5.2.4.4 Toxoplasmosis

Cryptogenic and asymptomatic infection of Toxoplasma gondii is common throughout the world. In patients with compromised immune system, particularly in AIDS, the parasite is activated, resulting in lethal Toxoplasma encephalitis. When primary infection occurs in pregnant women without serum antibody, the placental tissue is infected, causing congenital toxoplasmosis in the fetus [59]. Ruptured protozoan cysts of AIDS-associated cerebral toxoplasmosis were reactive with the serum from a healthy individual serologically with high-titer IgG. The same serum decorated trophozoites of T. gondii dispersed in the meningeal space in an aged HIV-negative female with progressive supranuclear palsy, confirming the diagnosis of Toxoplasma meningitis (Figure 35) [21, 22].

#### Figure 35.

antibody ACA5 to Acanthamoeba spp. (a gift from Prof. Hiroshi Tachibana, Department of Infectious Diseases, Tokai University School of Medicine, Isehara) [57].

Acanthamebic keratitis (left, H&E; center, reactivity with the serum of patient of acanthamebic meningoencephalitis; right, reactivity with monoclonal antibody ACA5 to Acanthamoeba sp.). Superficial keratectomy specimen from a young contact lens wearer reveals scattered amebic cysts (arrows) in the corneal stroma, and the microbes (cysts) are visualized by immunostaining using both the diluted patient's serum and

Indian-type cutaneous leishmaniasis (left, gross appearance of the neck; center, H&E; right, reactivity with patient's own serum; inset, Giemsa stain on a stamp cytology preparation). Solitary skin ulcer is characteristic of this clinical form endemic in India. Biopsy specimen from a Japanese patient shows numerous round pathogens (Leishmania tropica) in the cytoplasm of macrophages in the dermis. The diluted patient's own serum visualizes the pathogen. Giemsa preparation demonstrates a pair of the nucleus and kinetoplast (smaller dot) in

Amebic dysentery, colonic infection of Entamoeba histolytica, is endemic in areas

with poor sanitation and is often associated with AIDS [58]. Surgically resected colon specimen from an HIV-negative Japanese male patient demonstrated amebic trophozoites invading the ulcerated colon wall. As shown in Figure 34, the patient's own serum visualized the pathogen, and the localization was comparable with immunostaining using a monoclonal antibody EHK153 to E. histolytica (a gift from Prof. Yuji Tachibana, Department of Infectious Diseases, Tokai University School of

5.2.4.3 Amebic dysentery

the monoclonal antibody.

Figure 32.

Figure 33.

96

the protozoan cell.

Immunohistochemistry - The Ageless Biotechnology

Medicine, Isehara) [4, 20–23].

Toxoplasmosis (upper panels, toxoplasma encephalitis in AIDS; lower panels, toxoplasma meningitis in a non-AIDS patient; left, H&E; right, reactivity with the serum from a healthy individual serologically with high-titer IgG). Ruptured protozoan cysts in AIDS-associated cerebral toxoplasmosis are reactive with the serum. The same serum decorates trophozoites of Toxoplasma gondii (arrows) dispersed in the meningeal space in an aged HIV-negative female with progressive supranuclear palsy.
