Managing severe warm autoimmune haemolytic anaemia after the SARS-Cov- 2 vaccine with emergency splenectomy and eculizumab

Autoimmune haemolytic anaemia (AIHA) is rare but described after the SARS-CoV- 2 Pfizer-BioNTech vaccine. We present a case of severe refractory warm AIHA after this vaccine, managed with emergency splenectomy and complement inhibition with eculizumab. A male in his teens with a history of liver transplant for biliary atresia (aged 2 years) and AIHA (aged 6 years) presented to his district general hospital with jaundice, dark urine, fatigue and chest discomfort 48 h after the first dose of SARS-CoV- 2 Pfizer-BioNTech vaccine (BNT162b2 mRNA). Investigations revealed haemoglobin (Hb) of 70 g/L and bilirubin of 98 mumol/L, which was treated as AIHA. The patient initially responded to prednisolone (1 mg/kg, 60 mg) but subsequently deteriorated and failed to respond to second-line rituximab (375 mg/m2) and two units of packed red blood cells (PRBC). By day 29 the patient had developed life-threatening anaemia culminating in a Hb of 35 g/L (after transfusion), lactate dehydrogenase (LD) of 1293 units/L and bilirubin of 228 mumol/L. This necessitated an immediate transfer to our tertiary centre for specialist support. Further investigations revealed a haptoglobin <0.1 g/L and direct antiglobulin test (DAT) strongly positive for IgG (4+) and negative for C3d. The peripheral blood film showed severe anaemia, nucleated red cells, anisocytosis and spherocytes with no autoagglutination, schistocytes or platelet clumps. Thrombocytopaenia (platelets 49 +/- 109/L) was present. Differentials were ruled out, such as paroxysmal nocturnal haemoglobinuria and heparin-induced thrombocytopaenia. HIV and hepatitis serology were negative, as were adenovirus, cytomegalovirus and Epstein-Barr virus PCR assays. A CT showed splenomegaly of 15.5 cm. Urinalysis found urobilinogen and bilirubin at high concentrations and negative urinary haemosiderin. Together, the investigations were consistent with warm AIHA. On day 29, four units of PRBC were transfused alongside 100 mg methylprednisolone and 1 g/kg IVIG. On day 30 the patient deteriorated despite the escalated treatment: Hb had only increased to 54 g/L, bilirubin was 200 mumol/L and LD was rising. Considering this life-threatening fulminant haemolysis, an emergency splenectomy was performed. This slowed haemolysis but did not completely ameliorate it: by day 33 the patient had received 15 units of PRBC. Thus, eculizumab, a terminal complement pathway inhibitor, was trialled to arrest intravascular haemolysis, alongside rituximab, repeat IVIG 1 g/kg, prednisolone 40 mg and tacrolimus 2 mg. This showed a favourable response, requiring less frequent transfusions and settling haemolysis. This case highlights the rare complication of warm AIHA with the SARS-CoV- 2 Pfizer-BioNTech vaccine, the use of emergency splenectomy for disease control, and the potential of eculizumab for refractory cases.

Complement activation in COVID-19 and targeted therapeutic options: A scoping review.

Increasing evidence suggests that activation of the complement system plays a key role in the pathogenesis and disease severity of Coronavirus disease 2019 (COVID-19). We used a systematic approach to create an overview of complement activation in COVID-19 based on histopathological, preclinical, multiomics, observational and clinical interventional studies. A total of 1801 articles from PubMed, EMBASE and Cochrane was screened of which 157 articles were included in this scoping review. Histopathological, preclinical, multiomics and observational studies showed apparent complement activation through all three complement pathways and a correlation with disease severity and mortality. The complement system was targeted at different levels in COVID-19, of which C5 and C5a inhibition seem most promising. Adequately powered, double blind RCTs are necessary in order to further investigate the effect of targeting the complement system in COVID-19.

Anti-C5a antibody vilobelimab treatment and the effect on biomarkers of inflammation and coagulation in patients with severe COVID-19: a substudy of the phase 2 PANAMO trial.

We recently reported in the phase 3 PANAMO trial that selectively blocking complement 5a (C5a) with vilobelimab led to improved survival in critically ill COVID-19 patients. C5a is an important contributor to the innate immune system and can also activate the coagulation system. High C5a levels have been reported in severely ill COVID-19 patients and correlate with disease severity and mortality. Previously, we assessed the potential benefit and safety of vilobelimab in severe COVID-19 patients. In the current substudy of the phase 2 PANAMO trial, we aim to explore the effects of vilobelimab on various biomarkers of inflammation and coagulation. Between March 31 and April 24, 2020, 17 patients with severe COVID-19 pneumonia were enrolled in an exploratory, open-label, randomised phase 2 trial. Blood markers of complement, endothelial activation, epithelial barrier disruption, inflammation, neutrophil activation, neutrophil extracellular trap (NET) formation and coagulopathy were measured using enzyme-linked immunosorbent assay (ELISA) or utilizing the Luminex platform. During the first 15 days after inclusion, change in biomarker concentrations between the two groups were modelled with linear mixed-effects models with spatial splines and compared. Eight patients were randomized to vilobelimab treatment plus best supportive care (BSC) and nine patients were randomized to BSC only. A significant decrease over time was seen in the vilobelimab plus BSC group for C5a compared to the BSC only group (p < 0.001). ADAMTS13 levels decreased over time in the BSC only group compared to the vilobelimab plus BSC group (p < 0.01) and interleukin-8 (IL-8) levels were statistically more suppressed in the vilobelimab plus BSC group compared to the BSC group (p = 0.03). Our preliminary results show that C5a inhibition decreases the inflammatory response and hypercoagulability, which likely explains the beneficial effect of vilobelimab in severe COVID-19 patients. Validation of these results in a larger sample size is warranted.

Genetic prediction of ICU hospitalization and mortality in COVID-19 patients using artificial neural networks.

There is an unmet need of models for early prediction of morbidity and mortality of Coronavirus disease-19 (COVID-19). We aimed to a) identify complement-related genetic variants associated with the clinical outcomes of ICU hospitalization and death, b) develop an artificial neural network (ANN) predicting these outcomes and c) validate whether complement-related variants are associated with an impaired complement phenotype. We prospectively recruited consecutive adult patients of Caucasian origin, hospitalized due to COVID-19. Through targeted next-generation sequencing, we identified variants in complement factor H/CFH, CFB, CFH-related, CFD, CD55, C3, C5, CFI, CD46, thrombomodulin/THBD, and A Disintegrin and Metalloproteinase with Thrombospondin motifs (ADAMTS13). Among 381 variants in 133 patients, we identified 5 critical variants associated with severe COVID-19: rs2547438 (C3), rs2250656 (C3), rs1042580 (THBD), rs800292 (CFH) and rs414628 (CFHR1). Using age, gender and presence or absence of each variant, we developed an ANN predicting morbidity and mortality in 89.47% of the examined population. Furthermore, THBD and C3a levels were significantly increased in severe COVID-19 patients and those harbouring relevant variants. Thus, we reveal for the first time an ANN accurately predicting ICU hospitalization and death in COVID-19 patients, based on genetic variants in complement genes, age and gender. Importantly, we confirm that genetic dysregulation is associated with impaired complement phenotype.

Sars-Cov-2 Vaccination in Patients with Paroxysmal Nocturnal Hemoglobinuria: An Italian Multicenter Survey

SARS-CoV-2 infection and vaccination have raised concerns in paroxysmal nocturnal hemoglobinuria (PNH). In fact, PNH patients carry an increased infectious risk secondary to complement inhibition treatment or associated bone marrow failure (BMF), and may therefore benefit from preventive strategies such as vaccinations. On the contrary, vaccines can be numbered among inflammatory complement amplifiers (e.g., infections, traumas, surgery), potentially triggering a disease exacerbation. In PNH patients on complement inhibitors, this phenomenon has been defined pharmacodynamic breakthrough hemolysis (BTH). Based on isolated reports of BTH following SARS-CoV-2 vaccines, we conducted a survey among 5 Italian reference centers to evaluate complications and BTH occurrence in PNH patients who completed the SARS-CoV-2 vaccination schedule from January, 2 2021 until the time of writing. Adverse events, hematologic and hemolytic parameters were recorded within 7-10 days before and after each dose of vaccine. A total of 67 patients (females/males 43/24, median age 47.6 years, range 21-90.5) were eligible for the analysis. According to the International PNH Interest Group classification, 45 patients suffered from hemolytic PNH, 20 from PNH in the context of BMF syndromes (aplastic anemia or myelodysplastic syndrome), and 2 from subclinical PNH. Fifty-five subjects (82%) were on regular complement inhibition therapy, i.e., eculizumab (N=35), ravulizumab (N=13), subcutaneous anti-C5 (N=3), anti-factor B (N=2) and ravulizumab + anti-factor D combination (N=2). Vaccines (Comirnaty/Pfizer-BioNTech N=53, mRNA-1273/Moderna N=12, and ChAdOx1 nCov-19/AstraZeneca N=2) were complessively well-tolerated, with 3 non-hematologic adverse events after the first dose (2 fever and 1 exercise-induced tachycardia, grade 1 according to CTCAE v5.0) and 2 after the second one (fever, accompanied by vomit in one patient, grade 1). During the observation period, 3 BTH and 1 hemolytic exacerbation were recorded (5.9% of patients), as detailed in Table 1. The most severe episode occurred in a young woman (Patient 3) on subcutaneous ravulizumab who experienced a hemoglobin (Hb) drop >2 g/dL, marked clinical signs of intravascular hemolysis and lactate dehydrogenase (LDH) increase >1.5 x upper limit of normal (ULN) from baseline, which is considered a clinical BTH according to the criteria proposed by the Severe Aplastic Anemia Working Party of the European group for Bone Marrow Transplantation. The patient required hospitalization for additional treatment with recombinant erythropoietin and anti-thombotic/bacterial prophylaxis. The second more severe BTH was registered in a male patient (Patient 1) on oral anti-factor B who experienced a Hb drop >2 g/dL without an overt hemolytic flare, and required hospitalization for intravenous antibiotic therapy (concomitant urinary tract infection). The remaining two patients experienced a subclinical BTH (Patient 2) and a hemolytic flare (Patient 4, not on complement inhibition). On the whole, a median delta variation from usual values of Hb and LDH of -25% (range -26+3%) and +80% (+18+105%) were observed, respectively. Of note, 3 episodes occurred after the second dose of vaccine, generally within 24-48 hours. Anti-complement drugs were not modified/discontinued in any of the 3 patients on regular treatment. Patients not experiencing BTH (94.1%) showed stable hematologic parameters after the first dose (Hb/LDH median delta variations from baseline -1%/+1%, range -14+12%/-32+40%) and the second dose of vaccine (Hb/LDH median delta variations from baseline +1%/0%, range -18+47%/-76+41%). Of note, 4 patients with a previous SARS-CoV-2 infection completed the vaccination without any complication/PNH exacerbation. In conclusion, this survey shows that BTH/hemolytic flares following SARS-CoV-2 vaccines are observed in about 6% of PNH patients, may be clinically relevant but manageable, and should not discourage vaccination. BTH has been registered mostly few days after the second dose of vaccine, suggesting a “booster⠝ effect favoring a higher inflammatory response. Watchful clinical and laboratory monitoring is advised, in order to promptly recognize severe hemolytic flares in both treated and naïve patients. [Formula presented] Disclosures: Fattizzo: Novartis: Speakers Bureau;Kira: Speakers Bureau;Alexion: Speakers Bureau;Annexon: Consultancy;Momenta: Honoraria, Speakers Bureau;Apellis: Speakers Bureau;Amgen: Honoraria, Speakers Bureau. Bianchi: Agios pharmaceutics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sica: Jazz Pharma: Consultancy;Alexion: Consultancy. Barcellini: Novartis: Other: Invited speaker, Research Funding;Agios: Membership on an entity's Board of Directors or advisory committees;Alexion Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees, Other: Invited speaker, Research Funding;Bioverativ: Membership on an entity's Board of Directors or advisory committees;Incyte: Membership on an entity's Board of Directors or advisory committees.

Complement inhibition initiated recovery of a severe myasthenic crisis with COVID-19.

We report on a patient with refractory Myasthenia gravis with acetylcholine receptor antibodies with two prior myasthenic crises suffering from COVID-19 with rapid evolving weakness and respiratory failure. Respiratory failure developed and prolonged mechanical ventilation was necessary. After plasmapheresis, residual, severe generalized and bulbar weakness persisted. Complement inhibition with eculizumab was, therefore, introduced and lead to rapid recovery. In refractory myasthenic crisis individualised therapies could be successful.

Computational analysis of complement inhibitor compstatin using molecular dynamics.

The complement system plays a major role in human immunity, but its abnormal activation can have severe pathological impacts. By mimicking a natural mechanism of complement regulation, the small peptide compstatin has proven to be a very promising complement inhibitor. Over the years, several compstatin analogs have been created, with improved inhibitory potency. A recent analog is being developed as a candidate drug against several pathological conditions, including COVID-19. However, the reasons behind its higher potency and increased binding affinity to complement proteins are not fully clear. This computational study highlights the mechanistic properties of several compstatin analogs, thus complementing previous experimental studies. We perform molecular dynamics simulations involving six analogs alone in solution and two complexes with compstatin bound to complement component 3. These simulations reveal that all the analogs we consider, except the original compstatin, naturally adopt a pre-bound conformation in solution. Interestingly, this set of analogs adopting a pre-bound conformation includes analogs that were not known to benefit from this behavior. We also show that the most recent compstatin analog (among those we consider) forms a stronger hydrogen bond network with its complement receptor than an earlier analog.