In 1974, Frizzera et al[1] described angioimmunoblastic lymphadenopathy with dysproteinemia (AILD). In some classifications, similar atypical lymphoproliferative disorders were later grouped as lymphogranulomatosis X or immunoblastic lymphadenopathy. The disorder is now classified as angioimmunoblastic T-cell lymphoma (AITL). Both terms are in common use.
AITL is a type of peripheral T-cell lymphoma (PTCL) that is clinically characterized by high fever and generalized lymphadenopathy. Approximately 40-50% of patients also have cutaneous involvement. As the disorder progresses, hepatosplenomegaly, hemolytic anemia, and polyclonal hypergammaglobulinemia may develop. In one series, other symptoms included weight loss (58%), hepatomegaly (60%), polyclonal hyperglobulinemia (65%), and generalized adenopathy (87%). Patients are usually aged 40-90 years.
AITL may represent a spectrum of disease ranging from a hyperplastic but still benign immune reaction to frank malignant lymphoma. Because clonal expansion of T cells has been demonstrated in most but not all cases of AITL, the following three subclassifications have been introduced:
AITL-type dysplasia with an oligoclonal T-cell pattern has frequently been shown to progress into AITL-type lymphoma. Thus, this subclassification may reflect the existence of stages in the development of the disease rather than independent disease entities.
Krenacs et al have suggested that the phenotype of neoplastic cells in AITL appears consistent with the phenotype of activated follicular B-helper T cells.[2] It has become clear that AITL is a clonal T-cell disorder involving deregulation of B-cells and endothelial cells against a background involving a unique malignant microenvironment.
Biopsies of the bone marrow, lymph node, and skin are key in diagnosing AITL (see Workup). Many agents have been used to treat AITL, but none has proved universally or consistently effective (see Treatment and Management).
AITL can occur with other neoplasms. AITL has been reported to occur concurrently with plasma cell leukemia.[3] AITL has also been noted to manifest with a leukemic presentation.[4]
For other discussions on lymphoma, see the overview topic Non-Hodgkin Lymphoma.
Evidence exists that angioimmunoblastic T-cell lymphoma (AITL) develops in a serial fashion. The initial reaction may be an unbalanced immune response to an unknown antigen. This stage is followed by an oligoclonal phase that is driven by persistence and ineffective handling of the primary and initial stimulus. Further events, assumed to take place on a molecular level, may then evolve into malignant monoclonal disease.
In AITL, the factors that result in the serial evolution into malignant lymphoma have yet to be defined. Patients frequently pass through a phase of atypical immune reactions, such as an allergic drug reaction or an allergic reaction to an arthropod bite. Latent viral infection may also be involved (see Etiology).
AITL is mainly derived from CD2+ CD3+ CD4+ CD5+ CD7- mature T-helper cells with varying expression and partial loss of detectable CD4. A significant number of non-neoplastic T cells (resting CD4+ T cells and activated small- or medium-sized CD8+ lymphocytes) may coexist with a minor neoplastic T-cell population.
Dunleavy et al noted that overexpression of the chemokine CXCL13 and vascular endothelial growth factor–A in AITL suggests that it may be derived from follicular helper T cells.[5]
Using immunohistochemistry, Grogg et al noted CD10 and CXCL13 staining in bone marrow samples in a subset of patients with AITL.[6] The lymphomatous infiltrate in some bone marrow specimens from these AITL patients contained numerous small or scattered large B cells, and these cells resembled either benign lymphoid aggregates or T-cell–rich large B-cell lymphoma, respectively. Trilineage hematopoietic hyperplasia and plasmacytosis were other changes noted by Grogg et al.
Murakami et al reported that the oncogene c-Maf was expressed in the majority of AITLs studied.[7] c-Maf is also overexpressed in approximately half of multiple myelomas.
Tripodo et al have suggested that mast cells have a role in the proinflammatory microenvironment of AITL.[8] They observed that mast cells, which preferentially occurred in AITL cases, directly synthesized interleukin 6 and correlated with the presence of interleukin 17–producing T cells.
In late 2013, Kashara et al reported on 85 cases of AITL with 219 genes from the United States and Europe. All cases had TET2 mutations. In addition, loss-of-function mutations were noted: 4 in TP53, 3 in ETV6, 2 in CCND3, and 5 in EP300. Gain-of-function mutations were also found: 2 in JAK2, and 4 in STAT3 (n=4).[9]
In a separate study, somatic RHOA mutations that encoded a p.Gly17Val alteration were found in 68% of AITL samples. Interestingly, whenever the mutation p.Gly17Val occurred, the TET2 mutation occurred as well.[10]
Elevated absolute monocyte numbers can predict unfavorable outcomes in AITL.[11]
Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) and their clinicopathological implications were investigated in peripheral T-cell lymphoma (PTCL), including AITL.[12]
Data from in situ hybridization and polymerase chain reaction tests suggest that angioimmunoblastic T-cell lymphoma (AITL) may be linked to latent infection with a variety of viruses, such as Epstein-Barr virus (EBV),[13] cytomegalovirus (CMV), and herpesvirus type 6. A deletion mutant of the LMP1 oncogene of EBV is associated with the evolution of angioimmunoblastic lymphadenopathy into B immunoblastic lymphoma.
The body's immune system is also thought to misapprehend some antigens, resulting in the cascade of cytokines and gene expression that underlies AITL. The actual proximate cause is not known. The role of EBV infection in skin lesions is not clear.
Patients with Sjögren syndrome are at increased risk for developing lymphoma. Although most lymphomas in these patients are of the B-cell variety, AITL constitutes the majority of T-cell lymphomas associated with Sjögren syndrome.[14]
Medications linked to the induction of AITL include salazosulfapyridine, azithromycin, and doxycycline.
The exact incidence of angioimmunoblastic T-cell lymphoma (AITL) is not known. In the United States, approximately 1-2% of non-Hodgkin lymphomas are associated with AITL. In one case series in Korea, 1 of 78 cases of lymphoma was diagnosed as AITL. In a series of 3194 cases of lymphoma in Japan, 2.35% were diagnosed as AITL.
The female-to-male ratio in AITL remains uncertain. In 2000, in a series of 10 patients, Martel et al reported 7 women and 3 men.[15] In 1995, Siegert et al reported a female-to-male ratio of 1:1.4 in a series of 62 patients.[16]
Although AITL has been reported in children, most patients are middle aged or elderly. Siegert et al reported a median patient age of 64 years (range, 21-87 y) in a series of 62 patients.[16]
Overall, angioimmunoblastic T-cell lymphoma (AITL) has a moderately aggressive course, with occasional spontaneous remissions or protracted responses to therapy. The median survival is 24 months. AITL can evolve into high-grade lymphomas of T- or B-cell type, Epstein-Barr virus (EBV)–positive B-cell lymphomas, and chronic lymphatic leukemia (CLL), among other kinds of lymphoma and leukemia. Most patients eventually die of infections due to immunologic compromise.
A univariate analysis by Siegert et al showed that survival was significantly related to the following[16] :
Schlegelberger et al found that certain cytogenetic findings were associated with a significantly lower incidence of therapy-induced remissions and a significantly shorter survival duration.[17] These cytogenetic findings included the following:
Patients and their families must understand that angioimmunoblastic T-cell lymphoma (AITL) is usually a fatal disease and is accompanied by many potentially serious infections.
For patient education information, see the Cancer Center, as well as Lymphoma and Skin Cancer.
Angioimmunoblastic T-cell lymphoma (AITL) usually starts in a nonspecific fashion. Clinical manifestations are typical of lymphoma and may include the following:
As the disease progresses, patients may experience bone pain, ascites, and hepatosplenomegaly. Initially, AITL has a waxing and waning course; however, as it progresses, symptoms persist.
Patients can present with unusual infections. For example, Mönkemüller and Bronze reported a case of immunoblastic lymphadenopathy that presented as an acute abdomen and mixed bacteremia with Eikenella corrodens and group C Streptococcus infection.[18] Some patients have had disseminated infections with herpesvirus type 6 and other viral infections.
Incongruous clinical symptoms raise the possibility of AITL. For example, one reported case of AITL manifested as sick sinus syndrome, and others have had the appearance of collagen vascular diseases. Some patients have a history of collagen-vascular diseases, such as rheumatoid arthritis and dermatomyositis.
AITL can mimic tuberculosis. Singh et al reported a case of AITL with pulmonary involvement that was initially mistaken for tuberculosis based on fine-needle aspiration cytology and was treated with antituberculous therapy for 3 months.[19] The case was subsequently diagnosed as AITL based on lymph node biopsy results.
Hosoki et al described AITL developing with lymphocytic pleural effusion.[20]
Rare cases of AITL associated with proliferative glomerulonephritis have been reported. De Samblanx et al described a 67-year-old man with a nephrotic syndrome secondary to a proliferative glomerulonephritis, which was coincident with AITL.[21]
Batinac et al reported a case of AITL in an elderly patient who presented with generalized pruritic maculopapular eruption and fever after taking doxycycline.[22] Renner et al described eosinophilic cellulitis (Wells syndrome) in association with angioimmunoblastic lymphadenopathy.[23]
All organ systems can be affected by AITL. Typical findings at presentation include the following:
Skin manifestations are the presenting sign of AITL in 40-50% of patients. Cutaneous involvement by AITL exhibits a highly variable presentation, typically with mixed features of an erythematous eruption with or without papules. The most commonly described lesions are a nonspecific morbilliform eruption mimicking a viral exanthem or drug eruption. Approximately 50% of patients with AITL-associated rash report pruritus. Other skin manifestations reported include nodules, annular lesions, and erythroderma. Vasculitis has been reported in AITL, including leukocytoclastic vasculitis, cutaneous medium-vessel vasculitis, and paraneoplastic vasculitis.[24]
There also are reports of patients with AITL with chronic urticarial eruptions.[24]
Skin laxity has been reported as a presenting sign of AITL.[25] Linear IgA dermatosis associated with cutaneous involvement of AITL has been reported. The patient presented with lesions that resembled toxic epidermal necrolysis, and immunofluorescence study revealed heavy IgA linear deposition in the dermoepidermal junction.[26]
Ferran et al suggested that the "deck-chair sign" (ie, rash with sparing of skin creases) is specific for cutaneous involvement by AITL.[27] AITL with scleromyxedemalike lesions and serum monoclonal protein has been reported,[28] as have subcorneal pustules and deep dermal-hypodermal nodules[29] and toxic epidermal necrolysis.[30]
Other possible findings include systemic lymphadenopathy, lacrimal and salivary gland involvement, and hepatosplenomegaly. Renal findings include renal amyloidosis, proliferative glomerulonephritis, and acute interstitial nephritis. Miura et al reported acute renal failure resulting from immunoglobulin M–lambda glomerular thrombi and membranoproliferative glomerulonephritis–like lesions in a patient with AITL.[31]
Pulmonary findings are varied and include hypoxemia. Some patients have interstitial pneumonia or bronchopneumonia. Patients with bronchopneumonia can have opportunistic infections, such as Pneumocystis jiroveci pneumonia; a case of cytomegalovirus infection has also been reported. Jarrett et al reported a case of shortness of breath and peripheral edema.[32]
Neurologic, rheumatologic, and related findings include retrobulbar neuritis, neuropathy, polyneuropathy, arthritis, papilledema, myelofibrosis, and inflammatory myopathy.
Goenka et al described a case of angioimmunoblastic lymphadenopathy with multiple polyps of the gastrointestinal tract. The patient presented with fever, abdominal mass, ascites, diarrhea, generalized lymphadenopathy, anemia, and marked peripheral eosinophilia.[33]
Angioimmunoblastic T-cell lymphoma (AITL) is frequently associated with immunological abnormalities, including autoimmune cytopenias, hypergammaglobulinemia, and the presence of various autoantibodies. A few reports on AITL have also described the development of myelofibrosis.[34]
Pure red cell aplasia due to AITL has also been reported.[35]
Angioimmunoblastic T-cell lymphoma (AITL) must be distinguished from reactive processes that mimic it.[36] AITL is usually diagnosed at advanced stages because its symptoms are nonspecific; thus, in older people, so-called B symptoms (ie, fever, weight loss, lymphadenopathy) should prompt investigation for AITL, leukemia, and lymphoma.
Reactive processes can mimic AITL; moreover, infections can occur with AITL, and AITL can evolve into high-grade lymphoma. These situations should be considered when assessing and treating AITL.
Other problems to be considered in patients with possible AITL include the following:
Almost any laboratory value can be abnormal in angioimmunoblastic T-cell lymphoma (AITL). As is true with its clinical symptoms, the presence of incongruous laboratory values, especially pancytopenia, should prompt a consideration of AITL as a diagnosis.
Patients with AITL may exhibit laboratory findings characteristic of autoimmune disease, such as the following:
Other blood chemistry values that can be abnormal include the following:
Anemia with hemoglobin with values below 10 g/dL can be present, and a direct Coombs test can be positive. Often, thrombocytopenia with platelet counts below 100 × 109/L is present. Platelet-associated immunoglobulin G can be present. In many patients, whole complement activity (CH50) is reduced. Pancytopenia can also be present. These changes are related to compromised bone marrow function.
In some cases, trisomies 3, 5, and X in AITL can be detected with fluorescence in situ hybridization (FISH). Cells with +5, +15, +19, +21, and +22 trisomies have been seen as well.
AITL shows a high proportion of tumor necrosis factor alpha–positive T-lymphocytes. In addition, the percentages of interleukin (IL)-2, IL-4, IL-5, IL-6, IL-13, and interferon-gamma–positive T-lymphocyte counts are relatively higher than in other diseases. These data underlie the state of multiple hypercytokinemia typically observed in AITL.
Flow cytometry has potential utility for the diagnosis of AITL.[40, 41, 42] Chen et al reported that multiparameter flow cytometry identified a distinct population of immunophenotypically aberrant T cells in 15 of 16 cases.[40] Yuan et al suggested that finding coexpression of CD10 on flow cytometry can help discriminate AITL from other peripheral T-cell lymphomas (PTCLs).[42]
Tumor cells in AITL express T-cell–associated antigens and are usually CD4 positive. The clonality of cells can be detected, with T-cell clonality eventually detected in 75% of cases. After treatment, residual disease can be detected by polymerase chain reaction (PCR) by analyzing the rearrangement of TCR genes. Polymerase chain reaction amplification and sequencing of immunoglobulin H (IgH) genes is advisable because a gene rearrangement is detected in 10% of cases.
Yamane et al reported AITL with polyclonal proliferation of plasma cells in peripheral blood and marrow.[43] Cho et al found that 70% of cases of AITL involve bone marrow and that CD5, bcl-6, and CD10 were useful markers of bone marrow infiltration.[44]
Radiographs and CT scans can demonstrate lymphadenopathy. They may also demonstrate pulmonary abnormalities, such as pleural effusions and multiple opacities, predominantly basal, of variable size. Radiographic findings include bilateral mediastinal and hilar lymphadenopathy, pleural effusion, interstitial shadow, alveolar shadow, and atelectasis. Diffuse CT contrast enhancement of cervical lymph nodes can aid in diagnosing angioimmunoblastic lymphadenopathy.
Magnetic resonance imaging of bone marrow can demonstrate angioimmunoblastic lymphadenopathy. MRI scans show lymphadenopathy, but this finding is not diagnostic.
Gallium scans and radiographic appearances may assist in diagnosing AITL, but lymph node biopsy is necessary to distinguish AITL from lymphoma.
Biopsies of the bone marrow, lymph node, and skin are key in diagnosing AITL. AITL is diagnosed by a positive biopsy result obtained from an affected lymph node, although sometimes, biopsy results are only suggestive of AITL, not diagnostic. In patients with ascites (25% of cases), paracentesis with cytologic examination of ascitic fluid is indicated.
Skin biopsy samples in AITL demonstrate a perivascular dermal infiltrate with eosinophils, histiocytes, plasma cells, and lymphoid cells. The infiltrate can be patchy. The number of blood vessels can be increased. The endothelial cells, which are often cuboidal, are prominent.
In some cases, skin histologic analysis shows extensive perivascular and periadnexal mixed lymphoid infiltrates, including centroblasts and immunoblasts, with a high proliferative index and with focal erythrocyte extravasation.
In skin lesions, T-cell and B-cell blasts predominate, together with endothelial cell proliferation. T-cell receptor gene rearrangement analysis reveals a monoclonality T cell; however, B-cell proliferations are usually polyclonal.
Histologic examination of the lymph nodes can show nearly complete effacement of the follicular architecture, a mixed lymphoid infiltrate, and numerous high endothelial venules in an expanded T-cell zone. In some cases, the lymph nodes show diffuse obliteration of their architecture by lymphoid infiltrates consisting of lymphocytes, immunoblasts, plasma cells, and histiocytes, together with numerous high endothelial venules surrounded by an expanded network of follicular dendritic cells.
Immunohistochemical analysis can demonstrate preservation of at least some follicular structures.
Attygalle et al reported that clear cells and Epstein-Barr virus (EBV) infection (when present) are useful distinguishing features and that CD10 is a sensitive and specific marker of AITL.[45] Hyperplastic follicles are present in a significant minority of AITL patients.
Sakai et al described an AITL patient initially presenting with replacement of bone marrow with polymorphic cellular infiltrates containing aggregates of CD10-positive T cells, along with peripheral plasmacytosis.[46] Karube et al reported on 11 cases of adult T-cell lymphoma/leukemia in which morphologic features were suggestive of AITL, but the immunohistochemical features of the disease—CD10 and CXCL13 expression in lymphoma cells and proliferation of CD21-positive follicular dendritic cells—were not detected.[47]
Dorfman et al reported that programmed death–1 (PD-1), a member of the CD28 costimulatory receptor family, is expressed by germinal center-associated T cells in reactive lymphoid tissue. These researchers suggest PD-1 as a useful marker for AITL.[48]
Bone marrow infiltration by AITL demonstrates variable patterns that correlate with prognosis. PD-1 and BCL6 can be used to identify lymphoma infiltrates.[49]
The standard staging system used for angioimmunoblastic T-cell lymphoma (AITL) is the Ann Arbor system which was developed for Hodgkin disease but is also used in non-Hodgkin lymphoma. Unfortunately, the Ann Arbor system does not provide a completely reliable match for prognosis in patients with AITL, but it is the only system available.
The Ann Arbor staging system uses both the number of sites of involvement and the presence of disease above or below the diaphragm. It defines the following 4 stages of disease:
Patients are divided into 2 subsets according to the absence (subset A) or presence (B) of systemic symptoms. Fever of no evident cause, night sweats, and weight loss of more than 10% of the patient's body weight are considered systemic symptoms. Even though itching is frequently present, it should not be considered a systemic symptom.
Bulky disease (eg, a lesion of 10 cm or more in the longest diameter) is designated by appending "X" to the stage designation. Extranodal involvement is identified by the following modifiers:
Many agents have been used to treat angioimmunoblastic T-cell lymphoma (AITL), but none has proved universally or consistently effective. The dosing regimens of these treatments have not been definitively set.
Corticosteroids have long been first-line agents for AITL.[50] Prednisone has been used alone or in combination with cyclophosphamide, vincristine, or both. The combination of cyclophosphamide, daunorubicin, Oncovin (vincristine), and prednisone (CHOP) has been used before or after prednisone and with or without interferon-alfa as consolidation. In retrospective analyses, CHOP and CHOP-based regimens have produced complete remission rates of about 60%.[51, 52]
In 2018, the US Food and Drug Administration approved brentuximab vedotin for treatment of adult patients with previously untreated systemic anaplastic large cell lymphoma or other CD30-expressing peripheral T-cell lymphomas (PTCLs), including AITL and PTCL not otherwise specified, in combination with cyclophosphamide, doxorubicin, and prednisone (CHP). Approval as frontline therapy was based on the ECHELON-2 phase 3 clinical trial (n = 452). Brentuximab plus CHP was superior to CHOP for progression-free survival (P = .011). Overall survival was also improved compared with CHOP (P = .024).[53]
Two thirds of patients treated with low doses of recombinant interferon alfa-2a (used as a single agent) achieved an objective remission, while, in the remaining one third of patients, no change or progressive disease was observed. The median remission duration was 3.5 months. Thus, interferon seems a promising agent in the treatment of AITL, but its role must be further defined.
Other therapeutic approaches that have been tried include the following:
Methotrexate has not been found to be effective.
High-dose chemotherapy followed by autologous bone marrow transplantation represents a promising new treatment modality for patients with advanced lymphoma and may conceivably be useful in AITL. Rodríguez et al described prolonged survival for patients with AITL after high-dose chemotherapy and autologous stem cell transplantation.[55] Shinohara et al reported durable remission after the administration of rituximab for Epstein-Barr virus (EBV)–negative, diffuse large B-cell lymphoma that developed after autologous peripheral blood stem cell transplantation for AITL.[56]
Dunleavy et al have suggested that novel therapeutic strategies that include immunomodulation with agents such as cyclosporine and angiogenesis inhibition with drugs such as bevacizumab may prove helpful.[5] There are reports of sustained remission from AITL induced by alemtuzumab.[57, 58]
Bendamustine has shown promise as a treatment agent for patients with angioimmunoblastic lymphadenopathy in a phase 2 trial, in particular in this study of 60 patients, 27 (45%) of whom were refractory to previous treatments.[59]
Korean researchers reported on a case of cervical lymphadenopathy mimicking AITL that was actually dapsone-induced hypersensitivity syndrome. It promptly responded to steroid therapy.[37]
A report in 2013 from the Netherlands noted a response to lenalidomide durable out to 2 years in a patient refractory to 2 other lines of chemotherapy treatment.[60]
In a few cases, the removal of the spleen has improved the symptoms of angioimmunoblastic T-cell lymphoma (AITL) or induced remission. A 5-month-old girl with AITL was treated with interferon-alfa, cyclosporin A, deoxyspagarine, and azathioprine, alternating regimens of low-dose 6-mercaptopurine, cyclophosphamide, and methotrexate, and results were inconsistent. At age 58 months, a splenectomy was performed, which induced a prolonged complete remission of the AITL, without any medication.
Nakashima et al reported successful coil embolization of a ruptured hepatic aneurysm in a patient with polyarteritis nodosa accompanied by AITL.[61]
Management of angioimmunoblastic T-cell lymphoma (AITL) requires consultations with all specialists who can deal with its myriad specific manifestations. An oncologist/hematologist should supervise the care of these patients. Because most patients die of infectious complications, an infectious disease specialist should also be involved.
Patients must be monitored for infections and must be educated about the importance of seeking medical care if they develop a fever or other constitutional symptoms. In most patients, angioimmunoblastic T-cell lymphoma (AITL) eventually progresses to immunocompromise, and the assessment and treatment of infection becomes a critical aspect of care.
Many agents have been used to treat angioimmunoblastic T-cell lymphoma (AITL), but none has proved universally or consistently effective. The dosing regimens of these treatments have not been definitively set.
In 2018, the US Food and Drug Administration approved brentuximab vedotin for treatment of adult patients with previously untreated systemic anaplastic large cell lymphoma or other CD30-expressing peripheral T-cell lymphomas (PTCLs), including AITL and PTCL not otherwise specified, in combination with cyclophosphamide, doxorubicin, and prednisone (CHP).[53]
Antibody conjugate binds to cells expressing the CD30 antigen and forms a complex that is internalized within the cell and monomethyl auristatin E (MMAE) is released; MMAE induces cell cycle (G2/M phase) arrest by binding to tubules and disrupting the cellular microtubule network.
Brentuximab vedotin is a CD30-directed antibody-drug conjugate (ADC) consisting of chimeric IgG1 antibody cAC10, specific for human CD30 and the microtubule disrupting agent, MMAE, or vedotin. It is indicated for previously untreated systemic anaplastic large cell lymphoma or other CD30-expressing PTCLs, including AITL and PTCL not otherwise specified, in combination with cyclophosphamide, doxorubicin, and prednisone.