There are many lymphoproliferative disorders that are associated with organ transplantation and immunosuppressant therapies. In most reported cases, these cause B cell lymphoproliferative disorders; however, some T cell variations have been described. The T cell variations are usually caused by the prolonged use of T cell suppressant drugs, such as sirolimus, tacrolimus, or ciclosporin.

Apoptosis is one of the major mechanisms of cell death targeted by cancer therapies. Reduced susceptibility to apoptosis increases the resistance of cancer cells to radiation and cytotoxic agents. B-cell lymphoma-2 (Bcl-2) family members create a balance between pro and anti-apoptotic proteins. Pro-apoptotic proteins include Bax and Bak. Anti-apoptotic proteins include Bcl-2, Bcl-X, Bcl-w, Mcl-1. When anti-apoptotic family members are overexpressed, apoptotic cell death becomes less likely.

- Oblimersen sodium (G3139, Genasense) targets BCL-2 mRNA

- ABT-737 (oral form navitoclax, ABT-263). A small molecule that targets anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-X and Bcl-w). ABT-737 binds anti-apoptotic Bcl-2 proteins with an affinity two or three orders of magnitude more potent than previously reported compounds. High basal levels of Mcl-1 expression are associated with resistance to ABT-737. Combining ABT-737 with second agents that inactivate Mcl-1 may reduce this effect. ABT-737 has demonstrated single-agent efficacy against cell lines from lymphoid malignancies known to express high levels of Bcl-2, including DLBCL. It has also been found to be synergistic with proteasome inhibitors.

- Fenretinide. A synthetic retinoid that induces apoptosis of cancer cells and acts synergistically with chemotherapeutic drugs by triggering the activation of 12-Lox (12-lipoxygenase) leading to oxidative stress and apoptosis via the induction of the transcription factor Gadd153 and the Bcl-2-family member protein Bak.

The 5 year survival has been noted as 89% in at least one study from France of 201 patients with T-LGL leukemia.

Lymphocyte-variant hypereosinophilia usually takes a benign and indolent course. Long term treatment with corticosteroids lowers blood eosinophil levels as well as suppresses and prevents complications of the disease in >80% of cases. However, signs and symptoms of the disease recur in virtually all cases if corticosteroid dosages are tapered in order to reduce the many adverse side effects of corticosteroids. Alternate treatments used to treat corticosteroid resistant disease or for use as corticosteroid-sparing substitutes include interferon-α or its analog, Peginterferon alfa-2a, Mepolizumab (an antibody directed against IL-5), Ciclosporin (an Immunosuppressive drug), imatinib (an inhibitor of tyrosine kinases; numerous tyrosine kinase cell signaling proteins are responsible for the growth and proliferation of eosinophils {see clonal eosinophilia}), methotrexate and Hydroxycarbamide (both are chemotherapy and immunosuppressant drugs), and Alemtuzumab (a antibody that binds to the CD52 antigen on mature lymphocytes thereby marking them for destruction by the body). The few patients who have been treated with these alternate drugs have exhibited good responses in the majority of instances. Reslizumab, a newly developed antibody directed against interleukin 5 that has been successfully used to treat 4 patients with the hypereosinophilic syndrome, may also be of use for lymphocyte-variant eosinophilia. Patients suffering minimal or no disease complications have gone untreated.

In 10% to 25% of patients, mostly 3 to 10 years after initical diagnosis, the indolent course of lymphocyte-variant hypereosinophilia changes. Patients exhibit rapid increases in lymphadenopathy, spleen size, and blood cell numbers, some cells of which take on the appearance of immature and/or malignant cells. Their disease soon thereafter escalates to an angioimmunoblastic T-cell lymphoma, peripheral T cell lymphoma, Anaplastic large-cell lymphoma (which unlike most lymphomas of this type is Anaplastic lymphoma kinase-negative), or Cutaneous T cell lymphoma. The malignantly transformed disease is aggressive and has a poor prognosis. Recommended treatment includes chemotherapy with Fludarabine, Cladribine, or the CHOP combination of drugs followed by bone marrow transplantation.

Syk inhibitors include :

- Fostamatinib

- Tamatinib

Chronic signaling through the B-cell receptor appears to contribute to the survival of DLBCL. These survival signals can be blocked by Syk inhibitors. However, since the BCR signaling pathway is not as important to the GCB DLBCL as it is to the ABC subtype, Syk inhibitors may not be effective against GCB DLBCL

PTLD may spontaneously regress on reduction or cessation of immunosuppressant medication, and can also be treated with addition of anti-viral therapy. In some cases it will progress to non-Hodgkin's lymphoma and may be fatal. A phase 2 study of adoptively transferred EBV-specific T cells demonstrated high efficacy with minimal toxicity.

There is currently minimal therapeutic intervention available for BENTA disease. Patients are closely monitored for infections and for signs of monoclonal or oligoclonal B cell expansion that could indicate B cell malignancy. Splenectomy is unlikely to reduce B cell burden; peripheral blood B cell counts rose significantly in three patients who underwent the procedure. It remains to be determined whether immunosuppressive drugs, including B cell-depleting drugs such as rituximab, could be effective for treating BENTA disease.

Alemtuzumab has been investigated for use in treatment of refractory T-cell large granular lymphocytic leukemia.

The typical patient with angioimmunoblastic T-cell lymphoma (AITL) is either middle-aged or elderly, and no gender preference for this disease has been observed. AITL comprises 15–20% of peripheral T-cell lymphomas and 1–2% of all non-Hodgkin lymphomas.

Treatment is most commonly directed at autoimmune disease and may be needed to treat bulky lymphoproliferation. First line therapies include corticosteroids (very active but toxic with chronic use), and IVIgG, which are not as effective as in other immune cytopenia syndromes.

Second line therapies include: mycophenolate mofetil (cellcept) which inactivates inosine monophosphate, most studied in clinical trials with responses varying (relapse, resolution, partial response). It does not affect lymphoproliferation or reduce DNTs, with no drug-drug interactions. This treatment is commonly used agent in patients who require chronic treatment based on tolerance and efficacy. It may cause hypogammaglobulinemia (transient) requiring IVIgG replacement.

Sirolimus (rapamycin, rapamune) which is a mTOR (mammalian target of rapamycin) inhibitor can be active in most patients and can in some cases lead to complete or near-complete resolution of autoimmune disease (>90%) With this treatment most patients have complete resolution of lymphoproliferation, including lymphadenopathy and splenomegaly (>90%) and have elimination of peripheral blood DNTs. Sirolimus may not be as immune suppressive in normal lymphocytes as other agents. Some patients have had improvement in immune function with transition from cellcept to rapamycin and it has not been reported to cause hypogammaglobulinemia. Hypothetically, Sirolimus may have lower risk of secondary cancers as opposed to other immune suppressants and requires therapeutic drug monitoring. It is the second most commonly used agent in patients that require chronic therapy. It is mostly well tolerated (though side effects include mucositis, diarrhea, hyperlipidemia, delayed wound healing) with drug-drug interactions. It has better activity against autoimmune disease and lymphoproliferation than mycophenolate mofetil and other drugs; however, sirolimus requires therapeutic drug monitoring and can cause mucositis. A risk with any agent in pre-cancerous syndrome as immune suppression can decreased tumor immunosurvellence. Its mTOR inhibitors active against lymphomas, especially EBV+ lymphomas. The Goal serum trough is 5-15 ng/ml and can consider PCP prophylaxis but usually not needed.

Other treatments may include drugs like Fansidar, mercaptopurine: More commonly used in Europe. Another is rituximab but this can cause lifelong hypogammaglobulinemia and a splenectomy but there is a >30% risk of pneumococcal sepsis even with vaccination and antibiotic prophylaxis

There is no proven or standard first-line chemotherapy that works for the majority of AITL patients. There are several clinical trials that offer treatment options that can fight the disease. Stem cell transplantation is the treatment of choice, with the allogeneic one being the preference because AITL tends to recur after autologous transplants.

Viral infection is a very common cause of lymphoproliferative disorders. In children, the most common is believed to be congenital HIV infection because it is highly associated with acquired immunodeficiency, which often leads to lymphoproliferative disorders.

A second regimen under evaluation is R-EPOCH (rituximab with etoposide-prednisone-vincristine-doxorubicin-cyclophosphamide), which demonstrated a 5-year progression-free survival (PFS) of 79% in a phase II trial. A phase III trial, CALGB 50303, is now comparing R-EPOCH with R-CHOP in patients with newly diagnosed DLBCL.

One area of active research is on separating patients into groups based on their prognosis and how likely they are to benefit from different drugs. Methods like gene expression profiling and next-generation sequencing may result in more effective and more personalized treatment.

BENTA disease is a rare genetic disorder of the immune system. BENTA stands for "B cell expansion with NF-κB and T cell anergy" and is caused by germline heterozygous gain-of-function mutations in the gene CARD11 (see OMIM entry #607210). This disorder is characterized by polyclonal B cell lymphocytosis with onset in infancy, splenomegaly, lymphadenopathy, mild immunodeficiency, and increased risk of lymphoma. Investigators Andrew L. Snow and Michael J. Lenardo at the National Institute of Allergy and Infectious Disease at the U.S. National Institutes of Health first characterized BENTA disease in 2012. Dr. Snow's current laboratory at the Uniformed Services University of the Health Sciences is now actively studying this disorder.

Multiagent chemotherapy is recommended, but the preferred regimen is controversial, as is consolidative radiotherapy.

The germinal center subtype has the best prognosis,with 66.6% of treated patients surviving more than five years. The IPI score is used in prognosis in clinical practice. Lenalidomide has been recently shown to improve outcomes in the non-germinal center subtype. Ratios of immune effectors such as CD4 and CD8 to immune checkpoints such as PD-L1 and M2 macrophages are independent of and additive to the cell of origin and IPI in DLBCL, and are applicable to paraffin-embedded biopsy specimens. These findings might have potential implications for selection of patients for checkpoint blockade and/or lenalidomide within clinical trials.

For children with diffuse large B-cell lymphomas, most studies have found 5-year survival rates ranging from about 70% to more than 90%.

The disease is an uncontrolled proliferation of B cell lymphocytes latently infected with Epstein-Barr virus. Production of an interleukin-10, an endogenous, pro-regulatory cytokine, has also been implicated.

In immunocompetent patients, Epstein-Barr virus can cause infectious mononucleosis in adolescents, which is otherwise asymptomatic in children during their childhood. However, in immunosuppressed transplant patients, the lack of T-cell immunosurveillance can lead to the proliferation of these EBV-infected of B-lymphocytes.

However, calcineurin inhibitors (tacrolimus and ciclosporin), used as immunosuppressants in organ transplantation inhibit T cell function, and can prevent the control of the B cell proliferation.

Depletion of T cells by use of anti-T cell antibodies in the prevention or treatment of transplant rejection further increases the risk of developing post-transplant lymphoproliferative disorder. Such antibodies include ATG, ALG and OKT3.

Polyclonal PTLD may form tumor masses and present with symptoms due to a mass effect, e.g. symptoms of bowel obstruction. Monoclonal forms of PTLD tend to form a disseminated malignant lymphoma.

Plasma cells, also called plasma B cells, plasmocytes, plasmacytes, or effector B cells, are white blood cells that secrete large volumes of antibodies. They are transported by the blood plasma and the lymphatic system. Plasma cells originate in the bone marrow; B cells differentiate into plasma cells that produce antibody molecules closely modelled after the receptors of the precursor B cell. Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction.

Memory B cells are a B cell sub-type that are formed within germinal centers following primary infection and are important in generating an accelerated and more robust antibody-mediated immune response in the case of re-infection (also known as a "secondary immune response").

MBL has been found in less than 1% of asymptomatic adults under age 40, and in around 5% of adults older than 60. Exact numbers depend on the population studied and the sensitivity of the diagnostic technique.

Like CLL, it appears to be more common in males.

It is also a common finding among older adults with unexplained lymphocytosis.

Recent studies suggest that CLL is very often preceded by MBL,

and that MBL progresses to CLL requiring treatment at a rate of around 1-2% per year. Advancing age and high initial B cell count predispose to progression from MBL to CLL; however, only a small fraction of people with MBL die because of CLL.

Thus, MBL could be regarded as a premalignant condition from which some cases progress to CLL (much similar to the progression of some cases of monoclonal gammopathy of undetermined significance to multiple myeloma).

No treatment is required, but follow-up might be able to detect new diagnoses of CLL. However, this might lead to increased costs, repeated investigations, unnecessary anxiety about cancer and health insurance concerns, while there is no means to prevent progression to CLL.

A lymphocyte is one of the subtypes of white blood cell in a vertebrate's immune system. Lymphocytes include natural killer cells (Phagocytes) (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). They are the main type of cell found in lymph, which prompted the name "lymphocyte".

Autoimmune lymphoproliferative syndrome (ALPS), also known as Canale-Smith syndrome, is a form of lymphoproliferative disorder (LPDs). It affects lymphocyte apoptosis. It is a RASopathy.

It is a rare genetic disorder of abnormal lymphocyte survival caused by defective Fas mediated apoptosis. Normally, after infectious insult, the immune system down-regulates by increasing Fas expression on activated B and T lymphocytes and Fas-ligand on activated T lymphocytes. Fas and Fas-ligand interact to trigger the caspase cascade, leading to cell apoptosis. Patients with ALPS have a defect in this apoptotic pathway, leading to chronic non-malignant lymphoproliferation, autoimmune disease, and secondary cancers.

Natural killer (NK) cell therapy is used in pediatrics for children with relapsed lymphoid leukemia. These patients normally have a resistance to chemotherapy, therefore, in order to continue on, must receive some kind of therapy. In some cases, NK cell therapy is a choice.

NK cells are known for their ability to eradicate tumor cells without any prior sensitization to them. One problem when using NK cells in order to fight off lymphoid leukemia is the fact that it is hard to amount enough of them to be effective. One can receive donations of NK cells from parents or relatives through bone marrow transplants. There are also the issues of cost, purity and safety. Unfortunately, there is always the possibility of Graft vs host disease while transplanting bone marrow.

NK cell therapy is a possible treatment for many different cancers such as Malignant glioma.

Lymphocyte-variant hypereosinophila, also termed lymphocyte variant eosinophilia, is a rare disorder in which eosinophilia or hypereosinophilia (i.e. a large or extremely large increase in the number of eosinophils in the blood circulation) is caused by aberrant population of lymphocytes. These aberrant lymphocytes function abnormally by stimulating the proliferation and maturation of bone marrow eosinophil-precursor cells termed colony forming unit-Eosinophils or CFU-Eos.

The overly stimulated CFU-Eos cells mature to apparently normal eosinophils, enter the circulation, and may accumulate in, and severely damage, various tissues. The disorder is usually indolent or slowly progressive but may proceed to a leukemic phase and at this phases is sometimes classified as acute eosinophilic leukemia. Hence, lymphocyte-variant hypereosinophilia can be regarded as a precancerous disease.

The order merits therapeutic intervention to avoid or reduce eosinophil-induced tissue injury and to treat its leukemic phase. The latter phase of the disease is aggressive and typically responds relatively poorly to anti-leukemia chemotherapeutic drug regimens.

Little is yet known about the causes of MBL, but as it is a "forme fruste" of CLL the etiologies of these two conditions would be closely related. Genetic changes that can be found in CLL have also been found in MBL, and relatives of people with CLL have a much higher chance of having MBL (13% of first-degree relatives in one study).

One concern about MBL is related to blood transfusions. MBL was found in 0.14% of blood donors in one study. It is unknown whether blood transfusion can transmit MBL.