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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary immunodeficiency syndromes may be seen as "experiments of nature", giving insights into the organization and function of the human immune system. The principal categories of primary immunodeficiency syndromes: severe combined immunodeficiency, agammaglobulinemia and isolated T-cell defects (e.g. Di George Syndrome) are still used in view of their leading clinical presentations. However, detailed analysis of individual cases and families now shows a plethora of different diseases in each category. In this review the relationship of primary immunodeficiency diseases of the B-cell system and autoimmune phenomena are discussed. The pathology of thymus in severe combined immunodeficiency is shown: central maturation defects of the T-cell system are not due to "dysplasia" of the thymus but rather to enzyme defects of the lymphatic cells. Severe alterations of the thymus may also be caused by graft versus host disease. The clarification of genetic defects of lymphoid differentiation and maturation today may lead to improved early and prenatal diagnosis as well as specific gene therapy. The success of bone marrow transplantation in many cases of primary immunodeficiency disease syndromes may be considered as a consequence of successful gene therapy.
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PMID:[Inborn immunodeficiencies]. 172 40

A hypothesis is presented in which the immunodeficiency and cell loss leading to acquired immune deficiency syndrome and the clonal deletion associated with immunologic tolerance occur through a common mechanism. In a previous publication we proposed that the interaction of human immunodeficiency virus (HIV) with CD4 delivers activation signals that disrupt immune system regulation. In this article, we compare the biology of HIV infection with recent discoveries concerning the "two-signal" molecular mechanism for thymic selection. We propose that two-signal activation is normally followed by clonal expansion and the programmed death of most or all daughter cells through mechanisms that are proportional to the strength and duration of the activation signals. In the thymus, self-reactive cells are trapped in the continuous presence of both antigen signals (signal 1) and costimulatory signals (signal 2), leading to clonal deletion. In mature lymphocytes, we propose that HIV infection contributes a chronic high-affinity signal 2, which shifts the equilibrium of antigen-activated T-cell populations further toward programmed death. This leads to incremental memory cell deficits and gradual clonal deletion at a rate dependent on the frequency of antigen exposure and the ability of an HIV quasispecies to induce signal 2.
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PMID:The relationship between AIDS and immunologic tolerance. 173 6

Pathological abnormalities of the thymus were found in 3 of 37 fetuses aborted from human immunodeficiency virus (HIV)-infected mothers. These lesions were located predominantly in the thymic cortex, which contains mostly immature lymphocytes. Areas of focal lymphocyte depletion were infiltrated with CD4+ macrophages and were associated with abnormalities of the epithelial stromal network. No evidence of extensive HIV infection in any of the 37 thymuses was detected by either immunofluorescence or in situ hybridization techniques, although rare cells that expressed HIV antigens were found in 3 fetuses. Although less extensive, this thymic fetopathy was similar to that described in postnatal acquired immunodeficiency syndrome thymuses, strongly suggesting that the lesions were related to HIV infection. Thymic fetopathy might represent the initial injury to the lymphoid system in HIV-infected infants in whom early and severe immunosuppression develops.
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PMID:Thymic abnormalities in fetuses aborted from human immunodeficiency virus type 1 seropositive women. 173 99

Sixteen years of observation over a large group of children with the syndrome of the enlarged thymus with the use of up-to-date methods of examining the CNS, immune, endocrine, neuroendocrine systems and the autopsy data allowed the heterogeneity and polymorphism of the given syndrome to be revealed. Both transitory and stable enlargement of the thymus may be observed. The syndrome of the stable-enlarged thymus is likely to be formed in the intrauterine period and postnatally as well. It may be associated and not associated with thymus-dependent immunodeficiency. The morphological investigation of the thymus may show an enlargement of the cortical area with enhanced T lymphocyte proliferation in it or formation of lymphoid follicles. In clinical practice, the syndrome of the stable-enlarged thymus should be differentiated with thymic tumor. The working classification of the syndrome and concept of the pathogenesis of the stable-enlarged thymus are offered.
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PMID:[Heterogeneity and polymorphism of the thymus hyperplasia syndrome in children in the first 3 years of life]. 178 94

Thymus hyperplasia may be congenital (thymomegaly) and acquired (acquired thymomegaly, "tumour-like" hyperplasia, lymphofollicular hyperplasia). Congenital thymomegaly is represented by variants with hypo- and hyperfunction of an adequately formed thymus and results from the congenital neuro-endocrine disturbances. Thymomegaly with a thymus hypofunction is a marker of the immunodeficiency. Acquired thymomegaly is also represented by two variants with hypo- and hyper-function of the thymus and is in fact a "phenocopy" of the congenital one. "Tumor-like" thymus hyperplasia is a rare form of its pathology with a thymic weight reaching 800 g thus resulting in a syndrome of the mediastinum organs compression. Lymphofollicular thymus hyperplasia can not be always considered to be a thymus pathology but it is characteristic of autoimmune and infectious-allergic diseases with lymphoid follicles localizing in the hyperplastic intralobular perivascular spaces. Thymus parenchyma changes depend on the main disease and play a main role in the development of thymus dysfunction, for example, in the autoimmune diseases. Formation of lymphoid follicles in the dilated perivascular spaces is a non-specific process.
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PMID:[Thymus hyperplasia: classification, problems of patho- and morphogenesis, importance in human pathology]. 179 75

Surgical material from 55 children, from 2 to 15 years of age with an abdominal form of pseudotuberculosis (appendix, lymph nodes, ileum) and the immunogenesis organs (lymphoid tissue of the small intestine, lymph nodes, appendix, spleen and thymus) of 277 rabbits infected with virulent strains of the Yersinia pseudotuberculosis I serovar at the dose of 10(8) bacterial bodies were investigated. The results testify to the disturbance of all parts of the immuno-phagocytic system in pseudotuberculosis with the development in some cases of secondary immunodeficiency due to the specific damage of the lymphoid tissue and the functional deficiency of phagocytes. This probably results from the cytotoxicity of the pathogenic factor inhibiting the host defense mechanisms. The tendency to pseudotuberculosis exacerbation and recurrence is associated with the development of the immunodeficiency.
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PMID:[Secondary immunodeficiency in Pseudotuberculosis in man and in experiment]. 179 14

The spontaneously diabetic BB (BBd) rat displays marked T lymphopenia. The present study was designed to investigate whether the immunodeficiency in this animal may be associated with deficiency of purine nucleoside phosphorylase (PNP) and possibly adenosine deaminase (ADA). The activities of these two enzymes were measured in lymphoid and non-lymphoid cells from both non-diabetes-prone (BBn) and BBd rats as well as from streptozotocin-induced diabetic (STZ) BBn rats. There were no significant differences between BBn and BBd rats in ADA activities in thymocytes, skeletal muscle or brain. However, ADA activity was increased (P less than 0.01) by 50% in BBd mesenteric lymph node lymphocytes and splenocytes as compared with BBn cells, but was not altered in cells from STZ-BBn rats. On the other hand, the PNP activity in BBd thymocytes was only 61% (P less than 0.01) of that observed in BBn cells. This PNP deficiency was not the consequence of diabetes per se, as its activity was normal in thymocytes from STZ-BBn rats. There were no significant differences in PNP activities between BBn and BBd rats in all other cell types examined. The diabetic BB rat may be a novel source of PNP-deficient thymocytes (mainly immature T cells) for studying biochemical mechanisms of immunodeficiency in association with decreased PNP activity. The findings also raise the question of whether a causal relationship exists between PNP deficiency and the recently demonstrated abnormality in T cell maturation in the thymus of the BBd rat.
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PMID:Deficiency of purine nucleoside phosphorylase activity in thymocytes from the immunodeficient diabetic BB rat. 183 79

Two patients with Di George syndrome are presented. Diagnosis was done at ages 4 months and 16 days respectively. Their main clinical symptoms were hypocalcemic convulsions, unusual facies (hyperthelorism, low set prominent ears, micrognathia, short philtrum) and cardiac malformations (vascular ring with right aortic arc, aberrant left innominated artery and ligamentum arteriosus in one of them and Tetralogy of Fallot with pulmonary valve atresia in the other). The first patient is now a 3.5 year old boy, his vascular ring was repaired and he has hypoparathyroidism but no clinical nor laboratory evidence of cellular immunodeficiency. The other patient had evidence of heart failure at her second week of life, she died at age sixteen days and, at necropsy, Fallot's tetralogy with pulmonary valve atresia, closed ductus arteriosus, histologically normal ectopic thymus and absent parathyroid glands were demonstrated. We postulate that these cases correspond to partial forms of Di George syndrome.
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PMID:[Di George syndrome]. 184 46

State of immunologic and nonspecific resistance of the organism, ultra- and histostructure of the thymus, histopathology of the wall of experimental staph abscess reproduced in animals given low doses of the herbicide simazine for a long time have been studied. It is established that simazine induced the immunodeficiency state underlain by pathologic changes in the thymus. Against this background experimental abscesses developed more rapidly, alterative and exudative processes in their wall proceeding more intensively and proliferative ones--attenuating. This provides prolongation of the abscesses healing phase for an indefinite time and chronization of the process.
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PMID:[The immunomorphological characteristics of a focal staphylococcal infection against a background of long-term exposure to low doses of simazine]. 186 56

A 7-year-old leukemic girl developed pancytopenia following chemotherapy and was given several transfusions of nonirradiated blood. Within 2 weeks she developed a maculopapular rash, fever, abnormal liver function, diarrhea, and wasting. She became septic and died 6 weeks later. Transfusion-associated graft-versus-host disease (GVHD) was suspected clinically. At autopsy, changes diagnostic of GVHD were present in the skin and liver. The remarkable feature of the case was the histopathology of the thymus, which was morphologically "dysplastic," i.e., minute, lymphoid depleted, devoid of a corticomedullary demarcation, and completely lacking in Hassall's corpuscles. These changes were virtually identical to those seen in the thymus of children with severe combined immunodeficiency disease (SCID). There was no evidence of preexisting immune deficiency. There is compelling experimental evidence that GVHD can produce changes in the thymus that are identical to those of "thymic dysplasia." These observations have led to the hypothesis that immunodeficiency associated with GVHD may stem, in part, from injury to thymic epithelium resulting in defective T cell maturation. As a corollary of this hypothesis, it has been suggested that the pathogenesis of some forms of SCID may involve GVHD-associated injury to the thymus by a maternal allograft acquired in utero. This report further documents thymic pathology in human GVHD and discusses these changes in the light of these ideas.
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PMID:Thymic involution with loss of Hassall's corpuscles mimicking thymic dysplasia in a child with transfusion-associated graft-versus-host disease. 186 63


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