COVID-19 and Cold Agglutinin Hemolytic Anemia

Understanding autoimmune response after SARS-CoV-2 infection and the pathogenesis/mechanisms of long COVID

COVID-19 posed a major challenge to the healthcare system and resources worldwide. The popularization of vaccines and the adoption of numerous prevention and control measures enabled the gradual end of the COVID-19 pandemic. However, successive occurrence of autoimmune diseases in patients with COVID-19 cannot be overlooked. Long COVID has been the major focus of research due to the long duration of different symptoms and the variety of systems involved. Autoimmunity may play a crucial role in the pathogenesis of long COVID. Here, we reviewed several autoimmune disorders occurring after COVID-19 infection and the pathogenesis of long COVID.

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.

Cold Agglutinin Disease and COVID-19: A Scoping Review of Treatments and Outcomes

Background

Reports suggest that patients with both acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and cold agglutinin disease (CAD) may experience poorer survival when treated with rituximab. We conducted a scoping review to evaluate severe outcomes, including intensive care unit (ICU) admission and mortality, in coronavirus disease 2019 (COVID-19) patients with CAD on various treatments, including rituximab.

Methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). Four literature databases were searched on December 19, 2023, for studies reporting lab-confirmed SARS-CoV-2 and CAD, excluding rheumatological conditions.

Results

Of the 741 screened articles, 19 were included. Studies, predominantly case reports (17/19) or case series (2/19), were mainly from the USA (8/19) and India (3/19), with others across Europe and Asia. Among 23 patients (61% female, median age 61 years), 21/23 had a new CAD diagnosis; only two had pre-existing CAD. Overall, 74% recovered, 21% died, and outcomes for one were unreported. Nine (39%) were ICU-admitted. Of rituximab-treated patients (n = 4), 25% were ICU-admitted, none died. Non-rituximab treatments (n = 19) saw 42% ICU admissions and 26% mortality.

Conclusions

This review found no increased risk of severe outcomes in CAD and COVID-19 patients treated with rituximab.

COVID-19 and SLE: Infection and autoimmunity at its best

If one had any doubts before the pandemic regarding the correlation between infections and autoimmunity, COVID-19 left us fascinated on the strong bond between the two entities. The immune and autoimmune reactions seen in patients infected with SARS-CoV-2 have served as a base for this assumption. Later on, the use of immunosuppressants such as systemic glucocorticoids, among other biological agents, turned this assumption to a fact. This was no different when it comes to the vaccines against COVID-19. Through several postulated mechanisms these vaccines, although generally considered safe, are thought to have the potential to result in autoimmune reactions making them not more innocent than the infection itself. When systemic lupus erythematous (SLE) is viewed as a classical autoimmune multisystemic disorder, the connection with SARS-CoV-2 infection and COVID-19 vaccination is of extreme importance. This is because early reports during the pandemic have shown increased rates of SARS-CoV-2 infection among patients known previously to have SLE and much more interestingly, cases of new-onset SLE after COVID-19 have been documented in the literature. Subsequently vaccines against COVID-19, those mRNA-based and adenovirus-vector based, were reported to induce new SLE cases, trigger immune thrombocytopenia or lupus nephritis, two common presentations of SLE, or exacerbate flares. In our paper, we concluded various aspects of available and recent data regarding SLE and COVID-19 as both an infection and vaccination.

The striking mimics between COVID-19 and malaria: A review

Objectives

COVID-19 is a transmissible illness triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since its onset in late 2019 in Wuhan city of China, it continues to spread universally, leading to an ongoing pandemic that shattered all efforts to restrain it. On the other hand, in Africa, the COVID-19 infection may be influenced by malaria coinfection. Hence, in this review article, we aimed to give a comprehensive account of the similarities between COVID-19 and malaria in terms of symptoms, clinical, immunological, and molecular perspectives.

Methodology

In this article, we reviewed over 50 research papers to highlight the multilayered similarities between COVID-19 and malaria infections that might influence the ontology of COVID-19.

Results

Despite the poor health and fragile medical system of many sub-Saharan African countries, they persisted with a statistically significantly low number of COVID-19 cases. This was attributed to many factors such as the young population age, the warm weather, the lack of proper diagnosis, previous infection with malaria, the use of antimalarial drugs, etc. Additionally, population genetics appears to play a significant role in shaping the COVID-19 dynamics. This is evident as recent genomic screening analyses of the angiotensin-converting enzyme 2 (ACE2) and malaria-associated-variants identified 6 candidate genes that might play a role in malaria and COVID-19 incidence and severity. Moreover, the clinical and pathological resemblances between the two diseases have made considerable confusion in the diagnosis and thereafter curb the disease in Africa. Therefore, possible similarities between the diseases in regards to the clinical, pathological, immunological, and genetical ascription were discussed.

Conclusion

Understanding the dynamics of COVID-19 infection in Sub-Saharan Africa and how it is shaped by another endemic disease like malaria can provide insights into how to tailor a successful diagnostic, intervention, and control plans that lower both disease morbidity and mortality.

Hemolytic anemia in COVID-19

COVID-19 is a global pandemic triggered by the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 entry point involves the interaction with angiotensin-converting enzyme 2 (ACE2) receptor, CD147, and erythrocyte Band3 protein. Hemolytic anemia has been linked to COVID-19 through induction of autoimmune hemolytic anemia (AIHA) caused by the formation of autoantibodies (auto-Abs) or directly through CD147 or erythrocyte Band3 protein-mediated erythrocyte injury. Here, we aim to provide a comprehensive view of the potential mechanisms contributing to hemolytic anemia during the SARS-CoV-2 infection. Taken together, data discussed here highlight that SARS-CoV-2 infection may lead to hemolytic anemia directly through cytopathic injury or indirectly through induction of auto-Abs. Thus, as SARS-CoV-2-induced hemolytic anemia is increasingly associated with COVID-19, early detection and management of this condition may prevent the poor prognostic outcomes in COVID-19 patients. Moreover, since hemolytic exacerbations may occur upon medicines for COVID-19 treatment and anti-SARS-CoV-2 vaccination, continued monitoring for complications is also required. Given that, intelligent nanosystems offer tools for broad-spectrum testing and early diagnosis of the infection, even at point-of-care sites.

COVID-19 and Immune-Mediated RBC Destruction

OBJECTIVES

To summarize the epidemiologic, clinical, and laboratory characteristics of autoimmune hemolytic anemia (AIHA) secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination.

METHODS

We conducted a systematic review using standardized keyword search to identify all reports of SARS-CoV-2 infection or vaccination and AIHA across PubMed, Web of Science, Scopus, and Google Scholar through September 24, 2021.

RESULTS

Fifty patients (mean [SD] age, 50.8 [21.6] years) diagnosed with coronavirus disease 2019 (COVID-19) and AIHA were identified. AIHA subtypes and number of patients were as follows: cold AIHA (n = 18), warm AIHA (n = 14), mixed-type AIHA (n = 3), direct antiglobulin test (DAT)-negative AIHA (n = 1), DAT-negative Evans syndrome (n = 1), Evans syndrome (n = 3), and subtype not reported (n = 10). Mean (SD) hemoglobin at AIHA diagnosis was 6.5 [2.8] g/dL (95% confidence interval, 5.7-7.3 g/dL). Median time from COVID-19 symptom onset to AIHA diagnosis was 7 days. In total, 19% (8/42) of patients with COVID-19-associated AIHA with reported outcomes were deceased. Four patients (mean [SD] age, 73.5 [16.9] years) developed AIHA following SARS-CoV-2 vaccination: Pfizer-BioNTech BNT162b2 vaccine (n = 2); Moderna mRNA-1273 vaccine (n = 1); undisclosed mRNA vaccine (n = 1). AIHA occurred after 1 dose in 3 patients (median, 5 days).

CONCLUSIONS

SARS-CoV-2 infection and vaccination are associated with multiple AIHA subtypes, beginning approximately 7 days after infectious symptoms and 5 days after vaccination.

Severe Anemia Due to Cold Agglutinin Syndrome in a COVID-19 Patient with IgM Monoclonal Gammopathy of Undetermined Significance Successfully Treated with Corticosteroids

Secondary cold agglutinin syndrome (CAS) is autoimmune hemolytic anemia secondary to infections and lymphoid disorder. We here report the first Asian case of CAS secondary to novel coronavirus disease 2019 (COVID-19). A 72-year-old Japanese woman presented with a 2-week history of dyspnea and cough, and laboratory data revealed severe hemolytic anemia with a hemoglobin level of 4.7 g/dL. She was diagnosed with COVID-19, CAS, and monoclonal gammopathy of undetermined significance (MGUS). The anemia responded to corticosteroids administered for COVID-19 and required maintenance therapy. Although corticosteroids are not a standard therapy for CAS, they might be effective for CAS secondary to COVID-19 complicated with MGUS.

Complement Mediated Hemolytic Anemias in the COVID-19 Era: Case Series and Review of the Literature

The complex pathophysiologic interplay between SARS-CoV-2 infection and complement activation is the subject of active investigation. It is clinically mirrored by the occurrence of exacerbations of complement mediated diseases during COVID-19 infection. These include complement-mediated hemolytic anemias such as paroxysmal nocturnal hemoglobinuria (PNH), autoimmune hemolytic anemia (AIHA), particularly cold agglutinin disease (CAD), and hemolytic uremic syndrome (HUS). All these conditions may benefit from complement inhibitors that are also under study for COVID-19 disease. Hemolytic exacerbations in these conditions may occur upon several triggers including infections and vaccines and may require transfusions, treatment with complement inhibitors and/or immunosuppressors (i.e., steroids and rituximab for AIHA), and result in thrombotic complications. In this manuscript we describe four patients (2 with PNH and 2 with CAD) who experienced hemolytic flares after either COVID-19 infection or SARS-Cov2 vaccine and provide a review of the most recent literature. We report that most episodes occurred within the first 10 days after COVID-19 infection/vaccination and suggest laboratory monitoring (Hb and LDH levels) in that period. Moreover, in our experience and in the literature, hemolytic exacerbations occurring during COVID-19 infection were more severe, required greater therapeutic intervention, and carried more complications including fatalities, as compared to those developing after SARS-CoV-2 vaccine, suggesting the importance of vaccinating this patient population. Patient education remains pivotal to promptly recognize signs/symptoms of hemolytic flares and to refer to medical attention. Treatment choice should be based on the severity of the hemolytic exacerbation as well as of that of COVID-19 infection. Therapies include transfusions, complement inhibitor initiation/additional dose in the case of PNH, steroids/rituximab in patients with CAD and warm type AIHA, plasma exchange, hemodialysis and complement inhibitor in the case of atypical HUS. Finally, anti-thrombotic prophylaxis should be always considered in these settings, provided safe platelet counts.

A Case of Coombs-Negative Hemolytic Anemia Prompting Diagnosis of SARS-CoV-2

Case reports have discussed coronavirus disease of 2019 (COVID-19) patients presenting with hemolytic anemia, specifically with a positive direct antiglobulin test. However, Coombs-negative hemolytic anemia in COVID-19 patients has been rarely reported. We present an unusual case of Coombs-negative hemolytic anemia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which responded with evidence-based COVID-19 treatments. We demonstrate the importance of considering SARS-CoV-2 as a cause of Coombs-negative hemolytic anemia, and we illustrate how treatment of the underlying COVID-19 illness, even if it is just supportive care, will help resolve the associated hemolysis.

Anti-SARS-CoV-2 and anti-cytokine storm neutralizing antibody therapies against COVID-19: Update, challenges, and perspectives

Coronavirus disease 2019 (COVID-19) has been declared by the World Health Organization (WHO) as a pandemic since March 2020. This disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The only available tools to avoid contamination and transmission of this virus are physical distancing, the use of N95 and surgical masks, and hand hygiene. Vaccines are another essential tool to reduce the impact of the pandemic, though these present challenges in terms of production and logistics, particularly in underdeveloped and developing countries. One of the critical early research findings is the interaction of the spike virus protein with the angiotensin-converting enzyme 2 (ACE2) human receptor. Developing strategies to block this interaction has therefore been identified as a way to treat this infection. Neutralizing antibodies (nAbs) have emerged as a therapeutic approach since the pandemic started. Infected patients may be asymptomatic or present with mild symptoms, and others may evolve to moderate or severe disease, leading to death. An immunological phenomenon known as cytokine storm has been observed in patients with severe disease characterized by a proinflammatory cytokine cascade response that leads to lung injury. Thus, some treatment strategies focus on anti-cytokine storm nAbs. This review summarizes the latest advances in research and clinical trials, challenges, and perspectives on antibody-based treatments (ABT) as therapies against COVID-19.

Adaptive Immunity and the Risk of Autoreactivity in COVID-19

While first and foremost considered a respiratory infection, COVID-19 can result in complications affecting multiple organs. Immune responses in COVID-19 can both protect against the disease as well as drive it. Insights into these responses, and specifically the targets being recognised by the immune system, are of vital importance in understanding the side effects of COVID-19 and associated pathologies. The body's adaptive immunity recognises and responds against specific targets (antigens) expressed by foreign pathogens, but not usually to target self-antigens. However, if the immune system becomes dysfunctional, adaptive immune cells can react to self-antigens, which can result in autoimmune disease. Viral infections are well reported to be associated with, or exacerbate, autoimmune diseases such as multiple sclerosis (MS) and systemic lupus erythematosus (SLE). In COVID-19 patients, both new onset MS and SLE, as well as the occurrence of other autoimmune-like pathologies, have been reported. Additionally, the presence of autoantibodies, both with and without known associations to autoimmune diseases, have been found. Herein we describe the mechanisms of virally induced autoimmunity and summarise some of the emerging reports on the autoimmune-like diseases and autoreactivity that is reported to be associated with SARS-CoV-2 infection.

Cold agglutinin disease and COVID-19 requiring therapeutic plasma exchange

A 70-year-old man with known cold autoimmune haemolytic anaemia was referred to the emergency department with increased shortness of breath on exertion. He had been confirmed positive for non-variant COVID-19 infection 1 week earlier based on nasopharyngeal swab PCR assay. CT thorax demonstrated diffuse patchy bilateral ground glass opacities, consistent with COVID-19 pneumonia. Bloodwork demonstrated severe cold agglutinin mediated haemolytic anaemia. To help stabilise the patient, he was transferred to a tertiary care hospital for urgent therapeutic plasma exchange. Key supportive therapy included folic acid supplementation, ensuring the patient was kept warm and warmed infusions including transfusions via the apheresis machine. The patient made a good recovery following plasma exchange, and his haemoglobin levels remained stable by discharge.

SARS-CoV-2 and Autoimmune Cytopenia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with a variety of clinical manifestations related to viral tissue damage, as well as a virally induced immune response. Hyperstimulation of the immune system can serve as a trigger for autoimmunity. Several immune-mediated manifestations have been described in the course of SARS-CoV-2 infection. Immune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AIHA) are the most common hematologic autoimmune disorders seen in the course of SARS-CoV-2 infection. Vaccine-induced thrombocytopenia is a unique autoimmune hematologic cytopenia associated with SARS-CoV-2 vaccination. This paper will review the current literature on the association of SARS-CoV-2 infection and vaccination with autoimmune cytopenias and the clinical course of autoimmune cytopenias in patients with COVID-19.

Autoimmune and Rheumatic Manifestations Associated With COVID-19 in Adults: An Updated Systematic Review

Background: Numerous cases of the coronavirus disease 2019 (COVID-19) with autoimmune and rheumatic manifestations have been reported. Despite the available reviews that summarized its autoimmune/rheumatic manifestations, a systematic approach is still lacking. Therefore, we conducted a comprehensive systematic review in order to give an overview upon these rare but clinically significant manifestations.

Methods: We performed a literature search of PubMed and EMBASE as of October 9, 2020. All articles relevant to either systemic or organ-specific autoimmune and rheumatic manifestations potentially associated with COVID-19 were collected. The reviewed literature were limited to adults ≥18 years.

Results: Although most of the existing evidence was based on case reports or case series without a long-term follow-up, a variety of autoimmune/rheumatic manifestations were associated with COVID-19. The manifestations that have a consistent association with COVID-19 include autoimmune cytopenia, cutaneous vasculitis, encephalitis, and Guillain-Barre syndrome. Such association is conflicting as regards to antiphospholipid syndrome, hemophagocytic lymphohistiocytosis, and myasthenia gravis.

Conclusion: Our systematic review indicated the potential of the COVID-19 virus to trigger a myriad of autoimmune and rheumatic manifestations, which should be considered amid global efforts to combat COVID-19.

COVID-19 and autoimmune diseases

PURPOSE OF REVIEW

The aim of this study was to evaluate the relationship between infection with SARS-CoV-2 and autoimmunity.

RECENT FINDINGS

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome (SARS) associated coronavirus 2 (SARS-CoV-2). Although most of the infected individuals are asymptomatic, a proportion of patients with COVID-19 develop severe disease with multiple organ injuries. Evidence suggests that some medications used to treat autoimmune rheumatologic diseases might have therapeutic effect in patients with severe COVID-19 infections, drawing attention to the relationship between COVID-19 and autoimmune diseases. COVID-19 shares similarities with autoimmune diseases in clinical manifestations, immune responses and pathogenic mechanisms. Robust immune reactions participate in the pathogenesis of both disease conditions. Autoantibodies as a hallmark of autoimmune diseases can also be detected in COVID-19 patients. Moreover, some patients have been reported to develop autoimmune diseases, such as Guillain--Barré syndrome or systemic lupus erythematosus, after COVID-19 infection. It is speculated that SARS-CoV-2 can disturb self-tolerance and trigger autoimmune responses through cross-reactivity with host cells. The infection risk and prognosis of COVID-19 in patients with autoimmune diseases remains controversial, but patient adherence to medication regimens to prevent autoimmune disease flares is strongly recommended.

SUMMARY

We present a review of the association between COVID-19 and autoimmune diseases, focusing on similarities in immune responses, cross-reactivity of SARS-CoV-2, the development of autoimmune diseases in COVID-19 patients and the risk of COVID-19 infection in patients with preexisting autoimmune conditions.

Hematologic autoimmune disorders in the course of COVID-19: a systematic review of reported cases

OBJECTIVE

As COVID-19 is a new emerging disease, the hematological/immunological changes that develop in the infected patients remain unknown. This study aims to systematically review the hematologic autoimmune complications in these patients.

METHOD

Data from three online databases including Medline (via PubMed), Scopus and Web of Science were searched on 19 December 2020, and after excluding duplicate, irrelevant and inappropriate records, eligible documents were identified. Afterwards, information such as patients' history, presentations, paraclinical data, treatment course and outcome were extracted from the records.

RESULTS

A total of 58 documents were considered to be eligible for data extraction which described 94 patients with COVID-19 who developed hematologic autoimmune disorder in their course of infection. Of these patients with COVID-19, the most common hematologic autoimmune disorder was immune thrombocytopenic purpura (55 cases) followed by autoimmune hemolytic anemia (22 cases). Other hematologic autoimmune disorders include antiphospholipid syndrome, thrombotic thrombocytopenic purpura, Evans syndrome and autoimmune neutropenia.

CONCLUSION

The current study would help us to always consider an autoimmune etiology for cases with abnormal hematologic finding which further lead to an appropriate treatment of the patients, especially when the symptoms present in about 1-2 weeks after the first manifestation of the infection symptoms. Maybe, at least in this pandemic, it should be recommended to evaluate patients with unexpected and unexplained decrease in their hemoglobulin or platelet count for COVID-19. Another challenging issue is the treatment options. Given the multiorgan involvement and multifaceted nature of the infection, an individualized approach should be taken for each patient.

The JANUS of chronic inflammatory and autoimmune diseases onset during COVID-19 - A systematic review of the literature

The diverse clinical manifestations of COVID-19 is emerging as a hallmark of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. While the initial target of SARS-CoV-2 is the respiratory tract, it is becoming increasingly clear that there is a complex interaction between the virus and the immune system ranging from mild to controlling responses to exuberant and dysfunctional multi-tissue directed autoimmune responses. The immune system plays a dual role in COVID-19, being implicated in both the anti-viral response and in the acute progression of the disease, with a dysregulated response represented by the marked cytokine release syndrome, macrophage activation, and systemic hyperinflammation. It has been speculated that these immunological changes may induce the loss of tolerance and/or trigger chronic inflammation. In particular, molecular mimicry, bystander activation and epitope spreading are well-established proposed mechanisms to explain this correlation with the likely contribution of HLA alleles. We performed a systematic literature review to evaluate the COVID-19-related autoimmune/rheumatic disorders reported between January and September 2020. In particular, we investigated the cases of incident hematological autoimmune manifestations, connective tissue diseases, antiphospholipid syndrome/antibodies, vasculitis, Kawasaki-like syndromes, acute arthritis, autoimmune-like skin lesions, and neurologic autoimmune conditions such as Guillain-Barré syndrome. We screened 6263 articles and report herein the findings of 382 select reports which allow us to conclude that there are 2 faces of the immune response against SARS-CoV-2, that include a benign virus controlling immune response and a many faceted range of dysregulated multi-tissue and organ directed autoimmune responses that provides a major challenge in the management of this viral disease. The number of cases for each disease varied significantly while there were no reported cases of adult onset Still disease, systemic sclerosis, or inflammatory myositis.

Are Patients With Autoimmune Cytopenias at Higher Risk of COVID-19 Pneumonia? The Experience of a Reference Center in Northern Italy and Review of the Literature

During COVID-19 pandemic the care of onco-hematologic and autoimmune patients has raised the question whether they are at higher risk of infection and/or worse outcome. Here, we describe the clinical course of COVID-19 pneumonia in patients with autoimmune cytopenias (AIC) regularly followed at a reference center in Northern Italy. The study period started from COVID-19 outbreak (February 22, 2020) until the time of writing. Moreover, we provide a review of the literature, showing that most cases reported so far are AIC developed during or secondary to COVID-19 infection. At variance, data about AIC pre-existing to COVID infection are scanty. The 4 patients here described (2 autoimmune hemolytic anemias, AIHA, 1 Evans syndrome, and 1 immune thrombocytopenia) with COVID-19 pneumonia belong to a large cohort of 500 AIC patients, making this study nearly population-based. The observed frequency (4/501; 0.7%) is only slightly superior to that of the general population admitted to hospital/intensive care unit (0.28/0.03%, respectively) in Lombardy in the same period of observation. All cases occurred between March 21 and 25, whilst no more AIC were recorded later on. Although different in intensity of care needed, all patients recovered from COVID-19 pneumonia, with apparently no detrimental effect of previous/current immunomodulatory treatments. AIHA relapse occurred in two patients, but promptly responded to therapy. With limitations due to sample size, these results suggest a favorable outcome and a lower-than-expected incidence of COVID-19 pneumonia in patients with previously diagnosed AIC, and allow speculating that immunomodulatory drugs used for AIC may play a beneficial rather than a harmful effect on COVID-19 infection.

Infectious Complications in Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) may be frequently challenged by infectious complications, mainly as a result of immunosuppressive treatments administered. Furthermore, infectious agents are known triggers of AIHA onset and relapse. Although being risk factors for mortality, infections are an underestimated issue in AIHA. This review will collect the available evidence on the frequency and type of infectious complications in AIHA, detailing the risk related to each treatment (i.e., steroids, rituximab, splenectomy, classic immunosuppressive agents, and new target drugs). Moreover, we will briefly discuss the infectious complications in AIHA secondary to other diseases that harbor an intrinsic infectious risk (e.g., primary immunodeficiencies, systemic autoimmune diseases, lymphoproliferative disorders, solid organ and hematopoietic stem cell transplants). Finally, viral and bacterial reactivations during immune suppressive therapies will be discussed, along with suggested screening and prophylactic strategies.