Diagnostic utility of programmed cell death ligand 1 (clone SP142) immunohistochemistry for malignant lymphoma and lymphoproliferative disorders: A brief review

EBV-positive mucocutaneous ulcer arising in methotrexate-treated rheumatoid arthritis patients: a clinicopathological study of 12 cases with analysis of PD-L1 expression

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a newly recognized disease entity characterized by EBV-positive atypical B-cell proliferation. EBVMCU is a localized self-limited disease that affects mucosa and skin, especially the oral cavity. EBVMCU develops in immunosuppressive patients, such as those with methotrexate (MTX)-administrated rheumatoid arthritis (RA). Here we clinicopathologically analyzed 12 EBVMCU patients in a single institution. All cases were administrated MTX for RA, and five cases occurred in the oral cavity. All cases except one had demonstrated spontaneous regression after withdrawal of the immunosuppressive agent. We found 4 of 5 cases in the oral cavity had preceding traumatic events in the same site within a week before the onset of EBVMCU. Although there is no detailed and large study that has analyzed the trigger of EBVMCU, a traumatic event would indeed be a significant trigger for EBVMCU in the oral cavity. The cases were histologically classified; six cases were diffuse large B-cell lymphoma-type, five were polymorphous-type, and one was Hodgkin-like lesion type due to morphological appearance and immunophenotype. The PD-L1 expression was also examined by two antibodies for PD-L1 (E1J2J and SP142). Both antibodies revealed identical results for PD-L1 expression, and three cases were positive for PD-L1. The application of SP142 for evaluating the immune status of lymphomagenesis has also been proposed. Nine of 12 cases were negative for PD-L1, which implies that most EBVMCU cases may be caused by an immunodeficiency, rather than an immune-evasion, mechanism. However, as three cases were positive for PD-L1, immune escape may underly the pathogenesis in a subset of EBVMCU cases.

Thrombocytopenia, anasarca, and renal insufficiency as severe and rare complications of Hodgkin lymphoma: a case report

BACKGROUND

Patients with Hodgkin lymphoma exhibit various clinical presentations. Needle biopsy of the lymph nodes is a minimally invasive procedure and a useful diagnostic method for malignant lymphomas. However, at times it is difficult to differentiate malignant lymphomas from reactive lymph node changes using a small amount of biopsy material.

CASE PRESENTATION

A 77-year-old Japanese man was referred to the emergency department of our hospital owing to high fever and disturbance of consciousness. We diagnosed sepsis due to an acute biliary tract infection because he presented with Charcot's triad-fever, jaundice, and right-sided abdominal pain. However, he did not respond well to antimicrobial therapy and his high fever persisted. Considering the swelling of the right cervical, mediastinal, and intraperitoneal lymph nodes and splenomegaly detected on computed tomography, a differential diagnosis of malignant lymphoma was needed. Hence, we performed a needle biopsy of the right cervical lymph node; however, the amount of sample obtained was insufficient in establishing a definitive diagnosis of malignant lymphoma. Furthermore, during hospitalization, the patient developed thrombocytopenia, anasarca, and renal insufficiency. These symptoms seemed to be the typical signs of the thrombocytopenia, anasarca, fever, reticulin fibrosis or renal insufficiency, and organomegaly syndrome. Next, an external incisional mass biopsy of the right cervical lymph node was performed, which helped identify Hodgkin and Reed-Sternberg cells. Collectively, we established a definitive diagnosis of Hodgkin lymphoma with lymphoma-associated hemophagocytic syndrome.

CONCLUSIONS

This case highlights the importance of performing an external incisional mass biopsy of the lymph nodes for the early diagnosis and treatment, if malignant lymphoma is strongly suspected.

The Immunology of DLBCL

Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy and is the most common type of malignant lymphoid neoplasm. While some DLBCLs exhibit strong cell-autonomous survival and proliferation activity, others depend on interactions with non-malignant cells for their survival and proliferation. Recent next-generation sequencing studies have linked these interactions with the molecular classification of DLBCL. For example, germinal center B-cell-like DLBCL tends to show strong associations with follicular T cells and epigenetic regulation of immune recognition molecules, whereas activated B-cell-like DLBCL shows frequent genetic aberrations affecting the class I major histocompatibility complex. Single-cell technologies have also provided detailed information about cell-cell interactions and the cell composition of the microenvironment of DLBCL. Aging-related immunological deterioration, i.e., immunosenescence, also plays an important role in DLBCL pathogenesis, especially in Epstein-Barr virus-positive DLBCL. Moreover, DLBCL in "immune-privileged sites"-where multiple immune-modulating mechanisms exist-shows unique biological features, including frequent down-regulation of immune recognition molecules and an immune-tolerogenic tumor microenvironment. These advances in understanding the immunology of DLBCL may contribute to the development of novel therapies targeting immune systems.

Diagnostic approach for classic Hodgkin lymphoma in small samples with an emphasis on PD-L1 expression and EBV harboring in tumor cells: a brief review from morphology to biology

Classic Hodgkin lymphoma (CHL) was first described in 1832 by Thomas Hodgkin, and is characterized by a small number of Hodgkin and Reed-Sternberg cells in a rich inflammatory background. However, even in this modern era, due to the histological and biological overlap with CHL and other B-cell malignancies, including mediastinal grey zone lymphoma and other lymphomas accompanied by "Hodgkinoid cells", their discrimination is challenging and sometimes impossible. The complexity and ambiguity of the boundaries of CHL and its related diseases make the definition of CHL unresolved. Our group has studied the significance of PD-L1 expression and infection of Epstein-Barr virus (EBV) in the diagnosis of CHL, emphasizing their pathological role, clinical significance, and high reproducibility even in daily clinical practice. In this review, we summarize the diagnostic strategy of CHL and its histological lookalikes based on neoplastic PD-L1 expression and infection of EBV, and attempt a reappraisal of the definition of CHL.

Gray zone lymphoma effectively treated with cyclophosphamide, doxorubicin, vincristine, prednisolone, and rituximab chemotherapy: A case report

BACKGROUND

B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma (BCLu-DLBCL/cHL), also referred to as gray zone lymphoma (GZL), is known to share features with cHL and DLBCL. However, GZL is often difficult to diagnose. There is no consensus regarding the optimal therapeutic regimen. Most reported cases of GZL have been in Caucasian and Hispanic individuals, and its incidence is lower in African-American and Asian populations, including the Japanese population.

CASE SUMMARY

A 69-year-old female presented at our hospital with a growing mass on the right side of her neck. An elastic, soft mass measuring 9 cm × 6 cm was palpable in the right cervical region. Laboratory analyses showed pancytopenia, increased serum lactate dehydrogenase levels, and markedly increased levels of soluble interleukin-2 receptor. Enhanced computed tomography (CT) and fluorodeoxyglucose positron emission tomography (PET)/CT revealed multiple lesions throughout her body. She was diagnosed with GZL based on the characteristic pathological findings, the immunophenotype [CD20+, PAX5+, OCT2+/BOB1 (focal+), CD30+, CD15-], and the strong positive expression of neoplastic programmed cell death protein ligand 1 (PD-L1) in her lymphoma cells. The lymphoma was stage IV according to the Lugano classification and high-risk according to the International Prognostic Index for aggressive non-Hodgkin lymphoma. The patient received cyclophosphamide, doxorubicin, vincristine, prednisolone, and rituximab (R-CHOP) chemotherapy because the tumor cells were CD20+. She has remained in complete remission for 3 years.

CONCLUSION

GZL was diagnosed based on histopathology and immunophenotyping with ancillary PD-L1 positivity. R-CHOP chemotherapy was an effective treatment.

Enhanced PD-L1 Expression in LMP1-positive Cells of Epstein-Barr Virus-associated Malignant Lymphomas and Lymphoproliferative Disorders: A Single-cell Resolution Analysis With Multiplex Fluorescence Immunohistochemistry and In Situ Hybridization

Epstein-Barr virus (EBV) is associated with various types of human malignancies and with programmed death ligand (PD-L) 1 expression in neoplastic cells. However, in EBV-associated malignant lymphomas and lymphoproliferative disorders (LPDs), there is limited information regarding PD-L1 expression profiles among different histologic types and patterns of EBV latency. First, we investigated PD-L1 and EBV latent gene expression using conventional immunohistochemistry and in situ hybridization in 42 EBV-associated malignant lymphomas and LPDs. Classic Hodgkin lymphoma showed the highest PD-L1 expression with diffuse expression in all cases, followed by diffuse large B-cell lymphoma/Burkitt lymphoma, LPDs, and extranodal NK/T-cell lymphoma. EBV latency at the case level was not associated with PD-L1 expression. We further evaluated the expression of PD-L1 and EBV latent genes in tumor cells at single-cell resolution using multiplex fluorescence imaging. This analysis revealed that positivity rates of latent membrane protein (LMP) 1 in tumor cells were 1.0% to 89.5% (mean 35.4%) in latency type II/III cases, and LMP1+ cells showed more frequent PD-L1 expression than LMP1- cells (P<0.0001, paired t test). In contrast, no association was observed between EBV nuclear antigen 2 and PD-L1 expression. Notably, tumor cells exhibiting Hodgkin/Reed-Sternberg cell-like morphology co-expressed PD-L1 and LMP1 more often than those that do not. Our observations suggested that LMP1 upregulates PD-L1 expression and is a potential biomarker for predicting the efficacy of immune checkpoint inhibitors. In addition, the heterogeneous expression of PD-L1 and EBV latent genes may produce diverse tumor cells with different oncogenic and immune-evasive properties, leading to resistance to targeted therapies.