Plasma exchange and immunosuppressive therapy in a case of mild haemophilia A with inhibitors and a life-threatening lower limb haemorrhage

Introduction

The development of inhibitors in severe haemophilia A is a well-known serious complication of exposure to factor VIII (FVIII) concentrates. It occurs in up to 30% of patients and makes bleeding episodes refractory to standard treatment. In mild haemophilia A treatment with FVIII concentrates is indicated after trauma and for surgery; this treatment, too, may be complicated by the occurrence of inhibitors, with the frequency of this complication being reported to be between 3% and 13%^1–3. In such patients it represents a major challenge and changes the phenotype from mild to severe, so that the patients are at risk of spontaneous bleeding. Unlike in severe haemophilia A, only few risk factors have been recognised, such a positive family history of inhibitors, age at first exposure, age at peak treatment, some missense mutations in the factor VIII gene and intensive FVIII replacement treatment, often in the setting of surgery and continuous infusion delivery^3–6.

According to the main guidelines^7–9, bleeding episodes in patients with haemophilia and inhibitors should be treated with bypassing agents prior to immune tolerance induction (ITI). The success of ITI is higher when its initiation is delayed until the inhibitor titre has fallen below 10 BU/mL. For patients with mild haemophilia A and inhibitors, a trial of bypassing therapy on demand should precede consideration of ITI. The choice of therapy depends on the inhibitor titre: large doses of FVIII can be sufficient to control major haemorrhage if the antibody titre is less than 5 BU/mL, while if it is higher FVIII overtreatment is unlikely to be effective without the removal of antibodies. In this case, recombinant activated factor VII (rFVIIa) or activated prothrombin complex concentrates (FEIBA) are recommended in the acute phase of bleeding; when one of these fails, the other product may be used. If both the bypassing agents cannot ensure control of bleeding, an alternative approach could be the use of concomitant antibody removal and high-dose FVIII, as historically proposed three decades ago by Nillson and colleagues^10–11 and still considered effective^12–14. A similar approach has also been used in the setting of acquired haemophilia A^15,16.

High-titre antibodies can be removed temporarily by extracorporeal adsorption of the antibody to protein A-sepharose or to polyclonal sheep antibodies in columns^17–19. Therapeutic plasma exchange (TPE) still has a role in the treatment of coagulation factor inhibitors, as reported in international guidelines ¹³.

ITI has been used in few patients with mild haemophilia A and the success rate in such patients seems lower than that in patients with severe haemophilia A^3,14. The success of this approach is defined as the elimination of the inhibitors, the normalization of the half-life of infused FVIII and the absence of an anamnestic response. The eradication of inhibitors may be achieved with immune modulation using drugs such as steroids and cyclophosphamide^10,11.

We present the case of a patient with mild haemophilia A with high titre inhibitors and life-threatening bleeding unresponsive to bypassing agents. The critical situation required the use of both removal of the antibodies by TPE, overtreatment with plasma-derived FVIII concentrates and stabilisation of the clinical response with immunosuppressive therapy and early start of ITI.

Case report

We describe the case of a 19-year old patient with mild haemophilia A (FVIII 10%). The diagnosis was made at the age of 1 year because of the boy’s family history. The patient had an F8 mutation Val 2251Ala (exon 25). He had never been treated with FVIII concentrates until October 2011, when he presented with a ruptured spleen due to a car crash and was admitted into the local hospital. Before emergency surgery, he was treated with B-domain-deleted recombinant FVIII concentrate (monoctocog alfa), followed by other doses of the concentrate until the fifth day after surgery, for a total dose of 16000 U, with full control of haemostasis. Furthermore in the first days after surgery, he was vaccinated against Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis. After 22 days a progressive prolongation of the patient’s activated partial thromboplastin time (aPTT), not corrected by the infusion of B-domain-deleted FVIII concentrates, was observed. The infusion of full-length FVIII concentrate to test the recovery caused adverse reactions: hypotension, precordial pain and blurred vision. The patient was transferred to our Unit, with the suspicion of inhibitor development. Coagulation tests showed an aPTT ratio of 2.35, FVIII: C less than 0.3%, and antibodies against FVIII at a level of 15.5 BU/mL. On the second day after his transfer into our Unit he developed a large, spontaneous haematoma of the right lower limb with rapid onset and evolution to compartment syndrome and severe anaemia despite the use of rFVIIa concentrates at a dose of 100 mg/kg every 3 hours. The patient needed to be treated with an emergency fasciotomy and was transferred to the Intensive Care Unit because of severe haemorrhagic shock (haemoglobin 6.1 g/dL). For the haemorrhage, 12 units of red cell concentrates were infused in the first 3 days after the fasciotomy.

Because of the high titre of FVIII inhibitors and the difficulties in controlling the haemorrhage despite the use of bypassing agents, 4 days after the fasciotomy we applied a modified Malmo treatment model^10,11, preceded by TPE (Table I): briefly, about 1.2 plasma volumes were exchanged during each procedure, using a third-generation cell separator device. Four TPE were consecutively performed; no complication occurred during or after each session (no vasovagal episodes, tachycardia or tachypnoea).

Table I.

aPTT, factor VIII levels and inhibitor titres before the first session and just after each session of plasma exchange.

	aPTT (seconds) (normal range 20–32)	FVIII: C (%)(normal range 70–150)	Inhibitor titre (BU/mL)
Before first plasma exchange	75.3	0.3	15.5
After first plasma exchange	50.1	6.1	6
After second plasma exchange	33.8	30.8	1.33
After third plasma exchange	39.2*	11.7*	0.83
After fourth plasma exchange	34.5	30	0.41

^*Detected 2 hours after the end of the plasma exchange session and infusion of FVIII concentrate.

The patient was also treated with steroids, cyclophosphamide and immunoglobulins (Table II), obtaining a reduction of the inhibitor titre and control of bleeding by using high doses of plasma-derived FVIII (neutralising and incremental dose) (Figure 1). Before the first session of TPE, a central vein catheter was introduced into the patient’s femoral vein, just after a dose of rFVIIa, without complications. After the first two TPE sessions, performed in the Intensive Care Unit, the need for transfusion was significantly reduced; the patient was infused with in a total of only four units of red cell concentrates between the fifth and the seventh day after fasciotomy. After the resolution of the life- and lower limb-threatening bleeding, the patient was treated with 100 U/kg of plasma-derived FVIII concentrate every other day, in the ITI regimen, from November 2011 until May 2012, when FVIII inhibitors became undetectable and the half-life of infused FVIII was restored to normal (FVIII level >50% of the peak 6 hours after the infusion) (Table III).

Table II.

The Malmo Treatment Model¹⁰–¹¹ and our modification.

Malmo Treatment Model	Treatment applied to our patient
Immunoadsorption, if needed	Plasma exchange on 11/02, 11/03, 11/04 and 11/05
Neutralisation of inhibitor and replacement with factor concentrates	Neutralisation and replacement with factor concentrates (Emoclot-Kedrion 5000 U [Kedrion Castelvecchio Pascoli, Italy] every 8 hours)
Cyclophosphamide 12–15 mg/kg bw intravenously for 2 days, then orally 2–3 mg/Kg bw for an additional 8–10 days	Cyclophosphamide 12.5 mg/kg bw intravenously for 2 days (11/05 and 11/06), then orally 2.5 mg/kg bw for another 2 days (11/07 and 11/08)
Intravenous immunoglobulins 0.4 g/kg bw for 5 days	Intravenous immunoglobulins 1 g/kg bw for the first 2 days (11/5 and 11/6), then 0.4 g/kg bw for another 2 days (11/7–11/08)
-	Methylprednisolone 80 mg daily for 2 days (11/4–11/05), then 40 mg daily from 11/06 to 11/10, then 20 mg daily until 11/29

Figure 1.

aPTT, FVIII level, inhibitors titre during the acute phase of bleeding and treatment.

Table III.

aPTT and factor VIII levels at the end of ITI (May 2012), after infusion of FVIII concentrate at a dose of 100 U/kg bw.

Time	aPTT (seconds)	FVIII:C (%)
Before infusion	41.1	4.3
After 30 minutes	24.2	124.9
After 60 minutes	24.6	100.2
After 3 hours	26.4	85
After 6 hours	27.8	67.3

FVIII-inhibitors: 0 BU/mL.

His lower limb function recovered completely after prolonged physiotherapy and his mild phenotype has been regained. At present, 1 year after the end of ITI, the patient has a FVIII activity of 8.7%, no spontaneous bleeding and no detectable inhibitors.

Discussion

In mild haemophilia A some missense mutations in the F8 gene are recognised as being associated with a major risk of triggering inhibitor development. These mutations are localised in the A2 domain of the heavy chain and the junction of the C1 and C2 domains of the light chain of the FVIII molecule (4-fold increased risk of inhibitors compared to the risk associated with mutations of other regions). In a north-European retrospective study the mutation most strongly associated with risk of inhibitor development is Arg593Cys⁶. In a prospective study by Eckhardt and Colleagues²⁰, 43 patients with mild haemophilia A were characterised on the basis of genetic mutations: one with the Arg593Cys and one with the Arg531Cys have developed low titre inhibitors after surgery replacement therapy.

Our patient has a Val2251Ala mutation (exon 25), which is also associated with the risk of development of inhibitors, as recently described in a study concerning an Italian population of patients with mild haemophilia²¹. He was treated for the first time at the age of 19, after trauma and emergency surgery for a ruptured spleen. He developed high-titre inhibitors after only 6 days of exposure, but with peak treatment for surgery.

As far as regards the type of concentrate, our patient was treated with repeated boluses of B-domain-deleted recombinant FVIII concentrate. A recent meta-analysis suggested that this type of recombinant FVIII may be associated with a greater risk of inhibitor development compared to that of full-length products²², although this was not confirmed by a large study on inhibitors in a population of previously untreated patients with severe haemophilia A²³. In this study the risk of inhibitor development was similar among plasma-derived products, first-generation full-length recombinant products, second-generation B-domain-deleted recombinant products and third-generation recombinant products. The use of recombinant FVIII products in children with severe haemophilia A did not have a significant effect on the risk of inhibitor development, as compared with the use of plasma-derived products; switching among them was not associated with a risk of inhibitor development.

In our case the recognised risk factors for inhibitors were genetic predisposition, peak treatment and splenectomy. Exposure to immunological danger signals, such as multiple vaccinations may also have played a role, as already recognised in the setting of severe haemophilia, although not yet described in mild haemophilia.

When inhibitors reduce the possibility of effective control of bleeding episodes, they can be removed temporarily by immunoadsorption or TPE, facilitating high-dose FVIII infusion: this treatment was introduced at Malmo^10,11 and the first successful tolerance induction was performed in 1982 with the protocol that was to become the Malmo Treatment Model. It included immunoadsorption if required by the initial inhibitor concentration. In most cases a single dose of steroids (50–150 mg) was given at the start of treatment, but this was not mandatory and not considered as part of the tolerance protocol²⁴. Cyclophosphamide was given intravenously for 2 days (12–15 mg/kg bw) and then orally (2–3 mg/kg bw) for an additional 8–10 days. FVIII was given daily with the intention to maintain the patient’s factor concentrate at a haemostatically effective level for at least 2–3 weeks. From the fourth day after the start of the protocol, intravenous immunoglobulins were given daily at doses of 0.4 g/kg bw for 5 days A similar approach has been successfully used in the different setting of acquired haemophilia, with the Modified Bonn-Malmo Protocol^15,16. In acquired haemophilia drugs such as glucocorticoids and cyclophosphamide have gained an established role in conventional treatment²⁵, while their role is not completely clarified in congenital haemophilia complicated by inhibitors¹⁴.

Inhibitors can be bypassed by activated prothrombin complex concentrates or rFVIIa, so the removal of antibodies by immunoadsorption or TPE is less common. Since our patient had adverse reactions (hypotension, precordial pain and blurred vision) to recombinant full-length FVIII infusion, we used rFVIIa concentrate, instead of FEIBA, for the treatment of his muscle haemorrhage, thereby avoiding other exposure to exogenous FVIII.

Despite the use of the bypassing agent, the patient developed a critical haemorrhage and compartment syndrome with the need for emergency fasciotomy. After the surgery, he had severe haemorrhagic shock requiring large amounts of red blood cell transfusions: it was necessary to clear the inhibitors rapidly and start overexposure to FVIII in an Intensive Care Unit, under strict surveillance. In this life-threatening setting, we applied the Malmo treatment model in order to obtain a rapid decrease of inhibitor titre and to control the severe bleeding with overtreatment with plasma-derived FVIII concentrates and immunosuppressive therapy given at the maximum peak of immune response. We chose to reduce the dosage of cyclophosphamide, associating steroids, in order to prevent infectious complications, after the recent splenectomy of a patient with a non-optimal performance status even before surgery (40 kg bw for a 19-year old male).

In the presence of coagulation factor inhibitors, the goals of therapy are cessation of bleeding and suppression of further inhibitor production. The auto-antibodies can be removed by either immunoadsorption or TPE. It seems that sepharose-bound staphylococcal protein A (SPA) immunoadsorption, although expensive, can be more effective than TPE or sepharose-bound polyclonal sheep antibodies against human Ig SPA. In fact SPA can interact with the immune system, resulting in immunomodulation: a decrease in activated monocytes and cytotoxic T cells, a change in T-cell population, and a decrease in autoreactive T-cell activity. TPE is effective and less expensive when well conducted by experienced personnel and can remove the inhibitor rapidly while allowing the patient to be supplied contemporaneously with fresh-frozen plasma rich in FVIII. Indeed, immunoadsorption and TPE are both recommended in the international apheresis guideline¹³.

We applied TPE treatment, as already conducted by Kucharski and colleagues in Warsaw²⁶: they modified the Malmo protocol performing serial TPE instead of immunoadsorption, obtaining tolerance in 66.6% of 15 high responder patients. In our case, the reduction of the inhibitor titre per session was consistent with data reported in the literature on immunoadsorption¹⁹ and four sessions were sufficient to reduce the titre of alloantibodies significantly (congenital haemophilia with inhibitors).

The regimens for the induction of tolerance are based on repeated infusion of factor concentrates: one recommends 25–50 U/kg bw every other day²⁷, another indicates a dose of 200–300 U/kg bw daily²⁸. The treatment is successful when tolerance is achieved, defined as the elimination of detectable inhibitors, the normalization of the half-life of infused factor and the absence of anamnestic response.

We integrated the Malmo Treatment Model with this approach, because of the persistence of detectable antibodies in the first weeks after the application of the protocol, and we obtained a complete durable response after 6 months of the ITI regimen with plasma-derived FVIII concentrate 100 U/kg bw every other day and restoration of the patient’s mild phenotype.

Conclusions

In this case of mild haemophilia A with inhibitors, bypassing agents were ineffective at stopping a life-threatening haemorrhage; plasma exchange, followed by immunosuppression and high doses of FVIII concentrates, was able to reduce the inhibitor titre and to stop the severe bleeding, saving the life and lower limb function of the young patient. After controlling the haemorrhage, we started an ITI protocol, which successfully restored the previous FVIII levels and phenotype after 6 months of treatment with plasma-derived FVIII concentrates. The patient currently does not have either spontaneous bleeding or detectable inhibitors more than 1 year after the end of ITI.

This case is an example of the emergency management of a haemophilic patient with inhibitors using a procedure available at all blood transfusion services.