Non Neutralizing Antibodies to Tissue Type Plasminogen Activator in the Serum of Acute Myocardial Infarction Patients Treated with the Recombinant Protein

Outcome of Repeated Thrombolysis in Debrecen Thrombolysis Database

INTRODUCTION

Recombinant tissue plasminogen activator (rtPA) is an efficient therapy of acute ischemic stroke. The risk of a recurrent ischemic stroke is high. This prospective single center study aimed to assess whether or not the repeated rtPA treatment is beneficial for acute stroke patients.

METHODS

All thrombolysed patients' data at the Department of Neurology, University of Debrecen have been recorded in the Debrecen Thrombolysis Database (DTD) since 2004. We identified 21 patients with repeated thrombolysis. Stroke severity by the NIH stroke scale score (NIHSSS) and imaging findings by the Alberta Stroke Programme Early CT Score were evaluated on admission and 1 day later. The modified Rankin Scale score at 3 months and case fatality at 1 year were evaluated. We compared the first and second thrombolyses, and we screened for bleeding and allergic reactions to determine safety.

RESULTS

Within the 27-month median time, 18 patients were thrombolysed twice, with complete follow-up. In recurrent stroke patients, diabetes mellitus, congestive heart failure, and anticoagulation were more common. Admission cholesterol levels were decreased. After the first and second treatments, 24-hour NIHSSS were 3 (1;6) and 7 (1;10), respectively. At 3 months, good outcome was significantly higher after the first treatment than those of DTD, with no differences between the 2 attempts. There was little difference in 3-month and 1-year outcomes, regardless of laterality-ipsilateral or contralateral hemisphere-in recurrent strokes. One patient had nonsymptomatic intracranial bleeding after repeated rtPA treatment.

DISCUSSION

Recurrent rtPA treatment may be safe and effective in patients who have mild or moderate residual symptoms after the index stroke.

Assessment of Anti-Tissue Type Plasminogen Activator Antibodies in Patients With Prosthetic Heart Valve Thrombosis: The ATA Trial

BACKGROUND

Thrombolysis is an effective treatment strategy for prosthetic valve thrombosis (PVT). Recombinant tissue-type plasminogen activator (rt-PA) is widely used as a thrombolytic agent. Infusion of rt-PA may trigger the production of anti-tissue plasminogen activator (tPA) antibodies (ATAs). We aimed to evaluate the possible relationship between ATA levels and PVT formation, and the role of baseline ATA levels on outcomes of thrombolytic therapy in patients with PVT.

METHODS

This prospective, single-center cohort study included 28 patients with PVT undergoing thrombolysis and 31 controls with normal prostheses. Plasma samples were collected from patients with PVT at baseline and at 15th, 30th, 90th, and 180th days after thrombolysis and from controls at baseline only. The ATA levels were assessed in human plasma by an enzyme-linked immunosorbent assay.

RESULTS

Baseline ATA-immunoglobulin (Ig) G and IgM were significantly higher in patients with PVT than in controls. The levels of IgM and IgG peaked at 15th and 30th days after rt-PA infusion, respectively. Subtherapeutic international normalized ratio and baseline ATA-IgM were independent predictors of PVT. Thrombolysis failed in 6 patients (21%) in whom baseline IgM levels were significantly higher than successfully lysed patients. Rethrombosis occurred in 9 patients (32%) in whom baseline IgG levels were significantly higher than those without rethrombosis. There was a moderate positive correlation between baseline and 15th-day IgM levels and the dose of rt-PA needed for successful lysis.

CONCLUSION

The ATA levels tended to be higher in patients with PVT at the time of initial diagnosis compared to controls without PVT. In addition, such patients with PVT and high ATA levels may be at high risk for failed thrombolysis or rethrombosis.

Repeated thrombolytic therapy in patients with recurrent acute ischemic stroke

Background and Purpose

Widespread use of thrombolytic treatments, along with improved chances of survival after an initial ischemic stroke, increases the possibility of repeated thrombolysis. There are few reports, however, regarding repeated thrombolysis in patients who have suffered acute ischemic stroke. We explored the number and outcome of patients with repeated thrombolytic therapy in the era of multimodal thrombolytic treatments.

Methods

We investigated patients with acute ischemic stroke who had received thrombolytic treatments for a period of 10 years. Number of thrombolysis was determined in each patient. Recanalization was defined as Thrombolysis in Cerebral Infarction grading ≥2a. Symptomatic hemorrhagic transformation was defined as any increase in the National Institutes of Health Stroke Scale score that could be attributed to intracerebral hemorrhage. A good outcome was defined as a modified Rankin scale score ≤2.

Results

Of the 437 patients who received thrombolytic treatments, only 7 underwent repeated thrombolysis (1.6%). The median age at the time of repeated thrombolytic therapy was 71 years old; 4 of the patients were female. All patients had 1 or more potential sources of cardiac embolism. Recanalization was achieved in all patients, in both the first and the second thrombolysis. No symptomatic intracranial hemorrhage occurred after repeated thrombolytic treatments. Five patients (71.4%) showed good outcomes at 3 months.

Conclusions

Repeated thrombolysis for recurrent acute ischemic stroke appears to be safe and feasible. Among patients who experience recurrent acute ischemic stroke, thrombolytic therapy could be considered even if the patient has had previous thrombolytic treatments.

Anti-t-PA antibodies in acute myocardial infarction after thrombolysis with rt-PA

BACKGROUND

Thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) is successfully used in acute myocardial infarction with ST elevation (STEMI). Reocclusions follow rt-PA treatment in up to 30% of patients within one year. The infusion of rt-PA may induce the production of anti-t-PA antibodies which could interfere with the function of the native t-PA molecule.

METHODS

In order to detect and characterise anti-t-PA antibodies, plasma samples were collected from 30 STEMI patients (20 treated and 10 not treated with rt-PA) at baseline before rt-PA infusion and then 15, 30, 90 and 180 days after STEMI and from 40 healthy subjects at baseline only. Immunoenzymatic, chromatographic and chromogenic methods were employed.

RESULTS

An increase of anti-t-PA antibodies was observed 15 days (IgM, p=0.0001) and 30 days (IgG, p=0.0001) after rt-PA infusion. Six patients had large increases of anti-t-PA IgG which bound the catalytic domain of t-PA (two cases) or kringle 2 domain (four cases), were of IgG1 or IgG3 subclasses and interacted with the t-PA molecule in fluid phase.

CONCLUSION

The infusion of rt-PA may induce the production of specific antibodies that bind active sites of t-PA, thus potentially reducing its in vivo function.

Life-Threatening Anaphylactoid Reaction in an Acute Ischemic Stroke Patient With Intravenous rt-PA Thrombolysis, Followed by Successful Intra-Arterial Thrombolysis

An anaphylactoid reaction to recombinant tissue plasminogen activator (rt-PA) is an uncommon but fatal complication. A 39-year-old man was admitted within 1 hour of the onset of a right hemispheric stroke. He was not taking any specific medication, including angiotensin-converting enzyme (ACE) inhibitors. A systemic anaphylactoid reaction developed immediately after rt-PA infusion. However, the symptoms were improved after treatment with a steroid and antihistamine. Subsequent intra-arterial thrombolytic therapy resulted in complete recanalization and clinical improvement. To our knowledge, this is the first report of a life-threatening anaphylactoid reaction after rt-PA treatment followed by successful intra-arterial thrombolytic therapy in a patient who had not taken an ACE inhibitor.

Angioneurotisches orolinguales Ödem nach rt-PA-Lyse eines Schlaganfalls

Angioneurotic orolingual edema associated with the use of rt-PA (recombinant tissue plasminogen activator) for systemic thrombolysis are described in the literature, but only as isolated case reports. Strangely, the rate of anaphylactic reactions to rt-PA is higher (1.9%) when they are used in the treatment of acute stroke than when they are given to treat acute myocardial infarction (0.02%). Patients who are taking ACE inhibitors seem to be at increased risk of such a potentially life-threatening event. We now report on two patients, in each of whom asymmetric angioneurotic edema was observed following successful thrombolysis with rt-PA. Both these patients were taking ACE inhibitors. It was possible to avoid intubation and ventilation in both cases. Therapy with ranitidine, clemastine, and a C1 esterase inhibitor resulted in the resolution of symptomatic angioneurotic edema within hours.

Antibodies to tissue-type plasminogen activator (tPA) in patients with antiphospholipid syndrome: evidence of interaction between the antibodies and the catalytic domain of tPA in 2 patients

The causes of thrombosis and pregnancy loss in antiphospholipid syndrome (APS) are still unknown, although several hypotheses have been proposed and hypofibrinolysis has been implicated. Anti-tissue-type plasminogen activator (tPA) antibodies may induce fibrinolytic defects and preliminary data indicate an association with thrombosis in APS. We measured plasma anti-tPA antibody levels in 91 consecutive patients with APS, 91 healthy controls, 40 patients with antiphospholipid antibodies without APS symptoms, and 23 patients with systemic lupus erythematosus (SLE) without antiphospholipid antibodies and APS symptoms. Patients with APS had anti-tPA antibody levels higher than controls (P = .0001), patients with SLE (P = .0001), and asymptomatic antiphospholipid patients (P = .05). A subgroup of 53 patients had plasma levels of tPA antigen higher (P = .0001) and tPA activity lower (P = .05) than controls, with an inverse correlation (r = -0.454; P = .003) between anti-tPA antibody levels and tPA activity and no correlation with tPA antigen. The 2 patients with the highest antibody levels had tPA activity below the normal range. Their antibodies were, respectively, IgG1 and IgG3; both recognized human tPA, recombinant tPA, and the catalytic domain of tPA, but not beta 2-glycoprotein I, prothrombin, or plasminogen. Our data indicate that anti-tPA antibodies specifically interacting with the catalytic domain of tPA can be found in patients with APS, representing a possible cause of hypofibrinolysis.

Hypersensitivity reactions associated with recombinant tissue-type plasminogen activator and urokinase

Anaphylaxis or angioedema in response to recombinant tissue-type plasminogen activator or urokinase have been reported in only a few isolated cases. Both agents are endogenous proteins and thus considered non-antigenic. Activation of fibrinolysis may per se facilitate anaphylactoid reactions by pathophysiologic pathways that are not well understood. We report a unique case, review the literature and discuss implication for the clinician. The 25-year-old patient underwent thrombolytic treatment for extensive thrombosis of pelvic and deep lower extremity veins. The patient developed protracted anaphylactoid reactions during recombinant tissue-type plasminogen activator continuous intravenous infusion. After changing treatment to urokinase, the same symptoms recurred with more severe intensity, despite corticosteroid premedication. Symptoms resolved within hours after treatment with histamine receptor blockers. This unique observation, i.e. sequential occurrence of anaphylactoid reactions during recombinant tissue plasminogen activator and urokinase treatments, adds to existing evidence for an unspecific non-antigenic pathomechanism, and for a class effect of thrombolytics. Steroids do not prevent, but histamine receptor blockers seem to be an effective treatment of this unusual complication of thrombolytic therapy.

Human immune response to recombinant human proteins

Delivery of pharmacological doses of proteins to people has raised concerns of inducing immune responses, especially when the protein is provided in multiple doses over an extended period of time. Immune responses could impact the therapeutic exposure and efficacy of the protein itself. In addition, there have been fears of anaphylaxis or autoimmunity. This review summarizes the available literature regarding the measurement and evaluation of immune responses observed during clinical assessment of recombinant human proteins. Immune responses have ranged from none at all to inactivation and/or accelerated clearance. Presence of antibodies does not necessarily impact therapeutic viability. While responses are related to frequency and route of delivery, there is no clear relationship that enables one to predict the clinical experience.

Antibodies to tissue-type plasminogen activator in plasma from patients with primary antiphospholipid syndrome

A reduction in fibrinolysis has been described in association with thrombosis in the primary antiphospholipid syndrome (PAPS). In this study, we measured anti-tissue-type plasminogen activator (t-PA) antibodies and anti-fibrin-bound t-PA antibodies as possible causes of hypofibrinolysis in 39 patients with PAPS. We also evaluated the differences in anti t-PA antibodies between patients without previous thrombosis (20 patients) and patients with previous episodes of thrombosis (19 patients: deep vein thrombosis in nine, ischaemic stroke in six, arterial leg thrombosis in one, hepatic vein thrombosis in one, thrombophlebitis in one and cerebral venous thrombosis in one). Anti-t-PA antibodies were measured by an enzyme-linked immunosorbent assay (ELISA), and anti-t-PA fibrin-bound antibodies were measured by a solid-phase fibrin immunoassay (SOFIA) in 39 patients with PAPS and in 39 controls matched for gender and age. High levels of IgG anti-t-PA were found in three out of 39 patients with PAPS, and all three patients had a history of thrombosis; four other patients, one of whom had a history of thrombotic events, had high titres of antibodies directed against fibrin-bound t-PA. In addition, patients with ischaemic stroke had significantly higher levels of IgG anti-t-PA than patients without thrombosis (P = 0.029). In conclusion, our data showed that, in patients with PAPS, the highest levels of anti-t-PA antibodies were present in subjects with previous thrombotic events. The discrepancy in the results obtained with two methods of detection of anti-t-PA antibodies, ELISA and SOFIA, indicates a different interaction of the antibodies with the t-PA molecules, which are directly bound to polystyrene plates in ELISA and bound to fibrin as a bridging molecule in SOFIA.