Frequency and visual outcomes of ocular toxoplasmosis in an adult Brazilian population.

Although ocular toxoplasmosis is a leading cause of posterior uveitis worldwide, there is scarce information about the real-life frequency of ocular lesions, visual outcomes, and risk factors for poor prognosis. We conducted a community-based cross-sectional study with 721 adults living in Cássia dos Coqueiros, Southeast Brazil, consisted of visual acuity measurement, dilated ocular examination, a risk-factor questionnaire, and peripheral blood collection for anti-T. gondii serology. Presumed toxoplasmic lesions were recorded on video and analyzed by experienced and masked ophthalmologists. Ocular toxoplasmosis was determined if at least one suspected lesion was appointed by two graders in the presence of positive anti-T. gondii serology. Forty-eight eyes (n = 42 participants; 6.7% among those with positive anti-T. gondii serology) with ocular toxoplasmosis were found. Most lesions were single (n = 28; 58.3%), peripheral (n = 34; 77.1%) and unilateral (85.7% of participants); no active lesions were found. Older age was associated with lesions larger than one-disc diameter (p = 0.047), and lower social stratum (OR: 2.89; CI 1.2-6.97; p = 0.018) was associated with the presence of toxoplasmic lesions. Although there were no differences in visual acuity between participants and eyes with or without ocular lesions (p > 0.05), unilateral blindness associated with ocular toxoplasmosis was identified in a reduced number of individuals.

Variability at the 3' untranslated region of the HLA-G gene: a study on patients with AIDS and cytomegalovirus retinochoroiditis.

Cytomegalovirus retinochoroiditis (CMV-R) is the primary cause of blindness among AIDS patients. Since HLA-G is associated with the modulation of the immune response, we hypothesized that variability at the 3' untraslated region (3'UTR) of the gene could be implicated on the predisposition to CMV-R. We evaluated whether HLA-G 3'UTR influences CMV-R development in Brazilian AIDS patients. Peripheral blood DNA was obtained from two groups of patients: (1) AIDS exhibiting CMV-R (n = 40) and (2) AIDS without CMV-R (n = 147). HLA-G 3'UTR typing was performed using sequencing analysis. Allele, genotype and haplotype frequencies were evaluated using Fisher's exact test accompanied by the calculation of the odds ratio and its 95% confidence interval (95% CI). The etiologic (EF) and preventive fractions were also estimated. Compared to AIDS patients without CMV-R, AIDS patients with CMV-R showed increased frequencies of the: (1) + 3001T allele, (2) the + 3001C/T genotype and (3) the UTR-17 (InsTTCCGTGACG) haplotype (EFs = 0.02-0.04). The UTR-3 (DelTCCGCGACG) haplotype was associated with protection against CMV-R development. Although the risk for developing CMR-V at the population level was relatively low (EF), the identification of HLA-G 3'UTR variation sites may help to further evaluate the role of post-transcriptional factors that may contribute to the existent immunosuppresion caused by HIV per se.

HLA-C Alleles and Cytomegalovirus Retinitis in Brazilian Patients with AIDS.

PURPOSE: Since cytomegalovirus retinitis (CR) is an important cause of visual impairment among AIDS patients and HLA-C alleles have been associated with AIDS disease outcome, we typed HLA-C locus in patients with AIDS exhibiting or not CR. METHODS: Three groups of individuals were studied: (i) 49 patients with AIDS and CR (Group I), (ii) 161 patients with AIDS without CR (Group II), and (iii) 202 healthy HIV-negative individuals (Group III). HLA-C typing was performed using commercial kits. RESULTS: The HLA-C∗07 allele group was underrepresented in AIDS patients with CR (P=0.005) when compared to controls or when compared to AIDS patients without CR (P=0.006). The HLA-C∗05 allele group was overrepresented in Group II in comparison to Group III (P=0.017). The frequency of the HLA-C∗16 allele group was increased in Group III in comparison to Group II (P=0.004). CONCLUSION: The HLA-C∗07 allele group conferred protection against the development of CR in Brazilian AIDS patients, whereas the HLA-C∗05 and HLA-C∗16 allele groups were associated with AIDS susceptibility or protection, respectively.

Visual impairment and myopia in Brazilian children: a population-based study.

PURPOSE: To determine the frequency of myopia and other causes of visual impairment (VI) in individuals aged 10 to 15 years who live in a typical Brazilian city. METHODS: Random selection of geographically based clusters was performed to obtain a sample of children aged 10 to 15 years in Gurupi City, Tocantins, Brazil. From June to August 2007, children in 12 clusters were enumerated through a door-to-door survey. All children with an uncorrected visual acuity (VA) worse than 20/32 in either eye were scheduled for ophthalmologic evaluation, including VA and ocular motility testing, cycloplegic refraction, and external, biomicroscopic, and dilated funduscopic examinations. The primary cause of VI was determined for eyes with an uncorrected VA of 20/40 or worse. RESULTS: A total of 1590 children were examined; 814 (51%) were boys and 776 (49%) were girls. The prevalence of uncorrected, presenting and best-corrected VA of 20/40 or worse in the better eye was 5.72%, 2.83%, and 0.81%, respectively. The primary cause of VI in one or both eyes was refractive error in 65 (89%) of 73 children, amblyopia in 4 (5.5%) of 73 children, retinal disorders in 3 (4.1%) of 73 children, and congenital cataracts in 1 (1.4%) of 73 children. In this population, the prevalence of VI-related myopia was 3.14%. CONCLUSIONS: The prevalence of VI among children aged 10 to 15 years in this typical Brazilian city is low and similar to other school-based studies, and most of the VI is caused by uncorrected myopia.

Frequency of HLA class 1 and 2 alleles in Brazilian patients with AIDS and cytomegalovirus retinitis.

PURPOSE: To evaluate the human leucocyte antigen (HLA) class 1 (HLA-A and HLA-B) and HLA class 2 (HLA-DRB1 and HLA-DQB1) allele profiles in the susceptibility to cytomegalovirus retinitis (CMV-R) in patients with AIDS. METHODS: Cytomegalovirus retinitis was clinically diagnosed by indirect binocular ophthalmoscopy. Human leucocyte antigens class 1 were typed using a complement-dependent microlymphocytotoxicity assay, and HLA class 2 alleles were identified using amplified DNA hybridized to sequence-specific oligonucleotide primers. RESULTS: The frequencies of HLA class 1 antigens and HLA class 2 alleles observed in patients and controls were similar; however, HLA-A31 antigen was over-represented in patients with AIDS, independent of the presence of CMV-R. CONCLUSION: There was no association between HLA molecules/alleles and CMV-R in Brazilian patients with AIDS. However, the results support the role of the HLA system in the susceptibility to developing AIDS.