Immunotherapy-associated autoimmune hemolytic anemia

Mitigation of checkpoint inhibitor-induced autoimmune hemolytic anemia through modulation of purinergic signaling

ABSTRACT

Immune checkpoint inhibitors (ICPis) have revolutionized cancer immunotherapy but also can induce autoimmune hemolytic anemia (AIHA), a severe disease with high mortality. However, the cellular and molecular mechanism(s) of AIHA secondary to ICPi therapy (ICPi-AIHA) are unclear, other than being initiated through decreased checkpoint inhibition. Herein, we report ICPi-AIHA in a novel mouse model that shows similar characteristics of known human ICPi-AIHA (eg, autoantibodies, hemolysis, and increased mortality). During ICPi-AIHA, there is the simultaneous reduction of 2 regulatory T-cell populations (FoxP3+ and Tr1 [type 1 regulatory cells]) and an increase in inflammatory T helper cell 17 (TH17). Moreover, a novel CD39+CD73-FoxP3-CD25- CD4+ T-cell subset (ie, CD39 single positive [CD39SP]) emerges, and early increases in CD39SP predict AIHA development; CD39 is an ectonuclease that breaks down adenosine triphosphate (ATP). Additionally, we found that boosting ATPase activity by injecting recombinant apyrase mitigates AIHA development and significant CD39SP reductions, both suggesting a functional role for CD39 and demonstrating a novel therapeutic approach. Importantly, CD39SP are detectable in multiple mouse models developing AIHA and in patients with AIHA, demonstrating applicability to idiopathic and secondary AIHA. Highlighting broader autoimmunity relevance, ICPi-treated NZB mice experienced accelerated onset and severity of lupus, including AIHA. Moreover, ICPi treatment of healthy B6 animals led to detectable CD39SP and development of autoantibodies against multiple autoantigens including those on red blood cells and platelets. Together, our findings provide further insight into the cellular and molecular mechanisms of ICPi-AIHA, leading to novel diagnostic and therapeutic approaches with translational potential for use in humans being treated with ICPi.

The role of PD-1/PD-L1 signaling pathway in cancer pathogenesis and treatment: a systematic review

Aim: Cancer as a complex disease poses significant challenges for both diagnosis and treatment. Researchers have been exploring various avenues to find effective therapeutic strategies, with a particular emphasis on cellular signaling pathways and immunotherapy. One such pathway that has recently been suggested is the PD-1/PD-L1 pathway, which is an immune checkpoint signaling system that plays an important role in regulating the immune system and maintaining tissue homeostasis. Cancer cells exploit this pathway by producing PD-L1, which attaches to PD-1 on T cells, thus inhibiting immune responses and enabling the cancer cells to escape detection by the immune system. This study aimed to evaluate the role of the PD-1/PD-L1 pathway in cancer pathogenesis and treatment. Method: This study was performed based on the principles of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). All in vitro , in vivo , and clinical studies that were published in English have been considered during a thorough search of the Scopus, Web of Science, and PubMed databases without date restriction until March 2024. Results: According to the studies reviewed, the PD-1/PD-L1 signaling axis suggests promising therapeutic effects on various types of cancers such as non-small cell lung cancer, melanoma, breast cancer, hepatocellular carcinoma, squamous cell carcinoma, and colorectal cancer, among others. Additionally, research suggests that immune checkpoint inhibitors that block PD1/PD-L1, such as pembrolizumab, atezolizumab, nivolumab, durvalumab, cemiplimab, avelumab, etc. , can effectively prevent tumor cells from escaping the immune system. Moreover, there might be a possible interaction between microbiome, obesity, etc. on immune mechanisms and on the immune checkpoint inhibitors (ICIs). Conclusion: Although we have gained considerable knowledge about ICIs, we are still facing challenges in effectively prescribing the appropriate ICIs for individual patients. This is largely due to the complex interactions between different intracellular pathways, which need to be thoroughly studied. To resolve this issue, it is necessary to conduct more reliable clinical trials that can produce a scientific consensus.

[In macrohematuria, medication history also needs to be considered : Penicillin-induced immune hemolysis: a case report and review of literature]

BACKGROUND

Drug-mediated immune hemolysis is a rare but potentially life-threatening condition. Based on a case of penicillin-induced immune hemolysis, a structured literature review of case reports and studies on penicillin-mediated Drug-Induced Immune Hemolytic Anemia (DIIHA) was carried out.

CASE REPORT

A 28-year-old male patient presented to the emergency department with gross hematuria and non-specific abdominal complaints. The patient had a 10-day history of respiratory infection with bacterial tonsillitis, treated orally with penicillin V on an outpatient basis. Laboratory diagnostics detected pathologically altered direct and indirect hemolysis parameters. After stopping the medication, the patient's condition could be stabilized.

CONCLUSION

Diagnosis of penicillin-mediated immune hemolysis requires structured cooperation between clinic and laboratory, as clinical and serological findings may be highly variable with the risk of misdiagnosis. Due to the rarity of the disease, this case report is intended to raise awareness with respect to the triad of abrupt drop in hemoglobin levels in connection with drug therapy and in combination with a strongly positive direct Coombs test.

PTPRC functions as a prognosis biomarker in the tumor microenvironment of cutaneous melanoma

Cutaneous melanoma is one of the most malignant types of skin cancer, with an extremely poor prognosis. Immune cells infiltrated in the tumor microenvironment (TME) affects melanoma initiation, progression, prognosis and immunotherapy strategies in melanoma. The potential utility of TME-related genes as a prognostic model for melanoma and as a predictor of immunotherapeutic response merits further exploration. In this study, we determined that an immune-related gene, protein tyrosine phosphatase receptor type C (PTPRC), was positively correlated with the positive prognosis of melanoma patients. Integration of this gene with TNM classification created a predictive model that showed better performance in determining overall survival than others. PTPRC expression was positively correlated with the levels of immune checkpoint molecules, and PTPRC knockdown significantly enhanced the migration, invasion, and proliferation of melanoma cells. Finally, immunohistochemical results from HPA and Real-time quantitative PCR of clinical tissues confirmed that PTPRC expression was higher in melanoma than in normal skin. In conclusion, PTPRC served as a potential predictor of survival and response to immunotherapy in melanoma patients. The risk model combining the PTPRC and TNM classifications holds the potential to be a promising tool for prognostic prediction of cutaneous melanoma. This will help in the effective clinical management of melanoma patients.

Rituximab in steroid-refractory immune-related pancreatitis: a case report

The use of immune checkpoint inhibitors (ICIs) for treating several types of cancer is increasing, but they may be associated with immune-related adverse events (irAEs). Pancreatitis is a rare irAE, mostly responsive to steroid treatment. There are no published data on the management of steroid-refractory ICI-induced pancreatitis. Rituximab has shown efficacy in the setting of relapsing non-ICI-induced autoimmune pancreatitis. However, its use has not been tested for treating immunotherapy-related pancreatitis. Here, we present the case of a patient with steroid-refractory immune-related pancreatitis successfully treated with rituximab as a potential strategy for irAE management.

Hematological toxicities of immune checkpoint inhibitors and the impact of blood transfusion and its microbiome on therapeutic efficacy and recipient's safety and survival outcome:A systematic narrative appraisal of where we are now!

Classically, patients with solid and hematologic malignancies have been treated with a combination of chemotherapy with or without a holistic targeted strategy using approved conventional therapy. While the evidence-based use of Immunomodulatory drugs and Immune checkpoint inhibitors (ICIs), including those targeting the PD-1, PD-L1 and CTLA-4, have reshaped the treatment paradigm for many malignant tumors and significantly stretched the life expectancy of patients, as for any interventional therapy, the rise in ICI applications, was associated with the observation of more immune-related hematological adverse events. Many of these patients require transfusion support during their treatment in line with precision transfusion. It has been presumed that transfusion-related immunomodulation (TRIM) and the microbiome can pose immunosuppressive effects on the recipients. Looking to the past and beyond and translating available data into practice in the evolving role of pharmaceutical therapy to ICI-receiving patients, we performed a narrative review of the literature on the immune-related hematological adverse events of ICIs, immunosuppressive mechanisms linked to blood product transfusions, as well as the detrimental impact of transfusions and its related microbiome on the sustained efficacy of ICIs and the patients' survival outcomes. Recent reports are pointing to the negative impact of transfusion on ICI response. Studies have concluded that packed RBC [PRBC] transfusions lead to an inferior progression-free and overall survival in patients with advanced cancer receiving ICIs, even after adjustments for other prognostic variables. The attenuation of the effectiveness of immunotherapy likely results from the immunosuppressive effects of PRBC transfusions. It is, therefore, wise to look retrospectively and prospectively at the impact of transfusion on ICI effects and adopt, in the interim, a restrictive transfusion strategy, if applicable, for those patients.

[Autoimmune haemolytic anaemia]

Autoimmune haemolytic anaemias (AIHA) are acquired haematological disorders caused by increased peripheral erythrocyte destruction mediated by autoantibodies against erythrocyte antigens. They classified according to aetiology into primary and secondary, and according to the type of antibody and reaction temperature into AIHA due to warm antibodies (w-AIHA) and AIHA due to cold antibodies (c-AIHA). The mainstay of management in w-AIHA remains glucocorticoid therapy, and the early addition of rituximab has shown good results in recent studies. Primary c-AIHA is mainly treated with rituximab, alone or in combination with chemotherapy. New drugs such as Syk inhibitors, anti-FcRn Ig and complement inhibitors are in advanced development and will expand the therapeutic arsenal, especially in refractory or relapsed cases.

Immunotherapy-associated Autoimmune Hemolytic Anemia

Over the past decade, the role of immunotherapy treatment in cancer has expanded; specifically, indications for immune checkpoint inhibitors (ICI) have multiplied and are used as first-line therapy. ICIs include cytotoxic T-lymphocyte-associated protein 4 and programmed cell death protein 1 inhibitors, as monotherapies or in combination. Autoimmune hemolytic anemia (AIHA) has emerged as a rare yet serious immune-related adverse event in ICI use. This review describes diagnosis and management of immunotherapy related AIHA (ir-AIHA) including an algorithmic approach based on severity of anemia. Suggested mechanisms are discussed, guidance on ICI resumption provided and prognosis reviewed including risk of recurrence.

Nucleic Acid Probe-Based Difunctional Hematology Analysis Kit for Peripheral Blood Cell Analysis

Traditional "one for one channel" long-wavelength probes in hematology analyzers limit their resolution and detection efficiency. In this study, we developed a "one for two channels" probe named NATO, which shows a short wavelength (λ_abs = 460 nm), good nucleus and nucleolus location, and a high signal-to-noise ratio to nucleic acids. When NATO was made into a hematology analysis kit and applied in an automated hematology analyzer, short-wavelength absorbance endows NATO with higher resolution, which in turn leads to better separation of red blood cells and platelets in the blood shadow of the differentiating (DIFF) channel. In addition, this kit showed terrific performance in both DIFF and reticulocytes channels. Our study sheds light on the development of hematology analysis in an automated hematology analyzer by proposing a nucleic acid probe with difunction and higher resolution.

Management and Outcomes of Hematological Immune-related Adverse Events: Systematic Review and Meta-analysis

Data regarding clinical outcomes and management of hematological manifestations of immune checkpoint inhibition (ICI) is limited to case reports, series, and a few retrospective reviews. We aimed to determine the rate of response of hematological immune-related adverse events (irAEs) to immunosuppressive therapy. MEDLINE (OVID), EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception to the present day. Retrospective reports were included without language restrictions. The risk of bias was evaluated with the Cochrane Collaboration's tool. The primary outcome of this study was the rate of response to immunosuppression. Eighty studies (14 case series and 66 individual case reports) were analyzed with a total of 135 patients with ICI-related hematological irAEs. Data analysis showed an average proportional response rate to immunosuppression among hematological irAE entities of 50% (range: 25%-70%). The heterogeneity index (I2) was 0% among reports within each entity. There is a wide spectrum of hematological manifestations to ICI therapy, and to date there is no large randomized-controlled trial data to evaluate the efficacy of treatment strategies for hematological irAEs. We found a variable overall response rate to immunosuppression therapy of around 50%, without statistically significant heterogeneity among different irAE types but significant differences among the different countries of publication. Future studies evaluating the optimal dose and duration of immunosuppressive agents for patients with hematological irAEs should be undertaken.

Nivolumab-Induced Autoimmune Haemolytic Anaemia and Safety of Subsequent Use of Ipilimumab: A Case Report

Autoimmune haemolytic anaemia (AIHA) is a rare immune-related adverse event and appears to be more common with anti-PD1/PDL1 than anti-CTLA4. Little is known about the safety of re-treating with anti-PD1/PDL1 or changing to anti-CTLA4. We present a case of grade 4 AIHA due to nivolumab (PD1-inhibitor) treatment in a patient with melanoma for adjuvant setting after surgery and the safeness of subsequent treatment with ipilimumab (anti-CTLA4). After the remission of AIHA with steroids, ipilimumab was started with the rationale of its different mechanism of action. Fortunately, AIHA did not recur. The mechanism by which checkpoint inhibitors cause AIHA is likely by augmenting or redirecting immune surveillance, especially by activating pre-existing red blood cell autoantibodies, but further studies must be done. To our knowledge, this is the first case published in the literature with the change of immunotherapy treatment to anti-CTLA4.

An Uncharacteristic Presentation of Evans Syndrome Following Treatment With Dupilumab

Evans syndrome is a rare autoimmune disorder where patients develop autoimmune hemolytic anemia (AIHA), immune thrombocytopenia (ITP), and less commonly immune neutropenia. Patients typically present with fatigue, pallor, jaundice, petechiae, or epistaxis. A 27-year-old man with a history of atopic dermatitis for which he recently began treatment with dupilumab presented to the emergency department with a headache and blurry vision. Multiple Roth spots were seen on fundoscopic examination. Laboratory studies were consistent with warm AIHA, confirmed by a positive direct antiglobulin test (DAT), and severe thrombocytopenia. He was diagnosed with Evans syndrome. He was treated with corticosteroids, rituximab, and intravenous immunoglobulin (IVIG). His recovery was prolonged with the slow improvement of anemia and thrombocytopenia. This is an atypical presentation of Evans syndrome with isolated symptoms of new-onset blurry vision and headache along with the finding of Roth spots. Another interesting feature in the case is the recent use of dupilumab. Dupilumab is a monoclonal antibody that inhibits the T-helper cells type 2 (Th2) signaling pathway by blocking interleukin (IL)-4 and IL-13 binding. This alteration in the immune response could have a role in the development of Evans syndrome.

Management of Hematologic Adverse Events Associated With Immune Checkpoint Inhibitors

Immune checkpoint inhibitors target suppressor receptors, including cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed cell death ligand 1 (PD-L1). The activated T cells are not antigen specific; therefore, the blockade of the immune checkpoint may result in the development of autoimmune adverse events. The most common immune-related adverse events (irAEs) are rash, colitis, and endocrinopathies. However, irAEs that affect the hematologic system are rare and can affect red blood cells (e.g., autoimmune hemolytic anemia), white blood cells, and platelets (e.g., immune thrombocytopenia). Usually one cell line is affected; however, in some cases, multiple cell lines can be affected. Other changes in the hematologic system can also be affected (e.g., cryoglobulinemia, cytokine release syndrome). Due to the rarity and lack of recognition of these AEs, the timing, spectrum of events, and clinical presentation are poorly understood. Management of hematologic irAEs usually involves the use of steroids; however, other agents (e.g., IVIG, cyclosporine, rituximab) or procedures (e.g., plasma exchange, transfusions) can also be used.

Alectinib-induced Immune Hemolytic Anemia in a Patient with Lung Adenocarcinoma

Drug-induced immune hemolytic anemia (DIIHA) is a rare condition with an increasing incidence associated with the frequent use of certain drugs. An 85-year-old woman with lung adenocarcinoma prescribed alectinib complained of dyspnea on exertion at our hospital. Based on her laboratory tests results on admission, we focused on the clinical course of anemia and hemolysis progression after alectinib administration. The patient's anemia and hemolysis gradually improved after discontinuation of alectinib, leading to a diagnosis of alectinib-induced IHA, presented here as the first case encountered in a patient with lung adenocarcinoma. Furthermore, we discuss the importance of correlating clinical laboratory findings in DIIHA.

Diagnosis and Management of Hematological Adverse Events Induced by Immune Checkpoint Inhibitors: A Systematic Review

There has been less volume of literature focusing on the Immune-related Hematological Adverse Drug Events (Hem-irAEs) of Immune Checkpoint Inhibitors (ICPis) in cancer patients. Furthermore, there has been no consensus about the management of hematological toxicity from immunotherapy in the recently published practice guidelines by the European Society for Medical Oncology (ESMO). We conducted a systematic review of case reports/series to describe the diagnosis and management of potentially rare and unrecognized Hem-irAEs. We searched Medline, OVID, Web of Science for eligible articles. Data were extracted on patient characteristics, Hem-irAEs, and management strategies. We performed quality assessment using the Pierson-5 evaluation scheme and causality assessment using the Naranjo scale. Our search retrieved 49 articles that described 118 cases. The majority of patients had melanoma (57.6%) and lung cancer (26.3%). The most common Hem-irAEs reported with ICPis (such as nivolumab, ipilimumab, and pembrolizumab) were thrombocytopenia, hemolytic and aplastic anemias. Less reported adverse events included agranulocytosis and neutropenia. Steroids were commonly used to treat these adverse events with frequent success. Other used strategies included intravenous immunoglobulins (IVIG), rituximab, and transfusion of blood components. The findings of this review provide more insights into the diagnosis and management of the rarely reported Hem-irAEs of ICPis.

Chemotherapy-induced cognitive impairment (CICI): An overview of etiology and pathogenesis

Many cancer patients treated with chemotherapy develop chemotherapy-induced cognitive impairment (CICI), often referred to as chemo-brain, which manifest during or post-treatment with variable degrees, onset and duration thereby affecting the patients' quality of life. Several chemotherapeutic agents have been studied to determine its possible association with cognitive impairment and to fully comprehend their contribution to CICI. A vast number of studies have emerged proposing several candidate underlying mechanisms and etiologies contributing to CICI such as direct neurotoxicity, BBB disruption, decreased hippocampal neurogenesis, white matter abnormalities, secondary neuro-inflammatory response and increased oxidative stress; however, the exact underlying mechanisms are still not well defined. This review summarizes CICI associated with most commonly used chemotherapeutic agents with emphasizes the possible underlying pathogenesis in both animal and clinical studies.

Pembrolizumab-induced Pure Red Cell Aplasia Successfully Treated with Intravenous Immunoglobulin

We herein report a 64-year-old man who was treated with pembrolizumab for relapsed Hodgkin lymphoma. After the third administration of pembrolizumab, he showed acute anemia with a positive direct anti-globulin test. Because of the markedly erythroid hypoplasia, he was diagnosed with pure red cell aplasia (PRCA) caused by pembrolizumab. He was initially treated with prednisolone, but the reticulocytes decreased after tapering prednisolone. He then received high-dose intravenous immunoglobulin (IVIG) with prednisolone, and PRCA was successfully treated. Although the pathogenesis of PRCA caused by immune checkpoint inhibitors (CPIs) remains unclear, IVIG treatment may be effective for some steroid-refractory CPI-induced PRCA cases.

Pembrolizumab-induced pancytopenia in a patient with squamous cell lung cancer

Immune checkpoint inhibitors (ICIs) are reportedly effective against many kinds of neoplasm, but may be responsible for several kinds of immune‐related adverse events (irAEs). Among these irAEs, the incidence of myelosuppression due to ICIs is relatively low. Corticosteroids are needed to control most cases of myelosuppression. Here, we report an 88‐year‐old woman with squamous cell lung cancer who was administered pembrolizumab. After five cycles of pembrolizumab, she developed severe pancytopenia. The pancytopenia improved under observation without steroid administration after cessation of pembrolizumab. During recovery from this irAE, the patient also maintained long‐term antitumor efficacy.

Key points

Significant findings of the study

There are several kinds of immune‐related adverse events. We encountered a case of pembrolizumab‐induced pancytopenia with squamous cell lung cancer.

What this study adds

Corticosteroids are needed to control most cases of myelosuppression induced by ICIs, but pancytopenia induced by pembrolizumab in our case improved without steroids.

Role of Immune Checkpoint Inhibitors in Gastrointestinal Malignancies

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of several solid and hematological malignancies. ICIs are not only able to produce long and durable responses, but also very well tolerated by patients. There are several approved indications of use of ICIs in treatment of metastatic gastrointestinal malignancies including gastric, esophageal, colorectal and hepatocellular carcinoma. In addition, ICIs can be used in microsatellite instability-high (MSI-H) and high tumor mutational burden (TMB) tumors in chemotherapy-resistant setting. Despite having good efficacy and superior safety profile, ICIs are clinically active in small subset of patients, therefore, there is a huge unmet need to enhance their efficacy and discover new predictive biomarkers. There are several ongoing clinical trials that are exploring the role of ICIs in various gastrointestinal cancers either as single agent or in combination with chemotherapy, radiation therapy, targeted agents or other immunotherapeutic agents. In this review, we discuss the published and ongoing trials for ICIs in gastrointestinal malignancies, including esophageal, gastric cancer, pancreatic, hepatocellular, biliary tract, colorectal and anal cancers. Specifically, we focus on the use of ICIs in each line of therapy and discuss the future directions of these agents in each type of gastrointestinal cancer.

Tolerization of recent thymic emigrants is required to prevent RBC-specific autoimmunity

Autoimmune hemolytic anemia (AIHA) leads to accelerated destruction of autologous red blood cells (RBCs) by autoantibodies. AIHA is a severe and sometimes fatal disease. While there are several therapeutic strategies available, there are currently no licensed treatments for AIHA and few therapeutics result in treatment-free durable remission. The etiology of primary AIHA is unknown; however, secondary AIHA occurs concurrently with lymphoproliferative disorders and infections. Additionally, AIHA is the second most common manifestation of primary immunodeficiency disorders and has been described as a side effect of checkpoint inhibitor therapy. Given the severity of AIHA and the lack of treatment options, understanding the initiation of autoimmunity is imperative. Herein, we utilized a well-described model of RBC biology to dissect how RBC-specific autoreactive T cells become educated against RBC autoantigens. We show that, unlike most autoantigens, T cells do not encounter RBC autoantigens in the thymus. Instead, when they leave the thymus as recent thymic emigrants (RTEs), they retain the ability to positively respond to RBC autoantigens; only after several weeks in circulation do RTEs become nonresponsive. Together, these data suggest that any disruption in this process would lead to breakdown of tolerance and initiation of autoimmunity. Thus, RTEs and this developmental process are potential targets to prevent and treat AIHA.

Autoimmune haemolytic anaemias: A retrospective study of 93 patients

INTRODUCTION

Autoimmune haemolytic anaemia (AIHA) is an infrequent and heterogeneous disease in its pathophysiology and clinical behaviour, therefore it is generally managed empirically.

PATIENTS AND METHODS

We conducted an observational, retrospective and multicentre study of 93 patients diagnosed with AHAI in 9 Spanish hospitals between 1987 and 2017, with a median follow-up of 28 months.

RESULTS

Median age of 67 years; 85% AHAI for hot antibodies and 64% primary AHAI. The lowest haemoglobin values at diagnosis related to patients under 45 years of age and serological type IgG+C. Of the patients, 92% received first line treatment, 54% second line, and 27% third line. The warm AHAI were treated in first line with steroids, with overall responses of 83% and complete of 58%. Rituximab in monotherapy or in association with steroids was administered to 34 patients with overall responses close to 100% (complete responses 40-60%), relegating splenectomy to the third line. The immunosuppressive treatment was administered in patients with autoimmune diseases or in corticoid-dependent patients.

DISCUSSION

We found high rates of response to steroids, with very prolonged treatments that cause side effects and corticoid dependence in a third of patients. The combination of steroids with rituximab in the first line, could be indicated in patients with low levels of haemoglobin and serological type IgG+C. The high relapse rates make necessary the development of randomised studies with new drugs or the combination with existing ones, which allow longer response times and with fewer side effects.

Immune-related adverse events of checkpoint inhibitors

Cancer immunotherapies have changed the landscape of cancer treatment during the past few decades. Among them, immune checkpoint inhibitors, which target PD-1, PD-L1 and CTLA-4, are increasingly used for certain cancers; however, this increased use has resulted in increased reports of immune-related adverse events (irAEs). These irAEs are unique and are different to those of traditional cancer therapies, and typically have a delayed onset and prolonged duration. IrAEs can involve any organ or system. These effects are frequently low grade and are treatable and reversible; however, some adverse effects can be severe and lead to permanent disorders. Management is primarily based on corticosteroids and other immunomodulatory agents, which should be prescribed carefully to reduce the potential of short-term and long-term complications. Thoughtful management of irAEs is important in optimizing quality of life and long-term outcomes.

[Toxicities of immune checkpoint inhibitors and their management]

Immunotherapeutic strategies, notably immune checkpoint inhibitors, have become a standard of care for the treatment of advanced cancers, with a growing spectrum of activity. These monoclonal antibodies target the co-inhibitory signals between tumor cells or antigen-presenting cells and T cells, thereby enhancing antitumour T cell activity. However, the occurrence of immune-related adverse events, that can affect all organ-system, represents a major limiting factor to the clinical development of these antibodies. Management of such toxicity requires a close collaboration between oncologists and organ-specialists, by using glucocorticoids and/or other immunosuppressive therapies, with the common objective not alter anti-tumor response.

Pembrolizumab-induced autoimmune haemolytic anaemia and cholangitis

Increasing numbers of patients are now offered immunotherapy as part of their cancer treatment. These treatments, while often very effective, have a wide range of adverse effects that are distinct from those of traditional chemotherapy regimens. Thyroid disease, dermatological disease, colitis and pneumonitis are some of the most commonly reported immune side effects. We present a case of life-threatening de novo autoimmune haemolytic anaemia (AIHA) complicated by immune cholangitis induced by pembrolizumab. An 81-year-old woman with metastatic melanoma completed a two-year course of pembrolizumab in August 2018 and six weeks later presented to hospital with jaundice. Admission haemoglobin (Hb) was 91 g/L, rapidly decreasing to 31 g/L, at which point she required admission to the intensive care unit. AIHA is a rare but potentially life-threatening complication of checkpoint inhibitors and should be considered in patients presenting with anaemia during or after immunotherapy treatment.

Pembrolizumab-associated autoimmune haemolytic anaemia

Treatment paradigms have recently changed with the introduction of immunotherapy; autoimmune toxicities that can arise are frequently very different from the more familiar chemotherapy toxicities. We present a clinical case of autoimmune haemolytic anaemia (AIHA) secondary to pembrolizumab occurring in a 73-year-old male patient being treated for lung adenocarcinoma, who had received 13 cycles of pembrolizumab. Treatment was immediately stopped and he was treated with high dose steroids to which he responded both clinically and biochemically. There have been prior reports of immunotherapy-associated AIHA with the use of cytotoxic T-lymphocyte-associated antigen-4 inhibitors, such as ipilimumab, but very few reports of programmed death-1 (PD-1)/programmed death-ligand 1 (PDL-1) inhibitor associated AIHA. We highlight a rare case of AIHA as an adverse effect of pembrolizumab, a PD-1 inhibitor. Although unusual, it is important to be vigilant for haematological immune-related adverse events.

Haematological immune-related adverse events with immune checkpoint inhibitors, how to manage?

Immune checkpoint inhibitors (ICIs) are changing the treatments of many patients with cancer. These immunotherapies are generally better tolerated than chemotherapy, and their adverse events are immune-related mimicking autoimmune or inflammatory conditions. Although these immune-related adverse events mainly affect the skin, endocrine glands, digestive tract, joints, liver or lungs, all the organs can be theoretically affected, and the haematopoietic system is not spared. This review of the literature will focus on the haematological immune-related adverse events (Haem-irAEs). By reviewing the largest clinical trials of ICIs, we estimate the frequency of Haem-irAEs at 3.6% for all grades and 0.7% for grades III-IV. Frequency of Haem-irAEs of all grades was found to be higher with anti-programmed cell death 1 (4.1%) or anti-programmed cell death ligand 1 (4.7%) than with anti-cytotoxic T-lymphocyte-associated protein 4 (0.5%) (p < 0.0001). From the 63 cases with Haem-irAEs reported in the literature, the mean time to the onset was found to be 10 weeks after ICI initiation, and the large range for occurrence (1-84 weeks) and the regular incidence suggest that Haem-irAEs could occur at any time after ICI therapy. Among the 63 reported cases with Haem-irAEs, the distribution was immune thrombocytopenia (n = 18, 29%), pancytopenia or immune aplastic anaemia (n = 12, 19%), neutropenia (n = 11, 17%), haemolytic anaemia (n = 10, 16%), cytokine release syndrome with haemophagocytic syndrome (n = 7, 11%) and other Haem-irAEs including bicytopenia or pure red cell aplasia (n = 5, 8%). Haem-irAEs are generally highly severe adverse reactions with a mortality rate of Haem-irAEs reported to be 14% (9 deaths among the 63 cases reported). The more severe and life-threatening Haem-irAEs were both cytokine release syndrome with haemophagocytic syndrome and pancytopenia or aplastic anaemia. Haem-irAEs induced by ICIs are potentially life-threatening. By discussing their pathophysiological aspects and clinical picture, we propose in this review clinical guidelines for management.

Unexpected serious aplastic anemia from PD-1 inhibitors: beyond what we know

INTRODUCTION

The recent introduction of checkpoint inhibitor-based immunotherapy has revolutionized the treatment of advanced lung cancers, becoming standard of care in both first- and second-line treatment. New types of toxicity are emerging with the increasingly widespread use of these inhibitors.

CASE PRESENTATION

We describe a case of aplastic anemia in a patient with stage IV non-small cell lung cancer after a single administration of nivolumab.

CONCLUSIONS

Several similar case reports reported in literature show an increasing rate of toxicities from immunotherapy in this setting. These real-world data provide an insight into patient outcomes and treatment decisions being made in clinical practice.

AIHA and Pancytopenia as Complications of Pembrolizumab Therapy for Metastatic Melanoma: A Case Report

Immunotherapy has been an emerging treatment for metastatic melanoma and several other malignancies since 2015. Hematological immune-mediated adverse effects from immunotherapy are rarely reported but they can cause serious harm to patients. Antibodies such as ipilimumab, nivolumab and pembrolizumab target different immune checkpoints to promote T cell anti-tumour response. In particular, pembrolizumab is an antibody that inhibits programmed cell death receptor 1 (PD-1) to upregulate tumour suppression. In this report, we present a case of pembrolizumab-induced autoimmune hemolytic anemia and pancytopenia in a patient who was receiving pembrolizumab treatment for metastatic melanoma. This patient has a history of chronic lymphocytic leukemia and was diagnosed with metastatic melanoma in 2017. He developed symptomatic AIHA and pancytopenia after receiving 8 cycles of pembrolizumab in 2018. Pembrolizumab treatment was discontinued and he was treated with blood transfusion and prednisone. After 5 months of tapering prednisone treatment, his anemia and pancytopenia have improved toward successful recovery. Cancer patients already face an increased risk of immunosuppression with conventional chemotherapy. This case report also summarized all reported cases of PD-1 inhibitor hematological adverse effects in the treatment of oncological diseases. These incidents reflect the risk of immune-mediated hematologic adverse effects, which should be considered in all patients using immunotherapy.

Clinical and laboratory features of autoimmune hemolytic anemia associated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICPis) are a novel class of immunotherapeutic agents that have revolutionized the treatment of cancer; however, these drugs can also cause a unique spectrum of autoimmune toxicity. Autoimmune hemolytic anemia (AIHA) is a rare, but often severe, complication of ICPis. We identified 14 patients from nine institutions across the United States who developed ICPi-AIHA. The median interval from ICPi initiation to development of AIHA was 55 days (interquartile range [IQR], 22-110 days). Results from the direct antiglobulin test (DAT) were available for 13 of 14 patients: 8 patients (62%) had a positive DAT and 5 (38%) had a negative DAT. The median pretreatment and nadir hemoglobin concentrations were 11.8 g/dL (IQR, 10.2-12.9 g/dL) and 6.3 g/dL (IQR, 6.1-8.0 g/dL), respectively. Four patients (29%) had a preexisting lymphoproliferative disorder, and two (14%) had a positive DAT prior to initiation of ICPi therapy. All patients were treated with glucocorticoids, with three requiring additional immunosuppressive therapy. Complete and partial recoveries of hemoglobin were achieved in 12 (86%) and 2 (14%) patients, respectively. Seven patients (50%) were rechallenged with ICPis, and one (14%) developed recurrent AIHA. Clinical and laboratory features of ICPi-AIHA were similar in DAT positive and negative patients. ICPi-AIHA shares many clinical features with primary AIHA; however, a unique aspect of ICPi-AIHA is a high incidence of DAT negativity. Glucocorticoids are an effective first-line treatment in the majority of patients with ICPi-AIHA, and most patients who are rechallenged with an ICPi do not appear to develop recurrence of AIHA.

Hematological Side Effects of Immune Checkpoint Inhibitors: The Example of Immune-Related Thrombocytopenia

Immune-related hematological adverse events are amongst the rare but potentially life-threatening complications of immune checkpoint inhibitors. The spectrum of these toxicities is broadening as the number of patients exposed to these agents is increasing. Yet, they are still relatively unknown to many clinicians, possibly due to a lack of specific diagnostic criteria, which poses a challenge for their recognition and proper reporting, and partly due to their low incidence, often too low to be noted in most clinical trial publications. Since early detection and prompt intervention are crucial to prevent fatal consequences, it is of outmost importance that medical staff and patients be aware of these potential toxicities and learn to recognize and treat them adequately. This publication outlines strategies and offers guidance on the detection, diagnosis, risk assessment, monitoring and management of immune-related thrombocytopenia, a relatively common example of immune-related hematological toxicity of immune checkpoint inhibitors.

Nivolumab-induced cold agglutinin syndrome successfully treated with rituximab

Cold agglutinin syndrome is one of the rare immune-related adverse events of nivolumab. Rituximab should be considered for treatment of nivolumab-induced cold agglutinin syndrome.

Order of administration of combination cytokine therapies can decouple toxicity from efficacy in syngeneic mouse tumor models

In combination cancer immunotherapies, consideration should be given to designing treatment schedules that harmonize with the immune system's natural timing. An efficacious temporally programmed combination therapy of extended half-life interleukin 2 (eIL2), tumor targeting antibody, and interferon (IFN) α was recently reported; however, tumor-ablative efficacy was associated with significant toxicity. In the current work, altering the order and timing of the three agents is shown to decouple toxicity from efficacy. Delaying the administration of eIL2 to be concurrent with or after IFNα eliminates toxicity without affecting efficacy in multiple syngeneic tumor models and mouse strains. The toxicity resulting from eIL2 administration before IFNα is dependent on multiple systemic inflammatory cytokines including IL6, IL10, IFNγ, and tumor necrosis factor α. Natural killer (NK) cells are the main cellular contributor to toxicity, but are not essential for tumor control in this system. When pre-conditioned with eIL2, splenic NK cells became hyper-activated and upregulate IFNα signaling proteins that cause an excessive, toxic response to subsequent IFNα exposure. This work illustrates an example where accounting for the temporal dynamics of the immune system in combination therapy treatment schedule can favorably decouple efficacy and toxicity.

Severe toxicity from checkpoint protein inhibitors: What intensive care physicians need to know?

Checkpoint protein inhibitor antibodies (CPI), including cytotoxic T-lymphocyte-associated antigen 4 inhibitors (ipilimumab, tremelimumab) and the programmed cell death protein 1 pathway/programmed cell death protein 1 ligand inhibitors (pembrolizumab, nivolumab, durvalumab, atezolizumab), have entered routine practice for the treatment of many cancers. They improve the outcome for many cancers, and more patients will be treated with CPI in the future. Although CPI can lead to adverse events (AE) less frequently than for chemotherapy, their use can require intensive care unit admission in case of severe immune-related adverse events (IrAE). Moreover, some of these events, particularly late events, are poorly documented, so a high level of suspicion should be maintained for patients receiving CPI. Intensivists should be aware in general of the known complications and appropriate management of these AE. Nevertheless, a multidisciplinary collaboration remains essential for their diagnosis and management. This review described the most severe complications related to CPI.

Haematological immune-related adverse events induced by anti-PD-1 or anti-PD-L1 immunotherapy: a descriptive observational study

BACKGROUND

Anti-programmed cell death 1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) antibodies are novel immunotherapies for cancer that can induce immune-related adverse events (irAEs). These adverse events can involve all organs, including the haemopoietic system. Thus far, haematological irAEs (haem-irAEs) have not been extensively characterised. This study aims to provide a comprehensive report of the haem-irAEs induced by anti-PD-1 or anti-PD-L1.

METHODS

In this descriptive observational study, we included consecutive patients aged at least 18 years with grade 2 or worse haem-irAEs induced by anti-PD-1 or anti-PD-L1 immunotherapy registered in three French pharmacovigilance databases: the Registre des Effets Indésirables Sévères des Anticorps Monoclonaux Immunomodulateurs en Cancérologie (REISAMIC; a prospective registry of patients treated with anti-PD-1 or anti-PD-L1 at a single centre), the ImmunoTOX committee of Gustave Roussy (a national referral database of suspected irAEs in patients treated with immunotherapy), and the registry of the Centre de Référence des Cytopénies Auto-Immunes de l'Adulte (CeReCAI; a national database of autoimmune cytopenias). Cases were reviewed by a central committee; adverse events had to be classed as certainly or probably related to anti-PD-1 or anti-PD-L1 therapy, and their severity was assessed according to the Common Terminology Criteria for Adverse Events (version 4.03). The primary endpoint was clinical description of haem-irAEs, as reported in all databases, and their frequency, as reported in the prospective REISAMIC registry.

FINDINGS

We screened 948 patients registered in the three databases from June 27, 2014, to June 29, 2018 (745 from REISAMIC, 190 from the ImmunoTOX committee, and 13 from CeReCAI). 35 patients (21 men and 14 women) with haem-irAEs related to anti-PD-1 or anti-PD-L1 were included in the study. Of 745 patients in the REISAMIC registry treated with anti-PD-1 or anti-PD-L1, four had haem-irAEs, giving a frequency of 0·5%. Median age in the 35 patients was 65 years (IQR 51-75), and the most common tumour types were melanoma (15 [43%] patients), non-small-cell lung cancer (12 [34%] patients), and lymphoma (four [11%] patients). 20 (57%) patients received nivolumab, 14 (40%) received pembrolizumab, and one (3%) received atezolizumab. Among the 35 patients, neutropenia, autoimmune haemolytic anaemia, and immune thrombocytopenia were the most common types of haem-irAE (each in nine patients [26%]), followed by pancytopenia or aplastic anaemia (five patients [14%]), bicytopenia (one patients with thrombocytopenia plus anaemia and one patient with neutropenia plus anaemia [6%]), and pure red cell aplasia (one patient [3%]). The maximum grade of severity was grade 2 in three (9%) patients, grade 3 in five (14%) patients, and grade 4 in 25 (71%) patients; two (6%) patients died from febrile neutropenia during haem-irAE related to anti-PD-1. Haem-irAEs resolved in 21 (60%) of the 35 patients.

INTERPRETATION

Haem-irAEs induced by PD-1 or PD-L1 inhibitors are rare but potentially life-threatening events. The most common clinical presentations are neutropenia, autoimmune haemolytic anaemia, immune thrombocytopenia, and aplastic anaemia. Investigations into earlier detection and better management are warranted.

FUNDING

Gustave Roussy and Gustave Roussy Immunotherapy Program.

A case of pure red cell aplasia during nivolumab therapy for cardiac metastatic melanoma

Nivolumab is an antibody against programmed cell death 1 and functions as an immune checkpoint inhibitor for various malignancies, including unresectable melanomas. Nivolumab causes several immune-related adverse events, which typically include skin rash, pneumonitis, thyroid dysfunction, hepatitis, and colitis; in rare cases, anemia may be present. There are several reports of autoimmune hemolytic anemia that has developed in response to nivolumab; however, there are few reports of pure red cell aplasia (PRCA). We describe a patient who developed PRCA during nivolumab administration. A 70-year-old Japanese woman received nivolumab for cardiac metastasis from malignant melanoma from an unknown site. Twenty-one months after nivolumab administration (31 courses), treatment was discontinued because she developed severe anemia. Blood test results indicated normocytic, normochromic anemia, and reticulocytopenia, but all other components were normal. Bone marrow aspiration showed increased megakaryocytes and decreased erythroblasts; these findings were consistent with PRCA. Anemia improved without recurrence after treatment with corticosteroids and blood transfusions. The steroid dosage was reduced gradually, and to date, the patient has not experienced recurrence of anemia. The tumor decreased in size and the patient has shown a continued response to treatment with decrease in disease for 3 years. Although it is unclear how nivolumab causes PRCA, hematological toxicities have been reported in patients treated with immunotherapy drugs. PRCA might be an unrecognized immune-mediated adverse event that did not manifest during the clinical trial phase.

A case of autoimmune haemolytic anaemia after 39 cycles of nivolumab

With growing use of nivolumab, rare but serious side effects have surfaced in some patients. We present a case of autoimmune haemolytic anaemia that developed after 39 cycles of nivolumab. A 78-year-old man with metastatic lung adenocarcinoma, refractory to multiple lines of chemotherapy was switched to nivolumab. After around 2 years of stable course on nivolumab, he developed transfusion-dependent anaemia with haemoglobin of 8.6 g/dL. Nivolumab was held immediately. Bone marrow biopsy findings were inconclusive of myelodysplastic syndrome. Further testing was suggestive of haemolysis with haptoglobin <10 mg/dL, elevated reticulocyte count and identification of immunoglobulin G antibody. Haemoglobin improved significantly with initiation of 1 mg/kg prednisone in addition to rituximab weekly × four doses. The development of transfusion-dependent anaemia with the exposure to cytotoxic chemotherapy usually raises the question for myelodysplastic syndrome. In contradiction, our patient was diagnosed to have a haematological autoimmune complication related to immunotherapy.

Autoimmune haemolytic anaemia in a patient with advanced lung adenocarcinoma and chronic lymphocytic leukaemia receiving nivolumab and intravenous immunoglobulin

We describe a rare case of severe autoimmune haemolytic anaemia (AIHA) in the setting of underlying chronic lymphocytic leukaemia receiving intravenous immunoglobulin, history of warm IgG autoantibody and treatment with nivolumab for advanced non-small cell lung cancer. In this report, we describe AIHA as a potential serious immune-related adverse event from immune checkpoint inhibitors, discuss other potential contributing factors and review previously described cases of AIHA in patients receiving programmed death 1 (PD-1) inhibitors. In the era of immunotherapy, we hope to add literature to raise awareness of potential immune-related sequelae such as AIHA. We aim to highlight the importance of close monitoring for prompt identification and management of potentially fatal AIHA and immune-related adverse events of PD-1 inhibitors by holding immunotherapy and treating with high-dose steroids, particularly in subgroups which may be at increased risk.

Features of Effective T Cell-Inducing Vaccines against Chronic Viral Infections

For many years, the focus of prophylactic vaccines was to elicit neutralizing antibodies, but it has become increasingly evident that T cell-mediated immunity plays a central role in controlling persistent viral infections such as with human immunodeficiency virus, cytomegalovirus, and hepatitis C virus. Currently, various promising prophylactic vaccines, capable of inducing substantial vaccine-specific T cell responses, are investigated in preclinical and clinical studies. There is compelling evidence that protection by T cells is related to the magnitude and breadth of the T cell response, the type and homing properties of the memory T cell subsets, and their cytokine polyfunctionality and metabolic fitness. In this review, we evaluated these key factors that determine the qualitative and quantitative properties of CD4+ and CD8+ T cell responses in the context of chronic viral disease and prophylactic vaccine development. Elucidation of the mechanisms underlying T cell-mediated protection against chronic viral pathogens will facilitate the development of more potent, durable and safe prophylactic T cell-based vaccines.

TNFR2: A Novel Target for Cancer Immunotherapy

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy but exhibit variable efficacy and relapse and can induce autoimmunity. Tumor necrosis factor (TNF) receptor 2 (TNFR2) is a signaling molecule found on the surface of a subset of potent regulatory T cells (T_regs) that can activate the proliferation of these cells through nuclear factor kappa B (NF-κB). TNFR2 is also abundantly expressed on the surface of many human tumors. We propose that blocking TNFR2 might target abundant TNFR2⁺ tumor-infiltrating T_regs and directly kill TNFR2-expressing tumors. We also posit that TNFR2 inhibitors might potentially constitute safer and more targeted alternatives to ICI cancer treatment because the expression of TNFR2 on immune cells, concentrated in the tumor microenvironment of various cancers, appears to be more selective than that of checkpoint molecules.