complication, with no change in haemoglobin levels over 24 h. Thus, recombinant factor VII represents a therapeutic advance, as it can correct fully both coagulation and platelet function defects in cirrhosis and allow invasive procedures to be performed safely.

Performance of the platelet function analyser PFA-100 in testing abnormalities of primary haemostasis

The PFA-100 device is a new instrument for the in-vitro testing of platelet function. Primary haemostasis is stimulated by recording the closure time taken for platelets to seal a 150 microm aperture in the centre of a membrane coated with collagen and either epinephrine or ADP. Patients with type 3 von Willebrand's disease (n = 4) all had infinitely prolonged closure times (> 200 s) with both types of cartridge. A patient with afibrinogenemia exhibited only slightly prolonged closure times of 111 and 166 s for the ADP and epinephrine membranes, respectively. Patients with Glanzmann's thrombasthenia (n = 6) and Bernard Soulier syndrome (n = 2) had grossly prolonged closure times (> 200 s) with both types of cartridges. These results confirmed that the PFA-100 system was highly dependent on normal von Willebrand factor, glycoprotein Ib and glycoprotein IIb/IIIa levels but not on plasma fibrinogen. Patients with storage pool disease (n = 6) and Hermansky Pudlak syndrome (n = 7) had prolonged closure times with the epinephrine cartridge. There was no evidence of enhanced platelet function in patients with antiphospholipid syndrome, in sickle-cell disease or thalassemia. However, ingestion of aspirin resulted in a near consistent and significant prolongation of the closure time for the epinephrine cartridge but not for the ADP cartridge in both normal subjects and patients. The test offers a reliable, reproducible, rapid and simple means of assessing high-shear platelet function in vitro.

Experiences with continuous infusion of recombinant activated factor VII

A questionnaire was sent to 28 haemophilia treatment centres known to have used recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark), to collect data on continuous infusion of this product. This mode of administration was recently introduced for rFVIIa but there are several questions which remain to be answered in order to optimize this technique. Of the 26 responding centres, 14 had used rFVIIa in continuous infusion for 40 treatment episodes over a total of 283 days. In most of the cases the treatment was targeted at a factor VII level of 10 IU/ml, monitored by the one-stage clotting assay. This seemed to be adequate for most of the haemorrhagic and surgical procedures. Pretreatment pharmacokinetic evaluation was performed in only a minority of the cases but is probably of great importance given the wide variation observed in the clearance values. A strategy was necessary to prevent local thrombophlebitis, at least for infusions in peripheral veins; parallel infusion of heparin, saline or dextrose-saline proved effective. The question of optimal monitoring needs further attention. Haemorrhagic complications were significantly less frequent when treatment was combined with the antifibrinolytic tranexamic acid.

Hypercoagulability in patients with primary biliary cirrhosis and primary sclerosing cholangitis evaluated by thrombelastography

BACKGROUND/AIMS

Patients with primary biliary cirrhosis and primary sclerosing cholangitis survive variceal bleeding better than patients with alcoholic cirrhosis and have less bleeding at liver transplantation. Recently, patients with primary biliary cirrhosis have been found to have a higher incidence of thrombosis in the portal venous tree. We hypothesized that primary biliary cirrhosis and primary sclerosing cholangitis patients may be hypercoagulable.

METHODS

We used thrombelastography, which is a simple technique for evaluating whole blood clotting and fibrinolysis, to establish if hypercoagulability was present, defined by thrombelastography values greater than 2SD over controls: r<19 mm (this reflects plasma clotting factors), maximum amplitude (ma) >60 mm, and alpha angle >43 degrees (these reflect platelets and fibrinogen levels). We evaluated 47 primary biliary cirrhosis and 21 primary sclerosing cholangitis patients, 40 with non-cholestatic cirrhosis and 40 healthy subjects as control groups with thrombelastography, full blood count, prothrombin time, partial thromboplastin time and, fibrinogen concentrations. In those with hypercoagulability we evaluated protein S, C, anti-thrombin III levels and activated protein C phenotype.

RESULTS

All three thrombelastography abnormalities present together defined hypercoagulability: these were found in 13 of 47 (28%) primary biliary cirrhosis and in nine of 21 (43%) primary sclerosing cholangitis patients independent of cirrhosis, and bilirubin concentration, but in only 2 of 40 (5%) patients with noncholestatic cirrhosis and in none of the healthy controls (p<0.03 and p<0.0002, respectively). There was no correlation between the fibrinogen concentration (which was normal in all patients) or platelet count and the thrombelastography parameters. Only six of the 22 hypercoagulable patients had lower than normal values of protein S, C or antithrombin III. Activated protein C phenotype was normal in all.

CONCLUSIONS

This diffference between biliary and parenchymal liver disease may have clinical implications, which need to be defined.

Membranous obstruction of the inferior vena cava in a patient with factor V Leiden: evidence for a post-thrombotic aetiology

BACKGROUND

Membranous obstruction of the inferior vena cava is a rare cause of hepatic venous outflow obstruction in Caucasians. There has been much debate in the literature about its aetiology.

METHODS AND RESULTS

We describe a Caucasian with hepatic venous outflow obstruction due to an inferior vena cava web, who was found to have hypercoagulability due to factor V Leiden. Following balloon rupture of the membrane and anticoagulation, his symptoms resolved and he has remained well for a year.

CONCLUSIONS

The age at presentation in this patient, the presence of hypercoagulability and the excellent response to membrane rupture and anticoagulation suggest that in this case the membrane may have been derived from organised thrombus. Balloon rupture of the membrane and anticoagulation appears to be an effective treatment in such cases.

Factor IX inhibitors and anaphylaxis in hemophilia B

PURPOSE

We present clinical and laboratory data on 18 children from 12 hemophilia treatment centers in the United States, Canada, and Europe with the purpose of disseminating information regarding a recently recognized, potentially life-threatening complication of treatment in very young children with hemophilia B.

PATIENTS AND METHODS

Twelve hemophilia centers from the United States, Canada, and Europe provided clinical information and laboratory data concerning 18 children who had severe allergic reactions to infused factor (F) IX in close association with the development of an inhibitor to FIX. Laboratory testing for establishment of the diagnosis of hemophilia B and inhibitor to FIX was done locally at the centers treating these patients. FIX gene analysis was performed at one of six molecular genetics institutes.

RESULTS

All 18 children had severe hemophilia B, and in each an inhibitor antibody to FIX developed. The median age at the time of anaphylaxis (or anaphylactoid reaction) was 16 months, and the median number of exposure days to FIX was 11. The FIX inhibitor was detected almost simultaneously with the first occurrence of anaphylaxis in 12 of 18 patients. Maximum inhibitor titers were 4.5-600 Bethesda units (BU), with a median titer of 48 BU. FIX gene analysis, performed in 17 of 18 patients, demonstrated complete deletion of the FIX gene in 10 and major derangements in seven. Immune tolerance induction (ITI) regimens have been attempted in 12 patients, with generally poor responses. Two of the 12 experienced nephrotic syndrome while on ITI. Recombinant FVIIa has been successfully used to treat bleeding episodes in 11 of these children.

CONCLUSION

Physicians treating young children with hemophilia B should be aware of the potentially life-threatening complication of anaphylaxis. Children with complete gene deletions or major derangements of the FIX gene appear to be at greater risk. Those identified by genotype as being at greater risk may need to receive their first 10-20 treatments in a medical facility equipped for handling such emergencies. Recombinant FVIIa, although not licensed for use in the United States, appears to be the most suitable treatment option for bleeding episodes in such patients.

Pharmacokinetic in vivo comparison using 1-stage and chromogenic substrate assays with two formulations of Hemofil-M

In a study to demonstrate the safety and pharmacokinetics (half-life and recovery) of two different method M purified AHF (Hemofil-M) concentrates processed in the USA and Spain, two different methods of factor VIII assay (one-stage clotting and chromogenic) have been compared in vivo. The study was a single centre blinded, randomised, crossover study. Twelve patients with severe haemophilia A (VIII:C < 2 u/dl) were divided into two subgroups of six. None had received factor VIII concentrate within 48 h preceding the study. Twenty-four pharmacokinetic studies were performed in the 12 patients. Each subgroup received two different lots of study material (US and Spanish) at a dose of 50 u/kg seven days apart. A second randomisation was nominal potency, high: 1000 u or mid: 500 u per vial. The potency label was a one-stage clotting assay using the mega I standard. A standard pharmacokinetic study was performed over 24 h and each blinded sample was analysed in duplicate by a one-stage clotting (aPTT) and a chromogenic (Chromogenix AB; CS) assay at the Royal Free and NIBSC. Pharmacokinetic modelling was performed. The mean label for Hemofil-M using the chromogenic substrate assay was 79% that using the one stage assay (Mega I standard). The recovery was 17-28% higher measured by chromogenic compared to the clotting assay. Since most clinicians use the clotting assay, potency labelling using the chromogenic assay, will overestimate predicted Hemofil-M recovery by as much as 25%.

Acute Budd-Chiari syndrome treated by liver transplantation in a woman homozygous for factor V Leiden

We describe the first case of Budd-Chiari syndrome due to homozygosity for factor V Leiden resulting in resistance to activated protein C. This is now recognized as the most common procoagulant disorder, and may account for many cases of Budd-Chiari syndrome previously though to be idiopathic or due to a latent myeloproliferative disorder. A further unique feature of this case is that the patient required orthotopic liver transplantation following failure of portacaval shunting and progressive hepatic necrosis. We demonstrated that liver transplantation resulted in correction of the serum coagulation abnormality; however, it is unlikely to have cured the disorder as platelet factor V would still be of the Leiden phenotype.

The use of intermediate-purity clotting factor concentrates and HIV disease progression in men with haemophilia

On the basis of evidence from the immune systems of patients with haemophilia infected with HIV, patients in the UK have been switched to high-purity clotting factor concentrates. However, there is very little information currently available on the effect of intermediate-purity clotting factor concentrates on progression of HIV disease. Among 99 HIV-positive men with severe factor VIII deficiency registered at The Royal Free Hospital Haemophilia Centre, a 100 IU kg(-1) increase in the yearly amount of concentrate received did not appear to be associated with more rapid progression to AIDS, death or to a low CD4 count. However, the use of total concentrate usage may mask a more subtle effect of specific concentrate contaminants on the progression of HIV disease.

A comparison of factor VIII infusion methods

This paper describes a case study approach to evaluating practice. It compares two different methods of factor VIII infusion for a patient with haemophilia who underwent two orthopaedic operations.

CD4+ counts before and after switching to monoclonal high-purity factor VIII concentrate in HIV-infected haemophilic patients

Allogenic proteins that contaminate intermediate purity clotting factor concentrates may activate the immune system of HIV-infected haemophilic patients. In 37 haemophilic patients infected with HIV who had originally been treated with intermediate purity factor VIII concentrate and then changed to monoclonally-purified high purity factor VIII concentrate the rates of CD4+ decline (10(9)/l per year) were 0.06 before and 0.02 after a switch to high purity products (p = 0.01). The median follow-up of patients after the switch to high purity products was 1.7 years (range 0.2 to 3 years). This significant change in the rate of CD4 decline was independent of the starting CD4 count, age and antiretroviral therapy. This result is consistent with those from randomised trials of the introduction of high-purity concentrate. Given the strong association between the CD4+ count and survival, treatment with high purity rather than intermediate purity clotting factor concentrate may confer a survival benefit for HIV-infected haemophilic patients.

Cytolytic T-cell activity against mycobacterial antigens in HIV

OBJECTIVES

The declining incidence of tuberculosis (TB) in developed countries has recently been reversed with the advent of HIV disease. This study proposes to document in vitro T-cell responses to mycobacterial antigens in HIV-infected individuals.

DESIGN

T-cell-mediated immunity is recognized as one of the mechanisms of defence against TB. The cellular immunodeficiency and the importance of TB in the context of HIV disease has prompted use of in vitro assays of lymphocyte proliferation and cytolytic activity.

METHODS

Peripheral blood mononuclear cells isolated from 29 HIV-infected patients (four with recent TB) and 11 healthy volunteers were stimulated with purified protein derivative (PPD). The responding blasts were presented to autologous antigen-primed macrophages to measure specific cytolytic T-lymphocyte (CTL) activity in vitro.

RESULTS

T-cell proliferative responses were significantly lower in late stages of HIV disease. The degree of specific CTL activity was higher in healthy individuals than in Centers for Disease Control (CDC) stage II-III (P = 0.037), and CDC stage IV patients (P = 0.029).

CONCLUSIONS

The clinical presentation of TB tends to be typical in early stages of HIV disease and atypical in late stages. The manifestations reflect the degree of immunodepression. This study documents the declining proliferative and cytolytic T-cell-mediated responses in HIV patients with progression of immunodeficiency.

The effects of verapamil, diltiazem, nifedipine and propranolol on metabolic control in hypertensives with non-insulin dependent diabetes mellitus

The effects of one month's treatment with each of nifedipine, verapamil, diltiazem, propranolol and placebo, given in random order, on fasting plasma glucose, haemoglobin Alc, serum fructosamine, immunoreactive insulin, cholesterol, and triglyceride were studied in a group of 19 patients with hypertension and non-insulin dependent diabetes mellitus. The metabolic effects of the active drugs were generally small but fasting plasma glucose was increased by propranolol from 9.3 +/- 3.0 to 10.4 +/- 3.4 mmol/l (P less than 0.01) (mean +/- SD) and to 10.1 +/- 3.2 mmol/l (P less than 0.05) by nifedipine. Serum fructosamine was increased from 2.75 +/- 0.53 to 2.89 +/- 0.62 mmol/l (P less than 0.05) by diltiazem and to 2.91 +/- 0.65 (P less than 0.05) by propranolol. Verapamil increased fasting serum immunoreactive insulin: diltiazem and propranolol tended to reduce it. Propranolol but not the other drugs significantly increased serum triglyceride. Calcium antagonists may be preferable to beta adrenoceptor blockers for the treatment of hypertensive diabetics. Of the three calcium antagonists we studied, verapamil may have advantages over nifedipine and diltiazem.