Agammaglobulinaemia with B lymphocytes. Specific defect of plasma-cell differentiation

Specific anti-influenza virus antibody production in vitro by lymphocytes from a subset of patients with hypogammaglobulinemia

Specific anti-influenza virus antibody production in vitro was studied in peripheral blood mononuclear cells from 17 patients with hypogammaglobulinemia. Cells obtained from 6 of 12 patients with common variable hypogammaglobulinemia produced anti-influenza virus antibody, predominantly of the IgM isotype, when cultured in vitro with type A influenza virus. No antibody was produced in vitro, however, by cells from either of two patients with Bruton's type X-linked hypogammaglobulinemia or by cells from any of three patients with X-linked hypogammaglobulinemia and isolated growth hormone deficiency. These studies demonstrate that peripheral blood mononuclear cells from a subset of patients with common variable hypogammaglobulinemia retain the potential to produce specific antibody in response to antigenic stimulation.

Polyclonal activation of immunoglobulin secretion without prior DNA synthesis in human B lymphocytes induced by Klebsiella pneumoniae

The capacity of various cell preparations of Klebsiella pneumoniae K43 (Klebs) to induce [3H]thymidine uptake and immunoglobulin (Ig) secretion by human mononuclear blood cells (MNC) and their lymphocyte subpopulations was investigated. All Klebs preparations were virtually devoid of mitogenic properties, in contrast to control preparations of pokeweed mitogen (PWM) and group A streptococcal cell membranes (A-ScM). Klebs induced differentiation of B cells into Ig-secreting cells. B-cell populations that were sufficiently depleted of T cells to be unresponsive to A-ScM ("highly purified B cells") showed a marked response to Klebs. Similarly, the number of plaque-forming cells (PFC) in Klebs-driven cultures did not change after restitution of T cells, whereas the presence of restituted T cells augmented the B-cell response to PWM and A-ScM. Radical removal of adherent MNC ("monocytes"), however, completely abrogated the PFC response and [3H]thymidine uptake of both MNC activated by Klebs and MNC activated by PWM or A-ScM.

Properdin factor B and acute lymphocytic leukemia (ALL)

One hundred-sixty-four ALL patients were compared to 545 controls for differences in phenotype and gene frequencies at the Properdin factor B locus. In addition, 90 of the ALL patients were immune phenotyped. A significant association with the Bf F allele and ALL was found, resulting in an estimated relative risk of 3.62. There was no difference in the Bf S phenotype between ALL patients and controls. However, those homozygous for the Bf S allele are at a significantly low risk of 0.30 for developing ALL. ALL patients with a non-B/T cell type were 2.5 times more likely to be Bf SS homozygotes; in contrast, those patients with the pre-B cell type were 2.5 more likely to be Bf FF homozygotes. These data suggest association of the Bf locus with an ALL protection and/or susceptibility gene(s).

Characterization of a new chromosomal marker for acute lymphoblastic leukemia from a long-term cell line

A bone marrow aspirate from a child with acute lymphoblastic leukemia (ALL) at first relapse was used to establish cell line # 697. The cultured line and marrow aspirates taken at initial diagnosis and first relapse were examined and compared. Similarities in all patterns evaluated confirmed the leukemic origin of the line. Morphologically, the cells were typically lymphoblastic. Cytochemically, they were slightly acid phosphatase-positive and negative for peroxidase, ASD chloroacetate esterase, and nonspecific esterase. Immunologically, they were found positive for common-ALL antigen (CALLA), Ia-associated antigen, terminal deoxynucleotidyl transferase (TdT), and cytoplasmic IgM (cIgM) and slightly positive for surface IgM (sIgM). Testing for Epstein-Barr virus (EBV) capsid antigen was also positive. Cytogenetic evaluations performed on initial, relapse, and cell line specimens each revealed the presence of a pseudodiploid cell line characterized by a consistent marker chromosome. GTG-, QFQ-, and RF-banding identified the marker as being derived from a translocation involving chromosomes #7 and #19: t(7;19) (q11;q13). Iso 7q, -5, -9, and +2 were also found in significant association with the marker and were viewed as demonstrating continued karyotypic evolution within the cell line. From these data, cell line #697 has been classified as a leukemic line of B-cell lineage in a transitional stage between pre-B and mature B cells.

A short-term-culture ELISA system to detect IgG and autoantibody synthesis by human lymphocytes

A simple combined culture and assay system for small numbers of human lymphocytes is described which permits rapid detection of immunoglobulin adherent to 96-well plates after 18 h culture, by means of an enzyme-linked immunosorbent assay (ELISA). The method is capable of detecting thyroglobulin antibody secreted by cells obtained from fine needle aspiration of the thyroid and therefore allows investigation of B cells activated in vivo from different sites by quantitation of the amount of immunoglobulin or antibody secreted.

Diffuse follicular lymphoid hyperplasia of the small intestine without primary immunoglobulin deficiency

Three cases of follicular lymphoid hyperplasia extending to the whole length of small intestine are reported in three young adult patients of low economic status. The disease was revealed by chronic diarrhea with malabsorption and/or protein-losing enteropathy. In one patient, all transitional patterns were found between the hyperplastic follicles and a small intestinal multicentric centrocytic-centroblastic lymphoma. No abnormalities in humoral or cellular immunity were found in the three patients. In particular, serum immunoglobulins (except IgG in one case) and plasma cell populations of small intestinal lamina propria were normal. Diffuse follicular lymphoid hyperplasia of the small intestine in the absence of primary immunoglobulin deficiency appears to be a rare condition associated with (or leading to) intestinal malignant lymphoma in most cases. Patients usually belong to the same populations as those suffering from alpha-chain disease.

Polyclonal activation of human peripheral blood B lymphocytes by formaldehyde-fixed Salmonella paratyphi B. II. Heterogeneity of B lymphocytes

B-cell 'activation' in cultures stimulated with pokeweed mitogen (PWM), Staphylococcus aureus strain Cowan I, or formaldehyde-fixed Salmonella paratyphi B (SPB) was evaluated by enumeration of cells secreting immunoglobulin (Ig) and by quantitation of Ig released into culture supernatants. A dissociation between these two values was found after day 6 in cultures activated with PWM or SPB, suggesting that Ig-secreting cells (ISC) are heterogeneous in terms of Ig secretion rate. Generation of ISC in cultures activated with PWM or SPB was partially inhibited by hydroxyurea, but Ig levels in culture supernatants were not affected. These results indicate that there are at least two subpopulations of ISC in stimulated peripheral blood lymphocyte cultures, one sensitive to, and the other resistant to, hydroxyurea. The hydroxyurea-resistant subpopulation appeared to be more mature and to release most all of the Ig detected in culture supernatants. Furthermore, time-course studies of ISC numbers and Ig levels showed that each ISC in SPB-stimulated cultures (but not in PWM-stimulated cultures) was more active in Ig synthesis and secretion after day 8 than before day 6, indicating that after day 8 most of the ISC in cultures activated with SPB were hydroxyurea-resistant. These studies suggest that SPB is another useful polyclonal B-cell 'activator' for studies of human B-cell differentiation and function, and that SPB defines two distinct subsets of B cells.

T-cell subpopulations defined with monoclonal antibodies in patients with primary immunodeficiency

Peripheral blood mononuclear cells from 16 patients with common variable immunodeficiency and 4 with selective IgA deficiency were studied for the quantitative analysis of T-cells and T-cell subsets with distinct immunoregulatory properties, using a battery of monoclonal antibodies and the fluorescence-activated cell-sorter. The proportions of OKT4+ cells were decreased and OKT8+ cells were increased in patient groups when compared to normal controls analyzed simultaneously. 14/20 (70%) patients demonstrated a lower OKT4+/OKT8+ cell ratio compared to controls. Imbalance of immunoregulatory T-cells may explain one of the mechanisms of hypogammaglobulinemia in a subgroup of patients with primary immunodeficiency.

A rapid method for quantitation of cell surface IgM by an enzyme-linked immunosorbent assay

Previous methods for quantitating cell surface immunoglobulins have been relatively tedious or have depended upon use of radioisotopes or specialized equipment (e.g., fluorescence activated cell sorter). We describe a rapid, reproducible method for measuring cell surface Ig on a population of B lymphocytes or lymphoblastoid cell lines by employing an enzyme-linked immunosorbent assay (ELISA) that uses commercially available anti-human Ig-conjugated beads (Immunobeads). Standard curves can be generated that appear to mimic the reaction kinetics of anti-mu with viable cells. Reproducibility of surface mu quantitation depends upon (1) maintaining cell viability during the reaction procedure, and (2) avoiding buffers containing diethanolamine for the alkaline phosphatase reaction. Total Ig in populations of cells can easily be estimated by reacting 10,000 Xg supernatants from lysed cells with anti-Ig beads identical to the standard curve. Combining the methods of surface and total Ig determinations, we were able to analyze quantities of membrane and cytoplasmic mu in populations of lymphoid cells.

Polyclonal activation of human B lymphocytes by Fc fragments. I. Characterization of the cellular requirements for Fc fragment-mediated polyclonal antibody secretion by human peripheral blood B lymphocytes

Fc fragments derived from human immunoglobulin were found to be capable of inducing both a proliferative and polyclonal antibody response in human peripheral blood lymphocyte cultures. The cell population proliferating in response to Fc fragments belongs to the B cell lineage. Expression of polyclonal antibody formation requires the presence of both adherent monocytes and T cells. The role of the monocyte is to enzymatically cleave the Fc fragment into 19,000 mol wt Fc subfragments that are then able to induce polyclonal antibody secretion. Stimulation of polyclonal antibody production by Fc subfragments occurs in the absence of adherent monocytes but still requires the presence of T cells.

Nonimmune interaction of leukocytes with platelets and megakaryocytes

Platelet-leukocyte interaction was observed in an asymptomatic woman. After incubation in the patient's EDTA-plasma, autologous and allogeneic platelets adhered to the surfaces of neutrophils, monocytes, macrophages and, rarely, eosinophils. Monocytes, macrophages, and occasionally neutrophils phagocytosed platelets. Degranulation of peroxidase-positive lysosomes into the platelet-containing phagosome was demonstrated ultrastructurally. Bone marrow studies indicated that bands and earlier neutrophilic precursors did not participate in the reaction, and that neutrophils adhered to, and were rarely engulfed by megakaryocytes. Sequential exposure of the patient's EDTA-plasma to platelets and leukocytes indicated that a nondialyzable factor(s) was first absorbed by platelets which then interacted with leukocytes. The reaction proceeded best in the presence of EDTA at 21 degrees C, and was inhibited or dissociated by divalent cations or at 37 degrees C. Metabolic integrity of both platelets and leukocytes was also essential for the reaction since each was inhibited by formalin fixation and partially inhibited by the metabolic inhibitor 2-deoxyglucose. Formalin-treated platelets continued to absorb the plasma factor(s). The plasma and the cell fractions were inactivated by periodate and nonspecific protease. Treatment of the platelets with trypsin or the leukocytes with neuraminidase diminished the interaction by 50%. The reaction was also interfered with by concanavalin A. Immunofluorescent and immunoabsorption studies failed to identify an immune component of this interaction. These findings indicate that the plasma factor(s) and the cell surface receptors are nonimmune glycoconjugates and consequently differ from previously documented cases of platelet-leukocyte interaction.

Immunodeficiency associated with loss of T4+ inducer T-cell function

We investigated the immune function of a patient with anergy and acquired hypogammaglobulinemia. Despite normal numbers of B cells and T4+ inducer and T5+ suppressor T cells, this patient's lymphocytes did not produce immunoglobulin, proliferate in response to soluble antigens, or generate helper factors in vitro. In addition, her T4+ T cells did not express la molecules after stimulation by soluble antigen. In mixing experiments, her T cells did not induce immunoglobulin secretion by B cells from a normal, HLA-D-identical sibling; this failure was not due to excessive suppression, since the patient's T cells did not abrogate immunoglobulin production by the normal sibling's T and B cells. Moreover, the patient's B cells secreted immunoglobulin in the presence of the sibling's T4+ cells. In contrast to the deficient inducer cells, the patient's T5+ T cells were capable of expressing suppressor-cell functions. These results indicate that immunodeficiency may occur because of a selective loss of T4+ inducer function.

The role of mitogens and antigens in the generation of antibody-producing human B lymphocytes

Satisfactory experimental systems with which to study the antigen specific humoral immune response of human peripheral blood lymphocytes have not been available until recently. A commonly used method for the study of antibody production by human lymphocytes is that developed by Fauci and Pratt. This system is considered to be antigen nonspecific since the antigen against which the determined antibody is directed is not added to the cultures. We show here that the assumption of the Fauci-Pratt system being antigen nonspecific is not justified. An essential ingredient of this culture system is human serum that has been exhaustively absorbed with antigen (sheep red blood cells). This absorption procedure causes shedding of highly immunogenic antigenic fragments whose immunogenic activity we demonstrated using a recently developed antigen-dependent culture system. In the latter system, we have shown that the control of suppressor cells is a critical factor for the successful induction of antibody responses, particularly in view of the fact that lymphocyte mitogens must be added to cultured human lymphocytes to support their responsiveness. Appropriate timing of mitogen addition to the cultures was found to be an effective means of preferentially stimulating helper or suppressor activity. Pokeweed mitogen, a mitogen known to act on B and on T lymphocytes, Stimulates B cells responses readily but abrogates them prematurely by the simultaneous activation of suppressor cells. When pokeweed mitogen is added to an ongoing response with a delay of 48 hr, it enhances antibody responses markedly, presumably by providing additional help to B cells at a time when they have lost susceptibility to suppressor-cell effects.

Antigen-induced in vitro antibody production in humans: a model for B cell activation and immunoregulation

The precise events associated with B cell activation in humans are a subject of intense investigation. It has been difficult to develop an in vitro model of antigen-specific triggering of antibody synthesis by human peripheral blood mononuclear cells that is independent of exogenous mitogens. In the present study a sensitive and reproducible culture system and enzyme-linked immunosorbent assay have been established wherein antigen alone is used to trigger antigen-specific antibody synthesis by mononuclear cells from subjects immunized to keyhole limpet hemocyanin (KLH). The in vitro antigen-induced anti-KLH response is comparable in magnitude to that induced by pokeweed mitogen, is predominantly IgM in isotype, and is accompanied by a simultaneous increase in polyclonal antibody production. Anti-KLH responses were seen at in vitro KLH concentrations as low as 0.05 microgram/ml. However, concentrations of KLH greater than 5 microgram/ml resulted in profound suppression of the anti-LHL response while continuing to trigger large amounts of total polyclonal immunoglobulin synthesis. This suppression by high concentrations of antigen was also observed in pokeweed mitogen-driven anti-KLH production. These observations are consistent with previous results from the mouse model showing a close association between antigen-specific and polyclonal responses and the phenomenon of antigen-induced, antigen-specific suppression. Thus, an in vitro model of antigen induction of antigen-specific antibody synthesis in human peripheral blood mononuclear cells has been demontrated and should prove useful in exploring the mechanism of human B cell activation and immunoregulation.

Immunoregulatory defects in a family with selective IgA deficiency

Defects in regulation of the humoral immune system were examined in a family with selective IgA deficiency. Two patients (mother and son) were clinically well and had selective abnormalities of B lymphocytes that can differentiate into IgA plasma cells plus specific T cell suppression of IgA production. One patient (daughter) had several clinical problems and received nine monthly transfusions of normal plasma. Prior to therapy, this patient had abnormal immunoregulation of both B and T lymphocyte population that cooperated in the formation of all cases of immunoglobulin-producing cells. After treatment, her clinical problems were resolved and her cellular abnormalities appeared identical in those in her mother and brother.

Isolated marrow lymphoma: an entity of possible T-cell derivation

Seven adults had a distinct clinicopathologic type of lymphoproliferative disorder of the bone marrow. All patients presented with weakness and pancytopenia; no evidence of gross extramedullary involvement was found. In 5 cases severe and prolonged bone marrow hypoplasia was associated with combination chemotherapy; 1 patient died of infection during initial therapy. In 6 of the 7 cases, clinical improvement occurred following therapy. As a terminal event, 2 patients developed a leukemic phase. Tumor cell from 4 patients were studied immunologically, and in 2 patients surface marker characteristics suggestive of T-cell tumor origin were found. In 2 cases, ultrastructural studies of lymphoid cells were compatible with a T-cell neoplasm. The above data suggest that these cases represent a distinct type of chemotherapy-sensitive lymphoma in which conservative initial treatment may induce a response without prolonged bone marrow hypoplasia.

Acute lymphoblastic leukemia in idiopathic refractory sideroblastic anemia: evidence for a common lymphoid and myeloid progenitor cell

Acute leukemia of myeloblastic or erythroblastic morphology occasionally occurs as a complication of idiopathic refractory sideroblastic anemia, but the development of acute lymphoblastic leukemia has not been previously reported in these cases. A patient with idiopathic refractory sideroblastic anemia is described in whom acute lymphoblastic leukemia occurred. The leukemic cells were characterized by typical lymphoblastic morphology on Wright's stain, periodic acid-Schiff-positive cytoplasmic clumps, elevated levels of deoxynucleotidyl transferase (143 units/10(8) cells), high numbers of specific glucocorticoid binding sites (16,845 sites/cell, Kd = 5.40 x 10(-9) M), non-B, non-T cell immunologic characteristics and clinical responsiveness to therapy with vincristine, prednisone, and methotrexate. Ultrastructural studies of the lymphoblasts identified ferruginous material in lysosomes and occasional mitochondria similar to but less abundant than that seen in abnormal sideroblasts. The concurrence of these two disorders supports the theory that in humans both lymphoid and myeloid cell lines arise from a common pluripotent stem cell.

Myelopoiesis in immunologically classified subgroups of childhood acute lymphocytic leukemia

Soft agar culture studies of 43 immunologically characterized patients with childhood acute lymphocytic leukemias (ALL) are presented. The immunologic subsets studied include "null"-cell, pre-B-cell, and T-cell leukemias. Abnormal myelopoiesis, including high peripheral blood and low marrow, colony-forming cell numbers, low colony-stimulating activity, and normal maturation of colony-forming cells in vitro was noted in each group as previously described for immunologically uncharacterized ALL. We conclude that immunologic subsets of childhood lymphoblastic leukemia cause similar abnormalities of myelopoiesis. Lack of differences in growth characteristics among immunologic subsets of ALL make it impossible to use this tissue culture technique in subclassification of these leukemic disorders.

Immunocytological studies in a case of Bruton's disease

Immunopathological findings in a case with infantile X-linked agamma globulinemia (Bruton's disease) are reported and compared to similar data from two cousins of the patient. Besides a severe decrease in B-lymphocytes in blood and lymph node, residual B-cells showed an almost total defect in Ig surface receptor expression. In addition, there was an unusual lymphocyte population which apparently exhibited E-rosette formation (i.e. T-cell characteristics) and phagocytosis. The data suggest that in Bruton's disease there may be a disturbance of the T-cell system besides the well known B-cell deficiency.

Activation of human B lymphocytes (the in vitro polyclonal B cell activator-induced plaque-forming cell system)

The characteristics of human B lymphocyte triggering, differentiation, and regulation are described using the polyclonally induced anti-sheep red blood cell hemolytic plaque-forming cell assay system. Technical and methodologic considerations, cellular requirements and mechanisms of regulation including suppressor and helper influences are discussed. Also considered are theoretical concepts regarding normal immune response versus pathologic immune states and the potential biologic role of polyclonal activation in these human immune mechanisms.

Human B cell function in a polyclonally induced plaque forming cell system. Cell triggering and immunoregulation

The use of a sensitive PFC assay against a specific antigenic determinant (SRBC) following polyclonal triggering of human lymphocytes has provided a unique insight into the complex mechanisms of triggering of human B cells. The system is under the strict regulation of a delicate balance between helper and suppressor influences reflecting in certain circumstances the activity of distinct subsets of immunoregulatory cells. Lymphoid cells in certain diseases characterized by disordered immunoregulation, when as system, may in effect be manifesting an abnormal expression of immunoregulatory mechanisms operable in normal immune responses. In vivo activation of lymphoid cells by PBAs may have an important role in disease states as well as in the subsequent in vitro expression of B cell function. Furthermore, it is quite possible that under certain circumstances some B cell responses which appear to be purely antigen-specific may be reflections of synergy between PBA substances and specific antigen. The use of PBAs as probes and sensitive PVC systems as assays has already proven fruitful in the dissection of the complex mechanisms of nonspecific B cell triggering in man and may indeed ultimately lead to an understanding of the mechanisms of specificity of immune reactivity.

Agammaglobulinaemia associated with the occurrence of a monoclonal immunoglobulin

A patient is described with a monoclonal immunoglobulin of the IgG class in the serum and no detectable IgM and IgA. Extensive immunological investigations showed the absence of B-lymphocytes in bone marrow and peripheral blood. Moreover, plasma cells were not present in the bone marrow. The monoclonal IgG was synthesized in the gastrointestinal tract. The cellular immune-status of the patient was synthesized in the gastrointestinal tract. The cellular immune-status of the patient was normal. Clinically the patient suffered from gastrointestinal and severe respiratory tract infections. It was concluded that the findings are consistent with the diagnosis congenital agammaglobulinaemia with concurrence of monoclonal IgG. It was postulated that the cell clone in the gastrointestinal tract resulted from an escape of a pre-B cell clone from the recongized arrest of pre-B cells in congenital agammaglobulinaemia.

Recognition of antigens by T lymphocytes

The present review briefly summarizes our knowledge of antigen-specific B and T lymphocyte receptors. Antigen-specific receptors on mammalian B lymphocytes are mainly monomeric IgM and IgD consisting of conventional immunoglobulin heavy and light chains. The nature of the T lymphocyte receptor which can specifically recognize antigens is not yet fully defined. However, it seems that conventional light chains do not participate in the build up of this receptor, and that the receptor is made up of heavy chains of a new immunoglobulin class which has to be further characterized and which we call Tau-chain. The variable region of the T lymphocyte receptors share idiotypic determinants with the corresponding B lymphocyte receptors. The possible linkage between the T cell idiotypes present on the Tau-chains and molecules which are under the control of genes of the Major Histocompatibility Complex of the species are discussed. In the last part of the review two methods for the induction of specific transplantation tolerance in adult animals are described. These methods are based on the concept that T lymphocytes reactive against alloantigens bear idiotypic determinants against which a specific auto-immune response can be initiated.

Primary selective deficiency of immunoglobulin M

Selective deficiency of IgM as a primary disorder is seldom encountered1--3, and the syndrome remains ill-defined4. It is generally accepted that for a diagnosis to be made, the serum IgM level should be consistently below 2 SD of normal, no other immunodeficiencies are present, and it is not secondary to other disease processes4. This report of an additional case may provide further insight into this rare disease.

Successful restoration of immunity in the DiGeorge syndrome with fetal thymic epithelial transplant

A 13-month-old girl presented with right upper lobe pneumonia and hypocalcaemic seizures: investigations showed hypoparathyroidism and impaired cell-mediated immune responses. Other features of the DiGeorge syndrome included hypertelorism, short philtrum of the lip, right-sided aortic arch, and aberrant origin of the left subclavian artery. Successful restoration of the immunodeficiency was achieved by transplantation of fetal thymic epithelium.

Hypoimmunoglobulinaemia with deficiency of pre-B cells

No pre-B cells were found in the marrows of two girls with congenital antibody deficiency who lacked B cells. The presence of variable T-lymphocyte defects in these and thymoma patients lacking pre-B cells favours a metabolic aetiology rather than selective failure of a single cell series.

Pre-B-cell leukemia. A new phenotype of childhood lymphoblastic leukemia

Large lymphoid cells containing small amounts of cytoplasmic IgM (clgM) but undetectable surface immunoglobulin (slg) have recently been recognized as precursors of B lymphocytes. They are a small, rapidly dividing pool of normal marrow lymphoblasts. Since lymphoblasts in most childhood acute lymphoblastic leukemias lack slg and other conventional B-lymphocyte and T-lymphocyte markers, we examined the possibility that some leukemias represent "pre-B"-cell neoplasms. In four of 22 consecutive patients, leukemic cells had the clgM+.slg- phenotype of pre-B cells. These patients' cells shared "common acute-lymphoblastic-leukemia" antigens and "B-cell" alloantigens, but differed in expression of several developmental features characteristic of the B-cell line. Pre-B-cell leukemias were readily responsive to chemotherapy. We conclude that a distinct subpopulation of previously unclassified leukemias reflects oncogenic transformation at the earliest recognizable stage in differentiation along the B-cell axis.

Transient B cell immaturity with intractable diarrhoea: a possible new immunodeficiency syndrome

A male boy is described, who suffered from an intractable diarrhoea and several infections and who died in a severe marasmic state at the age of 8 months. Immunological studies revealed a block in the normal differentiation of B cells to Ig-producing plasma cells. After the age of 5 months, however, this block disappeared, leading to a dramatic increase in circulating Ig, most pronounced in the IgM class. In the intestine, plasma cells could only be detected after the age of 5 months, and then with a marked preponderance of IgM cells. Our results thus indicate a reversible block in the normal maturation of B cells in our patient. An older brother may have had a similar disease, suggesting a possible genetic basis for the disorder.

Phagocyte dysfunction in common variable immune deficiency

The history of a 13-year old boy is reported who suffered from frequent bacterial, enteroviral, and protozoal infections since late infancy. A decrease in the serum levels of IgG2, IgG3, IgA, a neutrophil dysfunction, and a partial cellular immune deficiency could be demonstrated. A deficiency of folic acid produced a pancytopenia which enhanced the patient's susceptibility to infections. The combined substitution of gammaglobulins and folic acid only was able to break this vicious cycle.

Selective IgA deficiency and Crohn's disease: report of two cases

Two patients are described with Crohn's disease and selective IgA deficiency. Serum IgA was undetectable in each case, and immunoperoxidase studies of the lamina propria showed a gross diminution of IgA-bearing plasma cells. Peripheral blood lymphocytes, however, showed normal numbers of IgA-bearing lymphocytes. The typical clinical course and histology in these two patients suggest that IgA-mediated responses in the mucosa are not involved in the pathogenesis of Crohn's disease.

Primary deficiencies in humoral immunity

Patients with primary disorders of B lymphocytes and immunoglobulins usually display increased susceptibility to bacterial infections but atopic, autoimmune, and malignant disorders are also more common in these patients. The spectrum of these disorders ranges from a virtual absence of B cells and immunoglobulins to selective deficiencies of immunoglobulin subclasses. The diagnosis is dependent upon the demonstration of the immunologic deficits by specialized laboratory procedures which include the quantitation of immunoglobulins, the formation of antibodies in vivo and in vitro and the demonstration of B cells in the tissues or the peripheral blood. There are five major points in the management of these patients: (1) the delineation of the immunologic defects by laboratory testing, (2) the use of parenterally injected human immunoglobulins, (3) the rapid identification of infecting organisms and the prompt institution of appropriate antibiotic therapy, (4) screening the family for immunodeficiency in those cases which are of genetic origin, and (5) genetic counseling.