We retrospectively studied 232 patients with cold agglutinin disease (CAD) at 24 centers in five countries. In Norway and a northern region of Italy, the study was close to being population-based. For the first time, we demonstrate 4-fold differences between cold and warmer climates regarding prevalence (20 versus 5 cases/million) and incidence (1.9 versus 0.48 cases/million/year). Mean baseline hemoglobin level was 9.3 g/dL, but 27% had hemoglobin < 8 g/dL. Identification of typical features of 'CAD-associated lymphoproliferative disorder' in the bone marrow was greatly increased by centralized biopsy assessment. CAD seems to be associated with a slightly increased risk of venous thrombosis. This work included a follow-up study of therapies, focusing on the long-term outcomes of the rituximab plus bendamustine and rituximab plus fludarabine regimens. Rituximab plus bendamustine therapy resulted in responses in 35 (78%) of 45 patients; 24 (53%) achieved complete response. Interestingly, these rates were still higher than observed in the original (2017) prospective trial, and we also found a shift towards deeper responses with time. This is explained by the prolonged time to response seen in many patients, probably related to long-lived plasma cells. In patients responding to rituximab-bendamustine, median response duration was not reached after 88 months, and estimated 5-year sustained remission was 77%. The regimen appeared safe regarding late-occurring malignancies. Rituximab plus fludarabine therapy seems to carry a higher risk of long-term adverse effects.
Background
The COVID‐19 vaccine from AstraZeneca (AZD1222) is one of several vaccines introduced to provide immunity against SARS‐CoV‐2. Recently, more than 50 cases have been reported presenting a combination of thrombosis, thrombocytopenia, and remarkably high levels of anti‐platelet factor 4 (PF4)/polyanion antibodies post‐AZD1222 vaccination. Now linked to the vaccine, the condition is referred to as vaccine‐induced immune thrombotic thrombocytopenia. The European Medicines Agency still recommends vaccination with AZD1222, but several European countries have temporally paused and/or restricted its use because of the perceived risk of this severe side effect. Because there is no description of PF4/polyanion antibody testing in the clinical trials, knowledge about the prevalence of such antibodies in a vaccinated cohort is needed.
Objectives
To investigate prevalence of thrombocytopenia and anti‐PF4/polyanion antibodies in a population recently vaccinated with AZD1222.
Patients/Methods
Four hundred and ninety‐two health care workers recently vaccinated with the first dose of AZD1222 were recruited from two hospitals in Norway. Study individuals were screened for thrombocytopenia and the presence of anti‐PF4/polyanion antibodies with a PF4/PVS immunoassay. Side effects after vaccination were registered.
Results
The majority of study participants had normal platelet counts and negative immunoassay. Anti‐PF4/polyanion antibodies without platelet activating properties were only detected in six individuals (optical density ≥0.4, range 0.58–1.16), all with normal platelet counts. No subjects had severe thrombocytopenia.
Conclusions
We found low prevalence of both thrombocytopenia and antibodies to PF4/polyanion‐complexes among Norwegian health care workers after vaccination with AZD1222.
Primary chronic cold agglutinin disease (CAD) is an autoimmune haemolytic anaemia in which a specific bone marrow lymphoproliferative disorder causes production of cold agglutinins (CA). Binding of CA to erythrocyte surface antigens results in a predominantly extravascular haemolysis that is entirely complement dependent. Because of complement activation, exacerbations are common during febrile infections, trauma or major surgery. Involvement of the terminal complement pathway with C5-mediated intravascular haemolysis is probably not prominent in stable disease but is supposed to be of importance in exacerbations following acute phase reaction.We report on a patient with CAD prone to exacerbation of haemolysis during acute phase reactions who was scheduled for cardiac surgery. To prevent her having an exacerbation of haemolysis, we chose to treat her prophylactically with eculizumab along with the usual perioperative precautions. Aortic valve replacement was undertaken with full cardiopulmonary bypass at normothermia. The procedure was successful; no exacerbation of haemolysis was observed, and transfusion requirements did not exceed what could be expected.
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