Lymphadenopathy Associated With Neutralizing Anti-interferon-gamma Autoantibodies Could Have Monoclonal T-cell Proliferation Indistinguishable From Malignant Lymphoma and Treatable by Antibiotics: A Clinicopathologic Study

Pediatric lymphoproliferative disorders associated with inborn errors of immunity

Both non-malignant and malignant lymphoproliferative disorders (LPD) are commonly seen in patients with inborn errors of immunity (IEI), which may be the presenting manifestations or may develop during the IEI disease course. Here we review the clinical, histopathological, and molecular features of benign and malignant LPD associated with IEI and recognize the diagnostic challenges.

CXCL9 as a Reliable Biomarker for Discriminating Anti-IFN-γ-Autoantibody-Associated Lymphadenopathy that Mimics Lymphoma

The diagnosis of adult-onset immunodeficiency syndrome associated with neutralizing anti-interferon γ autoantibodies (AIGA) presents substantial challenges to clinicians and pathologists due to its nonspecific clinical presentation, absence of routine laboratory tests, and resemblance to certain lymphoma types, notably nodal T follicular helper cell lymphoma, angioimmunoblastic type (nTFHL-AI). Some patients undergo lymphadenectomy for histopathological examination to rule out lymphoma, even in the absence of a preceding clinical suspicion of AIGA. This study aimed to identify reliable methods to prevent misdiagnosis of AIGA in this scenario through a retrospective case-control analysis of clinical and pathological data, along with immune gene transcriptomes using the NanoString nCounter platform, to compare AIGA and nTFHL-AI. The investigation revealed a downregulation of the C-X-C motif chemokine ligand 9 (CXCL9) gene in AIGA, prompting an exploration of its diagnostic utility. Immunohistochemistry (IHC) targeting CXCL9 was performed on lymph node specimens to assess its potential as a diagnostic biomarker. The findings exhibited a significantly lower density of CXCL9-positive cells in AIGA compared to nTFHL-AI, displaying a high diagnostic accuracy of 92.3% sensitivity and 100% specificity. Furthermore, CXCL9 IHC demonstrated its ability to differentiate AIGA from various lymphomas sharing similar characteristics. In conclusion, CXCL9 IHC emerges as a robust biomarker for differentiating AIGA from nTFHL-AI and other similar conditions. This reliable diagnostic approach holds the potential to avert misdiagnosis of AIGA as lymphoma, providing timely and accurate diagnosis.

Primary effusion anaplastic large cell lymphoma with indolent clinical course and IRF4/DUSP22 rearrangement: a case report expanding the spectrum of effusion-based lymphoma

Effusion-based lymphomas arising from pleural cavities are mostly B cell lymphomas. Non-B cell origins are very rare. These non-B cell lymphomas are usually disseminated and aggressive, and their underlying genetic changes are indeterminate. Here, we reported the first case of primary effusion anaplastic large cell lymphoma (ALCL) with exclusive involvement of a single body cavity, indolent initial presentation, and IRF4/DUSP22 rearrangement. This 73-year-old man had been in his usual health until he presented with exertional dyspnea for 1 month. Physical examination and whole-body imaging indicated isolated left pleural effusion without lymphadenopathies or tumors. Thoracentesis revealed anaplastic large lymphoid cells that were CD30 + , CD3 - , CD8 + , TIA1 + , CD138 - , Epstein-Barr virus-encoded small RNA - , human herpesvirus 8 - , and ALK - . Fluorescence in situ hybridization exhibited IRF4/DUSP22 rearrangement. A primary effusion ALK-negative ALCL was diagnosed. There was no evident progression without chemotherapeutics until 4 months after the diagnosis. Our findings expanded the spectrum of effusion-based lymphoma. Recognition of this disease could prevent misdiagnosis and guide treatment strategies for patients.

Development of intravascular large B-cell lymphoma during prophylactic antibiotic treatment for anti-interferon-gamma autoantibody syndrome: A case report

Anti-interferon (IFN)-γ autoantibody-positive syndrome is one of the acquired non-HIV cellular immunodeficiencies, caused by abnormalities in the IFN-γ/interleukin (IL)-12 pathways. It is often diagnosed alongside the onset of disseminated mycobacterium infection, and requires continuous antimycobacterial chemotherapy; however, the detailed pathological mechanisms underlying this syndrome, including its prognosis, are not known. To the best of our knowledge, this is the first reported case of intravascular large B-cell lymphoma complicated by anti-IFN-γ autoantibody syndrome, presented in an 82-year-old woman. The patient had been diagnosed with anti-IFN-γ autoantibody immunodeficiency ten years ago. She had repeated subacute fever of undetermined origin for 13 months that made us suspect infections, such as disseminated mycobacterium disease and other viral and fungal infections, despite receiving prophylactic antimycobacterial chemotherapy with rifampicin and clarithromycin. However, all the screenings performed showed no evidence of infectious diseases; thus, she was finally diagnosed with intravascular large B-cell lymphoma via a random skin biopsy. Unfortunately, the patient debilitated rapidly and died. Evidence supporting a correlation between anti-IFN-γ autoantibody syndrome and carcinogenesis is still lacking, although it is known that patients with anti-IFN-γ autoantibody syndrome are at risk of persistent viral infection-related and T-cell lineage-related carcinogenesis. This case demonstrated that patients with anti-IFN-γ autoantibody syndrome are also at risk of developing B-cell lymphoma, such as intravascular lymphoma. This emphasizes that caution should be paid to increased risk of developing malignancy during the long-term management of anti-IFN-γ autoantibody syndrome with cellular immunodeficiency.

Anticytokine autoantibodies: Autoimmunity trespassing on antimicrobial immunity

Anticytokine autoantibodies can cause immunodeficiency or dysregulate immune responses. They may phenocopy genetically defined primary immunodeficiencies. We review current anti-type 1 and anti-type 2 interferon; anti-IL-12/23, anti-IL-17, and anti-GM-CSF autoantibodies; HLA associations; disease associations; and mechanistically based treatment options. Suspecting the presence of these autoantibodies in patients and identifying them at the onset of symptoms should ameliorate disease and improve outcomes.