Gene expression analysis revealed downregulation of complement receptor 1 in clonal B cells in cold agglutinin disease.

Cold agglutinin disease (CAD) is a rare B-cell lymphoproliferative disorder of the bone marrow, manifested by autoimmune hemolytic anemia caused by binding of monoclonal IgM autoantibodies to the I antigen. Underlying genetic changes have previously been reported, but their impact on gene expression profile has been unknown. Here, we define differentially expressed genes in CAD B cells. To unravel downstream alteration in cellular pathways, gene expression by RNA sequencing was undertaken. Clonal B-cell samples from 12 CAD patients and IgM-expressing memory B cells from 4 healthy individuals were analyzed. Differential expression analysis and filtering resulted in 93 genes with significant differential expression. Top upregulated genes included SLC4A1, SPTA1, YBX3, TESC, HBD, AHSP, TRAF1, HBA2, RHAG, CA1, SPTB, IL10, UBASH3B, ALAS2, HBA1, CRYM, RGCC, KANK2, and IGHV4-34. They were upregulated at least 8-fold, while complement receptor 1 (CR1/CD35) was downregulated 11-fold in clonal CAD B cells compared to control B cells. Flow cytometry analyses further confirmed reduced CR1 (CD35) protein expression by clonal CAD IgM+ B cells compared to IgM+ memory B cells in controls. CR1 (CD35) is an important negative regulator of B-cell activation and differentiation. Therefore, reduced CR1 (CD35) expression may increase activation, proliferation, and antibody production in CAD-associated clonal B cells.

Cold-antibody Autoimmune Hemolytic Anemia: its Association with Neoplastic Disease and Impact on Therapy.

PURPOSE OF REVIEW: Cold-antibody mediated autoimmune hemolytic anemia (cAIHA) is subclassified as cold agglutinin disease (CAD), secondary cold agglutinin syndrome (CAS), and paroxysmal cold hemoglobinuria (PCH). This review aims to address the occurrence of neoplastic disorders with these three entities and analyze the impact of such neoplasias on treatment for cAIHA. RECENT FINDINGS: "Primary" CAD is a distinct clonal B-cell lymphoproliferative disorder in probably all cases, although not classified as a malignant lymphoma. CAS is secondary to malignant lymphoma in a minority of cases. Recent findings allow a further clarification of these differential diagnoses and the therapeutic consequences of specific neoplastic entities. Appropriate diagnostic workup is critical for therapy in cAIHA. Patients with CAD should be treated if they have symptomatic anemia, significant fatigue, or bothersome circulatory symptoms. The distinction between CAD and CAS and the presence of any underlying malignancy in CAS have essential therapeutic implications.

Successful treatment of concurrent cold agglutinin disease and myelodysplastic syndrome.

Herein, we describe a case of severe anemia presenting with myelodysplastic syndrome with cold agglutinin disease that was successfully treated by a moderate dose of steroids followed by cyclosporine. In patients with myelodysplastic syndrome, autoimmunity in erythroid cells is occasionally demonstrated, and autoimmune hemolytic anemia is seen in some patients. However, hemolytic anemia with cold agglutinin in patients with myelodysplastic syndrome is less common, and the effect of corticosteroids for autoimmune hemolytic anemia caused by cold agglutinin is thought to be limited. Although the elevated levels of reticulocytes and LDH are usually caused by ineffective hematopoiesis in myelodysplastic syndrome, clinicians should be aware of latent cold agglutinin disease. In the present case, in addition to the improvement of erythroid dysplasia, the corticosteroid-sparing effect on cold agglutinin disease may have played a role in the mechanism underlying the effectiveness of cyclosporine.

Autoimmune Hemolytic Anemias: Challenges in Diagnosis and Therapy.

Background: Autoimmune hemolytic anemia (AIHA) is a rare disease due to increased destruction of erythrocytes by autoantibodies, with or without complement activation. Summary: AIHA is usually classified in warm AIHA (wAIHA) and cold agglutinin disease (CAD), based on isotype and thermal amplitude of the autoantibody. The direct antiglobulin test (DAT) or Coombs test is the cornerstone of AIHA diagnosis, as it is positive with anti-IgG in wAIHA, and with anti-C3d/IgM antisera plus high titer cold agglutinins in CAD. Therapy is quite different, as steroids and rituximab are effective in the former, but have a lower response rate and duration in the latter. Splenectomy, which is still a good option for young/fit wAIHA, is contraindicated in CAD, and classic immunosuppressants are moving to further lines. Several new drugs are increasingly used or are in trials for relapsed/refractory AIHAs, including B-cell (parsaclisib, ibrutinib, rilzabrutinib), and plasma cell target therapies (bortezomib, daratumumab), bispecific agents (ianalumab, obexelimab, povetacicept), neonatal Fc receptor blockers (nipocalimab), and complement inhibitors (sutimlimab, riliprubart, pegcetacoplan, iptacopan). Clinically, AIHAs are highly heterogeneous, from mild/compensated to life-threatening/fulminant, and may be primary or associated with infections, neoplasms, autoimmune diseases, transplants, immunodeficiencies, and drugs. Along with all these variables, there are rare forms like mixed (wAIHA plus CAD), atypical (IgA or warm IgM driven), and DAT negative, where the diagnosis and clinical management are particularly challenging. Key Messages: This article covers the classic clinical features, diagnosis, and therapy of wAIHA and CAD, and focuses, with the support of clinical vignettes, on difficult diagnosis and refractory/relapsing cases requiring novel therapies.

[Cold agglutinin disease: pathology, diagnosis, and treatment].

Cold agglutinin disease (CAD), an immune hemolytic disease mediated by the classical complement-dependent pathway, accounts for approximately 8% of autoimmune hemolytic anemia (AIHA) cases. Primary CAD is a clonal B-cell lymphoproliferative disease of the bone marrow that produces IgM type-M protein, while conventional secondary CAD is cold agglutinin syndrome (CAS). Clinical findings are broadly classified into chronic anemia due to hemolysis and symptoms associated with peripheral circulatory failure due to erythrocyte aggregation under cold exposure. Not all patients require drug therapy, but monoclonal antibody therapy against complement C1s is preferred for the former presentation and B-cell suppressors for the latter. As cold AIHA is treated differently than warm AIHA, misdiagnosis can significantly impact the outcome of treatment. The most important aspect of blood testing is temperature control of specimens. Cold agglutinin titer, IgM quantification, electrophoresis, and immunofixation methods may produce false-negative results if the serum is not temperature-controlled at 37-38°C until serum separation. Correct handling of specimens, along with knowledge of the various clinical features of CAD, will lead to correct diagnosis and appropriate treatment.

Anti-C1s humanized monoclonal antibody SAR445088: A classical pathway complement inhibitor specific for the active form of C1s.

The objective of this study was to characterize the complement-inhibiting activity of SAR445088, a novel monoclonal antibody specific for the active form of C1s. Wieslab® and hemolytic assays were used to demonstrate that SAR445088 is a potent, selective inhibitor of the classical pathway of complement. Specificity for the active form of C1s was confirmed in a ligand binding assay. Finally, TNT010 (a precursor to SAR445088) was assessed in vitro for its ability to inhibit complement activation associated with cold agglutinin disease (CAD). TNT010 inhibited C3b/iC3b deposition on human red blood cells incubated with CAD patient serum and decreased their subsequent phagocytosis by THP-1 cells. In summary, this study identifies SAR445088 as a potential therapeutic for the treatment of classical pathway-driven diseases and supports its continued assessment in clinical trials.

Collection and processing of hematopoietic progenitor cell products at risk of presenting with cold agglutination.

BACKGROUND AIMS: Cold agglutinins are commonly identified in transfusion laboratories and are defined by their ability to agglutinate erythrocytes at 3-4°C, with most demonstrating a titer >64. Similarly, cryoglobulins can precipitate from plasma when temperatures drop below central body temperature, resulting in erythrocyte agglutination. Thankfully, disease associated from these autoantibodies is rare, but unfortunately, such temperature ranges are routinely encountered outside of the body's circulation, as in an extracorporeal circuit during hematopoietic progenitor cell (HPC) collection or human cell therapy laboratory processing. When agglutination occurs ex vivo, complications with the collection and product may be encountered, resulting in adverse events or product loss. Here, we endeavor to share our experience in preventing and responding to known cases at risk of or spontaneous HPC agglutination in our human cell therapy laboratory. CASE REPORTS: Four cases of HPC products at risk for, or spontaneously, agglutinating were seen at our institution from 2018 to 2020. Planned modifications occurred, including ambient room temperature increases, tandem draw and return blood warmers, warm product transport and extended post-thaw warming occurred. In addition, unplanned modifications were undertaken, including warm HPC product processing and plasma replacement of the product when spontaneous agglutination of the product was identified. All recipients successfully engrafted after infusion. CONCLUSIONS: While uncommon, cold agglutination of HPC products can disrupt standard processes of collection and processing. Protocol modifications can circumvent adverse events for the donor and minimize product loss. Such process modifications should be considered in individuals with known risks for agglutination going to HPC donation/collection.

Sutimlimab provides clinically meaningful improvements in patient-reported outcomes in patients with cold agglutinin disease: Results from the randomised, placebo-controlled, Phase 3 CADENZA study.

Cold agglutinin disease (CAD) is a rare chronic autoimmune haemolytic anaemia, driven mainly by classical complement pathway activation, leading to profound fatigue and poor quality of life. In the Phase 3 CADENZA trial, sutimlimab-a C1s complement inhibitor-rapidly halted haemolysis, increased haemoglobin levels and improved fatigue versus placebo in patients with CAD without a recent history of transfusion. Patient-reported outcomes (PROs) included Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue), 12-Item Short Form Health Survey (SF-12), EuroQol visual analogue scale (EQ-VAS), Patient Global Impression of Change (PGIC) and Patient Global Impression of (fatigue) Severity (PGIS). Sutimlimab resulted in significant rapid and meaningful improvements versus placebo in PROs. From Week 1, the FACIT-Fatigue mean score increased >5 points above baseline (considered a clinically important change [CIC]). Least-squares (LS) mean change in FACIT-Fatigue score from baseline to treatment assessment timepoint was 10.8 vs. 1.9 points (sutimlimab vs. placebo; p < 0.001). Improvements in physical (PCS) and mental (MCS) component scores of the SF-12 were also considered CICs (LS mean changes from baseline to Week 26: PCS 5.54 vs. 1.57 [p = 0.064]; MCS 5.65 vs. -0.48 [p = 0.065]). These findings demonstrate that in addition to improving haematologic parameters, sutimlimab treatment demonstrates significant patient-reported benefits. Study registered at www.clinicaltrials.gov: NCT03347422.

Development of the Cold Agglutinin Disease Symptoms and Impact Questionnaire (CAD-SIQ).

OBJECTIVES: Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia. This study aimed to identify disease-related symptoms and impacts important to patients with CAD, and to develop a novel CAD-specific patient-reported outcome measure. METHODS: Adults with CAD were randomly selected from a United States patient panel to participate in concept elicitation (CE) interviews to identify important symptoms and impacts or cognitive debriefing (CD) interviews to assess the comprehension and relevance of the draft item set. RESULTS: Overall, 37 adults were included (mean [range] age 67.2 [35-87] years). In CE interviews (n = 16), the most frequently reported CAD-related symptoms were reactions to cold environments and fatigue (both 93.8%). CAD had negative impacts on enjoyable activities (81.3%) and daily activities (75.0%). Following CE, standard survey methodological principles were used to develop a draft item pool of 14 concepts. Items were refined through three iterative rounds of CD interviews (n = 21), yielding 11 final items: fatigue; cold sensitivity; dyspnea; wearing extra clothing; limited physical, social, and enjoyable activities; difficulty with usual activities; mood; frustration; and anxiety/stress. CONCLUSIONS: The novel 11-item CAD-Symptoms and Impact Questionnaire provides a measure of the symptoms and impacts of CAD that are important to patients.

Molecular pharmacology in complement-mediated hemolytic disorders.

In the last decade, a deeper understanding of the pathogenesis of complement mediated hemolytic disorders, such as paroxysmal nocturnal hemoglobinuria (PNH), cold agglutinin disease (CAD), warm type autoimmune hemolytic anemia (AIHA) with complement activation (wAIHA), and atypical hemolytic uremic syndrome (aHUS), paved the way to the therapeutic shift from purely supportive approaches to complement-targeted therapies. This resulted in a significant improvement in disease management, survival, and quality of life. In this review, we will provide a snapshot of novel therapies for complement-mediated hemolytic anemias with a focus on those ready to use in clinical practice. C5 inhibitors eculizumab and the long-acting ravulizumab, are the established gold standard for untreated PNH patients, whilst the C3 inhibitor pegcetacoplan should be considered for suboptimal responders to anti-C5 drugs. Several additional compounds targeting the complement cascade at different levels (other C5 inhibitors, factor B and D inhibitors) are under active investigation with promising results. In CAD, immunosuppression with rituximab remains the first-line. However, recently FDA and EMA approved the anti-C1s monoclonal antibody, sutimlimab, that showed dramatic responses and whose regulatory approval is soon awaited in many countries. Other drugs under investigation in AIHA include the C3 inhibitor pegcetacoplan, and the anti-C1q ANX005 for warm AIHA with complement activation. Finally, aHUS is an indication for complement inhibitors. Eculizumab and ravulizumab have been approved, whilst other C5 inhibitors, and novel lectin pathway inhibitors are under active investigation in this disease.

Sutimlimab: A Complement C1s Inhibitor for the Management of Cold Agglutinin Disease-Associated Hemolysis.

OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, safety, dosing and administration, and place in therapy of sutimlimab for the management of cold agglutinin disease (CAD)-associated hemolysis. DATA SOURCES: A literature search of PubMed (1966-October 2022) was conducted using the keywords sutimlimab, BIVV009, and cold agglutinin. Data were also obtained from prescribing information, meeting abstracts, and clinicaltrials.gov. STUDY SELECTION AND DATA EXTRACTION: All published prospective clinical trials, prescribing information, and meeting abstracts on sutimlimab for the treatment of CAD were reviewed. DATA SYNTHESIS: Sutimlimab is a first-in-class complement C1s inhibitor indicated for the treatment of CAD-associated hemolysis. This approval was based on the phase III CARDINAL trial, which evaluated sutimlimab in patients with CAD-associated hemolysis. The primary endpoint of achieving a hemoglobin of ≥12 g/dL or increase of ≥2 above baseline was achieved by 54% of patients with sutimlimab in the 26-week trial. The phase III CADENZA trial was a placebo-controlled trial in which sutimlimab has demonstrated a significant improvement in the composite endpoint of hemoglobin increase of ≥1.5 g/dL, avoidance of transfusion, and avoidance of additional CAD therapies (73% sutimlimab vs 15% placebo). RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON WITH EXISTING DRUGS: Sutimlimab rapidly halts hemolysis, improves hemoglobin, and improves quality-of-life in patients with CAD. Safety issues with sutimlimab include infusion-related reactions and risk of serious infections with encapsulated bacteria. CONCLUSIONS: Sutimlimab provides an additional therapeutic option in the treatment of CAD-associated hemolysis that can lead to rapid improvement in hemoglobin and anemia-related symptoms.

[Sjögren's syndrome combined with cold agglutinin disease: A case report].

Sjögren's syndrome(SS)is a chronic autoimmune disease that affects exocrine glands, especially salivary and lacrimal glands. The main clinical manifestations are dry mouth and dry eyes, but also multi-organ and multi-system can be involved. Cold agglutinin disease(CAD)is an autoimmune disease characterized by red blood cell agglutination in the blood vessels of extremities caused by cold agglutinin at low temperature, resulting in skin microcirculation disturbance, or hemolytic anemia. Cold agglutinin disease is divided into two categories, primary cold agglutinin disease and secondary cold agglutinin disease. Primary cold agglutinin disease is characterized with cold agglutinin titer of 1 ∶4 000 or more and positive Coomb's test. However, the Coomb's test is not necessarily positive and the cold agglutinin titer is between 1 ∶32 and 1 ∶4 000 in secondary cold agglutinin disease. Here, we reported an elderly patient admitted to hospital due to fever. He was diagnosed with respiratory infection, but he showed incompletely response to the anti-infection treatment. Further laboratory tests showed the patient with positive ANA and anti-SSA antibodies. Additionally, the patient complained that he had dry mouth and dry eyes for 1 year. Schirmer test and salivate gland imaging finally confirmed the diagnosis Sjogren's syndrome. During the hospital stay, the blood clots were found in the anticoagulant tubes. Hemolytic anemia was considered as the patient had anemia with elevated reticulocytes and indirect bilirubin. In addition, further examination showed positive cold agglutination test with a titer of 1 ∶1 024, and cold agglutinin disease was an important type of cold-resistant autoimmune hemolytic anemia. Furthermore, the patient developed cyanosis after ice incubating at the tip of the nose. Hence, the patient was diagnosed as CAD and he was successfully treated with glucocorticoids instead of anti-infection treatments. Hence, the patient was diagnosed with SS combined with secondary CAD. SS combined CAD are rarely reported, and they are both autoimmune diseases. The abnormal function of B lymphocytes and the production of autoantibodies might be the common pathogenesis of them. Cold agglutinin disease can lead to severe hemolytic anemia, even life-threatening. In clinical practice, timely recognizing and dealing with CAD might promote the prognosis of the patient.

[Novel therapeutic agents for hemolytic anemia].

In recent years, it has become clear that various diseases are caused by complement (related molecule) abnormalities (complementopathies) or are exacerbated by complement (complement-related diseases), and novel therapeutic agents targeting complement (anti-complement agents) are now being developed. Paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic stem cell disorder characterized by complement-mediated intravascular hemolysis due to a deficiency of complement regulatory factors, making it a perfect candidate for anti-complement agents. In 2007, the anti-C5 monoclonal antibody eculizumab was approved for PNH, as the first anti-complement agent. The indications for eculizumab are expanding, and aggressive development is underway for new anti-complement agents, not only for PNH but also a variety of other diseases. In addition, the anti-C1s antibody sutimlimab was approved last year for the treatment of cold agglutinin disease, a form of autoimmune hemolytic anemia. This presentation overviews novel anti-complement agents for these hemolytic anemias.

[Novel anti-complement therapeutics for hemolytic anemia].

The anti-C5 antibody eculizumab was approved in 2007 as the first anti-complement agent for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). While eculizumab's indication has been expanded to include other diseases, the development of new anti-complement agents has been aggressively pursued for various diseases. In PNH, the anti-C5 recycling antibody ravulizumab, which is an improved version of eculizumab, has been developed, with an extended dosing interval of 2 to 8 weeks, vastly improving convenience. The treatment of PNH with terminal complement inhibitors such as eculizumab and ravulizumab presents a new challenge-extravascular hemolysis. To address this issue, the proximal complement inhibitor, a C3 inhibitor called pegcetacoplan, was approved in the United States of America. Furthermore, the amplification loop inhibitors-a factor B inhibitor iptacopan, and a factor D inhibitor danicopan-are being developed. Recently, the anti-C1s antibody sutimlimab was approved for the treatment of cold agglutinin disease, a type of autoimmune hemolytic anemia. This article discusses novel anti-complement therapies for hemolytic anemia.

How do I warm HPC(A) products to maximize cell viability in the setting of cold agglutinin disease?

BACKGROUND: High titers of cold agglutinins jeopardize the quality of an apheresis product meant for autologous or allogeneic transplant. Management of transplant patients with cold agglutinin disease (CAD) is often experience-based and under reported, yet decisions must be made quickly to optimize product management and patient outcomes. There remains a lack of data quantifying cell recovery and viability when using various warming methodologies. STUDY DESIGN AND METHODS: To expand the published experimental data on this subject, our human cellular therapy lab compared cellular recoveries and viabilities after manipulation of cryopreserved apheresis products through various warming methodologies: (1) extended warming in a water bath, (2) warming via blood warmer and infusion pump, and (3) warming in a water bath followed by infusion pump as a control to assess potential shear stress effects. RESULTS: The presented studies demonstrate that all methods of product warming produce the same rates of recovery of total and viable cells across vital cell types prior to patient administration. Statistically, use of an extended water bath protocol provided a marginal benefit in recovery of total nucleated cells, though this effect is diminished when products are held for an extended period to simulate a delay in administration. DISCUSSION: These results can inform decisions to improve patient care and minimize product manipulation and loss. Centers are encouraged to use this information to guide proactive measures to establish a standard operating procedure to manage CAD cases.

Sutimlimab improves quality of life in patients with cold agglutinin disease: results of patient-reported outcomes from the CARDINAL study.

Patients with cold agglutinin disease (CAD) experience fatigue and poor quality of life. However, previous CAD-related studies have not explored patient-reported outcomes such as the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue. Sutimlimab, a C1s complement inhibitor, has been shown to halt haemolysis in CAD. Here, we present 26-weeks' patient-reported data from CARDINAL Part A (ClinicalTrials.gov, NCT03347396), which assessed efficacy and safety of sutimlimab in patients with CAD and recent history of transfusion. Aside from measuring changes in haemolytic markers, FACIT-Fatigue was measured at the treatment assessment timepoint (TAT; average of weeks 23, 25, and 26). Exploratory endpoints included the change in EuroQol 5-dimension 5-level questionnaire (EQ-5D-5L) and the 12-Item Short Form Health Survey (SF-12) at TAT, and Patient Global Impression of Change (PGIC), and Patient Global Impression of (fatigue) Severity (PGIS) at week 26. Mean (range) FACIT-Fatigue scores increased from 32.5 (14.0-47.0) at baseline (a score indicative of severe fatigue) to 44.3 (28.0-51.0) at TAT. Considerable improvements were reported for EQ-5D-5L at TAT, SF-12 scores at TAT, and PGIC and PGIS scores at week 26. Sutimlimab treatment resulted in sustained improvements in symptoms of fatigue and overall quality of life in patients with CAD. NCT03347396. Registered 20 November, 2017.

Survival in autoimmune hemolytic anemia remains poor, results from a nationwide cohort with 37 years of follow-up.

INTRODUCTION: Autoimmune hemolytic anemia (AIHA) is considered a chronic disease, with an overall good prognosis. However, recent reports indicate pre-mature mortality. Causes of death have not been evaluated previously. METHODS: In a nationwide setting, we identified all patients with warm type AIHA or cold agglutinin disease (CAD), and age-sex-matched comparators from Denmark, 1980-2016. We estimated overall survival and cause-specific mortality from anemia, infection, cardiovascular causes, hematological or solid cancer, bleeding, or other causes, using cumulative incidence proportions. RESULTS: We identified 1460 patients with primary AIHA, 1078 with secondary AIHA, 112 with CAD, and 130 801 comparators. One-year survival and median survival were, 82.7% and 9.8 years for primary AIHA, 69.1% and 3.3 years for secondary AIHA, and 85.5% and 8.8 years for CAD. Prognosis was comparable to the general population only in patients with primary AIHA below 30 years. In all other age and subgroups, the difference was considerable. Cumulated cause-specific mortality at 1 year was increased among patients versus comparators. DISCUSSION: All groups of autoimmune hemolytic anemia are associated with increased overall and cause-specific mortality compared to the general population. This probably reflects unmet needs in both treatment and follow-up programs.

Cold agglutinin anti-I antibodies in two patients with COVID-19.

BACKGROUND: Cold agglutinin syndrome (CAS) is associated with various diseases. Several studies of CAS associated with coronavirus disease 2019 (COVID-19) reported hemolytic anemia and thrombosis; however, the clinical significance of cold agglutinins (CA) in patients with COVID-19 is unclear. Here, we present two cases of CA identified in the context of COVID-19 without hemolytic anemia and clotting. CASE REPORT AND DISCUSSION: Two patients with no known risk factors for CA were diagnosed with COVID-19; peripheral blood smears reveal red blood cells (RBCs) agglutination. These patients showed a high CA titer. We confirmed retrospectively that the CA was an anti-I antibody. The two COVID-19 cases with a high CA titer showed no hemolysis or thrombosis. Mycoplasma pneumoniae is known to cause CAS, but not all patients who have a high CA titer show hemolysis. Coagulation abnormalities are documented in severe COVID-19 cases. Although CA increases the risk of thrombosis in those with lymphoproliferative diseases, the role of anti-I antibodies in COVID-19 is unclear. The impact of CAS on clinical presentations in COVID-19 remains a matter of verification. CONCLUSIONS: A high CA titer was identified in COVID-19 patients without hemolytic anemia and clotting. Anti-I antibodies were identified. Further studies are required to clarify the pathophysiology of CA in COVID-19.

Cryoglobulins and cold agglutinins for hand arm vibration syndrome.

BACKGROUND: Hand arm vibration syndrome (HAVS) is a condition caused by hand transmitted vibration from the use of hand-held vibrating tools or workpieces. The disease affects the vascular, neurological and musculoskeletal systems. The vascular component of HAVS is a form of secondary Raynaud's phenomenon. Other causes of disease must be excluded before attributing the cause to hand transmitted vibration. AIMS: To evaluate the prevalence, and utility of testing for, cryoglobulins and cold agglutinins in patients with HAVS symptoms. METHODS: A retrospective cohort study of 1183 patients referred for HAVS clinical assessment at St. Michael's Hospital, Toronto, Canada, between 2014 and 2020. The standard operating procedure at the clinic includes a detailed clinical and exposure history, physical examination, objective investigations and blood tests. Data were retrieved from patient chart review and laboratory investigation results for all cases with cryoglobulin and cold agglutinin testing. RESULTS: A total of 1183 patients had a serum cryoglobulin measurement. Eleven patients (1%) were positive. Seven positive results were 'low titre' (1% positive) and the other four results were 2%, 6%, 9% and 18%. The patient with a 9% positive cryoglobulin titre had previously diagnosed Sjögren's syndrome. There were no positive cold agglutinin tests in the 795 patients tested. CONCLUSIONS: Routine testing for cryoglobulins and cold agglutinins in patients with HAVS symptoms is not recommended because test positivity rates are negligible. Testing may be considered if the clinical history or routine blood investigations suggest evidence of underlying cryoglobulinaemia or cold agglutinin disease.

Incidentally discovered cold hemagglutinins within autologous blood bag and cardioplegia line in a patient with a recent history of COVID-19 undergoing coronary artery surgery.

INTRODUCTION: Cold agglutinin disease (CAD) is a rare autoimmune disorder characterized by destruction (hemolysis) of erythrocytes. In CAD, autoantibodies that cause agglutination at temperature of optimum +3-+4 ℃ degree cause symptoms. It is known that CAD often occurs after viral infections. Also, it has been reported in case reports that COVID-19 disease can cause CAD. CASE REPORT: 46-year-old male patient with a history of diabetes mellitus and hypertension presented to outpatient clinic in our department to have CABG surgery. He recovered from COVID-19 disease 1.5 months ago. Cardiopulmonary bypass was initiated and the cross-clamp was placed and antegrade Delnido cardioplegia solution was started to be given at +4 ℃. It was observed that the cardioplegia line was agglutinated. On the other hand, it was seen that the autologous blood taken by the anesthesiologist was also agglutinated and formed air bubbles and became unusable. X-clamp was removed and the heart rhythm recovered. The patient was consulted to hematology during postoperative intensive care follow-ups. The cold agglutinin test performed at of +4 ℃ was reported as positive. In this case, we associated the CAD with covid-19 for three main reasons. First one, the patient's complaints about CAD started after COVID-19 disease. Secondly, in the national health archive, the patient's pre-COVID-19 blood tests were completely normal but it was seen that LDH increased and RBC-HCT incompatibility started after COVID-19. As the third, when we search the literature, we have seen the COVID-19 related CAD in many case reports published by hematologists. CONCLUSION: With the rare cold agglutinin disease, it seems that we will encounter it more often after the COVID-19 pandemic. Except for deep hypothermia, the most important problem is seen during cardioplegia administration. Therefore, non-blood cardioplegia can be lifesaving.