Association Between RBC Antigen Allo-Antibodies and Immune-Related Adverse Events During Immune Checkpoint Inhibitor Treatment for Advanced Cancers

Positive direct antiglobulin tests in cancer patients on immune checkpoint inhibitors: A case series from India

Tumour cells activate immune checkpoints such as programmed death receptor-1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) signalling pathways to inhibit T lymphocyte activation and thus escape from immune surveillance. Immune checkpoint inhibitors (ICPis) reactivate T lymphocytes to recognize cancer cells by blocking CTLA-4 or PD-1. Autoimmune haemolytic anaemia is a rare, but often severe, complication of ICPis. Therefore, we performed a retrospective clinical case review, including serologic, haematology, and biochemistry laboratory results, of three patients who developed autoantibodies to erythrocytes following treatment with pembrolizumab, an anti-PD-1 inhibitor. Serologic testing of blood samples from these patients showed their red cells were positive for direct antiglobulin test (DAT+ for IgG in two cases and IgG with C3d in one case). Antibody detection test was negative. No patient had clinical and laboratory features of haemolysis. There were no additional immune-related adverse events. IgG antibodies coating red cells were neither IgG1 nor IgG3 in class and elution was found negative in all. In conclusion, immunohaematology laboratories should be aware of the possibility of erythroid autoantibodies and their nature in cancer patients receiving ICPis. The result of a positive DAT should be interpreted carefully in these patients to exclude other possible causes of anaemia.

Autoimmune hemolytic anemia in patients with relapsed Hodgkin's lymphoma after treatment with penpulimab, a monoclonal antibody against programmed death receptor-1

In August 2021, penpulimab, an anti-programmed cell death 1 (PD-1) monoclonal antibody, was approved in China for the treatment of adult patients with relapsed or refractory classic Hodgkin's lymphoma who completed at least second-line chemotherapy. Penpulimab is currently in clinical trials in China and Australia for the treatment of nasopharyngeal cancer and non-small cell lung cancer. Several clinical studies have shown that penpulimab is safe and effective, and no immune-related adverse events (irAEs) above grade 3 were observed. A 60-year-old woman with relapsed Hodgkin's lymphoma developed nausea and fatigue after receiving penpulimab monotherapy (200 mg every 2 weeks). Ten days after the second injection, the patient's condition worsened, and biochemical test results confirmed autoimmune hemolytic anemia (AIHA), with a hemoglobin level of 70 g/L (normal range, 115-150 g/L), an unconjugated bilirubin level of 19.08 µmol/L (normal range, 0-17 µmol/L), and positive direct antiglobulin test (DAT) results. On the same day, we treated her with prednisone (2 mg/kg), but her hemoglobin level continued to decline to 51 g/L one day after hormone therapy, so she received an intravenous infusion of washed red blood cells and underwent plasmapheresis, which eventually resolved the AIHA. Considering that the hemoglobin level was < 65 g/L and the irAE was grade 4, penpulimab was discontinued, and the symptoms of AIHA disappeared. From this event, we know that severe AIHA can occur after penpulimab use similar to other PD-1 antibodies. In this case, plasmapheresis showed a good therapeutic effect and should be used as a supplementary means when hormonal and immunosuppressive therapies cannot provide rapid symptom relief. In addition, we recommend regular direct antiglobulin testing, as well as haptoglobin, lactate dehydrogenase and other hemolysis-related laboratory tests, in patients prescribed penpulimab and similar drugs for the early diagnosis and treatment of AIHA.

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.

Rare side effect caused by atezolizumab, an immune checkpoint inhibitor: Cold agglutinin disease

INTRODUCTION

Immune checkpoint inhibitors are drugs that are included in the guidelines of hematological and solid cancer treatments, give highly effective results and increase T cell functionality. However, these drugs can cause immune-related adverse events resembling autoimmune diseases.

CASE REPORT

A 50-year-old male patient was admitted to an external center with complaints of chest pain and dyspnea. Thoracic CT revealed a 97 × 58 mm mass in the left lung, and a diagnosis of Small Cell Lung Cancer (SCLC) was made by biopsy. The PET/CT performed for staging was also evaluated as extensive stage small cell lung cancer. It was decided to give a combination of atezolizumab and carboplatin-etoposide to the patient.Management and outcome: The patient completed 3 cycles without any problem. Discordance was detected in the hemogram of the patient who came to the control for the assessment of response and had a regression in the imaging. Hemoglobin 9.6 g/dl (N: 14-17.5) hematocrit 14.8% (N: 41-51) were detected in the hemogram. Agglutinins were seen in the peripheral smear performed. Cold agglutinin (+4 positive) and indirect coombs (+3 positive) were found positive. Atezolizumab was stopped and methylprednisolone was started. After 10 days of treatment, discordance improved and methylprednisolone was discontinued by decreasing to half dose every 5 days.

DISCUSSION

With the increasing use of immune checkpoint inhibitors, the variety of side effects has increased and case reports have increased. After detection of cold agglutinin, IgG, cryoglobulin, mycoplasma pneumonia, hepatitis B, hepatitis C and HIV were found negative in the differential diagnosis, Our case appears to be immune checkpoint inhibitor-related Cold Agglutinin Disease (CAD). It should not be forgotten that immune checkpoint inhibitors, which are widely used, may cause CAD, and hemoglobin-hematocrit discordance should be paid attention to in routine controls.