\s=b\The clinical and pathologic features of 12 cases of malignant fibrous histiocytoma of the head and neck were studied. These tumors occurred in seven men and five women ranging in age from 21 to 75 years (average, 55 years). The sinonasal tract was the most common site (four cases), followed by the parotid area (two cases), oral cavity (two cases), soft tissues of the neck (two cases), mandible (one case), and larynx (one case). Pathologically, 11 of the tumors were subclassified as storiform-pleomorphic and one as inflammatory. All were treated initially with surgery with or without postoperative irradiation. Five (42%) of the patients experienced local recurrences, three (25%) developed distant metastases (especially to the lungs), and five (42%) died of their disease, all of the latter occurring within two years of diagnosis. No patient developed bona fide cervical lymph node metastasis, although one did have a positive paraparotid node as a result of direct extension from an adjacent tumor.(Arch Otolaryngol Head Neck Surg

The acceptance of the fetal allograft in the face of a completely competent maternal immune system remains a perplexing and critical problem in transplantation immunology . Varieties of potential mechanisms by which the fetus could avoid rejection have been proposed by Medawar (1) and by Billingham (2), and these proposals set the stage for much of the work in this field. The mechanisms proposed to prevent immune destruction of the fetus by the mother have postulated roles for blocking antibodies, immunosuppressive antibody-antigen complexes, nonimmunoglobulin immunosuppressive molecules, suppressor cells, and selective maternal immunoincompetence (reviewed in references 3-8). Many of these arguments turn on the question of what type of transplantation antigens encoded by the MHC are present in the placenta. Class I antigens have been demonstrated in the placenta of the mouse (9-13), human (14-21), and rat (22-24) using alloantisera and mAbs. Other studies in the human showed that the placenta also carries unique class I, or class I-like, antigens, the TLX antigens (25, 26), and class I molecules that carry only broadly crossreactive public antigenic determinants (27). Class II antigens are absent from the placenta in both the mouse (9, 28) and the human (14)(15)(16)(17)(18)(19) 29) .Studies in the rat demonstrated that during pregnancy the maternal strain in certain mating combinations made an antibody response to the paternal component of the fetal histocompatibility antigens without any prior sensitization (22, 30, 31) . The most potent response occurred when the u X a (female X male) haplotypes were mated. The alloantibody (22) and mAb (30) responses were directed against a placental class I molecule, the pregnancy-associated (Pa)' antigen, that has a broadly shared public antigenic determinant but not the allele-specific determinant of a classical class I transplantation antigen . The Pa antigen isolated from lymphocytes has a heavy chain of 46 kD and is associated with the ,B2-microglobulin molecule. It appears to be controlled by a diallelic system : the a, d, f, b, and m haplotypes carry the Pa antigen, whereas the n, c, l, u, g, k, and h haplotypes do not . Using alloantisera, both the Pa antigen and the allele-specific RT 1 .Aa antigen were shown to be in the basal, but not in the This work was supported by grants HD-08662 and HD-09980 from the National Institutes of Health.' Abbreviation used in this paper: Pa, pregnancy-associated.J. Exp. MED.

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lip monitored by specific airway conductance (sGaw) measure ments in a body plethysmograph. Every 3 min another dose was given, double the previous concentration, up to 6-4% histamine. A cumulative log dose-response curve was constructed.On separate days histamine challenges were repeated 10 min after intravenous injections of (1) chlorpheniramine 20 mg (H,receptor blocker), (2) cimetidine 200 mg (H 2 -receptor blocker), (3) chlorpheniramine 20 mg and cimetidine 200 mg. The anticholinergic activity of chlorpheniramine was estimated by comparing the effect of the chlorpheniramine and atropine (1-5 mg inhaled) on a methacholine bronchial challenge.In all subjects the histamine dose-response curve was reproducible and was significantly shifted to the right by chlorpheniramine. Cimetidine produced much less effect, although in four subjects the curves were shifted slightly to the right and in two to the left. Chlorpheniramine and cimetidine together produced the same response as chlorpheniramine alone. Chlorpheniramine showed significant anticholinergic action in only three subjects. Thus in normal subjects histamine-induced bronchoconstriction is mediated predominantly through the H,receptor.