Corneal changes in nine-banded armadillos with leprosy.

Leprosy is the third leading cause of blindness worldwide; however, little is known about the ocular changes that occur during the disease process. We have studied the eyes of two nine-banded armadillos with experimental Mycobacterium leprae infection by light and electron microscopy. Both animals had been inoculated intracutaneously, one 5 years and the other 2 years previously. Light microscopy revealed invasion by acid-fast bacilli which were seen in keratocytes and mononuclear phagocytes in all layers of the corneal stroma. In both animals, large macrophage granulomas were observed in the deep stroma, which was vascularized. Acid-fast bacilli were also were found in macrophages and vascular endothelial cells. By electron microscopy, numerous bacilli were found in the keratocytes, macrophages, and Schwann cells of myelinated and unmyelinated axons, and in the endothelial cells of blood vessels. The localization of M. leprae and the presence of inflammatory cells in the ocular tissue of both animals suggest that the bacilli reach the eye by the neural and/or vascular route. One animal showed much more extensive disease and bacillary yield than the other, indicating that ocular involvement may be independent of the generalized infection. Further studies of early ocular involvement in the armadillo and other animals could help to clarify the pathogenesis of this potentially blinding infection.

Serum and tear antibodies to Chlamydia after reinfection with guinea pig inclusion conjunctivitis agent.

Repeated inoculation of th eyes of guinea pigs with the naturally occurring Chlamydia psittaci agent, guinea pig inclusion conjunctivitis (GPIC), showed that animals gradually become susceptible to reinfection with the passage of time after primary infection. Higher levels of serum IgG antibody had a significant association with resistance to challenge inoculation only with a high dose (250 ELD50) but not with a low dose (25 ELD50) inoculum. With each inoculum, however, some animals with high serum antibody were susceptible. the presence of antibodies in tears did not correlate with resistance to the first low-dose challenge inoculation, but both tear IgG and secretory antibody did have a significant association with resistance on the second rechallenge with a high-dose inoculum. Topical treatment of the eye with immune serum or tears during primary infection reduced the amount of agent in the conjunctiva only during the period of application. Local treatment of the eye with heat-killed vaccine prior to primary infection did not produce detectable antibody or protect animals against challenge inoculation; this local immunization did "prime" the animals, however, so that they had an accelerated antibody response after infection. Although there is abundant evidence that local immunity has an important role in resistance to challenge inoculation with GPIC, serum and tear antibody levels correlate equally well with resistance to repeated ocular challenge inoculation. Effective immunization procedures for this chlamydial infection then would involve stimulation of both local and systemic immune responses.

Leprosy in a trachomatous population.

In an Egyptian leprosy hospital, 17% of 133 patients had a visual acuity of less than 3/60. Corneal opacity, phthisis bulbi, and cataract accounted for 85% of blindness. Leprosy and trachoma together produce blinding corneal opacity by exposure, leprous keratitis, and trichiasis and entropion. Inturned lids, a late result of conjunctival scarring due to childhood trachoma, were less frequent in patients with lepromatous leprosy than in patients with tuberculoid leprosy; because conjunctival scarring from trachoma depends on cell-mediated immunity, patients with lepromatous leprosy may not have had severe trachomatous scarring develop due to their lifelong abnormality in cellular immunity. In patients with leprosy, even when complicated by trachoma, simple measures to prevent or restore vision include medical treatment of leprosy, surgical correction of lid deformities, sector iridectomy for constricted pupils or central corneal opacities, and cataract extraction.

Experimental leprosy in African green monkeys (Cercopithecus aethiops): a model for polyneuritic leprosy.

Three African green monkeys (Cercopithecus aethiops) were inoculated intravenously and intracutaneously with Mycobacterium leprae derived from a naturally infected mangabey monkey. All developed cutaneous lesions at inoculation sites. One developed disseminated cutaneous lesions, while the cutaneous lesions in the other two regressed and eventually disappeared. The animals were examined at necropsy five years after inoculation. All three had active leprosy infection in peripheral nerves with extensive inflammation and fibrosis. The disease histologically resembled borderline-lepromatous leprosy. These findings add a new dimension to animal models of leprosy.

HSV-specific IgA from tears blocks virus attachment to the cell membrane.

The results of this investigation demonstrate that the IgA antibody in tears inhibits the attachment of herpes simplex virus (HSV) to cells and implicate immunoglobulin A (IgA) isotype antibody in the protection of the ocular surface. Tears were collected from the eyes of infected and uninfected rabbits and tested for the presence of infectious virus, for viral neutralization titer, and in an enzyme-linked immunoassay (ELISA) for antibody to HSV. Neither the tears from the uninfected rabbits nor the tears from the infected rabbits produced viral cytopathic effects on indicator cells in vitro. Tears from uninfected rabbits had no virus neutralization capacity while the tears from infected rabbits had titers of 1:10 to 1:40. Tears collected from HSV-1 infected rabbits, but not uninfected rabbits, had anti-HSV antibody titers as determined by the enzyme-linked immunosorbent assay. Lectin affinity column enrichment of IgA from the tears of uninfected and infected rabbits was examined for the capacity to block viral adsorption to cells using 32P-labeled virus. It was found that exposure of the radio-actively-labeled virus to the purified IgA fraction of tears from infected rabbits reduced the amount of virus binding to Vero cells, whereas the purified IgA obtained from uninfected tears had minimal activity. These results may imply a role for the IgA-containing fraction of tears from HSV-infected animals in preventing viral attachment to cells and suggest that antibody of this isotype plays a protective role at the ocular surface.

Ocular leprosy in nine-banded armadillos following intrastromal inoculation.

Leprosy shows a higher percentage of ocular involvement than any other systemic infection. In humans, the cornea is the first ocular tissue affected. Our previous studies in armadillos with naturally acquired and experimental disseminated leprosy showed that 44% had corneal infection. Mycobacterium leprae is found in armadillo burrows in Louisiana, U.S.A., and ocular abrasions may be the portal of entry for these organisms in wild armadillos. To test the cornea as a route of infection, we injected eight armadillos intrastromally with 2 x 10(6) M. leprae in 1 microliters. Two and 4 months later, the armadillos were sacrificed and their eyes processed for light- and electron-microscopy. After 2 months, M. leprae were found in histiocytes mainly in the corneal limbus, sclera and bulbar conjunctiva. At 4 months, however, there was a visible corneal leproma in one animal. Microscopically, it was found to be a histiocytic granuloma with heavy M. leprae invasion. In addition, cells were seen in the anterior chamber. Leprosy is endemic in regions where other corneal infections which compromise the epithelial barrier property are prevalent and where leprosy bacilli are found in the environment. The entry of leprosy bacilli into the cornea may produce lesions which spread posteriorly in the eye.

The skin window test in rhinoscleroma.

The skin window test was applied to evaluate the state of immunity in patients with rhinoscleroma. The use of the patient's own Klebsiella micro-organisms as antigen led to a negligible change in the percentage of lymphoblasts, whereas the use of foreign Klebsiella micro-organisms as antigen resulted in a pronounced change. This finding indicates an impaired cellular immune response. Application of Klebsiella microorganisms as antigen to normal subjects led to a comparatively high percentage of lymphoblastic transformation. This finding suggests the possible use of a standard Klebsiella antigen as a vaccine. The possible use of the skin window test to identify people with deficient T lymphocyte function is discussed as well as its use in monitoring the efficacy of such a vaccine in influencing the cellular immune response.

Stimulation of peroxidase by chlamydial infection: cytochemistry of guinea pig conjunctival epithelium.

Guinea pig inclusion conjunctivitis, a naturally occurring chlamydial disease of guinea pigs, resolves spontaneously after 3 to 4 weeks. The factors responsible for curbing the infection have not yet been specifically defined. Since Iwata (Invest. Ophthalmol. 15:297-301, 1976) reported cytochemical activity for peroxidase in the conjunctival epithelium of the normal rat, we undertook these studies to determine whether a similar activity exists in the guinea pig, and if so, whether it functions in the elimination of this Chlamydia psittaci infection. Tarsal conjunctivas of 14 normal guinea pigs, 34 infected ones, and 7 control guinea pigs (inoculated with yolk sac only) were excised and tested for peroxidase by the Graham and Karnovsky method (J. Histochem. Cytochem. 14:291-302, 1966). We found that peroxidase activity, virtually absent in normal animals, was intensely stimulated by the infection. This enzymatic activity appeared 2 days after inoculation of the conjunctiva with chlamydia and persisted for 6 to 7 weeks. The enzyme was localized in the rough endoplasmic reticulum and perinuclear cisternae of all layers of the conjunctival epithelium from the external surface to the basal lamina, including cells with no apparent inclusions as well as those heavily parasitized. Reaction in the Golgi complex was variable. No reaction, however, was ever evident in the chlamydial vacuoles or lysosomes, and the organisms continued to grow and multiply during peak enzymatic activity. We therefore concluded that the stimulated enzyme is apparently not directly responsible for the waning of the infection, but instead reflects an alteration of host metabolism that occurs as a consequence of the infection.

Cat scratch disease bacilli in the conjunctiva of patients with Parinaud's oculoglandular syndrome.

Unilateral conjunctivitis with regional lymphadenitis has been designated Parinaud's oculoglandular syndrome (POGS). The cause has been attributed to various infectious agents, especially leptothrix and the unidentified agent of cat scratch disease (CSD). In 1983-84 the cause of CSD in lymph node and skin was established as small pleomorphic gram-negative bacilli. We now report identical bacteria in the conjunctival lesions of 9 of 24 patients with POGS. This confirms the belief that the CSD bacillus is a major cause of POGS.

Experimental leprosy in the mangabey (Cercocebus atys): necropsy findings.

A mangabey monkey (Cercocebus atys) was inoculated intravenously and intracutaneously with acid-fast bacilli (AFB) from a mangabey with spontaneously acquired leprosy. It developed generalized lepromatous leprosy and died 46 months after inoculation. Necropsy revealed severe lepromatous infiltrates in the skin, nasal mucosa, peripheral nerves, and testicles. Internal organs were only minimally involved. The lesions seen at necropsy were very similar to those seen in untreated cases of human lepromatous leprosy. These findings further substantiate the mangabey monkey as a suitable animal model for the study of lepromatous leprosy.

Experimental borderline lepromatous leprosy with intraneural erythema nodosum leprosum in a mangabey monkey (Cercocebus atys).

A sooty mangabey monkey (Cercocebus atys) was inoculated with Mycobacterium leprae and developed borderline lepromatous leprosy and intraneural erythema nodosum leprosum. Previously studied mangabeys have developed only disseminated lepromatous leprosy without reactions. This case broadens the spectrum of leprosy seen in experimentally inoculated animals and further characterizes the nonhuman primate model of leprosy.

Histopathological changes in the eyes of mangabey monkeys with lepromatous leprosy.

Leprosy is the third leading cause of preventable blindness; however, little is known about the spread of infection to the eye. We have studied the eyes of three sooty managabey monkeys. Two were experimentally infected with Mycobacterium leprae; the third was not infected. In one of the infected animals there was histopathological evidence of lepromatous leprosy as evidenced by a chronic inflammatory infiltrate at the limbus, and detection of acid-fast bacilli in the corneal stroma, blood vessel walls, and corneal nerves. The latter were damaged as a result of the bacillary invasion. Electron microscopy revealed involvement and distortion of keratocytes with M. leprae and invasion of the corneal stroma by macrophages containing bacilli. Both infected animals showed focal collections of lymphocytes in the superficial stroma of the conjunctiva and in the ciliary body. This is the first report of the ocular manifestations of leprosy in any primate, including man, in which the duration of infection is known.

Experimental leprosy in a rhesus monkey: necropsy findings.

A 6-month-old male rhesus monkey (Macaca mulatta) was inoculated intravenously and intracutaneously with Mycobacterium leprae obtained from a naturally infected mangabey monkey. The animal developed generalized lepromatous leprosy, and was killed for pathological examination 56 months after inoculation. Lesions were observed in the skin, nasal mucosa, peripheral nerves, and peripheral lymph nodes, with relative sparing of viscera. The monkey was carefully evaluated for the retrovirus STLV-III infection and was found negative. The rhesus monkey thus provides another animal model for the study of leprosy.