IgM-containing Cells Research Articles

In vitro studies on human IgD. II. IgD-secreting cells preferentially elaborate IgD, lambda molecules.

The "IgD paradox" describes the unexpected finding that, despite a predominance of kappa (kappa) light (L) chains on the surface of IgD+ human B cells, the majority of monoclonal IgD proteins are of lambda (lambda) type. This potentially informative phenomenon appears to be based on a preferential association between delta (delta) heavy (H) and lambda L chains of IgD-secreting cells. The current studies analyze the phenomenon in vitro. Initial assays on tonsil "spent" supernatants showed that the higher IgD-"externalizing" cultures displayed progressively elevated IgD, lambda/kappa ratios due to parallel shifts in total IgD and IgD, lambda while IgD, kappa remained stable. The cells of the same higher-IgD cultures demonstrated that individual IgD-containing cells had a predominance of lambda chains in contrast to IgM-containing cells of the same cultures using fluorochrome-antibody double staining. Certain tonsil culture IgD-containing cells remarkably appeared to have exclusively lambda chain. These same tonsils show evidence of IgD secretion (Litwin, S. D. and Zehr, B. D., Eur. J. Immunol. 1987. 17:483); thus, these data align preferential delta-lambda chain association with IgD-secreting normal tonsil B cells in vitro and emphasize the usefulness of IgD, lambda/kappa ratio in monitoring IgD secretion. In another approach the relationship between the cellular location of IgD and the preferential delta-lambda chain association was studied using Triton X-114-partitioned cell lysates. IgD, lambda/kappa ratios were one or less in the detergent phase (membrane-enriched fraction) consistent with expected IgD, kappa predominance in membrane IgD. In contrast, the aqueous phase (intracellular-enriched fraction) of IgD-secreting cultures had 2-4 times higher supernatant IgD, lambda/kappa ratios. The restriction of high IgD, lambda/kappa ratios to intracellular fractions and supernatants of IgD-secreting cultured cells parallels the predicted distribution of secretory IgD. In sera studies, the correlation between total IgD and IgD, lambda/kappa ratio values was consistent with secreted sera IgD showing preferential lambda chain expression. It was concluded that the phenomenon of delta-lambda chain preferential association is expressed in vitro as well as in vivo; a property of normal, nonmalignant human IgD-secreting B cells; and closely related to the secretory form of IgD. In certain cultures, the delta-lambda chain preference was so striking as to imply limited heterogeneity of the IgD immune response.

Gluten challenge in children with dermatitis herpetiformis: a clinical, morphological and immunohistological study.

Twenty one children with dermatitis herpetiformis were studied in an attempt to evaluate the response in the skin, in jejunal morphology, and in jejunal immunoglobulin containing cell counts to gluten elimination and subsequent gluten challenge. In all of the 15 patients whose jejunal biopsy was studied after the eventual gluten challenge the jejunal lesion had returned in 2.4 to 28 months. The numbers of IgA- and IgM-containing cells were similarly raised in primary and postchallenge biopsies. In the 13 patients whose skin improved during a gluten free diet and who were challenged with gluten the rash worsened and the dapsone/sulphapyridine requirement increased. The jejunal deterioration was equally marked in the six patients whose gluten challenge was stopped because of an intractable rash as it was in those who completed the preplanned challenge. The specimens of the former, however, had significantly more IgA-containing cells than specimens of the latter. The number of intraepithelial lymphocytes clearly reflected the degree of intestinal damage. IgA-containing cells proved to be the most sensitive indicator of an immune reaction taking place in the gut of these patients. Even in the two children with initially normal or nearly normal jejunal mucosa, the IgA cell counts in the jejunal lamina propria were markedly raised.

Immunohistochemical distribution of immunoglobulin and secretory component in the ileum of normal and paratuberculosis-infected cattle

The immunohistochemical distribution of IgA, IgG, IgM and secretory component in the ileum of 10 normal and 21 paratuberculosis-infected cattle was investigated. Semi-quantitative analysis of the number of each class of Ig-containing cells in the lamina propria mucosa of infected ileums showed that IgG and IgM-containing cells and total Ig-containing cells were significantly more numerous than those in the normal ileums. There was no significant difference in the numbers of IgA-containing cells between the two groups of cattle. The distribution of IgA, IgM and SC was basically similar in the two groups. However, IgG-containing cells characteristically accumulated around the granulomas. It was considered that excessive local production of Ig in the intestinal mucosa, along with subsequent formation of immune complex or release of histamine from mast cells, could account for the occurrence of diarrhoea and participate in the pathogenesis of bovine paratuberculosis. A comparison of the local immunological state in paratuberculosis and Crohn's disease was made.

Distinct short-lived and long-lived antibody-producing cell populations.

This report analyzes the life span of Ig-containing cells (IgCC) in different sites of antibody production. The experimental approach was based upon the observations that most IgCC are derived from proliferating precursors while IgCC themselves are mainly nondividing end cells. Rats were given a continuous infusion of [3H] thymidine via an osmotic pump inserted in the peritoneal cavity. At intervals of 1, 3, 5 or 10 days after starting infusions, tissues were taken and analyzed by a combination of immunohistology and autoradiography to identify the proportions of IgCC which had gone through S phase of the cell cycle during the period of infusion. After 3 days infusion the median and (range) percent-labeled IgCC in the medullary cords of mesenteric and cervical lymph nodes and the red pulp of the spleen were, respectively, 88 (81-90), 75 (66-77) and 88 (82-93). Conversely that for IgCC in bone marrow was only 13 (11-17) and that in the lamina propria of the jejunum 47 (33-68). The rate of increase in labeling of bone marrow IgCC with length of infusion was approximately linear. Extrapolation of this slope suggests that bone marrow IgCC have a life span in excess of 3 weeks. The slopes of increase in IgCC labeled with time for lymph nodes and spleen were clearly biphasic suggesting that while most IgCC in these tissues have a life span of less than 3 days, there is also a minor population of long-lived IgCC. The lamina propria appears to have approximately equal proportions of long and short-lived IgCC. The life span of IgCC, with the exception of IgMCC, appears to be a feature of the site of antibody production rather than the Ig class produced. Almost all IgM-containing cells were found to be short lived.

Immunoglobulin-containing plasma cells in acute hepatitis.

Imunoglobulin(Ig)-containing plasma cells in human liver were investigated in different aetiological and histological forms of acute hepatitis. Liver specimens from 93 patients with acute hepatitis (A, B, non-A, non-B and drug-induced) were studied by conventional microscopy and by immunoperoxidase staining for IgG, IgA and IgM in paraffin sections. Plasma cells were found in 78 of 93 specimens and Ig-containing cells in 75. IgG-containing cells were significantly more abundant in acute hepatitis with bridging necrosis than in other forms (p less than 0.01), and there were more IgA-containing cells than in the classical and periportal forms (p less than 0.05). IgG-containing cells were more numerous in acute hepatitis with periportal or panacinar necrosis than in the classical form (p less than 0.05). IgG- and IgA-containing cells were less abundant in drug-induced hepatitis than in viral hepatitis (p less than 0.05). Among the viral groups the largest number of IgG-containing cells was found in non-A, non-B hepatitis, while IgA-containing cells were most abundant in type A. These differences were not statistically significant. IgM-containing cells were very scanty in all groups studied. It is concluded that Ig-producing plasma cells are common in acute viral hepatitis and presumably play a part in antibody-dependent immune reactions in this disease.

Monoclonal precipitating antibodies to porcine immunoglobulin M

Fusion of splenic immunocytes from a porcine IgM-immunized BALB/c mouse with SP2/0 mouse myeloma cells resulted in 231 primary hybrids. Culture fluids of the primary hybrids were screened for antibody production by enzyme-linked immunosorbent assay (ELISA) against porcine IgM and by radial immunodiffusion versus porcine serum. Culture fluids of 10 of the primary hybrids were positive in IgM-ELISA and radial immunodiffusion. Six of these primary hybrids (1A11, 1D10, 2D7, 2E2, 3B11, and 5C9) were cloned, and ascitic fluids were produced using cloned primary hybrids. The monoclonal antibodies (Mabs) in ascitic fluids were characterized as to their reactivity with porcine immunoglobulin isotypes. All six Mabs had mouse IgG1, K isotype and were μ-chain specific as they formed single precipitin lines against porcine serum and porcine IgM and no lines against porcine IgG, IgA, and fetal porcine serum in immunodiffusion and immunoelectrophoresis. In indirect ELISA, all Mabs reacted with porcine serum, porcine IgM, and μ-chains but did not react with porcine IgG, IgA, or light chains. All six Mabs were species-specific and recognized either of two antigenic regions of μ-chain. These Mabs have been successfully used to detect IgM-containing cells in tissue sections, to detect IgM in serum, and to quantitate surface membrane IgM-bearing cells in peripheral blood.

Distribution of secretory component and immunoglobulins in the developing lung.

The distribution of secretory component and immunoglobulins, IgA, IgG, and IgM in developing human lungs, ranging in age from 12 gestational weeks to 8 yr, was studied using the indirect peroxidase-labeled antibody method. Secretory component appeared first in the serous bronchial epithelium near the duct openings at the sixteenth gestational week, in goblet cells at the twentieth gestational week, and in bronchiolar epithelium at the twenty-second gestational week. The number of secretory component-positive cells (Y) in bronchial epithelium increased with age in weeks (X) according to the formula Y = 15.328 + 0.094 log X (p less than 0.001). Secretory component was almost absent in bronchiolar epithelium in atelectatic lungs with or without hyaline membrane. Secretory component-positive cells were never observed below the levels of respiratory bronchioles. Immunocompetent cells appeared in the bronchial walls after birth in normal lungs, but they appeared at the thirty-ninth gestational week in cases of pulmonary infection. The IgA- and IgM-containing cells were present around the bronchial glands in normal lungs, whereas IgG-containing cells were not associated with the glands. In normal lungs, IgA-containing cells were most prominent, followed by IgM-containing cells and IgG-containing cells. The apical portions of serous epithelial cells of bronchi and bronchial glands were positive for IgA and IgM. In bacterial and viral pulmonary infections, IgA-containing cells increased in number in the bronchial glands. The appearance of secretory component-positive cells long before immunoglobulin-containing cells in fetal lungs suggests that secretory component may play some role in the formation of the mucociliary blanket, instead of selective transport of IgA or IgM.

In situ effector pathways of allograft destruction : 2. Generation of the “humoral” response in the graft and the graft recipient

The frequency of both immunoglobulin (Ig)-synthesizing and Ig-secreting B cells have been analyzed in DA-to-WF rat renal allografts (and in control WF-to-WF autografts). We have correlated the in situ B-cell responses with corresponding events in the central lymphatic system of the recipient. Intracellular IgM- and IgG-containing plasma cells appeared in an allograft (but not in an autograft) very shortly after the transplantation. The numbers of both cell types in situ was approximately equal, the highest numbers of each being found on Day 4 after transplantation. A similar early response was observed in the recipient′s spleen, however, very few Ig-synthesizing cells were seen in the blood. Only a fraction of the Ig-synthesizing cells in the allograft were involved in immunoglobulin secretion. Thus, the recovery of IgG- and IgM-secreting cells from an allograft was 10 and 2% of intracellular IgG- and IgM-containing cells, respectively. It appears, therefore, that allograft-infiltrating Ig-synthesizing B cells either die or migrate elsewhere before secreting immunoglobulin. The B-cell response in the graft occurs very early and is disproportionally high when the very low frequency of B lymphocytes in the allograft is considered. The data provide no evidence for inflammatory B cells being an integral part of graft rejection. Indeed, the possibility remains that the inflammatory B-cell response observed during the rejection process represents a meaningless byproduct of the inflammatory response.

Immunoglobulin-containing cells in liver biopsies of patients with chronic hepatitis and primary biliary cirrhosis.

The numbers of IgA, IgM and IgG-containing cells were studied by means of an indirect immunoperoxidase technique and morphometry in liver biopsies of patients with primary biliary cirrhosis and chronic hepatitis, in whom serum immunoglobulin concentrations were also determined. In patients with primary biliary cirrhosis the absolute and relative number of IgM-containing cells in the liver was significantly higher, whereas the absolute and relative number of IgG-containing cells in the liver was significantly lower compared to patients with chronic hepatitis. IgM-containing cells in liver biopsies of patients with primary biliary cirrhosis correlated strongly with their serum IgM levels. It is concluded that determination of the pattern of immunoglobulin containing cells in liver biopsies may help in the differentiation of primary biliary cirrhosis from chronic hepatitis and that local production of IgM in the liver may contribute significantly to the high serum IgM levels in patients with primary biliary cirrhosis.

Genetic analysis of the inheritance of B cell hyperactivity in relation to the development of autoantibodies and glomerulonephritis in NZB x SWR crosses.

Autoimmune NZB mice have a primary B cell abnormality manifested by spontaneous hypersecretion of IgM in short-term cultures. The purpose of this study was to characterize the genes that specify this intrinsic B cell defect and determine their relationship to "autoimmunity" genes. The increase in IgM secretion was shown to result from two independently segregating genetic traits: a) an increased number of IgM-containing cells, and b) an increased rate of secretion of IgM per cell. In this study, approximately 600 NZB, SWR, F1, F2, and reciprocal back-cross mice were hemisplenectomized at 5 to 6 months of age to determine the number of IgM-containing cells and the secretion of IgM in 4-hr cultures. These animals were followed prospectively for the development of anti-DNA (native and denatured) and anti-red blood cell autoantibodies, and proteinuria, and studied at autopsy for the development of glomerulonephritis. The severity and incidence of renal lesions was influenced to some extent by the presence of B cell hyperactivity. However, a proportion of F2 and backcross progeny mice that did not show B cell hyperactivity eventually developed autoantibodies and autoimmune disease.

IgA ANTIGLIADIN ANTIBODIES: A MARKER OF MUCOSAL DAMAGE IN CHILDHOOD COELIAC DISEASE

Antigliadin antibodies in serum samples of 31 children with coeliac disease were measured by an enzyme-linked immunosorbent technique. In young patients (<2 years) tested before gluten withdrawal IgA antigliadin antibody levels were invariably above the levels of 36 controls. The titres fell rapidly when gluten was eliminated from the diet and rose on its reintroduction. The titres were not always greater than the control level in older untreated patients. IgA antigliadin antibodies seem to be a good marker of the immune reaction in the jejunum triggered by gluten. In 2 IgA-deficient patients gluten challenge caused an increase in IgM antigliadin antibodies, and at the same time the number of IgM-containing cells increased in the jejunal mucosa. Rising IgG antigliadin antibody levels after gluten elimination were seen in 6 patients, 5 of whom had very low complement C3 levels before gluten elimination.

Cellular basis for differences in humoral immune responses of sheep immunized with living or killed Staphylococcus aureus vaccines.

An immunohistological study was made of immunoglobulin-containing cells and antibody-containing cells in abscesses/granulomas which formed at the injection site, draining popliteal nodes and contralateral popliteal nodes of sheep given either a living Staphylococcus aureus vaccine (Group L), a killed S. aureus vaccine with Freund's complete adjuvant (FCA) (Group K) or FCA alone (Group C). The injections were made subcutaneously in the hind legs and second injections were given 4 weeks later in the same site. Very large numbers of IgM-containing cells were found in granulomas of Groups K and C at 1 week post-injection (PI) but by 2 weeks PI only small numbers were recorded. Following booster immunization, the numbers of IgM-containing cells were greater in abscesses from sheep in Group L than from granulomas from sheep in Group K. Levels for Group C remained low after 1 week PI. There was evidence that the very early IgM-containing cell response in Group K was largely unrelated to specific anti-staphylococcal antibody synthesis. The IgG2-containing cell response was significantly greater than the IgG1-containing cell response in abscesses and nodes in Group L. In contrast, for animals in Groups K and C the IgG1-containing cell response predominated over the IgG2-containing cell response in granulomas and draining nodes. There were generally greater numbers of cells containing anti-staphylococcal antibody in abscesses/granulomas and nodes in Group L than in Group K.

Morphometric and immunohistochemical study of jejunal biopsies from children with intestinal soy allergy.

A morphometric and immunohistochemical restudy was made of jejunal biopsy specimens from 5 patients with soy allergy and the results obtained were compared to those from specimens taken before soy feeding and to those at a later time. All the patients had had previous cow's milk allergy with malabsorption. Gastrointestinal symptoms presented within two weeks of starting the soy based formula but in two patients the symptoms were mild and these patients were able to continue soy feeding. Jejunal biopsy specimens taken within 3 days from the reaction to soy showed villous atrophy associated with crypt hyperplasia and an increased cell renewal rate. Also, these specimens showed an inflammatory reaction in the lamina propria and in the epithelium, and the numbers of IgA- and IgM-containing cells were increased. Later, when the soy proteins were eliminated, the morphology of the jejunum improved and the cell numbers were reduced to normal. The intestinal damage and the local immune reaction caused by soy proteins are similar to those seen in cow's milk allergy with malabsorption. The immunological mechanisms operating in these diseases are thought to be the cause of these changes.

The early phase of the immune response to live and killed [formula omitted] vaccines in sheep — Cellular and immunoglobulin parameters

Various cellular and protein parameters in efferent lymph were monitored during early stages of immune responses in the draining popliteal lymph nodes of sheep following injection with either live or killed Staphylococcus aureus vaccines. Significantly higher outputs of leucocytes and lymphoblasts were measured in lymph from animals injected with the live vaccine (Group 1) compared with animals given the killed vaccine (Group 2) and non-immunised controls (Group 3). At 48 h post-injection the mean output of leucocytes in lymph for Group 1 was 9.5 × 10 7 cells/h, and for Groups 2 and 3 comparable mean outputs were 5.2 × 10 7 and 2.2 × 10 7 respectively. There was a marked increase in IgM-containing cells in Group 1 animals, significant differences between Group 1 and 2 occurring 96 h post-injection. A difference was observed between the two immunised groups in the kinetics of output of cells containing antibody to a staphylococcal antigen extract. There was a slower increase in antibody-containing cells for Group 1 than for Group 2 animals. The mean proportion of antibody-containing cells reached 0.09% (of total leucocytes) at 72 h post-injection for Group 2 and 0.10% at 120 h post-injection for Group 1. Rapid increases in flow rate of lymph were recorded in animals in Group 1. These results were in contrast to lower corresponding values observed in sheep in Groups 2 and 3. There was a twofold increase in the lymph: serum (L:S) concentration ratio for IgG2 in animals in Group 1 and the evidence suggested that this was due to local synthesis of IgG2 by lymphoid cells in the abscess at the site of injection and/or in the draining popliteal lymph node. This change in L:S ratio for IgG2 was not recorded for sheep in Groups 2 and 3.

Dynamics of B-lymphocytes in the lungs of mice exposed to aerosolized influenza virus.

Immunoglobulin-containing cells were revealed by immunofluorescence in lung sections from mice infected with influenza virus by the aerosol route. The numbers of immunoglobulin A (IgA)- and IgM-containing cells were increasing by day 3 of the infection, whereas IgG-containing cells appeared a few days later. The responding B-cell populations appeared in two principal locations: along major airways and in consolidated lesions within lung parenchyma. IgA-containing cells were the most numerous isotype, occurring predominantly in the lamina propria of the airways. IgG-containing cells were the least frequently encountered class along airways and appeared most often within consolidated lung lesions in clustered groupings. Cells staining for mu chain appeared along the airways and in lung lesions. The population of IgM-containing cells declined approximately 30 days after infection. Cells producing alpha and gamma chains were still numerous on day 46. Assays for virus-reactive antibodies in lung secretions were positive on day 8 of the infection. The IgM titers were the first to decline, but virus-binding antibodies for all classes were still present on day 33. The implications of immune responses in viral pneumonitis were considered.

Cellular sites of immunoglobulins. VII. Localization of immunoglobulins in female mammary gland.

Direct immunofluorescent techniques are utilized to identify the type of infiltrating immunoglobulin in cells of the mature female mammary gland before menopause.In the average normal premenopausal breast, there are some immunoglobulin-containing cells infiltrating the intra- and interlobular stroma. They are predominantly IgA-containing cells, some are IgM-containing cells, and only a few are IgG-containing cells. Some secretory IgA and IgM immunoglobulins are also found in the apical portion of the acinar epithelial cells, but no IgG is detected.In the lactating mammary gland, the immunoglobulins, chiefly secretory IgA and IgM, are accumulated in the acinar epithelial cells and secreted into the lumen.Our present studies prove that the antibodies in mother's milk and colostrum are selectively secreted by IgA- and IgM-containing cells in the mammary glands, but they are probably carried by the lymphatics.

Immunoglobulin-containing plasma cells in chronic parotitis and malignant lymphomas of the parotid gland. Comparing immunocytochemical observations of frequency and localization.

IgA-containing plasma cells in the periductal gland tissue are part of the special secretory immune system of the salivary glands. The reaction of Ig-containing plasma cells (localization, frequency, specific Ig-content) was analyzed by the indirect immunoperoxidase method in chronic recurrent parotitis (9 cases), chronic myoepithelial parotitis (benign lymphoepithelial lesion, Sjögren's syndrome; 8 cases), and malignant lymphoma associated with chronic myoepithelial parotitis (11 cases). The following results were obtained: 1. In chronic recurrent parotitis, parallel to the increase in IgA in the salivary secretion, a marked multiplication of IgA-containing plasma cells was found in the inflammatory infiltrate and the remaining non-inflamed periductal parenchyma of the parotid gland. In the marginal zone of inflammation, a slight increase of IgG-containing plasma cells was also observed. 2. In chronic myoepithelial parotitis, the total plasma cellular infiltration was slightly less distinct than in chronic recurrent parotitis. The most remarkable increase in Ig-containing plasma cells developed in the marginal zones--away from the myoepithelial cellular islands--as well as in the area of ductular proliferations, and was characterized by a strong increase of IgG-containing plasma cells. At the same time, a slight increase of IgM-containing plasma cells was observed. No plasma cells were found in the myoepithelial cellular islands. 3. In the malignant lymphomas associated with myoepithelial parotitis, which were mainly highly differentiated lymphomas (immunocytomas, centrocytic-centroblastic lymphomas) and rarely poorly differentiated immunoblastic lymphomas, there was a distinct decrease of IgG-containing plasma cells when compared with the numbers in this group without lymphoma. The differing degrees of prevalence and Ig-content of the plasma cells partly describe the change taking place in the local secretory immune system of the parotid gland. The possible relationships between chronic recurrent parotitis and auto-immune myoepithelial parotitis on one hand and the stages of transition (prelymphoma) to malignant lymphoma on the other, are discussed.

Time of appearance of immunoglobulin-containing cells in the mucosa of the neonatal intestine.

In 46 intestinal specimens from infants 2 hr to 6 months old, the numbers of immunoglobulin-containing cells were counted by the direct immunofluorescent or direct immunoperoxidase technique. A restudy was made of biopsy specimens taken for diagnostic purposes, 34 from the rectum and 3 from the transverse colon of 30 infants at the Children's Hospital, Helsinki in 1971-1977, and in addition, of autopsy material recently collected from the intestines of 9 infants. Up to the age of 12 days, no immunoglobulin-containing cells were seen. A small number (1 to 2) of IgM-containing cells was seen in the lymph nodes of the 2 earlier specimens taken at the ages of 6 and 12 days. A rectal specimen from a 12-day-old infant showed 24 IgA- and 60 IgM-containing cells/mm2. In rectal specimens of infants less than 1 month old, the mean number of IgM-containing cells (26/mm2) was higher than that of IgA-containing cells (14/mm2), but older infants had a significantly higher mean number of IgA-containing cells (P < 0.01). The mean number of IgM-containing cells was the same in children 1 to 3 months (53 cells/mm2) and 3 to 6 months of age (59 cells/mm2), whereas the mean number of IgA-containing cells increased with age up to 6 months (112 and 163 cells/mm2). The youngest infant who had IgG-containing cells was 13 days old, although positive staining of intercellular spaces in the lamina propria and of the capillary endothelium by anti-IgG serum was observed in all specimens. The mean number of IgG-containing cells was low (5 cells/mm2) in all age groups. Sparse IgE-containing cells (less than 12 /mm2) were seen in 4 of the 46 specimens. In 5 patients, 2 or 3 consecutive specimens were available for the study; in these, the increase in the numbers of IgA- and IgM-containing cells was similar to the mean increase in cell numbers for the series as a whole.

The distribution of immunoglobulin-containing cells in canine small intestine

Peroxidase conjugated antisera to canine immunoglobulins G and A and to human immunoglobulin M, have been used to study the distribution of immunoglobulin-containing cells in the small intestine of the young and adult dog. At all levels of the small bowel of the adult dog, IgA:IgM:IgG cells have a 2:1:1 ratio while the greatest number of immunocytes is found in the duodenum and decreases towards the distal portion of the small intestine. The young puppy shows a predominance of IgM-containing cells in the small intestinal lamina propria during early life but the adult pattern of immunocyte distribution has been achieved by weaning.

Clinical findings and intestinal immunoglobulins in children with partial IgA deficiency.

We studied the intestinal morphology, and the jejunal and rectal immunoglobulins of 16 children with partial IgA deficiency, defined as serum IgA concentration more than two standard deviations below the mean for age, but higher than the lower limit of sensitivity of single radial immunodiffusion (0.02 g/l). Five of the patients had been treated with phenytoin, 2 had juvenile rheumatoid arthritis, 2 had ulcerative colitis and 5 had recurrent upper respiratory tract infections. The jejunal morphology was normal in every case. In 6 cases normalization of serum IgA occurred during the follow-up, while in one patient with ulcerative colitis the concentration fell below 0.02 g/l. In patients with recurrent infections, there was a decreased frequency of infections when the level of serum igA increased. In 4 patients, IgM-containing cells prodominated in both the jejunal and rectal mucosa, and IgM was increased in the intestinal juice. In 6 patients a significant increase in IgM-containing cells or a decrease in IgA-containing cells or both were seen in either the rectal or jejunal mucosa. There was no correlation between the number of IgA-containing cells in the intestinal mucosa and the serum level of IgA.