Maili Lehto

Allergy to ingested cereals in atopic children

Clinical features, hypersensitivity mechanisms, and differential diagnosis of cereal allergy or intolerance were investigated in children with atopic dermatitis (AD). On oral provocation, 18 children exhibited a positive response to wheat, three to rye, one to barley, and one to oats. Cereal‐induced symptoms were dermatologic, gastrointestinal, or oropharyngeal, and their onset after provocation was immediate (eight cases), delayed (14 cases), or both immediate and delayed (one case). A combination of type I allergy tests (prick test, RAST, and histamine‐release test) detected all immediate reactors and 9/14 delayed reactors. Of the five subjects remaining negative in these tests, three were positive in the patch or lymphocyte‐proliferation tests. Subjects with cereal allergy or intolerance frequently possessed IgE, IgA, and IgG antibodies against gliadin, but only one of these children was HLA‐DR3‐positive, and none had reticulin antibodies typical of celiac disease. Combining tests of immediate and delayed hypersensitivity can confirm allergy to cereals in a more reliable way. The coexistence of cereal allergy and celiac disease seems to be rare.

Diagnostic value of skin and laboratory tests in cow's milk allergy/intolerance.

The applicability of a panel of five skin and laboratory tests in the diagnosis of cows milk allergy/intolerance (CMAI) was investigated. The tests used were prick and patch tests, RAST, basophil histamine release test (BHRT) and lymphocyte proliferation test (LPT). Twenty‐two atopic children who had experienced either immediate or delayed cutaneous symptoms upon challenge with cows milk (CM), and 12 non‐milk‐allergic controls with atopic dermatitis (AD) were included in the study. RAST, prick test, BHRT and LPT to CM and patch test to α‐casein were positive in the CMAI group and non‐milk‐allergic atopic controls as follows: 59% and 33%, 57% and 0%, 55% and 17%, 77% and 17%, 33% and 0%. RAST, prick test and BHRT were more often positive in children exhibiting immediate reactions, and patch test and LPT more often positive in those having delayed reactions to CM. The panel of five tests detected 21/22 children with CMAI and gave false‐positive results in 5/12 of non‐milk allergic controls. The sensitivity and specificity of the panel in the diagnosis of CMAI were 95% and 58%, respectively.

Basophil histamine release and lymphocyte proliferation tests in latex contact urticaria. In vitro tests in latex contact urticaria.

Basophil histamine release and lymphocyte proliferation tests were examined with latex allergen prepared from surgical gloves in 15 patients with latex contact urticaria. The basophil histamine release test (BHRT) yielded positive results in 13/14 (93%) patients, whereas commercial latex RAST was positive in only 9/15 (60%) patients. Lymphocyte proliferation test (LPT) was positive in 3/15 (20%) patients, suggesting that cell‐mediated immune reactions may also occur in latex allergy. However, patch tests to latex were negative and neither were epidermal Langerhans cells able to present latex antigen to T lymphocytes in vitro.

Lymphocyte proliferation test as a diagnostic aid in chromium contact Sensitivity

We investigated the clinical applicability of the lymphocyte proliferation test (LPT) in chromium contact sensitivity, 6 out of 8 chromium‐sensitive patient were positive in the LPT, whereas none of 8 non‐chromium‐sensitive controls responded in vitro to tri‐ or hexavalem chromium compounds. LPT thus appeared to offer an additional diagnostic tool in chromium sensitivity. We also studied cellular interactions in 4 of our chromium‐sensitive patients. Sensitized T‐lymphocytes could he activated to proliferate only in the presence of accessory cells, of which epidermal Langerhans cells (LC) appeared more efficient than blood adherent cells.

Comparison of immunologic tests in the diagnosis of occupational asthma and rhinitis

In this study, three immunologic tests, skin prick test, RAST, and basophil histamine‐release test (BHRT), were compared by provocation in the diagnosis of occupational asthma and rhinitis. Twenty‐three positive bronchial or nasal challenges were performed on 16 patients (six farmers, six bakery workers, and four food industry workers) and asthma or rhinitis was diagnosed as caused by cereal flour or grain, cow epithelium, storage mites, garlic, or soy dust. A control group consisted of 12 patients, of whom four (two bakery workers, one food industry worker, and one farmer) were challenge‐negative, and the rest suffered from pollen allergy and seasonal rhinitis and were not challenged. The sensitivity and specificity of the prick test, RAST, BHRT, and a panel of them were as follows: 74 and 89%, 57 and 86%, 78 and 93%, and 91 and 71%, respectively. The overall concordance among these three type I allergy tests or between immunologic tests and challenge was relatively good.

Decreased monocyte production of interleukin-1 and impaired lymphocyte proliferation in atopic dermatitis.

SummaryWe studied lymphocyte proliferation and subsets in ten atopic dermatitis (AD) patients and ten healthy controls. In addition, monocyte production of interleukin 1 (IL-1) was investigated. Mean numbers of total T cells, T-cells subsets, and B cells did not significantly differ between AD patients and controls even though the patients had slightly decreased amounts of suppressor T lymphocytes. Proliferative responses of AD patients to purified protein derivative of tuberculin (PPD), concanavalin A (ConA), or allogeneic cells did not significantly differ from those of healthy controls at optimal stimulant concentrations. In contrast, at suboptimal concentrations, AD patients showed a diminished response to all of these stimulants. Monocytes from AD patients elaborated clearly less IL-1 than those from healthy controls.

Human Epidermal Langerhans Cells and Peripheral Blood Monocytes

We compared the functional capacities of human epidermal Langerhans cells (LC) and peripheral blood monocytes. Epidermal sheets were obtained by a suction blister device. After enzymatic treatmenl LC were enriched by attaching them to IgG‐located erythrocyte monolayers. On a per cell basis, LC were several times more efficient accessory cells than monocytes in augmenting nickel‐ and tuberculin (PPD)‐induced T‐cell proliferation. In mixed cell cultures LC stimulated both autologous and allogeneic T cells, whereas monocytes stimulated only allogeneic cells In addition. LC were significantly more potent allogeneic stimulators than monocytes. Although monocytes were weaker accessory cells and allogeneic stimulators than LC, they induced higher interleukin 1 (IL‐1) activities than LC‐enriched or LC‐depleted cells. These results indicate that there are functional differences between LC and monocytes and that antigen presentation and mediator secretion are not correlated.

Immediate decrease in antigen-presenting function and delayed enhancement of interleukin-I production in human epidermal cells after in vivo UVB irradiation

Human skin was irradiated in vivo with a single UVB dose (100 mJ/cm2 or 200 mJ/cm2) to examine simultaneously the antigen‐presenting function and interleukin‐1 (IL‐1) production capacity of irradiated epidermal cells (EC). Suction blisters were produced on irradiated areas on days 0, 3 and 7 after UVB. Irradiated EC were harvested and co‐cultured with autologous T lymphocytes in the presence of antigens (PPD, HSV) or mitogen (ConA). Culture supernatants were tested for IL‐1 activity using the thymocyte comitogenity assay. We found that a single 200 mJ/cm2 dose of UVB caused an immediate suppression of the antigen‐presenting function of EC, but no alteration in their IL‐1 production capacity or surface marker expression (ATPase, CD1). PPD‐and HSV‐induced lymphocyte proliferation was decreased 70‐80% and ConA‐driven proliferation 30% when compared to non‐irradiated EC. However, this suppression was restored on days 3 and 7 after UVB irradiation, this being coexistent with an increased capacity of EC to produce IL‐1. It remains to be elucidated whether the immediate UVB‐induced photoimmunosuppression observed in the present study is due to inhibitory mediators or impaired membrane function of EC or both.

Enrichment of dendritic cells from human peripheral blood.

A simplified method is described for purification of dendritic cells from human peripheral blood. The method is based on depletion of phagocytes with carbonyl iron and magnet, followed by centrifugation of nonphagocytic cells on Percoll and elimination of contaminating T lymphocytes, B lymphocytes, natural killer cells, and monocytes from the low‐density cell fraction by treatment with monoclonal antibodies and complement. The purity of enriched dendritic cells was about 80% and these cells represented 0.2% of the starting mononuclear cell population. Dendritic cells were potent autologous and allogeneic stimulators in mixed leukocyte cultures.

Suppression of autologous mixed leukocyte reaction in type 1 diabetes mellitus by in vivo-activated T lymphocytes

In vivo-activated interleukin 2 receptor-positive T lymphocytes (Tac cells) are demonstrable and the autologous mixed leukocyte reaction (AMLR) is impaired in several autoimmune diseases, including type 1 insulin-dependent diabetes mellitus (IDDM). We investigated AMLR in greater detail, together with possible relationships between AMLR and Tac lymphocytes in IDDM. Coculture experiments with HLA identical patient-healthy sibling pairs revealed that both responder and stimulator cells of diabetic patients function abnormally in AMLR. Suppressive Tac lymphocytes among responder T cells seemed to impair their proliferation. The removal of Tac cells by immunomagnetic beads led to a striking enhancement of proliferation, while the restoration of AMLR cultures with enriched Tac cells was accompanied by a diminished response. The reasons for the poor stimulatory capacity of patient cells are at present unknown but may be due to altered function and/or structure of HLA-DR molecules.