Morphological characteristics of the reversed halo sign that may strongly suggest pulmonary infarction.

AIM: To analyse the morphological characteristics of the reversed halo sign (RHS) on unenhanced chest computed tomography (CT), which raise suspicion of pulmonary infarction (PI) associated with pulmonary embolism (PE), and to compare these characteristics with those observed in the RHS caused by other diseases. MATERIAL AND METHODS: CT images of 145 patients (250 RHSs) were reviewed retrospectively. Sixty-four patients had the RHS due to PI; in 81 immunocompetent patients, the RHS was caused by alternative pulmonary diseases. All PIs secondary to PE were confirmed at CT angiography. Other diagnoses were confirmed using published criteria. Two independent thoracic radiologists, who were blinded patient demographics, clinical data, and final diagnoses, analysed the morphological CT features of the RHSs. RESULTS: Seventy-four RHSs were found in the PI group and 176 RHSs in the group of other diseases. Single RHSs were associated more frequently with PI compared with the group without PIs; three or more lesions were seen only in patients with other diseases. Low-attenuation areas inside the RHS, with or without reticulation, were observed in 94.59% of PI-associated lesions, and in no patient in the group without PI (p<0.001). Subpleural involvement (p<0.001) and lower-lung predominance (p=0.001) were also associated more frequently with PI. Pleural effusion was observed in 64.06% of patients with PI and in only 6.17% of those with other diseases (p<0.001). CONCLUSIONS: A single RHS with low-attenuation areas inside the halo, with or without reticulation, is highly suggestive of PI. Lower-lung predominance and pleural effusion also suggest PI.

Spontaneous cell proliferation is associated with poor sensitivity to glucocorticoids in patients infected with HTLV.

BACKGROUND: Human T-cell lymphotropic viruses (HTLV)-I/II have a special tropism for infecting T cells and inducing spontaneous lymphocyte proliferation. Leukaemia and neurological manifestations are associated with HTLV-I/II infections, and treatment is usually based on anti-inflammatory drugs including glucocorticoids. Although steroid resistance has been reported, it is unknown whether this condition is related to the infection itself or to the treatment. OBJECTIVE: We investigated whether spontaneous cell proliferation is associated with T-cell sensitivity to glucocorticoids. MATERIALS AND METHODS: Twenty-eight HTLV-I/II patients and 11 healthy age-matched controls took part in this study. Lymphocytes were isolated and cultured in vitro to measure spontaneous and mitogen-induced proliferation as well as cellular sensitivity to dexamethasone. RESULTS: Patients with HTLV-I/II infection showed similar stimulated and unstimulated T-cell proliferation as well as comparable sensitivity to dexamethasone in vitro. There were no group differences in the frequency of glucocorticoid responders versus non-responders. However, T cells of patients with spontaneous proliferation were unresponsive to mitogenic stimulation and were remarkably more resistant to dexamethasone than cells of patients with normal proliferation. CONCLUSION: These data suggest that the poor clinical response to steroids may be associated with spontaneous cell proliferation during HTLV infection.

Molecular epidemiology of human T-cell leukemia virus type I (HTLV-1) Brazil: the predominant HTLV-1s in South America differ from HTLV-ls of Japan and Africa, as well as those of Japanese immigrants and their relatives in Brazil.

To better understand the origin of human T-cell leukemia virus type l (HTLV-l) in South America, we conducted a phylogenetic study on 27 new HTLV-ls in Brazil. These were obtained from Brazilians of various ethnic origins, such as Japanese immigrants, whites, blacks and mulattos. We amplified and sequenced proviral DNAs of a part of the long terminal repeats. Phylogenetic trees revealed that all but 6 of the new isolates were not only similar to each other but also similar to HTLV-ls of other South American countries, including those from Amerindians. However, the isolates differed from the HTLV-ls of Africa and Japan. The other six isolates were from Japanese immigrants and were phylogenetically almost identical to HTLV-ls in Japan but different from the majority of South American HTLV-ls, including the other new Brazilian HTLV-ls. These findings indicate that the recent introduction of HTLV-1 from Japan is limited to Japanese immigrants. In addition, the results do not support the prevailing hypothesis that HTLV-ls in South America were introduced by blacks who were brought from Africa as slaves. Rather, these results suggest that the majority of HTLV-1s prevailing in South America have spread from Amerindians, some of whom are likely to have possessed this human retrovirus from the beginning of their settlement in South America.

Anticorpos "anti-human T lymphotropic" vírus tipos I e II (HTLV-I/II) em pacientes com artrite reumatóide / Antibodies anti-human T lymphotropic virus types I and II (HTLV-I/II) in pacients with rheumatoid arthritis

HTLV-I/II são oncorretrovírus associados à leucemia de células T do adulto e à mielopatia crônica progressiva. Poliartrite crônica simétrica e complexo sicca são eventualmente encontrados em casos de infecções por HTLV-I/II. Um recente estudo japonês evidenciou prevalência de 20 por cento de anticorpos anti-HTLV-I em pacientes com artrite reumatóide (AR), um achado significante comparativamente a controles de banco de sangue. Tanto quanto os autores sabem, não há estudos brasileiros a esse respeito. Objetivo: Avaliar a prevalência de anticorpos anti-HTLV-I/II em pacientes com AR, usando um ensaio enzimático (ELISA) e, quando necessário, Western blot para confirmação de positividade. Métodos: Foram estudados 69 pacientes com AR (55 mulheres e 14 homens, todos caucasóides), diagnosticados de acordo com os critérios do Colégio Americano de Reumatologia. A média de idade dos pacientes foi de 51 anos, e a duração média da doença, de 8 anos. Os soros desses pacientes foram inicialmente testados para anticorpos anti-HTLV-I/II em ELISA de segunda geração (Ortho). A positividade foi confirmada através de Western blot (Gene Labs, kit 2.4). Os grupos-controles consistiram de 1.416 doadores de banco de sangue testados por ELISA e 33 pacientes consecutivos com lúpus eritematoso sistêmico (LES), também testados em ELISA. O teste de Fisher foi utilizado para análise estatística, sendo valores de p<0,05 considerados relevantes. Resultados: Anticorpos anti-HTLV-I/II foram detectados em 5 dos 69 pacientes com AR através de ELISA (7 por cento). Destes, 4 (5,7 por cento) tiveram resultados confirmatórios para anti-HTLV-I em Western blot. Os 4 pacientes eram soropositivos para fator reumatóide, mas nenhum apresentava doença ativa. Nos doadores de sangue, 18 soros (1,27 por cento) foram positivos para anti-HTLV-I/II em ELISA (p=0,004, significativo em relação ao grupo com AR testado em ELISA). Nos pacientes com LES, nenhum caso de positividade foi encontrado em ELISA (p=0,07, insignificante em relação aos pacientes com AR). Conclusão: No estudo, a prevalência de anticorpos contra HTLV-I/II em pacientes com AR foi estatisticamente relevante quando comparada com a de doadores de sangue, mas não-significativa quando comparada com a de pacientes com LES. O papel da infecção por HTLV-I/II na AR deve ser clareado em estudos adicionais

HTLV-I-associated myelopathy/tropical spastic paraparesis in Brazil: a nationwide survey. HAM/TSP Brazilian Study Group.

To study the epidemiology of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Brazil, we conducted a nationwide survey between March 1994 and April 1995. Five centers from three regions of the country participated, enrolling 163 patients. Most patients came from the northeastern and southeastern regions (93.2%). Most enrollees were white women, 42.9% and 64.4%, respectively. The most common risk factors for infection included a history of venereal diseases (30.6%) and blood transfusion (21.6%). The median age at the beginning of the disease was 42 years. The main neurologic findings were spastic paraparesis, widespread brisk tendon jerks, bilateral Babinski's sign, and bladder dysfunction. Some interregional differences reached statistical significance. The ratio of females over males increased from south to north. In addition, in both southern and southeastern regions, whites prevailed, whereas in the northeast, mulattos predominated. This follows the normal distribution of the population in these regions. A significantly higher rate of venereal diseases was found in the southeast compared with the other regions studied. A history of intravenous drug use was more frequent among patients as the sample moves south. Finally, a fluctuating course of the disease was proportionally more frequent in the southern region.

HTLV-I associated myelopathy in Porto Alegre (Southern Brazil).

HTLV-I associated myelopathy/tropical spastic paraparesis (TSP/HAM) have been increasingly described in practically all regions of Brazil. Five confirmed and documented cases of patients with TSP/HAM in Rio Grande do Sul are reported; in all of them spastic paraparesis, neurogenic bladder and superficial and/or profound sensitive disorders were observed in variable degrees. One patient presented a relapsing-remitting course with a cerebellar ataxia (multiple sclerosis-like pattern). Everyone was submitted to clinical, serological, urodynamic, neurophysiologic and neuroradiologic investigation. The aim of this study was to present the southern region of Brazil as an area with significant endemicity for HTLV-I/II infection (prevalence of 0.42% between blood donors), and also to show the existence of patients with neurologic disease associated with this retrovirus.