Classic Hodgkin lymphoma is a lymph node cancer of germinal center B-cell origin. Hodgkin lymphoma tumors consist of a minority of malignant cells, known as 'Reed-Sternberg' (RS) cells, mixed with reactive lymphocytes and other benign inflammatory cells. A defining feature of RS cells is the presence of 2 nuclei (summary by Salipante et al., 2009).

A heterogeneous increase in IgM immunoglobulins characterized by a diffuse band on serum electrophoresis.

Normal peripheral blood lymphocytes, when stimulated by phytohemagglutinin (PHA) are cytotoxic for homologous and heterologous cells but not for autologous cells in monolayer culture. The cytotoxic effect is thought to be indicative of the immunological competence of the lymphocytes.

Classic ataxia-telangiectasia (A-T) is characterized by progressive cerebellar ataxia beginning between ages one and four years, oculomotor apraxia, choreoathetosis, telangiectasias of the conjunctivae, immunodeficiency, frequent infections, and an increased risk for malignancy, particularly leukemia and lymphoma. Individuals with A-T are unusually sensitive to ionizing radiation. Non-classic forms of A-T have included adult-onset A-T and A-T with early-onset dystonia.

Classic Hodgkin lymphoma is a lymph node cancer of germinal center B-cell origin. Hodgkin lymphoma tumors consist of a minority of malignant cells, known as 'Reed-Sternberg' (RS) cells, mixed with reactive lymphocytes and other benign inflammatory cells. A defining feature of RS cells is the presence of 2 nuclei (summary by Salipante et al., 2009).

Dyskeratosis congenita and related telomere biology disorders (DC/TBD) are caused by impaired telomere maintenance resulting in short or very short telomeres. The phenotypic spectrum of telomere biology disorders is broad and includes individuals with classic dyskeratosis congenita (DC) as well as those with very short telomeres and an isolated physical finding. Classic DC is characterized by a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia, although this may not be present in all individuals. People with DC/TBD are at increased risk for progressive bone marrow failure (BMF), myelodysplastic syndrome or acute myelogenous leukemia, solid tumors (usually squamous cell carcinoma of the head/neck or anogenital cancer), and pulmonary fibrosis. Other findings can include eye abnormalities (epiphora, blepharitis, sparse eyelashes, ectropion, entropion, trichiasis), taurodontism, liver disease, gastrointestinal telangiectasias, and avascular necrosis of the hips or shoulders. Although most persons with DC/TBD have normal psychomotor development and normal neurologic function, significant developmental delay is present in both forms; additional findings include cerebellar hypoplasia (Hoyeraal Hreidarsson syndrome) and bilateral exudative retinopathy and intracranial calcifications (Revesz syndrome and Coats plus syndrome). Onset and progression of manifestations of DC/TBD vary: at the mild end of the spectrum are those who have only minimal physical findings with normal bone marrow function, and at the severe end are those who have the diagnostic triad and early-onset BMF.

XMEN is an X-linked recessive immunodeficiency characterized by CD4 (186940) lymphopenia, severe chronic viral infections, and defective T-lymphocyte activation (Li et al., 2011). Affected individuals have chronic Epstein-Barr virus (EBV) infection and are susceptible to the development of EBV-associated B-cell lymphoproliferative disorders. Magnesium supplementation may be therapeutic (summary by Li et al., 2014).

Lymphoproliferative syndrome-1 is an autosomal recessive primary immunodeficiency characterized by onset in early childhood of Epstein-Barr virus (EBV)-associated immune dysregulation, manifest as lymphoma, lymphomatoid granulomatosis, hemophagocytic lymphohistiocytosis, Hodgkin disease, and/or hypogammaglobulinemia. Autoimmune disorders, such as autoimmune hemolytic anemia or renal disease, may also occur. Patients show a high EBV viral load and decreased invariant natural killer T cells. It is unknown whether patients with ITK mutations are intrinsically susceptible to development of lymphoma or dysgammaglobulinemia in the absence of EBV infection (summary by Stepensky et al., 2011; Linka et al., 2012). For a discussion of genetic heterogeneity of lymphoproliferative syndrome, see XLP1 (308240).

Immunodeficiency-110 (IMD110) is an autosomal recessive primary T-cell immunodeficiency syndrome characterized by progressive loss of naive T cells, recurrent bacterial, viral, and fungal infections, warts, and abscesses, and autoimmune manifestations. Patients are at risk for developing lymphoproliferative disorders or lymphoma, particularly associated with EBV. Some patients may show cardiac malformations, including atrial septal defect (Abdollahpour et al., 2012; Nehme et al., 2012).

Lymphoproliferative syndrome-2, also known as CD27 deficiency, is an autosomal recessive immunodeficiency disorder associated with persistent symptomatic EBV viremia, hypogammaglobulinemia, and impairment in specific antibody function resulting from impaired T cell-dependent B-cell responses and T-cell dysfunction (summary by van Montfrans et al., 2012). The phenotype can vary significantly, from asymptomatic borderline-low hypogammaglobulinemia, to a full-blown symptomatic systemic inflammatory response with life-threatening EBV-related complications, including hemophagocytic lymphohistiocytosis, a lymphoproliferative disorder, and malignant lymphoma requiring stem cell transplantation (summary by Salzer et al., 2013). For a discussion of genetic heterogeneity of lymphoproliferative syndrome, see XLP1 (308240).

IMD23 is an autosomal recessive primary immunodeficiency syndrome characterized by onset of recurrent infections, usually respiratory or cutaneous, in early childhood. Immune workup usually shows neutropenia, lymphopenia, eosinophilia, and increased serum IgE or IgA. Neutrophil chemotactic defects have also been reported. Infectious agents include bacteria, viruses, and fungi. Many patients develop atopic dermatitis, eczema, and other signs of autoinflammation. Affected individuals may also show developmental delay or cognitive impairment of varying severity (summary by Bjorksten and Lundmark, 1976 and Zhang et al., 2014).

Infantile-onset multisystem autoimmune disease-1 is characterized by early childhood onset of a spectrum of autoimmune disorders affecting multiple organs. Common manifestations include insulin-dependent diabetes mellitus and autoimmune enteropathy, or celiac disease, and autoimmune hematologic disorders. Other features include short stature and nonspecific dermatitis. More variable features include hypothyroidism, autoimmune arthritis, and delayed puberty. Some patients may show recurrent infections. The disorder results from an inborn error of cytokine signaling (summary by Flanagan et al., 2014 and Milner et al., 2015). Genetic Heterogeneity of Infantile-Onset Multisystem Autoimmune Disease See also ADMIO2 (617006), caused by mutation in the ZAP70 gene (176947) on chromosome 2q12, and ADMIO3 (620430), caused by mutation in the CBLB gene (604491) on chromosome 3q13.

IMAGEI is an autosomal recessive disorder characterized by intrauterine growth retardation, metaphyseal dysplasia, adrenal hypoplasia congenita, genital anomalies, and immunodeficiency. Patients exhibit distinctive facial features and variable immune dysfunction with evidence of lymphocyte deficiency (Logan et al., 2018). An autosomal dominant form of the disorder, without immunodeficiency (IMAGE; 614732), is caused by mutation in the CDKN1C gene (600856) on chromosome 11p15.

Familial autoinflammatory syndrome with or without immunodeficiency (AISIMD) is characterized by onset of various autoimmune features usually in the first decades of life, although later onset has been reported. Typical features include autoimmune cytopenia, hemolytic anemia, thrombocytopenia, and lymphadenopathy. More variable features may include autoimmune thyroiditis, psoriasis or eczema, nephritis, hepatitis, and symptoms of systemic lupus erythematosus (SLE; see 152700). Some patients may have recurrent infections or exacerbation of the disease with acute infection. Laboratory studies show variable findings, often decreased numbers of naive B cells, lymphopenia with skewed subsets, hypogammaglobulinemia, presence of autoantibodies, and a hyperinflammatory state. The disorder shows autosomal dominant inheritance with incomplete penetrance (summary by Hadjadj et al., 2020).

Immunodeficiency-87 and autoimmunity (IMD87) is an autosomal recessive immunologic disorder with wide phenotypic variation and severity. Affected individuals usually present in infancy or early childhood with increased susceptibility to infections, often Epstein-Barr virus (EBV), as well as with lymphadenopathy or autoimmune manifestations, predominantly hemolytic anemia. Laboratory studies may show low or normal lymphocyte numbers, often with skewed T-cell subset ratios. The disorder results primarily from defects in T-cell function, which causes both immunodeficiency and overall immune dysregulation (summary by Serwas et al., 2019 and Fournier et al., 2021).

Lymphoproliferative syndrome-3 (LPFS3) is an autosomal recessive early-onset immunologic disorder characterized by increased susceptibility to Epstein-Barr virus (EBV) infection in B cells, resulting in abnormal B-cell proliferation and increased susceptibility to B-cell malignancies, including Hodgkin lymphoma. Patients usually have hypogammaglobulinemia without lymphopenia, although some subsets of immune cells may be low and some patients may have recurrent infections. The disorder results from impaired signaling from proliferating B cells to effector T cells that provide immune surveillance. There may be an increased risk of solid tumors in heterozygous carriers (summary by Abolhassani et al., 2017). For a discussion of genetic heterogeneity of lymphoproliferative syndrome, see XLP1 (308240).

Immunodeficiency-109 with EBV-induced lymphoproliferation (IMD109) is an autosomal recessive primary immune disorder characterized by onset of recurrent sinopulmonary infections in childhood. Affected individuals are susceptible to infection with EBV and develop EBV viremia and EBV-associated lymphoproliferative disease or B-cell lymphoma. Immunologic work-up shows normal levels of T, B, and NK cells, with defective CD8+ T cell function after stimulation. Some patients may have hypogammaglobulinemia and poor antibody response to stimulation (Alosaimi et al., 2019).