Primary immunodeficiency syndromes and their manifestations in lymph nodes

Lymphoma in common variable immunodeficiency: interplay between immune dysregulation, infection and genetics

PURPOSE OF REVIEW

Common variable immunodeficiency represents the largest group of primary immunodeficiency patients. The variable clinical manifestations include an increased susceptibility to chronic infections, granulomatous disease and the lymphoproliferative predisposition to develop lymphoma. This review discusses the latest insights into common variable immunodeficiency and uses common variable immunodeficiency as a model to examine the links between immunodeficiency and chronic infections in causing lymphoma.

RECENT FINDINGS

Newly identified disease genes within the common variable immunodeficiency population, have advanced the understanding of human immunodeficiency and the molecular basis of B-cell biology. Refined laboratory techniques have better defined this heterogeneous condition by classifying the underlying B-cell and T-cell abnormalities. New sensitive methods have also identified the presence of persistent infections that may play a role in the development of lymphoma.

SUMMARY

There are several reasons for an increased risk of lymphoma in common variable immunodeficiency patients. These include genetics, immune dysregulation, radiosensitivity and chronic infections such as Helicobacter pylori, human herpes virus type 8 and cytomegalovirus. Chronic infections may enhance the development of lymphoma in an antigen specific manner. The interaction between chronic infections and the development of lymphoma is still unclear but studies to clarify this may lead to prevention measures and lymphoma reduction strategies.

Lymphoproliferative disease in antibody deficiency: a multi-centre study

We have undertaken a retrospective study of antibody deficient patients, with and without lymphoma, and assessed the ability of specific polymerase chain reaction (PCR) primers to determine if the detection of clonal lymphocyte populations correlates with clinical and immunohistochemical diagnosis of lymphoma. We identified 158 cases with antibody deficiency presenting during the past 20 years. Paraffin-embedded biopsy specimens or slides were available for analysis in a cohort of 34 patients. Of these patients, 29 had common variable immunodeficiency, one X-linked agammaglobulinaemia, one X-linked immunoglobulin deficiency of uncertain cause and three isolated IgG subclass deficiency. We have confirmed that lymphoma in antibody deficiency is predominantly B cell in origin. Clonal lymphocyte populations were demonstrated in biopsies irrespective of histology (16/19 with lymphoma and 11/15 without). Isolated evidence of clonality in biopsy material is therefore an insufficient diagnostic criterion to determine malignancy. Furthermore, our data suggest that clonal expansions are rarely the result of Epstein-Barr virus-driven disease.

Diagnostic role of tests for T cell receptor (TCR) genes

Rapid advances in molecular biological techniques have made it possible to study disease pathogenesis at a genomic level. T cell receptor (TCR) gene rearrangement is an important event in T cell ontogeny that enables T cells to recognise antigens specifically, and any dysregulation in this complex yet highly regulated process may result in disease. Using techniques such as Southern blot hybridisation, polymerase chain reaction, and flow cytometry it has been possible to characterise T cell proliferations in malignancy and in diseases where T cells have been implicated in the pathogenesis. The main aim of this article is to discuss briefly the process of TCR gene rearrangement and highlight the disorders in which expansions or clonal proliferations of T cells have been recognised. It will also describe various methods that are currently used to study T cell populations in body fluids and tissue, their diagnostic role, and current limitations of the methodology.

Malakoplakia of the colon in an infant with severe combined immunodeficiency (SCID) and charge association

We report on malakoplakia of the colon observed in a six month old girl in a setting of severe combined immunodeficiency (SCID) and a malformational syndrome termed CHARGE association. By the age of six months, hemorrhagic diarrhea had developed, and multiple ulcers were seen at colonoscopy. The biopsy specimen showed ulcerating malakoplakia. Immunodeficiency was primarily reflected by deprivation of CD4 cells in the peripheral blood, and CT scans failed to detect structures consistent with a normal thymus. There were also polylymphadenopathy and chronic erythroderma. The lymph node showed extreme hypoplasia of the follicular cortex and marked expansion of the paracortex. B cell counts progressively declined, and plasma cells were absent both in intact mucosa of the colon and in a lymph node. The patient died at eighteen months of respiratory failure following recurrent airway infections. Pediatric malakoplakia of the colon, though rare, may be regarded as an example of opportunistic bacterial infection in an immunocompromised host. Combined immunodeficiency (CID) has to be considered in such instances, in particular when malformational syndromes coexist affecting the development of the thymus.