The usefulness of routine screening for salivary secretory component

Secretory IgA is a dimeric immunoglobulin found in association with the J chain and secretory component (SC). It is secreted into saliva and other mucosal fluids and is involved in mucosal immunity. The absence of either SC or secretory IgA may be associated with recurrent sinopulmonary infections, diarrhea, and failure to thrive. We present a retrospective study of 1262 samples from 877 patients who were screened for salivary IgA, SC, and serum immunoglobulin levels. Forty-six patients (5.2%) of those tested were found to have absent salivary SC. Although only 19 of these patients (41.3%) could be retested, all were found to have SC on repeated testing. Of the patients whose initial samples of saliva exhibited no SC, 15% (6/46) had low or absent serum IGA (less than 10 mg/dl) in contrast to 8.6% (66/769) of patients whose saliva contained detectable SC, but this was not statistically significant (chi 2 = 1.93; p greater than 0.1). There was also no correlation between serum immunoglobulin levels and the absence of SC. Because of the rarity of salivary SC deficiency, routine screening is not valuable.

[Secretory immunoglobulin A in saliva of healthy children and children with airway diseases]

Using the Elisa-Test of Dakopatts, Hamburg, described by Ishiguro et al and modified by us (Mikrotitration plates instead of tubes, blocking up free bonding capacities in the plates with 1% gel fluid, altered incubation periods) we determined secretory IgA (SIgA) in saliva samples of 376 infants and children. The probands could be divided in three groups: Group 1, serving as controls, consisted of 163 healthy children. Group 2 comprised 111 children suffering from acute infection of the respiratory tract. Group 3 consisted of 102 children with chronic airways diseases, in particular, asthma. In the healthy infants and children we found age dependent increases of SIgA until the age of 4 years. The median values amounted 16.7 (newborns), 59.2 (1st year), 118.2 (2nd year), 149.2 (3rd year), 185.5 (4th year), 159 (5th year) and 175.8 mg/l (5th-13th year). A similar age dependent increase of SIgA was evident in the saliva samples of children suffering from acute infections of the respiratory tract. In the children with chronic airways diseases there was only a slight increase of SIgA during the first 4 years (mean = 78.0-113.5 mg/l) and an abrupt (statistically significant) rise in the fifth year. The median value of SIgA was 216 mg/l in the children aged 5-13 years. Serum IgA along with salivary IgA were measured in 128 children (r = 0.40, p less than 0.001). 6 children had a complete IgA deficiency and 4 children an incomplete IgA deficiency, i.e. low secretory IgA levels in saliva (36.8-50.0 mg/l) and lacking IgA in serum (less than 14 mg/dl).(ABSTRACT TRUNCATED AT 250 WORDS)

[D-penicillamine-induced IgA deficiency in the therapy of Wilson's disease]

Serum IgA deficiency was first noted in a 10 year old boy 8 months after the onset of D-penicillamine therapy. Special immunological examinations revealed a deficiency of the secretory component of IgA while cellular functions of T- and B-lymphocytes were normal. The patient showed discrete clinical signs compatible with IgA deficiency. Regular control of patients with Morbus Wilson and D-penicillamine treatment should include measurement of serum immunoglobulin levels.

Secretory IgA deficiency in pediatric patients: clinical and laboratory follow-up

This is a prospective three-year (1985-1988) clinical and laboratory follow-up study of 43 pediatric patients without any measurable secretory IgA, intending to describe the their natural course. We also intended to detect evidence which may allow to predict their future outcome, whether they would become asymptomatic or end up developing chronic disease. A direct statistical correlation was found between those patients who normalize their secretory IgA levels and their course in an asymptomatic state. Thus, if a child does not have any sIgA at all, the relative risk to get sick is 0.86 (86%), while in those having sIgA within normal ranges, the relative risk of disease decreases to 0.46 (46%), representing a p value less than or equal to 0.05. Among the analyzed variables and their influence on the fact that a patient may or may not synthesize sIgA, none of them showed a predictive value for bronchial asthma by itself. However, when sIgA and total serum IgE levels, were analyzed together (being the two variables demonstrating to influence), the probability of becoming asthmatic is much greater in the ones with elevated total serum IgE and absent sIgA. This group is significantly different from the one with normal IgE and sIgA levels (p less than or equal to 0.001). According to our experience in evaluating and controlling a pediatric patient with repeated episodes of bronchial obstruction and lacking sIgA, an immediate strict environmental control should be established in order to avoid all possible contacts with allergens.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoglobulin-producing cells in secretory immune system in patients with selective IgA deficiency

This study evaluated the class distribution and J chain-positivity of immunoglobulin-producing cells (Ig-PCs) in gastrointestinal mucosa and salivary glands of Japanese patients with selective IgA deficiency. The proportional patterns of gland-associated Ig-PCs showed an increase in not only IgM cells but also IgG cells, most of which were J chain-positive. This may represent a maturation arrest at B cell differentiation, rather than a compensatory phenomenon. No patients showed an increase of IgD cells in salivary glands. This behavior of IgD cells in Japanese patients may reflect associated diseases or ethnic difference in B cell differentiation.

Transient phenytoin induced IgA deficiency and permanent IgE increase

This is a report of a 9-year-old epileptic boy, who was studied over a period of 7 years. The seizures started when he was 2 months old. He was treated with phenytoin from the age of 2 years and 7 months. Serum and salivary IgA were absent with high IgE serum total. The routine immunologic studies were normal. The IgA was normalized after phenytoin withdrawal, but IgE determination increased progressively without any atopic symptoms. The T4 (helper)/T8 (suppressor) ratio decreased (1.0 and 1.2) on two different days, although above the normal limit. The phenytoin only modified the IgA levels. These data suggest that a primary immunoregulatory abnormality may be present in drug induced IgA deficiency.

The human IgA system: a reassessment

In healthy adults the total daily production of secretory and serum IgA exceeds that of other immunoglobulin classes. Secretory and serum IgA display features of mutual independence: they are represented by molecules with different physiochemical and immunochemical properties and antibody activities and are produced by cells with different organ distributions. Secretory and serum IgA also exhibit different effector functions: interaction of secretory IgA with environmental antigens results in prevention of the penetration of such antigens by a variety of mechanisms. Although the function of polymeric serum IgA antibodies in certain animal species involves elimination of antigenic substances by noninflammatory means, the primary function of serum IgA remains unknown. It is proposed that in humans monomeric serum IgA (which prevents activation of the complement systems, inhibits phagocytosis and antibody-dependent cellular cytotoxicity) may protect endogenous antigens expressed on various cells and tissues by preventing their interaction with humoral and cellular immune mechanisms that may lead to tissue damage.

The wasted mutant mouse. I. An animal model of secretory IgA deficiency with normal serum IgA

The wasted (wst) mutation was recently described as a spontaneous, recessive mutation leading to pathologic changes affecting both the neurologic and the immune systems of wst/wst homozygotes, which presented symptoms analogous to those observed in patients with ataxia-telangiectasia (A.T.). We studied the IgA system of wst/wst mutants and their normal littermates to determine whether IgA deficiency commonly found in A.T. patients was also affecting these mutants. Interestingly, although IgA plasma cells were totally absent from their entire (small and large) intestine, their serum contained a normal level of IgA with a normal ratio of monomeric vs polymeric IgA. The absence of gut IgA plasma cells was not due to malnutrition and was not compensated by the appearance of cells secreting any other isotypes. Studies at the precursor cell level showed the absence of IgA-specific B cell precursors in the Peyer's patches, whereas sIgA B cells and IgA plasma cells were found in normal numbers in the spleen of wasted mice. These data suggest that secretory and serum IgA may comprise distinct systems and that the wasted mutant mouse is a potential model for the study of the physiology and regulation of IgA production.

Graft versus host disease-related secretory immunoglobulin A deficiency in bone marrow transplant recipients. Findings in labial saliva

Graft versus host disease-dependent decreases in salivary IgA levels were sought in labial gland saliva samples from bone marrow transplant recipients. Transplantation-associated, irradiation-related effects were also present, but these could be avoided if analyses were performed at 1 year or later after transplantation. Sampling of minor gland saliva eliminated the possibility of contamination with IgA-rich serum transudates arising from gingival or mucosal pathways which obscured results from previous studies using whole saliva samples. Patients with active extensive clinical disease had significantly depressed levels of salivary IgA. Since labial saliva is a principal source of total salivary IgA, the present findings may explain why patients with graft versus host disease are susceptible to infection via the sinobronchial portal.

[Ataxia-telangiectasis (author's transl)]

A case of ataxia-telangiectasis is reported, the pattern of cellulo-humoral immunity is altered with frequent infection of the respiratory tract. Emphasis is made on the new approach to brain alterations by means of cerebral angiogammagraphy and sequential gammagraphy.