MHC Class I Chain-Related Gene A Polymorphisms and Linkage Disequilibrium with HLA-B and HLA-C Alleles in Ocular Toxoplasmosis

This study investigated whether polymorphisms of the MICA (major histocompatibility complex class I chain-related gene A) gene are associated with eye lesions due to Toxoplasma gondii infection in a group of immunocompetent patients from southeastern Brazil. The study enrolled 297 patients with serological diagnosis of toxoplasmosis. Participants were classified into two distinct groups after conducting fundoscopic exams according to the presence (n = 148) or absence (n = 149) of ocular scars/lesions due to toxoplasmosis. The group of patients with scars/lesions was further subdivided into two groups according to the type of the ocular manifestation observed: primary (n = 120) or recurrent (n = 28). Genotyping of the MICA and HLA alleles was performed by the polymerase chain reaction-sequence specific oligonucleotide technique (PCR-SSO; One Lambda®) and the MICA-129 polymorphism (rs1051792) was identified by nested polymerase chain reaction (PCR-RFLP). Significant associations involving MICA polymorphisms were not found. Although the MICA*002~HLA-B*35 haplotype was associated with increased risk of developing ocular toxoplasmosis (P-value = 0.04; OR = 2.20; 95% CI = 1.05–4.60), and the MICA*008~HLA-C*07 haplotype was associated with protection against the development of manifestations of ocular toxoplasmosis (P-value = 0.009; OR: 0.44; 95% CI: 0.22–0.76), these associations were not statistically significant after adjusting for multiple comparisons. MICA polymorphisms do not appear to influence the development of ocular lesions in patients diagnosed with toxoplasmosis in this study population.     

Single nucleotide polymorphisms in the interferon gamma gene are associated with distinct types of retinochoroidal scar lesions presumably caused by Toxoplasma gondii infection

The association of single nucleotide polymorphisms (SNPs) in the interferon (IFN)-γ gene ( IFNG ) with different types of retinal scar lesions presumably caused by toxoplasmosis were investigated in a cross-sectional population-based genetic study. Ten SNPs were investigated and after Bonferroni correction, only the associations between SNPs rs2069718 and rs3181035 with retinal/retinochoroidal scar lesions type A (most severe scar lesions) and C (least severe scar lesions), respectively, remained significant. The associations of two different IFNG SNPs with two different types of retinal lesions attributable to toxoplasmosis support the hypothesis that different inflammatory mechanisms underlie the development of these lesions. The in vitro analysis of IFN-γ secretion by peripheral blood mononuclear cells stimulated with Toxoplasma gondii antigens was also investigated. The association between SNP rs2069718 and type A scar lesions revealed that differential IFN-γ levels are correlated with distinct genotypes. However, no correlation was observed with IFN-γ secretion levels and the SNP rs3181035 , which was significantly associated with type C scar lesions. Our findings strongly suggest that immunogenetic studies of individuals with congenital or postnatally acquired infection are needed to better understand the role of IFN-γ and its polymorphisms in the pathogenesis of ocular toxoplasmosis.     

New prospects in immunology of toxoplasmosis: skin-tests for control of immunity and immuno-assays and agglutination tests for the detection of specific IgM antibodies

An excretory-secretory (ES) antigen was extracted from supernatants of cell cultures infected with Toxoplasma gondii, purified and controlled according to current standards. In 638 volunteers, the correlation with fluorescent antibody was 94.2% and no false positive skin tests were noted. The skin test did not transform an originally negative serological test into a positive one. For the prevention of congenital toxoplasmosis, this sensitive, specific and inexpensive skin test can be widely used for the detection of immunity to Toxoplasma in women before their first pregnancy. During pregnancy, the detection of specific IgM is very important for the diagnosis of a recently acquired toxoplasmosis and allows for an immediate treatment. For this detection and for the diagnosis of congenital toxoplasmosis, five different serological tests were compared: Indirect Fluorescent Antibody-test (IFA), ELISA test, ELISA test After Capture of IgM (ACCAs), Reverse Enzyme Immuno Assay R-EIA), Double-Sandwich Enzyme Linked ImmunoSorbent Assay (DS-ELISA) and ImmunoSorbent AGglutination Assay (ISAGA). For 37 sera of recently acquired toxoplasmosis, IgM were detected in 98.7% with ISAGA, in 89.5% with DS-ELISA and ELISA in 83% with R-EIA and in 59% with IFA test. The best specificity is obtained with ISAGA, DS-ELISA and R-EIA, from controls with non immune patients (99 cases), patients with chronic toxoplasmosis (77 sera), rheumatoid factors (35 sera) or anti-nuclear antibodies (7 sera). In 21 sera from infants with congenital toxoplasmosis, ISAGA was positive in 13 cases (62%), IFA in 5 cases (24%), ELISA and R-EIA in 2 cases (9.5%) and DS-ELISA in 9 cases (43%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Delayed Cerebral Toxoplasmosis in a Kidney Transplant Patient: a Case Report

Cerebral toxoplasmosis is often life-threatening in an immunocompromised patient due to delayed diagnosis and treatment. Several differential diagnoses could be possible only with preoperative brain images of cerebral toxoplasmosis which show multiple rim-enhancing lesions. Due to the rarity of cerebral toxoplasmosis cases in Korea, the diagnosis and treatment are often delayed. This paper concerns a male patient whose cerebral toxoplasmosis was activated 21 years post kidney transplantation. Brain open biopsy was decided to make an exact diagnosis. Cerebral toxoplasmosis was confirmed by immunohistochemistry and PCR analyses of the tissue samples. Although cerebral toxoplasmosis was under control with medication, the patient did not recover clinically and died due to sepsis and recurrent gastrointestinal bleeding.     

Toxoplasma gondii isolates: multilocus RFLP-PCR genotyping from human patients in Sao Paulo State, Brazil identified distinct genotypes

This study investigated the genetic characteristics of Toxoplasma gondii samples collected from 62 patients with toxoplasmosis in Sao Paulo State, Brazil. DNA samples were isolated from blood, cerebrospinal fluid and amniotic fluids of 25 patients with cerebral toxoplasmosis and AIDS, two patients with acute toxoplasmosis, 12 patients with ocular toxoplasmosis, six newborns with congenital toxoplasmosis and 17 pregnant women with acute infection. Diagnosis of toxoplasmosis was based in clinical, radiological and laboratory features. Genotyping was performed using multilocus PCR–RFLP genetic markers including SAG1, SAG2, 5′- and 3′-SAG2, alt.SAG2, SAG3, BTUB, GRA6, C22-8, c29-2, L358, PK1 and Apico. Among the 62 clinical samples, 20 (32%) were successfully genotyped at eight or more genetic loci and were grouped to three distinct genotypes. Eighteen samples belonged to ToxoDB Genotype #65 and the other two samples were identified as ToxoDB Genotypes #6 and #71, respectively (http://toxodb.org/toxo/). Patients presenting Genotypes #6 and #71 had severe and atypical cerebral toxoplasmosis, characterized by diffuse encephalitis without extensive brain lesions. These results indicate that T. gondii Genotype #65 may have a high frequency in causing human toxoplasmosis in Sao Paulo State, Brazil. This unusual finding highlights the need to investigate the possible association of parasite genotypes with human toxoplasmosis.     

IgG and IgM western blot assay for diagnosis of congenital toxoplasmosis

The aim of this study was to evaluate the utility of western blot (WB) analysis as a diagnostic tool for congenital toxoplasmosis in 215 newborn infants. The children were submitted to clinical examinations to assess macular, neurological and hearing signals. The WB results obtained were compared to the persistence of IgG antibodies at the end of 12 months, which is regarded as the "gold standard" diagnosis of congenital toxoplasmosis. Association between the WB results and the clinical signs presented by the infants was also assessed. Of the 215 children, 177 had a confirmed congenital toxoplasmosis diagnosis and 38 were uninfected. IgG-WB showed a sensitivity of 73.5% and a specificity of 97.4%. IgM-WB showed a sensitivity of 54.8% and a specificity of 94.7%. The IgG-WB and IgM-WB combination increased the sensitivity to 86.5%. The IgM-WB-positive children had a 1.4-fold greater risk of presenting active macular lesions than did those that were IgM-WB-negative. This study showed that the WB assay is a useful tool to confirm a diagnosis of congenital toxoplasmosis and that the IgM-WB-positive results can indicate active macular lesions in newborn infants.     

Toxoplasma gondii: P30 peptides recognition pattern in human toxoplasmosis

In this study, human sera reactivity against nine peptides derived from the Toxoplasma gondii P30 protein was assessed by ELISA in patients with different clinical forms of toxoplasmosis. Same as has been reported in mice, sera from congenital, ocular and chronic asymptomatic toxoplasmosis patients recognized more strongly peptides from the protein’s carboxy-terminus, being peptide 2017 (amino acids 301-320) the one most strongly recognized by sera from patients with ocular toxoplasmosis. Serum samples collected from 13 patients without ocular infection, 13 with inactive chorioretinal scars, 6 with active ocular infection and 10 seronegative individuals were then screened for anti-2017 IgG. Peptide 2017 was recognized by all patients’ samples but not by sera from T. gondii-seronegative individuals. No statistically significant differences were found between the absorbance levels of groups with and without lesions or with active or inactive ocular lesions, as determined by ANOVA.     

Carney complex and lentiginosis

Initially described as the ‘complex of myxomas, spotty skin pigmentation and endocrine overactivity,’ Carney complex (CNC) is known as an autosomal dominant multiple neoplasia syndrome involving skin and cardiac myxomas, pigmented skin lesions and endocrine tumors. Pigmented cutaneous manifestations in CNC are important diagnostically because they can be used for the early detection of the disease and, thus, the prevention of life‐threatening complications of CNC related to heart myxomas and endocrine abnormalities. Specific for the disease skin lesions are present in more than half of the CNC patients. A major challenge is to distinguish pigmented skin lesions associated with CNC from other skin pathology, and thus accurately estimate the risk of cancer in affected patients; curiously, patients with CNC do not appear to have predisposition to skin cancers whereas this is not the case with other genetic syndromes associated with melanotic and other cutaneous lesions. In this paper, we review the current knowledge on cutaneous pathology associated with CNC and the most recent data on the molecular basis of the disease.     

Disseminated toxoplasmosis in a Mediterranean pregnant Risso's dolphin (Grampus griseus) with transplacental fetal infection

Fatal disseminated toxoplasmosis was diagnosed in a Risso's dolphin (Grampus griseus) dam and its fetus on the basis of pathologic findings, immunohistochemistry, and structure of the parasite. The dolphin was stranded alive on the Spanish Mediterranean coast and died a few hours later. At necropsy the dam was in good condition. From the standpoint of pathology, however, it had generalized lymphadenomegaly and splenomegaly, enlargement of and multifocal hemorrhage in the adrenal glands, diffuse mucosal hemorrhage of the glandular and pyloric stomach, ulcerative glossitis and stomatitis, focal erosions and reddening of the laryngeal appendix, and severe paraotic sinusitis with intralesional nematodes Crassicauda grampicola. The dolphin was pregnant, most probably in the first gestational trimester. The most prominent microscopic lesions were multifocal granulomatous encephalomyelitis, diffuse subacute interstitial pneumonia, mild multifocal necrotizing hepatitis and nonsuppurative cholangiohepatitis, gastritis and adrenalitis, mild lymphoid depletion, medullary sinus and follicular histyocitosis, and systemic hemosiderosis. The fetus had foci of coagulative and lytic necrosis in the kidneys, the lung, and the heart. Most lesions were associated with tachyzoites and tissue cysts of Toxoplasma gondii. The diagnosis was confirmed immunohistochemically. This is the first report on toxoplasmosis in a Risso's dolphin (G. griseus) and on transplacental transmission to an early-stage fetus in any cetaceans.     

Genetic variants of Malassezia pachydermatis from canine skin: body distribution and phospholipase activity

Malassezia pachydermatis isolates (n=185) from skin sites from dogs (n=30) were characterized genetically and biochemically following in vitro culture. Two regions in the chitin synthase-2 gene (chs-2) and the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA were sequenced, and the phospholipase activity of each isolate was assessed. Three chs-2 (i.e. Ac, Bc and Cc) and eight ITS-1 (i.e. AI1, AI2, AI3, AI4, BI1, CI1, CI2 and CI3) sequence types were defined for all 185 samples. The findings revealed that multiple M. pachydermatis genotypes/subgenotypes could be cultured from healthy dogs or from dogs with single or multiple, generalized skin lesions. Subgenotypes AI1 and BI1 were associated with all skin sites of dogs sampled, whereas subgenotype CI2 was mostly linked to a particular location. Isolates derived from skin lesions showed a significantly higher phospholipase activity compared with those from skin sites with no detectable lesions. Genotype B was mainly cultured from healthy skin; only four isolates (9.3%) had low phospholipase activity, whereas other genotypes/subgenotypes were predominantly associated with skin lesions and had a high phospholipase activity. The results of the present study suggest that the distribution pattern of particular genotypes or subgenotypes of M. pachydermatis on the skin of dogs relates to the affinity of the yeast to the host and to particular skin sites.     

Clinical Features and Treatment of Ocular Toxoplasmosis

Ocular toxoplasmosis is a disease caused by the infection with Toxoplasma gondii through congenital or acquired routes. Once the parasite reaches the retina, it proliferates within host cells followed by rupture of the host cells and invasion into neighboring cells to make primary lesions. Sometimes the restricted parasite by the host immunity in the first scar is activated to infect another lesion nearby the scar. Blurred vision is the main complaint of ocular toxoplasmic patients and can be diagnosed by detection of antibodies or parasite DNA. Ocular toxoplasmosis needs therapy with several combinations of drugs to eliminate the parasite and accompanying inflammation; if not treated it sometimes leads to loss of vision. We describe here clinical features and currently available chemotherapy of ocular toxoplasmosis.     

An Epidemiologic Study of 100 Cases of Toxoplasmic Uveitis: Implications for Diagnosis and Prevention

An epidemiologic study of 100 patients with active chorioretinitis, positive Sabin-Feldman methylene-blue dye-test, and favourable response to antitoxoplasmic drugs (spiramycin) was undertaken to establish a basis for rapid clinical diagnosis and institution of preventive measures for toxoplasmic uveitis. Eighty-two of the 100 patients, but only 19 of 100 controls, gave positive histories of exposure to likely sources of toxoplasmosis, such as hunting and handling of wild game, ingestion of raw meat, etc. Seventy-six of these 82 patients had positive toxoplasmin skin tests, but all subsequently had positive dye-tests. The important practical conclusion was reached that all cases with active chorioretinitis, positive toxoplasmin skin test, or history of exposure to known reservoirs of toxoplasmosis should be treated immediately, as dye-tests in such cases will almost invariably be positive. This clinical approach greatly improves the visual prognosis of toxoplasmic chorioretinitis, since specific therapy need not be delayed for several weeks until the result of the dye-test is known.     

A comparative study of the role of domestic cats and dogs in the epidemiology of toxoplasmosis]

A total of 2643 persons in 5 different regions were examined for toxoplasmosis by the immunofluorescence test and toxoplasmin skin test. The presence in the house of cats and dogs was taken into account. In two of the five regions under study there was revealed an increased incidence of toxoplasmosis in persons keeping cats; this confirmed the role of these animals as a source of toxoplasmosis infection. The absence of such increase in the incidence of the disease in other regions in explained by the character of buildings admitting migration of cats or the presence in the given region of other active sources of infection. Toxoplasmosis incidence in persons who kept or didn't keep dogs displayed no significant difference.     

Toxoplasmosis, distemper, and herpesvirus infection in a skunk (Mephitis mephitis).

A striped skunk (Mephitis mephitis) showing abnormal behavior had histopathologic lesions of toxoplasmosis and canine distemper in addition to intranuclear, eosinophilic inclusions in the reticuloendothelial cells of the spleen, liver and lung. The inclusions, on electron microscopic examination, were compatible with herpesvirus infection.     

Lethal toxoplasmosis in an aviary of kakarikis (Cyanoramphus spp.) in Australia

A small outbreak of fatal toxoplasmosis is described in 6 kakariki (Cyanoramphus spp.) in an aviary in Australia. Toxoplasma gondii-like tachyzoites were found associated with necrosis in intestine, spleen, liver, and lungs. Protozoal tachyzoites reacted positively with T. gondii-specific polyclonal antibodies. This is the first report of toxoplasmosis in kakariki.     

Skin lesions caused by Dermophthirius penneri (Monogenea: Microbothriidae) on wild-caught blacktip sharks (Carcharhinus limbatus)

Skin lesions caused by the ectoparasite Dermophthirius penneri Benz, 1987 (Monogenea: Microbothriidae) on 2 wild-caught blacktip sharks (Carcharhinus limbatus) from the northern Gulf of Mexico were studied using light and scanning electron microscopy. Grossly, lesions appeared as multifocal, well-demarcated, ovoid or irregularly shaped, light gray patches of skin. Scanning electron microscopy of lesions revealed gaps between placoid scales apparently created by detachment and loss of placoid scales, rotated and tilted placoid scales with blunt distal tips and shallow ridges, and a frayed epithelium that covered some placoid scales and filled some spaces between placoid scales. Light microscopy of lesions revealed epithelial hyperplasia accompanied by dermal infiltrates of moderate numbers of loosely arranged lymphocytes interposed between collagen bundles in the superficial layers of the stratum compactum. This report provides the first details of microbothriid skin lesions on wild sharks. Our results indicate that D. penneri caused chronic skin lesions not associated with bacterial infection or severe, debilitating, skin disease in the studied sharks.     

Effects of prostaglandin E 2 on rat skin: inhibition of sterol ester biosynthesis and clearing of scaly lesions in essential fatty acid deficiency

Severe scaly lesions in the skin, especially in the feet and tail, of the rat were induced by feeding a diet deficient in essential fatty acids (EFA). Analysis of the fatty acids in skin lipids of these EFA-deficient rats showed a marked increase of monoenoic acids (16:1 and 18:1) and eicosatrienoic acid (20:3), with concomitant decreases of dienoic acid (18:2) and tetraenoic acid (20:4). Topical application of prostaglandin E(2) (PGE(2)) to the scaly lesions resulted in clearance of the lesions, but did not significantly alter the composition of fatty acids in the skin. Intraperitoneal injection of PGE(2) had no observable effect on the skin lesions. Furthermore, incubation of skin specimens from the EFA-deficient rats with (14)C-labeled glucose showed a 4-5-fold increase of incorporation of glucose carbon into lipid fractions, particularly the sterol esters, and a 3-4-fold increase in pentose cycle activity. Addition of PGE(2) to the incubation mixture resulted in approximately 70% inhibition of sterol ester biosynthesis by skin of the EFA-deficient rats. These results suggest that the effects of PGE(2) in clearing the scales may be associated with its inhibitory effect on abnormal sterol esterification in the skin of the EFA-deficient rats.     

Ocular impairment of toxoplasmosis

The purpose of this review is to update the latest information about ocular toxoplasmosis. The infection can be congenital or acquired, but also depends about the immune condition of the patient and can affect the eye. Ocular symptoms are variable according to the age of the subject. Retinochoroiditis is the most common manifestation of toxoplasmic infection. Toxoplasmic retinochoroiditis typically affects the posterior pole, and the lesions can be solitary or multiple. Active lesions present as grey-white focus of retinal necrosis with adjacent choroiditis, vasculitis, hemorrhage and vitreitis. Anterior uveitis is a common finding. Atypical presentations include punctate outer retinitis, neuroretinitis and papillitis. Depending on the patient's age and the localization of the lesion, ocular symptoms vary usually presenting with reduced visual acuity or without symptoms. The laboratory diagnosis of toxoplasmosis is based on detection of antibodies and T. gondii DNA using polymerase chain reaction (PCR) which fulfillis clinical findings. Toxoplasmosis therapy includes antimicrobial drugs and corticosteroids. There are several regimens with different drug combinations including, among others, pyrimethamine, sulfadiazine, clindamycin, and trimethoprim-sulfamethoxazol.     

A Survey of Toxoplasmosis Among Mentally Retarded Children

To determine what role, if any, toxoplasmosis plays in the mental retardation of children, sera from 345 mentally retarded children were tested for the presence of antibodies to Toxoplasma gondii. The serological tests employed were the complement-fixation, the Sabin-Feldman dye test and the immunofluorescence test. The donors were also skin-tested with toxoplasmin.Of 345 mentally retarded donors nine gave a positive skin reaction, 15 possessed complement-fixing antibodies, 21 had immunofluorescent antibodies and 45 had dye test antibodies to T. gondii.The incidence of antibodies to T. gondii in the mentally retarded group was approximately the same as in the normal control group of the same age, and less than in the group suspected of having toxoplasmosis. It is concluded that in the children in this study toxoplasmosis played little or no role as a predisposing factor in the occurrence of congenital mental deficiency.     

Toxoplasmosis II. Studies of Animal Sera Using Complement-Fixation Tests

Serological studies were performed in guinea pigs, a sheep, calf, goat and two pigs experimentally infected with toxoplasmosis. The direct complement-fixation method was effective in detecting antibodies in guinea-pig, goat and sheep sera. The modified complement-fixation technique supplementing complement with normal bovine serum fraction, was required when testing bovine serum. With swine sera best reactions occurred in the indirect complement-fixation test and definite but low grade reactions were produced in the direct test after pro-complementary activity was removed by pH treatment of the sera. Allergic skin reactions were produced in the experimental animals but improvement in the antigen is necessary before the test could be used generally in the field as a diagnostic method for animal toxoplasmosis.