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We studied nine patients with bullous pemphigoid, a generalized cutaneous eruption- for evidence of mast-cell involvement during development of lesions. As in other reports, six of nine patients demonstrated a serum antibody directed against the epidermal basement-membrane zone. Direct immunofluorescence studies of lesions revealed depostion of immunoglobulin and complement proteins at the basement-membrane zone in six of nine and nine of nine patients, respectively. Participation of mast cells was suggested by a sequence of pathologic alterations in which there was progressive mast-cell degranulation and late eosinophil infiltration. In addition, a factor chemotactic for human eosinophils with the size and charge characteristics of the eosinophil chemotactic factor of anaphylaxis was identified in blullous fluid. The data indicate that, in addition to activation of the complement system, involvement of mast cells is an early and continuing event in the development of the cutanenous lesions of bullous pemphigoid.

The chemotactic responses of human blood neutrophils and of eosinophils of two different densities, which were resolved by centrifugation on gradients of polyvinylpyrrolidone-coated silica gel (Percoll), were quantified in modified Boyden micropore filter chambers using highly purified synthetic 1-0-hexadecyl-2-acetyl-sn-glyceryl-3-phosphocholine (AGEPC or PAFacether) and leukotriene B4 (LTB4) as stimuli. Maximal chemotactic responses of the densest eosinophils, less dense eosinophils, and neutrophils were evoked by 1 nM, 100 nM, and 1 microM PAFacether, respectively, and by 30-100, 30-100, and 10 nM LTB4. The magnitude of the maximal chemotactic response to PAFacether of the densest eosinophils was significantly greater than that of neutrophils. The eosinophil responses to PAFacether were chemotactic, as distinguished from chemokinetic, and were not influenced by the percentage of contaminating neutrophils. PAFacether is a more potent chemotactic factor for eosinophils than neutrophils and selectively attracts the densest population of human blood eosinophils.

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Peptidergic nerves in immune organs and lymphoid tissues of the lungs and gastrointestinal tract end on or in close proximity to lymphocytes, mast cells and macrophages. Vasoactive intestinal peptide, substance P and some other neuropeptides, that are recognized by distinct sets of cell surface receptors, regulate aspects of T cell differentiation in the thymus, such as negative selection, and contribute to mediating compartmental immune responses. The latter effects include stimulating expression of adhesive proteins by lymphocytes, enhancement of lymphocyte and macrophage migration in vascular and connective tissues, and modulation of proliferative and synthetic responses of lymphocytes to diverse antigens.