Abnormal lymphocyte capping in a patient with severe combined immunodeficiency disease

Unique disease heritage of the Dutch-German Mennonite population

The Dutch-German Mennonites are a religious isolate with foundational roots in the 16th century. A tradition of endogamy, large families, detailed genealogical records, and a unique disease history all contribute to making this a valuable population for genetic studies. Such studies in the Dutch-German Mennonite population have already contributed to the identification of the causative genes in several conditions such as the incomplete form of X-linked congenital stationary night blindness (CSNB2; previously iCSNB) and hypophosphatasia (HOPS), as well as the discovery of founder mutations within established disease genes (MYBPC1, CYP17alpha). The Dutch-German Mennonite population provides a strong resource for gene discovery and could lead to the identification of additional disease genes with relevance to the general population. In addition, further research developments should enhance delivery of clinical genetic services to this unique community. In the current review we discuss 31 genetic conditions, including 17 with identified gene mutations, within the Dutch-German Mennonite population.

A hereditary immunodeficiency characterized by CD8+ T lymphocyte deficiency and impaired lymphocyte activation

An unusual form of severe combined immunodeficiency in children from two different families was associated with absence of CD8+ T lymphocytes and normal numbers of CD4+ T lymphocytes that did not respond to stimulation by non-specific mitogens, specific antibodies against T cell receptor or specific antigens. The defect in the CD4+ cells was bypassed by activating agents which are independent of the T cell receptor. The combination of an activation defect and selective depletion of CD8+ T lymphocytes suggests that the defective pathway is important in the differentiation of immature thymocytes as well as the proliferation of mature lymphocytes.

Cutaneous lesions in severe combined immunodeficiency: two case reports and a review of the literature

Two patients with severe combined immunodeficiency (SCID) in whom cutaneous lesions were the first clinical feature were studied. Neither the morphology nor the histology of the lesions was uniform, although we have noted some common findings that can, in subsequent cases, lead us to suspect SCID. The immunologic defects were not uniform, representing the two poles of the spectrum of SCID. We believe that early recognition of the skin lesions is very important, since the patient's life expectancy can be increased by a bone marrow transplantation (1).

Genetics of human X-linked immunodeficiency diseases

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Severe combined immunodeficiency in man with an absence of immunoglobulin gene rearrangements but normal T cell receptor assembly

An autosomal recessive type of severe combined immunodeficiency disease (SCID) was characterized by an absence of immunoglobulins (Ig) in the serum and of Ig+ lymphocytes in bone barrow (BM) and peripheral blood. In the BM CD10+/terminal deoxynucleotidyl transferase-positive lymphocytes were identified. Epstein-Barr virus-transformed B lymphoblastoid cell lines (BLCL) obtained from BM and peripheral blood did not synthesize Ig. The Ig heavy and light chain gene complexes in the BLCL had retained the germ-line configuration. Mature T cells were present but their numbers in peripheral blood were decreased. T lymphoblastoid cells derived from peripheral blood expressed normal T cell receptor (TcR) CD3 complexes and manifested various genomic TcR rearrangements. It was concluded that this type of SCID entailed a complete arrest of B lymphocyte differentiation in an early stage prior to Ig rearrangements and a quantitative defect of T lymphocytes which nevertheless allowed development of mature T cells. Repeated failures of BM transplantation and the striking absence of Ig assembly suggested that this SCID defect resides in the BM microenvironment.

Tolerance of engrafted donor T cells following bone marrow transplantation for severe combined immunodeficiency

Patients transplanted for the treatment of severe combined immunodeficiency (SCID) frequently develop a unique state of split lymphoid chimerism. Such patients have T cells of donor origin, and non-T cells which are predominantly or exclusively of host origin. We have studied the reactivity of engrafted donor T cells to host and/or donor antigens in 12 patients transplanted for SCID, focusing on the characteristics of the tolerance to host and/or donor MHC antigens observed in nine of these patients who were recipients of T-cell-depleted, haploidentical parental bone marrow. In both proliferative and cytolytic assays, engrafted, donor-derived T cells were shown to be selectively nonreactive to histoincompatible host cells. This tolerance could not be ascribed to cells with suppressive activity in the engrafted T-cell population. T cells from a subset of patients, however, exhibited proliferative but not cytolytic reactivity to donor peripheral blood mononuclear cells. The responding cells were shown to be donor-derived CD3+ cells and were predominantly reactive to B-cell fractions from the donor. Two patients who received transplants from each parent in sequence engrafted T cells from one parent and had non-T cells of host, paternal, and maternal origin. The engrafted T cells proliferated weakly to B cells from the other parent, but were tolerant in cytolytic assays. Donor anti-donor reactivity was seen only in haploidentical split chimeras who had not been treated with cytotoxic drugs prior to T-cell engraftment. This proliferative reactivity toward donor may be due to an absence of donor derived Ia+ antigen presenting cells resident in the thymus of SCID patients at the time when the T-cell repertoire is being shaped.

Severe combined immunodeficiency with T lymphocytes retaining functional activity

Two cases of severe combined immunodeficiency (SCID) with normal numbers of T cells are reported. Studies of T-cell subsets showed an absence of TQ1+ lymphocytes and a very low percentage of CD4+ cells in Patient 2. Functional studies of T cells from this patient showed a normal suppressor activity. Patient 1 had normal percentages of T-cell subsets and his lymphocytes showed helper and suppressor activities but to a lesser degree than normal controls. Both cases stressed the heterogeneity of SCID in which T cells could be present and retain some of their functional activities.

Defective expression of T cell-associated glycoprotein in severe combined immunodeficiency

A T cell surface membrane-associated glycoprotein, Tp40 (40,000 mol wt), also designated as CD-7, was not expressed by the T cells of a patient with severe combined immunodeficiency. In addition to this abnormality, T cell proliferative responses to mitogens were defective and the IL-2 receptor expression was deficient on the patient's T lymphocytes. However, his T cells were found to provide help for the differentiation of normal B cells to Ig-secreting cells. Abundant circulating B cells were detected. These B cells proliferated normally in the presence of anti-mu antibodies and B cell growth factors, but did not differentiate into antibody-secreting cells when provided with the help of normal T cells. In addition, his activated B cells did not proliferate to IL-2 even though IL-2 receptors were expressed. A successful allogeneic histocompatible bone marrow transplantation resulting in T cell engraftment corrected both the T and B cell immunodeficiencies. These findings support the hypothesis that the Tp40 deficiency present in this patient is related to a defect of the T cell precursors, and that Tp40 plays important roles not only essential to T cell interactions but also to certain aspects of T-B cell interaction during the early lymphoid development.

Hypogammaglobulinemia with hyper-IgM, severe T-cell defect, and abnormal recirculation of OKT4 lymphocytes in a girl with chronic lymphadenopathy

We describe here one 8-year-old girl with an unusual form of immunodeficiency, characterized by hypogammaglobulinemia with hyper-IgM, severe T-cell defect, and chronic lymphadenopathy. Patient's B cells failed to produce IgG or IgA in vitro following stimulation with either pokeweed mitogen or Epstein-Barr virus, suggesting an intrinsic B-cell defect. Abnormal T-cell function was demonstrated by impaired in vivo delayed type hypersensitivity, reduction of mitogen-induced proliferation and interleukin 2 production, reduction of interferon-gamma production, and marked decrease of circulating OKT4+ cells. The latter cells were found in normal proportion in the patient's lymph node tissue. This finding suggests that the decrease of OKT4+ cells in peripheral blood was due to the abnormal recirculation of these cells. The identity of this syndrome with the infantile form of the acquired immunodeficiency syndrome was apparently ruled out by the failure to demonstrate HTLV-III-related sequences in patient's lymphocytes or virus-specific serum antibodies.

Metabolic defects in severe combined immunodeficiency in man and animals

Severe combined immunodeficiency (SCID) was originally thought to be one disease. Accumulating evidence indicates that SCID is a heterogeneous group of diseases that are clinically similar but are caused by quite different biochemical abnormalities. The best-studied form of SCID is that associated with an autosomal recessive inheritance pattern of adenosine deaminase (ADA) deficiency. Several biochemical mechanisms have been postulated to explain how a deficiency of ADA causes immune dysfunction. In forms of SCID not associated with ADA deficiency, other biochemical abnormalities have been detected. These abnormalities include deficiency in biotin-dependent carboxylases, alteration in lymphocyte surface membranes and irregularities in cytokine production. Two animal models for SCID now exist. Neither of these models is associated with ADA deficiency. Evidence for a possible defect in purine metabolism in one model has been demonstrated.

Diseases associated with immunosuppression

Impairment of any of the major components of the immune system (T-cells, B-cells phagocytes, complement) may result in clinical immunodeficiency. Immune defects can arise from intrinsic or heritable defects of lymphoid elements, failure of normal cellular differentiation, viral infection or other acquired causes. Clinical impairment of immunity is expressed as a marked susceptibility to opportunistic and pathogenic organisms which are difficult to control and by an increased risk of malignancy, allergy and autoimmune disease. Certain immunodeficiency disorders are associated with aberrant immune regulation. The major types of immune deficiency are characterized by unique patterns of infections depending on the level at which the defect occurs and the pathogenic mechanisms of the parasite. The basic defects of representative primary and secondary immunodeficiencies are discussed in relation to observed immunologic consequences.

Cell membrane receptor classes delimited through cap formation either with diamide or with membrane mobility agent, A2C

Receptors on normal human peripheral blood lymphocytes can be divided into two classes by means of the capping response exhibited in the presence of the reagents, diamide or colchicine (microtubule-related) and A2C (microtubule-independent). Diamide and colchicine promote capping of concanavalin A (Con A) receptors. Diamide capping is reversible, while colchicine capping is not reversible under the conditions used. A2C does not promote the capping of Con A receptors. In contrast, diamide and colchicine do not affect the rate at which either anti-immunoglobulin (anti-Ig) or wheat germ agglutinin (WGA) receptors cap, but A2C effectively enhances cap formation for both anti-Ig and WGA receptors. The simplicity of the classification method promises to be of use in the investigation of membrane receptors.

Microtubule assembly and conanavalin A capping in lymphocytes: reappraisal using normal and abnormal human peripheral blood cells

We have analyzed the assembly of microtubules and the distribution of concanavalin A(Con A)-receptor complexes in the same populations of human peripheral blood T and B lymphocytes. We hoped to resolve the prolonged controversy over the relationship of microtubules to Con A cap formation in lymphocytes and to explain the abnormally high spontaneous and colchicine-induced Con A capping that was observed recently in lymphocytes from a patient with an inherited form of severe combined immunodeficiency disease (SCID) characterized by total immunologic dysfunction despite normal numbers and distribution of T and B cells. The data establish that (i) microtubule disassembly is correlated with enhanced Con A cap formation on normal human lymphocytes; (ii) T and B cells differ significantly from each other and from circulating polymorphonuclear leukocytes with respect to their capping responses after exposure to colchicine; and (iii) there is an abnormal relationship of microtubule assembly to surface topography in the functionally defective SCID cells.