Anti-factor VIII antibodies in brothers with haemophilia A share similar characteristics.

INTRODUCTION: The development of neutralizing antibodies (inhibitors) against coagulation factor VIII (FVIII) is currently the most serious complication for patients with haemophilia A undergoing FVIII replacement therapy. Several genetic factors have been acknowledged as risk factors for inhibitor development. AIM: To analyze the influence of genetic factors on the nature of the humoral immune response to FVIII in eight brother pairs with inhibitors. METHODS: The domain specificity of FVIII-specific IgG was analysed by antibody binding to FVIII fragments and homologue-scanning mutagenesis (HSM). The FVIII-specific IgG subclasses were measured by direct ELISA. RESULTS: Of the 16 patient analysed with both methods, 12 had A2- and 13 had C2-specific IgG. The presence of A1-, A3- or C1-specific IgG was identified in nine of 14 patients analysed by HSM. IgG1, IgG2 and IgG4 subclasses contributed to the anti-FVIII IgG response, and the amount of FVIII-specific IgG1 (r = 0.66) and IgG4 (r = 0.69) correlated significantly with inhibitor titres. Patients with high concentrations of total anti-FVIII IgG (r = 0.69) or high inhibitor titres (r = 0.52) had a high proportion of FVIII-specific IgG4. Statistical analysis revealed trends/evidence that the subclass distribution (P = 0.0847) and domain specificity to HC/LC (P = 0.0883) and A2/C2 (P = 0.0011) of anti-FVIII IgG were more similar in brothers compared to unrelated subjects. CONCLUSION: Overall, our data provide a first hint that anti-FVIII IgG characteristics are comparable among haemophilic brothers with inhibitors. Whether genetic factors also influence the nature of patients' antibodies needs to be confirmed in a larger study population.

F8 haplotype and inhibitor risk: results from the Hemophilia Inhibitor Genetics Study (HIGS) Combined Cohort.

Ancestral background, specifically African descent, confers higher risk for development of inhibitory antibodies to factor VIII (FVIII) in haemophilia A. It has been suggested that differences in the distribution of FVIII gene (F8) haplotypes, and mismatch between endogenous F8 haplotypes and those comprising products used for treatment could contribute to risk. Data from the Hemophilia Inhibitor Genetics Study (HIGS) Combined Cohort were used to determine the association between F8 haplotype 3 (H3) vs. haplotypes 1 and 2 (H1 + H2) and inhibitor risk among individuals of genetically determined African descent. Other variables known to affect inhibitor risk including type of F8 mutation and human leucocyte antigen (HLA) were included in the analysis. A second research question regarding risk related to mismatch in endogenous F8 haplotype and recombinant FVIII products used for treatment was addressed. Haplotype 3 was associated with higher inhibitor risk among those genetically identified (N = 49) as of African ancestry, but the association did not remain significant after adjustment for F8 mutation type and the HLA variables. Among subjects of all racial ancestries enrolled in HIGS who reported early use of recombinant products (N = 223), mismatch in endogenous haplotype and the FVIII proteins constituting the products used did not confer greater risk for inhibitor development. Haplotype 3 was not an independent predictor of inhibitor risk. Furthermore, our findings did not support a higher risk of inhibitors in the presence of a haplotype mismatch between the FVIII molecule infused and that of the individual.

Extended IL10 haplotypes and their association with HIV progression to AIDS.

Interleukin-10 (IL-10) is a pleiotropic cytokine with both immunosuppressive and immunostimulatory functions. Its roles in infections and autoimmunity may have resulted in selective pressures on polymorphisms within the gene, leading to genomic coexistence of several semi-conserved haplotypes involved with diverse pathogen interactions during genomic evolution. Previous studies focused either exclusively on promoter haplotypes or on individual SNPs. We genotyped 21 single nucleotide polymorphisms in the human IL10 gene and examined this variation compared to other mammalian species sequences. Haplotype heterogeneity in human populations is centered around 'classic' 'proximal' promoter polymorphisms: -592, -819 and -1082. High-producing GCC haplotypes are by far the most numerous and diverse group, the intermediate IL-10 producing ACC-inclusive haplotypes seem to be related most closely to the ancestral haplotype, and the ATA-inclusive haplotypes cluster a separate branch with strong bootstrap support. We looked at associations of corresponding haplotypes with HIV progression. A haplotype trend regression confirmed that individuals carrying the low-producing ATA-inclusive haplotypes in European Americans progress to AIDS faster, and most likely explain the role of IL10. Our findings are consistent with the hypothesis that existing polymorphisms in this gene may reflect a balance of historic adaptive responses to autoimmune, infectious and other disease agents.

Value added: increasing the power to assess treatment outcome in joint haemorrhages.

Subject reports of efficacy of treatment of haemophilia-related joint bleeding are by definition subjective, yet are often the primary outcome in studies comparing therapies. Verbal descriptors such as effective, partially effective, poorly effective, not effective are treated as dichotomous or categorical variables in analyses, lowering the statistical power relative to that which might be achieved with a continuous variable. The aims of this study were to examine reports of pain recorded on a 100-mm visual analogue scale (VAS) during the course of joint bleeding; determine whether pain varied by treatment period among pairs reporting discordant outcomes on a verbal scale (one product effective, the other not effective); test whether the two products under study were equivalent with respect to VAS scores; and evaluate their relationship to verbal reports of efficacy. Data from the international, prospective, randomized, crossover FEIBA NovoSeven Comparative study of two bypassing agents used for treatment of 96 bleeding episodes in 48 participants were examined. VAS scores were associated with verbal descriptors of efficacy at every time point, and were equivalent between treatment periods. There were differences in mean scores at time points at which participants rated one treatment effective, the other not effective. As a continuous variable, the VAS score may have more power than a dichotomous variable and when used with verbal descriptions of efficacy can improve the overall accuracy of assessment. This report highlights an important consideration in the selection of outcome measurement that can be generalized to other haemophilia treatment research.

Physical activity by socioeconomic status in two population based cohorts.

In the current study, we examined physical activity in two population based cohorts of Allegheny County. Pennsylvania, which differed markedly in their socioeconomic status (SES), in order to evaluate the relationship of SES to physical activity patterns. A total of 917 individuals participated in a prevalence survey administered during a home visit in 1981. All of the participants were white. Households were randomly selected. An overall response rate of 84% was achieved. Activity was assessed using the Paffenbarger survey, which included the number of blocks walked, stairs climbed, sports and recreational activities, and hours spent in vigorous, moderate, and light activities. In both high and low SES individuals, activity was inversely associated with age and was higher in males than in females. The relationship of physical activity to SES differed depending on the dimension of activity assessed. Participation in sports was reported more frequently in high status males and females. SES was a significant predictor of walking activity in females, with low status females reporting more walking. The number of hours spent in moderate activities was greater, but the number of hours spent in light activities was lower, in low status males. There was little difference by SES in the composite activity score, average annual kilocalories per week. In summary, our research suggests that SES can impinge differently on separate manifestations of activity, and future research needs to identify how SES affects activity.

Long-term major joint outcomes in young adults with haemophilia: interim data from the HGDS.

A study of major joint outcomes, specifically range of motion and synovitis, was conducted with data from a subset of adolescents enrolled in the prospective Hemophilia Growth and Development Study (HGDS). Clinical observations were carried out over a 7-year period from 1989 to 1996. A secondary aim was to gain insight into factors that might influence decisions regarding maintaining or discontinuing prophylaxis during early adulthood. Twenty-nine participants (median age 17.4 at entry) were included. Median follow-up was 7 years (range: 4.8-7.7). Range of motion (ROM) and synovitis in six major joints (knees, elbows and ankles), were evaluated by physical examination every 6-12 months. At the baseline observation, 73.6% of joints showed no ROM abnormalities or synovitis, and all joints were normal in 11 patients. Of the 11 participants, 54.5% developed abnormalities and 28.1% of normal joints at baseline became abnormal during the follow-up. Ankles were the most severely affected and had persistent progression during late adolescence and adulthood. Elbows and knees did not show progression after the first few years of the follow-up. The progression of haemophilic arthropathy in adolescents and young adults varies from individual to individual and also in the site of affected joints. In view of this, the decision regarding discontinuation of prophylaxis in patients with haemophilia should be individualized.

Hepatitis C virus infection and neurocognitive function.

Hepatitis C virus (HCV) infection may be associated with neurocognitive deficits. The Hemophilia Growth and Development Study enrolled HIV-infected and HIV-uninfected patients and a group of nonhemophiliac siblings. After controlling for multiple factors, HCV monoinfection was not associated with deficits in adaptive behavior, intelligence, or attention/concentration.

Single nucleotide polymorphisms and haplotypes in the IL10 region associated with HCV clearance.

Hepatitis C virus (HCV) is an infectious blood-borne pathogen that usually persists as a chronic infection. However, approximately 15% of the time, patients can clear the virus, indicating that host differences could be critical in determining the course of HCV infection. The inflammatory response is crucial to resolving or failing to resolve an acute HCV infection. Some previous reports have implicated interleukin 10 (IL10) polymorphisms with successful anti-HCV therapy and natural viral clearance. We tested 54 single nucleotide polymorphisms (SNPs) in the IL10 region (+/-300 kb and 24 within the IL10 gene itself), which contains 13 genes including the IL10 immunomodulatory paralogs IL19, IL20, and IL24, for association with HCV clearance vs persistence. SNPs from two haplotype block regions, one at IL10 and the other from IL19/IL20, were associated with HCV clearance in African Americans (91 clearance cases and 183 chronically infected matched controls; P=0.05-0.002) while with expectation-maximization algorithm-reconstructed haplotypes, these associations remained (P=0.05-0.002). However, no significant associations were detected in European Americans (108 clearance and 245 chronic). Our results indicate that variants of the immunomodulatory IL10 and IL19/IL20 genes may be involved in natural clearance of HCV in the African-American population.

Growth hormone secretion in HIV-positive versus HIV-negative hemophilic males with abnormal growth and pubertal development. The Hemophilia Growth and Development Study.

UNLABELLED: Growth and pubertal development in hemophilic males, age 6-19 years at baseline, were evaluated over a 3.5-year period in 207 HIV-positive and 126 HIV-negative subjects as part of the Hemophilia Growth and Development Study. METHODS: Thyroid function, insulin-like growth factor I (IGF-1) levels, bone age, cranial magnetic resonance image normality, CD4+ counts, and serum testosterone levels of study participants were measured at baseline. An extensive endocrine evaluation was performed in subjects who demonstrated declines in height for age (measurement <5th percentile with two pervious heights >10th percentile), who had not achieved Tanner stage 4 level of pubertal development by age 15 years or who had abnormal growth velocity, which included assessment of peak stimulated growth hormone response after clonidine stimulation, 12-hour growth hormone profiles, and serum beta carotene levels (triggered protocol). RESULTS: For almost the entire group (-99%), thyroid function tests were normal for age. IGF-1 levels were normal for 93% of the cohort. A total of 120 subjects, 89 HIV-positive and 31 HIV-negative, had an abnormality of growth, pubertal development, or both; 34 (11.1%) HIV-positive and 4 (3.6%) HIV-negative subjects had declines in height (p = .001), 20 (23.3%) HIV-positive and 5 (15.8%) HIV-negative subjects had not achieved Tanner stage 4 by 15 years of age (p = .372) and 59 (43.4%) HIV-positive and 23 (25.6) HIV-negative subjects had abnormal growth velocity (p < 0.001). Among subjects with abnormal height or growth velocity, the HIV-positive group had significantly lower mean age-adjusted testosterone levels than did the HIV-negative group (p = .030). Within the HIV-positive group, older subjects with abnormal height or growth velocity had significantly lower mean bone age than subjects of similar age without growth abnormalities (p = .0092). Extensive testing was done in 39 patients (32 HIV-positive, 7 HIV-negative). Half of the HIV-positive subjects had mean 12-hour growth hormone levels <3 ng/ml, 47% had peak stimulated levels <10 ng/ml, 28% had peak spontaneous values <10 ng/ml, and 38% had low levels of IGF-1. In the HIV-positive cohort, there was no difference in the rate of abnormalities of growth hormone secretion between those with CD4+ counts > or = or <200 cells/mm3 and between those subjects that met the 1987 Centers for Disease Control (CDC) surveillance definition of AIDS. In the subset of HIV-positive patients with abnormal peak growth hormone levels after clonidine stimulation, growth hormone response correlated positively with CD4+ count (r = .657, p = .0056) and beta carotene concentration (R = .596, p = .0192). CONCLUSIONS: The results of this longitudinal study suggest that abnormalities of growth and pubertal development, particularly an abnormal growth velocity, are common in HIV-infected hemophilic boys and adolescents. These abnormalities might serve as indicators of the presence of HIV infection in this at-risk population. Since thyroid function tests and IGF-1 levels were normal, the etiology of growth impairment in HIV infection does not appear to be secondary to inadequate caloric intake or acquisition, or severe illness such as that caused by recurrent or persistent infection. Rather, HIV infection appears to lead to diminished growth hormone production or release and decreased androgen secretion, even before the development of AIDS and immunocompromise. These results provide a rationale for trials of treatment with growth hormone or androgens in patients with abnormalities of endocrine function.

HIV-associated immune dysfunction and delayed pubertal development in a cohort of young hemophiliacs. Hemophilia Growth and Development Study.

As part of the Hemophilia Growth and Development Study (HGDS), we investigated the relationship between HIV-associated immune dysfunction and delayed pubertal development in a cohort of 333 boys and adolescents with moderate or severe hemophilia who were between the ages of 6 and 19 years at study entry in 1989. Sixty-two percent of the cohort was infected with HIV in the late 1970s and early 1980s through exposure to contaminated clotting factor concentrates. The cohort was observed during follow-up at 6-month intervals; measurements taken at each follow-up visit included Tanner stage and CD4+ cell count. This analysis of data from the first 4 years of follow-up revealed statistically significant delays in pubertal development associated with increasing levels of immune dysfunction. Our results emphasize the importance of following pubertal development in HIV-infected adolescent boys since delays in maturation may reflect underlying disease progression.

Frequency and causes of hospitalization in HIV-negative children and adolescents with haemophilia A or B and its effect on academic achievement.

The aim of the study is to determine the causes and frequency of hospitalization in HIV-negative boys and adolescents with haemophilia and evaluate their impact on academic achievement. One hundred and twenty-six HIV-negative boys and adolescents were followed prospectively from 1989-96, at 14 comprehensive haemophilia treatment centres. One hundred and fifteen participants with haemophilia A or B were included in the investigation. These participants contributed an average of 57.8 months of follow-up. There were 203 hospitalizations in 65 participants and 50 participants were never hospitalized. Haemarthroses and soft tissue bleeds accounted for 46 and 44 causes of hospitalization. Central line infection was the third most common cause. Participants with inhibitor had the majority of central line infections and hospitalizations. Intracranial haemorrhage resulted in five hospitalizations in two participants. Other causes of bleeding accounted for 22% of hospitalizations. The median number of hospitalizations per year was 0.18. Duration of hospital stay was significantly related to lower spelling scores. Acute and chronic joint problems and soft tissue bleeds still account for the majority of hospitalizations. Positive inhibitor status was associated with higher numbers of hospitalizations and central line infections. Academic achievement was affected, to some degree, by length of hospital stay.

Evidence for a shift from a type I lymphocyte pattern with HIV disease progression. Hemophilia Growth and Development Study.

Whether a shift from a type I (cell mediated) immune profile occurs with progressive HIV-related immune dysfunction is a matter of heated debate. We analyzed data for 333 HIV antibody-positive (HIV+) and -negative (HIV-) hemophilic children/adolescents, to examine whether the relationships among immunologic parameters and vaccine-related serology supported a shift with advancing HIV infection. In stepwise logistic regression analysis of HIV+ children's data, anergy to a panel of delayed hypersensitivity skin test antigens was positively associated with serum immunoglobulin A (IgA) levels (p = 0.012) and CD8+ cell counts (p = 0.021) and negatively associated with CD4+ cell counts (p = 0.002). Modeling supported anergy as a positive correlate of log IgA level (p = 0.046) and CD4+ lymphocyte count as a negative correlate, for HIV+ participants only (p < 0.0001). For mumps, the proportion of vaccinated HIV+ participants with protective IgG antibody titers was higher among those with CD4+ lymphocyte counts < 200 cells/mm3 (p = 0.058). For HIV+ participants < 14 years of age, this same trend was seen for measles and rubella, but was not seen in any age group for bacterial vaccine antigens. The intercorrelations among skin test anergy, CD4+ lymphocyte counts, serum IgA levels, and viral vaccine antigen-related serologic titers for HIV+ participants are consistent with an association between progressive HIV-related immune dysfunction and a predominance of type II (humoral immunity) or Type 0 (mixed immunity), relative to type I, lymphocyte profiles.

Changes in hepatitis B serologic titers in HIV+ and HIV- children with haemophilia.

This longitudinal study examines differences in hepatitis B immune titres in children and adolescents with haemophilia to determine if they are dependent on how immunity was acquired (vaccination or natural infection), and whether they are related to the child's HIV status and/or are influenced by HIV disease progression. Serologic titres (HBcAb, HBsAb) and HBsAg were measured prospectively at baseline, and at years 1, 2 and 3 of follow-up in 126 HIV- and 207 HIV+ children and adolescents with haemophilia. Analyses were performed to assess the impact of HIV status on the measured titres, and for HIV+ subjects to examine the association with CD4+ lymphocyte counts and p24 antigen status. The results show that HIV+ children were more likely than HIV- children to lose vaccine-induced immunity as indicated by the loss of HBsAb. There was an increased risk of losing HBsAb with higher CD4+ counts and younger age. Re-immunization was not successful in seven of eight HIV+ children. Two subjects (one HIV+, one HIV-) entered the study HBsAg- but became HBsAg+ over the course of follow-up. Seven HIV+ subjects lost natural immunity as indicated by the loss of HBcAb. The loss of either HBsAb or HBcAb in HIV--subjects was negligible to absent. In conclusion, because of the loss of immunity in HIV+ children the viral safety of factor replacement concentrates for these children is an important consideration. HIV- children rarely lose immunity, therefore frequent measures of HBsAb are not necessary.

Surveillance of infectious complications associated with central venous access devices in children with haemophilia.

PURPOSE: To analyse the risk factors for infection associated with central venous access device (CVAD) use in children with haemophilia. METHODS: Risk factors for CVAD infection among patients with congenital haemophilia who had had a CVAD implanted at a single institution were evaluated utilizing the following variables: age at CVAD placement, age at end of study, number of days with a CVAD, percentage of lifetime with a CVAD, and history of inhibitor. RESULTS: Fifty-nine patients had a total of 97,936 (median 1768 days per patient) CVAD days in the study period. The median age at CVAD placement was 2.7 years (range 0-14.0). Twenty-six (44%) patients reported CVAD infections during the study period from January 1993 to October 2000. Twenty-four patients had their CVAD replaced, 17 (71%) of whom reported having infections and seven (29%) of whom had a history of inhibitor. The strongest predictor for having any infections was inhibitor status (P=0.16), although none of the risk factors had statistically significant effects. Among the 26 patients reporting infections, 42% had more than one CVAD-related infection. Seven patients had multiple infections involving the same organism. The mean rate of infection was 0.45 per 1000 catheter days, with a 95% confidence interval of 0.33-0.60. Those with a history of inhibitor had an infection rate of 0.66 compared with 0.38 per 1000 catheter days (P=0.09) for those without a history of inhibitor. Patients who were older (greater than the median age of 2.7) at CVAD placement had a lower rate of infection (0.29 vs. 0.65, P<0.01) compared with those < or =2.7 years. Adjustment for inhibitor status had little impact on these results. For the group as a whole, the median time to first infection was 1977 days from CVAD placement. Patients who were older at CVAD placement or study exit had lower relative hazards of infection (P=0.05 and P=0.09 respectively), while those who had inhibitors had a higher but not statistically significant relative hazard of 1.88 (P=0.13). CONCLUSIONS: These data reveal that while considerable numbers of patients develop CVAD-related infection, the interval between catheter placement and infection can be quite long. In addition, the earlier in life a CVAD is placed, the higher the risk of infectious complications, as evidenced by the tendency towards a higher infection rate. Measures to prevent CVAD-related infection might be focused on very young patients who appear to be at higher risk.

Hemophilia morbidity, cognitive functioning, and academic achievement.

Data from the Hemophilia Growth and Development Study (HGDS) were used to evaluate the association between hemophilia morbidity, measured by abnormalities in coordination and gait (CG), and intellectual ability and academic achievement. The CG abnormalities observed in the HGDS participants (n = 333) were primarily due to hemophilia-related morbidity. Although HGDS participants performed within the average range for age on measures of intellectual ability, there were meaningful differences between CG outcomes at baseline and throughout the 4 years of study. Participants without CG abnormalities consistently achieved higher scores than those with CG abnormalities on Reading, Spelling, and Arithmetic subtests of the Wide Range Achievement Test-Revised. Our findings suggest that lowered achievement is related to the functional severity of hemophilia.

Response to measles, mumps, and rubella revaccination among HIV-positive and HIV-negative children and adolescents with hemophilia. Hemophilia Growth and Development Study.

The effect of human immunodeficiency virus (HIV) infection on response to measles, mumps, and rubella revaccination in children and adolescents with hemophilia was evaluated. Antibody levels of measles, mumps, and rubella were assayed at baseline and two annual examinations in 207 HIV-positive and 126 HIV-negative hemophiliacs participating in the Hemophilia Growth and Development Study (HGDS). Response to revaccination was analyzed for participants whose antibody levels were below the cut-off at the start of a year-long observation period. Among HIV-positive participants, antibody levels were below cut-off in 52 subjects for measles, in 71 for mumps, and in 96 for rubella. Among HIV-negative participants, antibody levels were low in 23 subjects for measles, in 23 for mumps, and in 31 for rubella. For measles and mumps antigens, revaccination was associated with a significant increase in redraw antibody levels for HIV-negative participants. Although there was an increase in the mean measles titers for revaccinated HIV-positive participants, it was not significant. Revaccination was associated with an increase in rubella antibodies in HIV-positive and HIV-negative participants. Revaccination with measles and mumps was associated with an increase in antibody levels in HIV-negative participants but not in HIV-positive participants. Both HIV-positive and HIV-negative participants responded to rubella revaccination with an increase in antibody levels.