Immunosuppressive treatment for acquired haemophilia: current practice and future directions in Germany, Austria and Switzerland

Acquired haemophilia is an autoimmune disorder characterised by autoantibody formation against coagulation factor VIII. Immunosuppressive treatments including steroids, cytotoxic drugs, rituximab or combinations thereof have been used to eradicate autoantibodies. Very few prospective studies exist evaluating the use of these treatments. Here, we performed a survey among 73 physicians from 57 haemophilia treatment centres in order to describe current practice patterns and critical issues for future research in acquired haemophilia. The results demonstrate a high diversity of first- and second-line treatments. Factors influencing treatment decision were underlying disorder, severity of bleeding and inhibitor titre. Frequently used first-line treatments were steroids plus cyclophosphamide (44%) and steroids alone (11%). Second-line treatment was most often rituximab (30%), with or without steroids and/or cyclophosphamide. Most participants indicated to change from first- to second-line treatment after 4 weeks in case of failure to obtain partial remission (31%), continued bleeding (40%) or continued severe bleeding requiring bypass treatment (59%). Immunoadsorption was preferred for first- and second-line treatment by 10% and 9% of participants, respectively. These results highlight critical issues in the field. Open questions and directions for future research are discussed.

Mutations affecting disulphide bonds contribute to a fairly common prevalence of F13B gene defects: results of a genetic study in 14 families with factor XIII B deficiency

Severe factor XIII (FXIII) deficiency is a rare autosomal recessive coagulation disorder affecting one in two million individuals. The aim of the present study was to screen for and analyse F13B gene defects in the German population. A total of 150 patients presenting with suspected FXIII deficiency and one patient with severe (homozygous) FXIII deficiency were screened for mutations in F13A and F13B genes. Twenty-five individuals presented with detectable heterozygous mutations, 12 of them in the F13A gene and 13 of them in the F13B gene. We report on the genotype-phenotype correlations of the individuals showing defects in the F13B gene. Direct sequencing revealed 12 unique mutations including seven missense mutations (Cys5Arg, Ile81Asn, Leu116Phe, Val217Ile, Cys316Phe, Val401Glu, Pro428Ser), two splice site mutations (IVS2-1G>C, IVS3-1G>C), two insertions (c.1155_1158dupACTT, c.1959insT) and one in-frame deletion (c.471-473delATT). Two of the missense mutations (Cys5Arg, Cys316Phe) eliminated disulphide bonds (Cys5-Cys56, Cys316-Cys358). Another three missense mutations, (Leu116Phe, Val401Glu, Pro428Ser) were located proximal to other cysteine disulphide bonds, therefore indicating that the region in and around these disulphide bonds is prone to functionally relevant mutations in the FXIII-B subunit. The present study reports on a fairly common prevalence of F13B gene defects in the German population. The regions in and around the cysteine disulphide bonds in the FXIII-B protein may be regions prone to frequent mutations.

Bilateral total knee arthroplasty in a patient with hemophilia A, high inhibitor titre and aneurysma spurium of the popliteal artery. A case report

The authors report on bilateral simultaneous knee arthroplasty in a 40-year-old male patient with haemophilia A, high inhibitor titre and an aneurysma spurium of the right popliteal artery. Both knees showed a fixed flexion deformity of 20 degrees. To build up haemostasis, treatment with activated prothrombin complex concentrate (APCC) and recombinant activated factor seven (rFVIIa) was initiated preoperatively. A tourniquet was used on both sides during the operation and factor VIII (FVIII) was administered to further correct coagulopathy. On the eleventh postoperative day the patient complained of increasing pain and pressure in the right knee. An ultrasound suggested aneurysm, which was confirmed by substraction angiography. Under the protection of rFVIIa the aneurysm could be coiled and further rehabilitation was uneventful. At one year post-op the patient presented a range of motion of 90/5/0 degrees for both knees and had returned to full time office work. This case indicates that haemophiliacs with high antibody titre and destruction of both knees can be operated on in one session in order to diminish the operative risk of two consecutive surgical procedures, thus allowing an effective rehabilitation programme. Because of the significant frequency of popliteal aneurysms, preoperative angiography is recommended.

Acquired factor XIII deficiency: a therapeutic challenge

Less than 60 cases of acquired factor (F)XIII deficiencies have been reported, most having distinct clinical features. To illustrate the therapeutic challenges of acquired FXIII inhibitors, we report a case of a 65-year-old patient with no previous bleeding history who suddenly developed massive haemorrhages associated to a strong and isolated FXIII inhibitor. No underlying disorder has been detected till now after three years of follow-up. Despite aggressive treatment with prednisone, rituximab, cyclophosphamide, immunoglobulin, immunoadsorption and immune tolerance his inhibitor is still present, although at low titre and with a clinical benefit since the patient has no more bleed since more than one year. Moreover the patient had a venous thromboembolic complication. After a review of the management of acquired FXIII deficiency patients and based on the management of acquired haemophilia we discuss a possible strategy for such difficult cases.

Phenotype-genotype correlation in eight Polish patients with inherited Factor XIII deficiency: identification of three novel mutations

Inherited factor XIII (FXIII) deficiency is known as one of the most rare blood coagulation disorder in humans. In the present study, phenotype and genotype of eight FXIII deficient Polish patients from five unrelated families were compared. The patients presented with a severe phenotype demonstrated by a high incidence of intracerebral haemorrhages (seven of eight patients), haemarthrosis (six patients) and bleeding due to trauma (five patients). Introduction of regular substitution with FXIII concentrate prevented spontaneous bleeding in seven patients. In all patients, mutations within the F13A gene have been identified revealing four missense mutations (Arg77Cys, Arg260Cys, Ala378Pro, Gly420Ser), one nonsense mutation (Arg661X), one splice site mutation (IVS5-1 G>A) and one small deletion (c.499-512del). One homozygous large deletion involving exon 15 was detected by failure of PCR product. The corresponding mutations resulted in severely reduced FXIII activity and FXIII A-subunit antigen concentration, while FXIII B-subunit antigen remained normal or mildly decreased. Structural analysis demonstrated that the novel Ala378Pro mutation may cause a disruption of the FXIII catalytic triad leading to a non-functional protein which presumably undergoes premature degradation. In conclusion, the severe phenotype with high incidence of intracranial bleeding and haemarthrosis was in accordance with laboratory findings on FXIII and with severe molecular defects of the F13A gene.

Congenital factor XIII deficiency in Pakistan: characterization of seven families and identification of four novel mutations

Deficiency of coagulation factor XIII (FXIII) belongs to the rare bleeding disorders and its incidence is higher in populations with consanguineous marriages. The aims of this study were to characterize patients and relatives from seven families with suspected FXIII deficiency from Pakistan and to identify the underlying mutations. As a first indicator of FXIII deficiency, a 5M urea clot solubility test was used. Plasma FXIII A- and B-subunit antigen levels were determined by ELISA. FXIII activity was measured with an incorporation assay. Sequencing of all exons and intron/exon boundaries of F13A was performed, and a novel splice site defect was confirmed by RT-PCR analysis. Genetic analysis revealed six different mutations in the F13A gene. Two splice site mutations were detected, a novel c.1460+1G>A mutation in the first nucleotide of intron 11 and a previously reported c.2045G>A mutation in the last nucleotide of exon 14. Neither of them was expressed at protein level. A novel nonsense mutation in exon 4, c.567T>A, p.Cys188X, was identified, leading in homozygous form to severe FXIII deficiency. Two novel missense mutations were found in exons 8 and 9, c.1040C>A, p.Ala346Asp and c.1126T>C, p.Trp375Arg, and a previously reported missense mutation in exon 10, c.1241C>T, p.Ser413Leu. All patients homozygous for these missense mutations presented with severe FXIII deficiency. We have analysed a cohort of 27 individuals and reported four novel mutations leading to congenital FXIII deficiency.

Hypofibrinogenemia and liver disease: a new case of Aguadilla fibrinogen and review of the literature.

INTRODUCTION Fibrinogen storage disease (FSD) is characterized by hypofibrinogenemia and hepatic inclusions due to impaired release of mutant fibrinogen which accumulates and aggregates in the hepatocellular endoplasmic reticulum. Liver disease is variable. AIM We studied a new Swiss family with fibrinogen Aguadilla. In order to understand the molecular peculiarity of FSD mutations, fibrinogen Aguadilla and the three other causative mutations, all located in the γD domain, were modelled. METHOD The proband is a Swiss girl aged 4 investigated because of fatigue and elevated liver enzymes. Protein structure models were prepared using the Swiss-PdbViewer and POV-Ray software. RESULTS The proband was found to be heterozygous for fibrinogen Aguadilla: FGG Arg375Trp. Familial screening revealed that her mother and maternal grandmother were also affected and, in addition, respectively heterozygous and homozygous for the hereditary haemochromatosis mutation HFE C282Y. Models of backbone and side-chain interactions for fibrinogen Aguadilla in a 10-angstrom region revealed the loss of five H-bonds and the gain of one H-bond between structurally important amino acids. The structure predicted for fibrinogen Angers showed a novel helical structure in place of hole 'a' on the outer edge of γD likely to have a negative impact on fibrinogen assembly and secretion. CONCLUSION The mechanism by which FSD mutations generate hepatic intracellular inclusions is still not clearly established although the promotion of aberrant intermolecular strand insertions is emerging as a likely cause. Reporting new cases is essential in the light of novel opportunities of treatment offered by increasing knowledge of the degradation pathway and autophagy.