ADAMS-TS13 Inhibitor Level and Risk of Relapse in Acquired Idiopathic Thrombotic Thrombocytopenic Purpura

Introduction: Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy due to reduced activity of ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, 13). This disorder can be due to a congenital deficiency state or be acquired (immune TTP (iTTP)) due to an antibody which either inhibits or causes clearance of ADAMTS13. The aim of our study was to determine whether ADAMTS13 inhibitor titer at initial presentation could serve as a predictor of refractory disease and relapse in iTTP. We also measured clinical outcomes across different gender and racial subgroups. Methods: The United States Thrombotic Microangiopathy (USTMA) iTTP registry was used to extract patient information for two academic institutions in Eastern North Carolina. Descriptive statistics were used to analyze the data. The first iTTP episode recorded in the data base was used as the index episode. All patients included in the final analysis had an ADAMTS13 activity of <10%. An inhibitor level of 5 Bethesda units was arbitrarily chosen as the cutoff between low (<5) and high (>/5) inhibitor level. Response time was defined as the number of days of plasma exchange (PEX) required to achieve a platelet count of 150,000 for two consecutive days. Relapse was defined as occurrence of a new episode of iTTP 30 days after achievement of response. Refractory disease was defined as persistence of thrombocytopenia or absence of a sustained platelet count increment or platelet counts of < 50,000 despite 4-7 days of plasma exchanges and steroid treatment. Rituximab resistance was defined as lack of platelet recovery to more than 150,000 within 11 to 14 days of administration of the first dose of Rituximab. Results: A total of 161 patients with iTTP were identified. Ten patients had ADAMTS13 activity >10% and 15 patients did not have a reported inhibitor level. These subjects were not included in the final analysis. The cohort had 28% male (n =38/136) and 72% (n=98/136) female patients. There were more African American patients 73% (n=99/136) than Caucasians 24% (n=32/136). There were also 2 Hispanic, 1 Native American and 2 patients with unidentified race. Median ADAMTS3 inhibitor titer was 1.05 (Range 0-87). Forty three patients with ADAMTS13 activity <10 % had an inhibitor level of 0 (i.e undetectable).They were included in the low inhibitor group. Overall, 88% patients (n=120/136) had low inhibitor level and only 12% (n=16/136) had a high inhibitor. Thirteen percent females (n=13/98) and 8% (n=3/38) males had a high inhibitor level (p=0.387). Fourteen percent (n=14/99) African Americans and 6 % (n=2/32) Caucasians had a high inhibitor, p=0.23. In the low inhibitor group 30% (n=36/120) patients suffered at least one episode of relapse whereas 31% (n=5/16) had relapsed in the high inhibitor group. The median time to response was 6 days (range 1-76) in the low inhibitor group and 7 days (range 4-20) in the high inhibitor group (p=0.61). While looking at the various subgroups, median time to response for males was 6 days (range 4-21), females 6 days (range 1-76) , African Americans 6 days (range 3-29) , and Caucasians 6 days (range 1-76). The frequency of refractory disease was 31 % (n=5/16) in the high inhibitor group and 29% (n=34/119) in the low inhibitor group. At the time of enrollment in the registry, Rituximab was not a part of first line therapy. Only 26 out of 136 patients had received Rituximab. In the low inhibitor group 5 patients displayed Rituximab resistance whereas there were no patients in the high inhibitor group with Rituximab resistance. Conclusion: When evaluating patients presenting with iTTP in two centers in North Carolina, no correlation was found between a high inhibitor levels of >/ 5 Bethesda units and risk of relapse or refractory disease. A larger study is needed to evaluate this further. Disclosures No relevant conflicts of interest to declare.

Measurement of C1-Inhibitor function alone is sufficient for diagnosis of hereditary angioedema

The World Allergy Organisiation/European Academy of Allergy and Clinical Immunology (WAO/EAACI) 2017/2018 guidelines recommend measuring complement4 levels, followed by C1-inhibitor level and function for diagnosis of hereditary angioedema (HAE). We analysed 6 months’ worth of data generated in our laboratory which is a specialist regional immunology service and also provides laboratory service for the Barts Health immunology department, which is a GA2LEN/HAEi-Angioedema Centre of Excellence and Reference (ACARE) and hence, investigates a large number of patients for HAE. We found that an efficient and sensitive approach for laboratory diagnosis of HAE is to only test the C1-inhibitor function. This approach had a sensitivity of 100% and reduced the cost of laboratory investigations for HAE diagnosis by 45%.

Diagnosis and treatment of hereditary angioedema with normal C1-inhibitor level

Hereditary angioedema (HAE) with normal C1-inhibitor level is a rare potentially life-threatening disorder with autosomal dominant inheritance which was first described in 2000. Its clinical presentation is similar to HAE with C1-deficiency. The review is summarized data about its prevalence, mechanisms, genetics and diagnostic criteria. Different subtypes and treatment options (on demand, short term and long-term prophylaxis) are discussed. We describe family clinical cases of 2 female patients with normal C1-inhibitor and plasminogen gene mutation. Their features were late diagnosis (in 10 and 25 years after the onset of symptoms), family history (similar genetic mutation in 3 female members of the same family, including 1-asymtomatic) and combination of face, tongue, larynx and abdominal angioedema in patient and her sibling.

Review of Type III Non-Hereditary Angioedema Patients in Manitoba.

Introduction: Non-hereditary angioedema with normal C1 esterase inhibitor level and function (NHAE-nC1INH) is a novel entity. The diagnosis of NHAE-nC1INH requires a high index of suspicion, given that there are no laboratory tests to confirm the diagnosis. There is limited evidence on the treatment efficacy for short- and long-term prophylaxis, and acute attacks. The aim of the study is to describe a cohort of NHAE-nC1INH in Manitoba, including an estimate of prevalence, as well as to analyze the response to plasma derived C1esterase inhibitor (pdC1INH), and a bradykinin-2 receptor antagonist (Icatibant).Methods: A retrospective chart review of patients diagnosed with normal C1 esterase level and function angioedema seen at the Clinical Immunology and Allergy Clinic at the Health Sciences Centre in Winnipeg, Manitoba, was done. Inclusion criteria included the following: (1) Reside within Manitoba (2) Aged 18 years and older (3) Angioedema without urticaria (4) Normal C1-INH antigenic level and function (5) No symptom resolution with antihistamines, epinephrine or corticosteroids. (6) No family history. Five patients were included in the study who met the above inclusion criteria. The five patients charts were reviewed. Response to pdC1INH and Icatibant were defined as time to improvement of angioedema symptoms.Results: Four out of five patients had an effective response to pdC1INH for prophylactic treatment and for on-demand treatment for angioedema episodes. pdC1INH was ineffective in 1 patient for prophylaxis and on-demand treatment; tranexamic acid was successful for prophylactic treatment in 1 patient who did not respond to pdC1INH for prophylaxis and for on-demand treatment. 3 of 5 patients have tried Icatibant. All three patients were not responsive to Icatibant.Conclusion: This study suggests that pdC1INH may be an efficacious treatment option for NHAE-nC1INH patients. Larger studies are required to better elucidate the effectiveness of on-demand and prophylactic treatment for NHAE-nC1INH.

Ezetimibe: An Unusual Suspect in Angioedema

We describe a case of new onset angioedema likely due to Ezetimibe therapy in an elderly patient with a prior history of drug-induced bradykinin reactions who had been on the medication for multiple years. This is the second reported incidence of Ezetimibe-associated angioedema in literature. A 90-year-old African American female presented with angioedema of the face and oral mucosa with associated difficulty speaking developing hours after taking Ezetimibe 10 mg PO. She denied adding any new or unusual foods to her diet. A thorough clinical history determined Ezetimibe was the likely culprit. Ezetimibe was immediately discontinued. The swelling subsided after administration of methylprednisolone 125 mg, epinephrine 1 mg/mL, injection 0.3 mL, diphenhydramine 25 mg, and famotidine 20 mg BID within 48 hours. The patient’s C1 esterase inhibitor level was measured to be within normal limits. Food panel allergy testing showed very low or undetectable IgE levels in all categories. Based on the limited reports in literature and our current case, we conclude that there is a likely association of angioedema with Ezetimibe. The mechanism, however, is unknown since it is not related to bradykinin or mast cell-mediated activation. Clinicians should advise patients taking Ezetimibe to report any swelling of the lips, face, and tongue and to immediately discontinue its use if these signs are present.

Features of the dynamics of inflammation and apoptosis markers in patients with different acute post-stroke period

The purpose of this was to study the dynamics of markers of inflammation and apoptosis in the serum of patients with ischemic stroke in the early post-stroke period. Materials and methods. The study involved 22 patients (mean age 60 ± 5.5 years) with different dynamics of neurological symptoms in the acute post-stroke period. Patients were examined twice: on the 1st and 10th day of observation. Quantitative assessment of the severity of neurological deficit using ESS and NIHSS scales was carried. Enzymatic activity of leukocyte elastase, functional activity of a1-proteinase inhibitor, level of autoantibodies to MBP (inflammatory markers), as well as the content of p53 and Bcl-2 proteins (markers of apoptosis) were determined in serum. The control group consisted of 35 somatically healthy people of the appropriate age and sex. Results. Identified the different features of the spectrum of the analyzed markers of inflammation and apoptosis in patients with positive and negative dynamics of neurological symptoms in the acute period of ischemic stroke assessed according to the ESS and NIHSS scales. The observed clinical and biological relationships reflect the features of the course of the early post-stroke period and can be considered as possible predictors of the development trajectory of acute brain ischemia.

Transplacental Hemophilia a and Prophylactic Treatment with Recombinant FVIIa in the Newborn Period

Acquired hemophilia due to inhibitor antibodies is a rare entity during childhood period. Moreover, transplacental hemophilia during the newborn period as a result of maternal IgG antibodies (inhibitors) which may cross the placenta into the foetal circulation is very rare and may cause life- threathening neonatal hemorrhages. The occurence of acquired hemophilia during or after delivery may lead bleeding tendencies in both the mother and baby. Here, we want to decribe a newborn baby who delivered from a mother with an initial diagnosis of acquired Hemophilia A and succesfully treated with a prohylactic rFVIIa. Case : A 27 years old women who was diagnosed with an acquired hemophilia A after her first delivery was admitted to our hospital for the second delivery.Her pregnancies were 15 months apart. Her FVIII level was found to be low (<1%) with a very high titer (>100NBU) inhibitor.She was treated with rFVIIa before C/S by adult hematologist and after giving a birth to a term boy without any bleeding complication, newborn baby was referred to our department because of having low FVIII level (0.3 %) with high titer inhibitor(320 NBU) and an abnormal aPTT mixing test on the first day of life. Cranial and abdominal USG was found to be normal and despite having no bleeding event we decide to give IVIG treatment due to very high titer of inhibitor level. On the 3rd day of life some blood in the stool was detected however there is no decrease in the Hb level. Prophylactic rFVIIa with a dose of 90µg/kg/daily was given during the next 4 weeks and inhibitor level was checked regulary. His inhibitor level was decraesed gradually on the first week 256NBU , second week 51 NBU and 4th week 2NBU with a FVIII level 2.7% and propylactic treatment was stopped on the 5th week of life. Although we did not able to detect inhibitor antibodies by trying to do aptt mixing test in the breastmilk, his mother did not have enough breatmilk and baby was supported by infant formula as well. There was a few numbers of cases with neonatal acquired hemophilia due to transplacental transfer of autoantibodies reported in the literature . It was reported that most inhibitors spntaneously disappear over a median 30 months after delivery and FVIII inhibitors are rarely present during labor and delivery in the next pregnancy. However, in our case 15 months after the first pregnacy he was delivered. The outcome of the transplasental acquired hemophilia cases reported in the literature was favorable with a resolution after a median of 3 months (range 0.2-3 months) despite one of them experienced intracranial hemorrhage.. Although peak inhibitor titer was reported to be 150BUin the literature, in our case it was the higher than the reported level (320NBU). However despite a very high peak inhibitor titer, we can speculate that due to limited intake of breastmilk which may also contain inhibitor antibodies may ameoliorate the prompt decrase of inhibitor antibodies. rFVIIa is safe and protect our patient from life-threatening bleeding events without any complication. Disclosures No relevant conflicts of interest to declare.

Effect of an angiotensin-converting-enzyme inhibitor on the plasma concentration of cytokines and vasoactive molecules in patients with coronary heart disease and hypertension

Aim. To investigate the plasma concentrations of cytokines and vasoactive molecules in patients with coronary heart disease (CHD) in the presence of hypertension in relation to the angiotensin-converting-enzyme (ACE) inhibitor level reflecting the degree of renin-angiotensin-aldosterone system (RAAS) inhibition. Subjects and methods. 72 patients with NYHA functional class (FC) II-III angina pectoris and 40 healthy persons at the age of 47-65 years were examined in a controlled cohort study. Enzyme immunoassay was employed to determine the serum concentrations of interleukins (IL) (IL-2, IL-12, IL-17A, and IL-24), the vasoactive molecules of bradykinin, serotonin, ACE, angiotensin-II (AT-II), NO, and endothelin-1 (ET-1), and plasma renin activity. In addition, the plasma level of the tetrapeptide N-acetyl-Ser-Asp-Lys-Pro was used as a marker for ACE inhibition. Results. The patients with CHD occurring in the presence of hypertension compared with the apparently healthy individuals displayed decreased ET-1 and NO production along with elevated levels of serotonin, AT-II, as well as IL-17A and IL-12. The found changes were accompanied by reduced renin activity. Thus, the individuals with low ACE inhibitor levels showed more pronounced production of the proinflammatory cytokine IL-17A, as well as high plasma concentrations of ACE and NO. The high ACE inhibitor level that reflects patient adherence to appropriate antihypertensive therapy is associated with the reduced production of IL-2 and with the minimum serum levels of ACE, AT-II, and NO, being characterized by the high production of IL-12 and serotonin at the same time. Conclusion. In patients with CHD and hypertension, the high plasma enzyme inhibitor concentration that reflects the activity of appropriate antihypertensive therapy, by contributing to the strengthening of the mechanisms of relaxation of blood vessels, is associated with the risk for proinflammatory activation of whole blood cells and platelets. The mean ACE inhibitor levels that reflect moderate RAAS suppression and are characterized by a relatively low proinflammatory activation of mononuclear cells may be more preferable than the maximum ones, from the point of view of slowing the progression of the subclinical inflammatory process of the vascular wall and preventing possible CHD exacerbations. This determines the feasibility of estimating the plasma level of an ACE inhibitor to control the depth of inhibition of RAAS activity.