Pembrolizumab-induced pneumonitis with a perilymphatic nodular pattern in a lung cancer patient: A radio-pathologic correlation

CD8+ Lymphocyte Infiltration Is a Specific Feature of Colitis Induced by Immune Checkpoint Inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICPIs) have revolutionized cancer therapy, although immune-related adverse events (irAEs) remain a serious issue. The clinical characteristics of colitis induced by ICPIs are very similar to inflammatory bowel disease. Recently, cluster of differentiation 8 positive (CD8⁺) lymphocyte infiltration into organs has been associated with the onset of irAEs. The present study compared the histological infiltration of CD8⁺ lymphocytes in irAE colitis with that in other colitis.

METHODS

Newly diagnosed and untreated patients were retrospectively enrolled. Biopsy specimens were obtained from endoscopic areas of high inflammation for immunohistochemical analysis of the number of cluster of differentiation 4 positive (CD4⁺) and CD8⁺ lymphocytes in the high-powered microscopic field with the most inflammation.

RESULTS

A total of 102 patients [12 with irAE colitis, 37 with ulcerative colitis (UC), 22 with Crohn's disease (CD), and 31 with ischemic colitis (IC)] were analyzed. In irAE colitis, CD8⁺ lymphocyte infiltration was significantly greater than that of CD4⁺ lymphocytes (p < 0.01). The amount of CD8⁺ lymphocyte infiltration was significantly higher in irAE colitis than in UC (p < 0.05), CD (p < 0.05), and IC (p < 0.01). The CD8⁺/CD4⁺ ratio was also significantly higher in irAE colitis (p < 0.01 versus UC, CD, and IC, respectively). The optimal cutoff CD8⁺/CD4⁺ ratio for diagnosing irAE colitis was 1.17 (sensitivity 83%, specificity 84%). The optimal cutoff number of CD8⁺ lymphocytes for diagnosing irAE colitis was 102 cells per high-power field (sensitivity 75%, specificity 81%).

CONCLUSIONS

Greater CD8⁺ lymphocyte infiltration and a higher CD8⁺/CD4⁺ ratio may be simple and useful biomarkers to distinguish irAE colitis from other forms of colitis.

Immune check-point inhibitor-related pneumonitis: acute lung injury with rapid progression and organising pneumonia with less severe clinical disease

AIMS

To improve understanding of the pathology of immune check-point inhibitor (ICI)-related pneumonitis, clinical, radiographic and histopathological features and outcomes were investigated in a cohort of patients who were treatment-naive before receiving ICI inhibition, who underwent lung biopsy, and in whom other potential causes of lung injury were excluded.

METHODS

Patients were retrospectively identified via searches of institutional pathology and clinical records. Patients treated with other modalities for cancer and patients with lung infections or other aetiologies that could cause pneumonitis were excluded. Clinical records were reviewed by pulmonologists. Imaging studies at presentation and follow-up were reviewed by a thoracic radiologist. Pathology was reviewed by thoracic pathologists.

RESULTS

Six patients with ICI-related pneumonitis were identified. Two patients presented with respiratory failure requiring mechanical ventilation, diffuse ground glass opacities (GGOs) on chest computed tomography (CT) and acute lung injury (ALI) pattern on transbronchial lung biopsies and had fatal outcomes, despite treatment. The remaining four patients presented with less severe symptoms, predominantly consolidations and patchy ground glass and part solid opacities on chest CT, organising pneumonia (OP) or chronic interstitial inflammation histologically, and showed favourable responses to treatment and remission within months.

CONCLUSIONS

This study highlights two radiological-pathological patterns of ICI-related pneumonitis with different behaviour: (1) severe respiratory symptoms and diffuse GGOs on imaging correlating with ALI pattern histologically and poor prognosis; and (2) mild respiratory symptoms and consolidations or patchy subsolid opacities on imaging correlating histologically with OP or chronic interstitial inflammation and good outcomes.

Immunotherapy: A Case Series

Immunotherapy is on the rise as a treatment option for advanced melanoma, non-small cell lung carcinoma, renal cell carcinoma, and melanoma among others. It consists of two main classes being cytotoxic T lymphocyte antigen 4 (CTLA 4) inhibitors and programmed cell death 1 (PD 1) inhibitors. We report a case series of four patients who were started on either pembrolizumab or nivolumab for the treatment of melanoma or lung cancer. While on immunotherapy, they developed various side effects related to the immunotherapy including pneumonitis, transaminitis, thyroiditis, nephritis, and hypophysitis. To treat this complication, immunotherapy must be discontinued or held with immunosuppressant initiation as treatment. Most often the immunosuppressant of choice is steroids. After symptoms improve, patients can decide along with the clinician on restarting or completely stopping immunotherapy. Within our case series, three of four patients had resolutions of their symptoms with steroid treatment with one who was lost to follow up. Of the three patients who were being followed up, one had a relapse of side effects after resuming immunotherapy and decided against further treatment with immunotherapy. Another patient is doing well resuming immunotherapy on a daily dose of steroids. The last patient decided to not continue with immunotherapy after experiencing a flare of his symptoms when he was being treated since he missed a few doses of steroids. Further research is needed about the risk of flares of complications when resuming immunotherapy alone or with immunotherapy and steroid treatment.

Investigational Biomarkers for Checkpoint Inhibitor Immune-Related Adverse Event Prediction and Diagnosis

BACKGROUND

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of multiple cancers. However, these promising therapies may also cause immune-related adverse events (irAEs) in a substantial proportion of patients. These autoimmune phenomena may affect almost any organ system and may occur at almost any point in therapy. In some instances, these toxicities are life-threatening and potentially permanent. Diverse clinical presentation and unpredictable timing further complicate their anticipation and diagnosis.

CONTENT

To improve patient safety and selection for ICI use, biomarkers for irAE diagnosis and prediction are under development. Clinicians may use traditional laboratory markers such as routine chemistries, creatinine clearance, thyroid function tests, and serum cortisol/adrenocorticotrophic hormone to monitor for specific irAEs, but noted aberrations may not necessarily represent an immune-mediated etiology. Novel biomarkers have the potential to be more specific to assist in the diagnosis of irAEs. The prediction of irAEs is more challenging. Apart from a history of autoimmune disease, no other clinical parameters are routinely used to project risk. Biomarker candidates under investigation for irAE diagnosis and prediction include blood cell analysis, chemokines/cytokines, autoantibodies, and genetic predisposition, such as human leukocyte antigen haplotype. Among other emerging candidates are immune-cell subsets, T-cell repertoire, fecal microbiome, tumor genomics, and radiomic characterization.

SUMMARY

Several conventional laboratory indexes of end-organ dysfunction are currently in routine clinical use for irAE monitoring and diagnosis. Novel biomarkers for the prediction and diagnosis of these irAEs, which primarily characterize patient immune function, represent an area of active investigation.