Lymphocytes in patients with variable immunodeficiency and panhypogammaglobulinemia. Evaluation of B and T cell surface markers and a proposed classification.

Peripheral blood lymphocytes from 15 patients with variable immunodeficiency and severe panhypogammaglobulinemia were evaluated for B and T cell surface markers. B cells were enumerated by immunofluorescent detection of both surface immunoglobulin (Ig) and the ability to bind aggregated Ig complexes. T cells were identified by their ability to form nonimmune rosettes with sheep red blood cells. Four distinct patterns were observed which were designated types I-IV. Type I: six patients had normal percentages (8.5-19.0%) of Ig-bearing B lymphocytes. Type II: four patients were observed to have B lymphocytes (4.5-15.0%) which lacked fluorescence-detectable surface Ig. Type III: the peripheral blood of these four patients contained a subpopulation (11.3-20.0%) of lymphocytes which apparently lacked both B and T cell markers ("null" cells). Type IV: one patient's blood was characterized by a subpopulation (18.0-22.0%) of lymphocytes which bore both B and T cell markers. Patients of each type had some clinical features in common. It is concluded that evaluation of lymphocyte surface markers provides a means of separating patients with variable immunodeficiency and panhypogammaglobulinemia into distinct groups which appear to differ in the nature of their fundamental defect.

[Articular involvement in the course of primary hypogammaglobulinemia]. / Interessamento articolare in corso di ipogammaglobulinemia primaria.

The Authors describe the main features of the most common forms of primary hypogammaglobulinaemia (PH) focusing on the articular involvement. Patients with Bruton's agammaglobulinemia (BA) and common variable immune deficiency (CVID) are predisposed to develop septic arthritis (including arthritis due to atypical microorganisms such as mycoplasma), arthralgia and symmetrical (usually non-erosive) polyarthritis. In BA and CVID complicated by recurrent infections, amyloidosis, which may be itself a cause of arthropathy, can occur. In addition, patients with CVID and selective IgA deficiency show an increased prevalence of juvenile rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome and primary biliary cirrhosis, while patients with selective IgA deficiency are prone to developing seronegative spondylarthropathies, including ankylosing spondylitis. The mainstay of treatment for BA and CVID is replacement therapy with human immunoglobulins. Septic arthritis should be promptly treated with antibiotics, whereas other types of arthritis usually respond well to non-steroidal antiinflammatory medications. In contrast, the second line agents commonly used to treat rheumatoid arthritis do not appear to be beneficial in patients with PH-associated arthritis.

From idiopathic infectious diseases to novel primary immunodeficiencies.

Primary immunodeficiencies are typically seen as rare monogenic conditions associated with detectable immunologic abnormalities, resulting in a broad susceptibility to multiple and recurrent infections caused by weakly pathogenic and more virulent microorganisms. By opposition to these conventional primary immunodeficiencies, we describe nonconventional primary immunodeficiencies as Mendelian conditions manifesting in otherwise healthy patients as a narrow susceptibility to infections, recurrent or otherwise, caused by weakly pathogenic or more virulent microbes. Conventional primary immunodeficiencies are suspected on the basis of a rare, striking, clinical phenotype and are defined on the basis of an overt immunologic phenotype, often leading to identification of the disease-causing gene. Nonconventional primary immunodeficiencies are defined on the basis of a more common and less marked clinical phenotype, which remains isolated until molecular cloning of the causal gene reveals a hitherto undetected immunologic phenotype. Similar concepts can be applied to primary immunodeficiencies presenting other clinical features, such as allergy and autoimmunity. Nonconventional primary immunodeficiencies thus expand the clinical boundaries of this group of inherited disorders considerably, suggesting that Mendelian primary immunodeficiencies are more common in the general population than previously thought and might affect children with a single infectious, allergic, or autoimmune disease.

The role of lymphokines in common variable hypogammaglobulinemia.

Common variable (acquired) hypogammaglobulinemia (CVH) is a rare primary immunodeficiency disease of great interest as an immunological model of defects in antibody production. In this article, Gavin Spickett and John Farrant discuss evidence of abnormalities in lymphokine production and responses in the generation of the functional failure. It is not yet clear whether the B cell is intrinsically abnormal or lacks appropriate signals, but the block appears to occur in the differentiation phase of B cells, since membrane (but not secreted) IgG is made. Some T-cell defects also occur in this disease. The cause of CVH is unknown, although a viral aetiology has been suggested. Better understanding of lymphokine networks may allow the provision of specific signals to overcome the block in antibody production.

Erythrocyte CR1 receptors in patients with hypogammaglobulinaemia.

Erythrocyte CR1 receptors were measured in 16 patients with primary hypogammaglobulinaemia and compared with those in 14 normal controls. There was no significant difference in the number of receptors in the two populations. One patient with hypogammaglobulinaemia had a very low number of receptors and subsequently developed red cell aplasia.

Isotypes of surface immunoglobulin on B lymphocytes from patients with immune deficiency.

Peripheral blood lymphocytes from patients with antibody deficiency diseases (primarily agammaglobulinemia) were examined for the presence of B-lymphocyte subsets defined by surface immonoglobulin isotypes. The patients could be classified into one of four groups based upon the presence or absence of particular isotype-defined subsets. Patients with type I agammaglobulinemia lacked cells bearing surface IgG as well as IgD-Igm+-bearing cells. Type II agammaglobulinemia had unusually large numbers of IgG-bearing cells, representing as many as 50% of the peripheral blood B lymphocytes, while other B-cell subsets were present in normal numbers. Type III agammaglobulinemia had apparently normal numbers of all B-cell subsets. Hyper IgM immunodeficiency lacked cells bearing surface IgG, but did have all three iGd/IgM-bearing B-cell subsets. This classification of patients based upon B-cell subsets present in peripheral blood directly correlates with previous functional studies of B cells from these patients. We suggest that abnormal in vitro function of cells from these patients results from abnormal populations of B cells in peripheral blood, which result from the underlying disease.

In vitro analysis of lymphocyte functions in common variable immunodeficiency: heterogeneity in B-cell defects.

Ten patients with common variable immunodeficiency were classified into three groups according to the number of circulating B-cells, i.e. B-cells being absent (three patients), very low (three patients) or within the normal range (four patients). The four patients in the last group showed significant proliferative responses to the T-independent B-cell mitogen, formalin-fixed Staphylococcus aureus, Cowan I. Further study of these patients by co-cultures with allogeneic T or B-cells in various combinations with pokeweed mitogen showed that two patients had an intrinsic B-cell defect without T-cell defect. The third patient had a T-cell dysfunction (i.e. his T-cells could only help the B-cells of some individuals) resulting in a defect in Ig production. The T-cells of the fourth patient showed poor helper function towards all controls. All six patients with absent or very low numbers of B-cells in group I and II had normal T-cell helper function. This study demonstrates that the immunological defect in common variable immunodeficiency is most often a B-cell defect at different stages of their differentiation with sometimes an additional T-cell dysfunction.

The lung and primary immunodeficiency.

Primary immunodeficiences (ID), once considered to be very rare, are now increasingly recognized thanks to more knowledge in the immunological field and to the availability of more sophisticated diagnostic techniques. The respiratory tract and especially the lung are the most common targets of primary ID, and respiratory infections and/or failure are the most frequent causes of early death when the immune defect is not corrected with HLA-identical bone-marrow trans lant or, in few selected cases, with thymic extracts. Many patients with Ig deficiency are severely affected by chronic and recurrent respiratory infections, unfortunately leading to bronchiectasis in the majority of such patients. Today early i.v. gammaglobulin administration can prevent bronchiectasis, and this increases the chances of a better prognosis and of an improved quality of life as well.

The radiology corner: the small bowel in immunoglobulin deficiency syndromes.

Recent advances in immunology have permitted recognition of a group of patients who have gastrointestinal manifestations as part of an immunoglobulin deficency syndrome. Such immunoglobulin deficiency may be primary or may be secondary to a variety of diseases. We have classified and described the small bowel roentgen features associated with the various immunoglobulin deficiency syndromes as follows: 1. the sprue pattern, as seen in hypogammaglobulinemic sprue and in Ig-A deficient sprue; 2. multiple nodular defects; 3. inflammatory changes secondary to giardiasis, associated with immune deficiency diseases; 4. thickening of the small intestinal folds, as seen in the plasma cell dyscrasias, lymphoma, intestinal lymphangiectasia and amyloidosis.