SummaryMolecular genetic studies have shown that development of antibodies to factor VIII (inhibitors) occurs most frequently in patients with severe haemophilia due to major gene lesions including inversions, stop codons and large deletions. Previous studies of HLA type were performed on inhibitor and non-inhibitor patients with diverse uncharacterised mutations which may have confounded detection of significant associations. We therefore selected a group of patients with a single mutation type, the prevalent intron 22 inversion, with or without inhibitors, to determine HLA genotype. Seventy-one such patients, 42 without and 29 with inhibitors (13 high, 9 low and 7 transient responders) were genotyped for MHC Class I HLA-A, -B, -C and Class II HLA-DQA, -DQB and -DRB loci. No strong correlation of any HLA-allele to inhibitor or non-inhibitor status was found. However, alleles of the haplotype HLA-A3, HLA-B7, HLA-C7, HLA-DQA0102, HLA-DQB0602, HLA-DR15 occurred more often in inhibitor patients. Since the alleles of this extended haplotype are common in the North European population only a very strong association would achieve statistical significance. Further studies of groups of patients similar to those studied here will be needed to confirm or exclude this association.

Patients with severe haemophilia A growing up before the establishment of prophylactic treatment frequently developed significant haemarthropathies. The goal of the following study was to clarify the role of haemarthropathic pain for haemophilic patients. Furthermore, we aimed to determine to what degree daily activities are influenced by the impairment and which therapeutic modalities are used in pain management. Using a questionnaire we consulted 71 haemophiliacs concerning their complaints and how they were treated in 1999 (average age 43 years; range 21-63 years). The pain in the large joints and spine and the effect of specific treatment was estimated by a visual analogue scale. On average, there were four joints with major pain and 0.5 with minor pain. The most frequent sources of pain were the ankle joints (45%), followed by the knee (39%), spine (14%) and elbow (7%). Fifty percent of all patients complained of pain throughout the day if no treatment was applied. In 29% of patients, pain persisted after application of factor VIII (FVIII), while 12% claimed that pain still remained after use of FVIII and pain killers. Restriction in activities of daily life was reported by 89% of the group and 85% reported on an impact of pain on their mood. Patients primarily used FVIII to decrease pain, followed in frequency by use of anti-inflammatory drugs, orthopaedic footwear, liniments and bandages. Haemophilic patients with haemarthropathy are chronic pain patients. By means of the questionnaire, it is possible to reveal the 'silent' sufferers. Sufficient pain treatment is essential so as to increase the patient's quality of life and avoid inadvertent abnormal postures possibly resulting in increased loading of joints and subsequent bleeding episodes.

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Background and Aims: To assess the risk of bleeding after percutaneous liver biopsy, we retrospectively analyzed 629 procedures with particular respect to patients with an increased a priori bleeding risk. Methods: Factors possibly related to the risk of bleeding were analyzed by univariate analysis. Those variables which were significant in the univariate analysis were then entered into a forward conditional logistic regression model. Results: Biopsy-related bleeding events defined as clinically overt complication (n = 10; 1.6%), an otherwise unexplained drop in serum hemogloblin concentration of greater than 2 g/dl (n = 45; 7.1%) or intra- or extrahepatic hematoma assessed by ultrasound (n = 17; 2.7%) were identified in 72 patients. 58% of the bleeding events occurred in patients with particular risk factors for bleeding. Biopsy-related mortality in the study cohort was 0.48%. Logistic regression analysis indicated mycobacterial infection [odds ratio (OR) 24.0], pre-biopsy prophylactic platelet substitution (OR 9.9), acute liver failure (OR 9.1), heparin administration on the day of biopsy (OR 8.7), advanced liver cirrhosis (OR 5.1), therapy with corticosteroids (OR 3.5) or metamizole (OR 2.8) and leukemia or lymphoma (OR 2.8) as significant (p ≤ 0.05) independent risk factors. Delayed bleeding (>24 h after biopsy) was identified in 70% of the bleeding events. Conclusions: In our study cohort which comprised a high proportion of patients with particular risk factors for bleeding, biopsy-related bleeding occurred more frequently and later than commonly observed and was associated with only a few prognostic factors. Considering these predictors before liver biopsy will aid to reduce the rate of bleeding complications.

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These findings exclude mutations that could be located deep in the introns and affecting either normal splicing or lead to mechanisms causing some unknown rearrangements of the FVIII gene. In fact, our results point to the presence of still unknown factor(s) causing HA, which might be either allelic or in the close proximity of the FVIII gene or non-allelic associated with other genetic loci that are involved in the processing of the FVIII protein.

The mechanisms responsible for the low factor VIII (fVIII) activity in the plasma of patients with mild/moderate hemophilia A are poorly understood. In such patients, we have identified a series of fVIII mutations (Ile2098Ser, Ser2119Tyr, Asn2129Ser, Arg2150His, and Pro2153Gln) clustered in the C1 domain and associated with reduced binding of fVIII to von Willebrand factor (vWf). For each patient plasma, the specific activity of mutated fVIII was close to that of normal fVIII. Scatchard analysis showed that the affinity for vWf of recombinant Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII mutants was reduced 8-fold, 80-fold, and 3-fold, respectively, when compared with normal fVIII. Given the importance of vWf for the stability of fVIII in plasma, these findings suggested that the reduction of fVIII binding to vWf resulting from the above-mentioned mutations could contribute to patients' low fVIII plasma levels. We, therefore, analyzed the effect of vWf on fVIII production by Chinese hamster ovary (CHO) cells transfected with expression vectors for recombinant B domain-deleted normal, Ile2098Ser, Ser2119Tyr, and Arg2150His fVIII. These 3 mutations impaired the vWf-dependent accumulation of functional fVIII in culture medium. Analysis of fVIII production by transiently transfected CHO cells indicated that, in addition to the impaired stabilization by vWf, the secretion of functional Ile2098Ser and Arg2150His fVIII was reduced about 2-fold and 6-fold, respectively, by comparison to Ser2119Tyr and normal fVIII. These findings indicate that C1-domain mutations resulting in reduced fVIII binding to vWf are an important cause of mild/moderate hemophilia A.