Ultrastructural aspects of delayed hypersensitivity

Ultrastructure of epididymal interstitial reactions following vasectomy and vasovasostomy

The response of the male reproductive tract to vasectomy includes inflammation of the interstitial tissue of the epididymis. The pathogenesis of epididymal interstitial reactions and characteristics of the responding cells were studied by electron microscopy in Lewis rats at intervals following bilateral vasectomy, vasectomy followed 1 month later by vasovasostomy, or sham operations. In areas of interstitial reaction, numerous macrophages, monocytes, lymphocytes, neutrophils, and plasma cells occupied the connective tissue. Macrophages, containing many lysosomes and vesicles, aggregated and assumed the appearance of epithelioid cells. Processes of adjacent macrophages interdigitated with one another and closely approached the surfaces of lymphocytes. Many plasma cells with distended rough endoplasmic reticulum appeared in the interstitium. The majority of animals in the vasectomy and vasovasostomy groups exhibited epididymal interstitial changes by 2-3 months; the cauda epididymidis was the region most often affected. The ultrastructural features were indicative of chronic granulomatous inflammation and were consistent with an immune response that includes antigen presentation by macrophages to lymphocytes, lymphocyte differentiation, and local antibody production by plasma cells. The nearly complete absence of sperm or recognizable parts thereof in the interstitial tissue in the areas of the reactions suggests that these lesions formed in response to soluble antigens leaking from the duct. Vasovasostomy was not effective in reversing or retarding epididymal inflammation at the intervals studied.

Tuberculin elicited cellular immune response in the lactating bovine mammary gland vaccinated intramammarily with Mycobacterium bovis

The development of a local antigen-specific sensitivity was monitored histologically and in secretions of the bovine mammary gland. Three cows in mid-lactation were immunized by injecting 50 microliter of a killed Mycobacterium bovis vaccine into the dorsal secretory tissue of the rear mammary glands; two cows served as unvaccinated controls. Ten weeks after vaccination, all cows were challenged by intramammary infusion of 1.0 microgram tuberculin in 5 ml phosphate-buffered saline (PBS). Three quarters of each cow received tuberculin at 72, 48, and 24 hours before slaughter; a control quarter received PBS at 72 hours. Vaccinated cows exhibited an intense, local cellular reaction to tuberculin in teat-end tissues at all times post infusion; PBS-infused glands were normal. A moderate leukocyte response in parenchymal tissues adjacent to the gland cistern of tuberculin-infused quarters was observed, but deep parenchymal tissues were normal; no effect on milk yield was found. Tuberculin-infused quarters exhibited histological responses in teat cisternal tissues similar to those in delayed-type hypersensitivity reactions. Leukocytic accumulation was primarily macrophages and lymphocytes with few neutrophils. Erythema was observed in the distal half of the cistern, and fibrin deposits were found in subepithelial connective tissues. The epithelium, although distended with leukocytes, was intact and numerous mitotic figures were present. Unvaccinated cows showed no response to challenge. Results demonstrated a marked and specific cellular response in sensitized cows to challenge with tuberculin.

Drug-induced acute interstitial nephritis with granulomas

To shed more light on the immunopathogenesis of drug-induced acute interstitial nephritis, a combined histologic, immunopathologic, and ultrastructural study of renal biopsy specimens from nine patients with drug-induced renal disease was performed. None of the patients had pre-existing renal disease or evidence of sarcoidosis or tuberculosis. The principal drugs included a hydrochlorothiazide-triamterene combination (Dyazide), hydrochlorothiazide, fenoprofen, and furosemide and triamterene. Renal insufficiency developed approximately four to ten weeks after initiation of drug therapy. In all cases, withdrawal of the drug(s) with or without steroid therapy resulted in restoration of normal or near-normal renal function. Histologically, all biopsy specimens showed acute interstitial nephritis characterized by an intense but patchy mononuclear cell interstitial infiltrate consisting of lymphocytes, monocytes, and plasma cells, modest numbers of eosinophils, patchy tubular atrophy, interstitial edema, and normal glomeruli. All biopsy specimens contained interstitial (and, in two cases, perivascular) non-caseating granulomas, which were numerous in one case, moderate in four cases, and rare in the remainder. Direct immunofluorescence was negative for IgG, IgM, IgA, C1q, C4, and C3 along glomerular and tubular basement membranes. Immunoperoxidase staining for lysozyme (performed in three cases) demonstrated many positive cells in the infiltrate. In two cases in which granulomas were present in prepared sections, the epithelioid and multinucleated giant cells did not stain for lysozyme. Electron microscopy of the granulomas in two cases revealed that the epithelioid and giant cells had "secretory" features characteristic of hypersensitivity granulomas. These findings provide further evidence for the participation of cell-mediated immunity in the pathogenesis of at least some cases of drug-induced acute interstitial nephritis.

Acute interstitial nephritis associated with thiazide diuretics. Clinical and pathologic observations in three cases

Renal failure insidiously developed in three patients treated with a combination of hydrochlorothiazide and triamterene five to 10 weeks after commencing therapy. All had normal renal function prior to therapy and none had preexisting renal disease. Two of the patients had eosinophilia and two had a fever. One patient was oliguric. Renal biopsy demonstrated acute interstitial nephritis histologically. Direct immunofluorescence did not disclose evidence of either immune complex or antitubular basement membrane antibody deposition. Withdrawal of the drug led to remarkable improvement with renal function returning to normal in two patients and near normal in the third. The sequence of events and the histologic findings strongly suggest that the acute interstitial nephritis was due to a drug-induced hypersensitivity reaction. Although hydrochlorothiazide appears to be the drug responsible for the reaction, certain observations suggest a possible potentiating role for triamterene.

Morphometric electron and light microscope analysis of lymphoid cells in coeliac disease

Lymphocytes in jejunal biopsies from normal subjects and from untreated, treated, and gluten-challenged coeliac patients were examined by accurate morphometric methods. There was no significant difference between lymphocytes from different sources and those in the jejunum. Transforming lymphocytes were ultrastructurally quite different from non-transforming lymphocytes. The appearance of transforming lymphocytes in the lamina propria in different groups of coeliac patients is in accordance with the increase in the number of plasma cells. In treated patients the results indicate a rapid humoral response to gluten challenge.

Diagnostic value of lysozyme activity estimation in the feces of infants with acute diarrhoea

The activity of lysozyme in feces was estimated in a control group of 50 healthy infants and in a group of 152 infants with acute diarrhoea. All infants investigated were artificially nourished. In the latter group the activity of lysozyme was estimated twice: a) at the beginning of clinically active phase of the disease and (b) in the convalescence period immediately after withdrawal of clinical symptoms. The range of normal values was 14.9--77.0 (average 44.0) of egg-white lysozyme units/g dry feces. In acute diarrhoea the activity of lysozyme in feces was found to be elevated in 72.4% of cases in the first determinations and in an additional 7.6% of cases in the second determination (i.e. a total of 80% of cases in both determinations). The average elevations of lysozyme activity in the feces and the dynamics of their normalization after withdrawal of clinical symptoms were generally related to the severity of the disease.

The nonkeratinocyte intraepithelial cell population in lichen planus. An ultrastructural characterization of cells in gingival lesions

Lesions of gingival lichen planus were studied ultrastructurally to determine the types of cells, other than keratinocytes, present within the epithelial layer and the relationship of these cells to each other and to the keratinocytes. Cell types identified included small and medium-sized lymphocytes, macrophages, mast cells, and Langerhans cells. Some cells lacked sufficient specific features to permit definitive identification. The cells were found either singly or in groups. Generally, some alteration in the intercellular spaces between keratinocytes was apparent, even in regions where the mononuclear cells were absent or in the process of crossing the basal lamina. Most of the mononuclear cells had cytologic features which indicated that they were active cells. Occasionally lymphocytes appeared, on a morphologic basis, to be interacting with adjacent keratinocytes.

Local renal graft-versus-host reaction: sequential ultrastructural study

A sequential study has been made of the ultrastructure of local renal graft-versus-host reactions produced in cyclophosphamide-pretreated rats by injection of either allogeneic or xenogeneic (mouse) spleen cells beneath the renal capsule. Early in the reaction, immunoblasts were seen between the outer cortical tubules, and there was associated interstitial oedema and tubular degeneration. In places, several small lymphocytes were observed clustered around and in close cytoplasmic contact with individual immunoblasts, perhaps representing interaction between donor and host cells. As the reaction proceeded, the number of lymphoid cells increased by immigration from peritubular vessels. Some tubules were invaded by lymphocytes but this was not closely related to the development of tubular injury. The reaction was maximum at one week and then decreased. Now, there was greater diversity of cells including macrophages, plasma cells and eosinophils, while many lymphoid cells became necrotic. It is concluded that most of the renal parenchymal injury is due to chemical mediators liberated from the infiltrating cells rather than to ischaemia or direct cytoplasmic interaction between leucocytes and tubular epithelium.