ABSTRACT
ABSTRACT INTRODUCTION: Human leukocyte antigens (HLA) are molecules that present antigen to the immune system; their presence or absence have been described as an influential factor in some diseases. HLA-B*27 is an HLA polymorphism that has been associated with increased susceptibility to ankylosing spondylitis (AS) and other spondyloarthropaty. The detection of HLA-B*27 has been used as diagnostic and prognostic tool in these cases, as well as in the differential diagnosis of other diseases. OBJECTIVE: Standardize the single specific primer-polymerase chain reaction (PCR-SSP) methodology for use in the Immunogenetics Laboratory of the Universidade Estadual de Maringá (UEM), considering its specificity and cost-effectiveness. MATERIAL AND METHODS: A total of 30 individuals without AS positive for HLA-B*27 allele and 10 AS negative individuals, were previously tested by PCR-sequence specific oligonucleotide (PCR-SSO) and, in this study, by PCR-SSP. RESULTS: One hundred percent of the patients tested confirmed their results, even with different subtypes. CONCLUSION: Considering the high reproducibility and the broad spectrum of subtypes covering, it was concluded that the PCR-SSP identifying method for HLA-B*27 can be used as a routine diagnostic tool for spondyloarthropathies.
RESUMO INTRODUÇÃO: Os antígenos leucocitários humanos (HLA) são moléculas que apresentam antígenos ao sistema imune; a presença ou a ausência deles é descrita como fator influente em algumas doenças. O HLA-B*27 é um polimorfismo do HLA que tem sido associado à maior predisposição à espondilite anquilosante (EA) e a outras espondiloartropatias. A detecção do HLA-B*27 é utilizada como ferramenta diagnóstica e prognóstica nesses casos, assim como no diagnóstico diferencial de outras doenças. OBJETIVO: Padronizar a metodologia de reação em cadeia da polimerase-iniciador específico (PCR-SSP) para utilização no Laboratório de Imunogenética da Universidade Estadual de Maringá (UEM), considerando sua especificidade e seu custo-benefício. MATERIAL E MÉTODOS: Foram utilizados 30 indivíduos comprovadamente sem EA positivos para o alelo HLA-B*27 e 10 indivíduos negativos, testados previamente por PCR-oligonucleotídeo específico (PCR-SSO) e, neste estudo, por PCR-SSP. RESULTADOS: Cem por cento dos pacientes testados tiveram seus resultados confirmados, mesmo com diferentes subtipos. CONCLUSÃO: Tendo em vista a alta reprodutibilidade e o amplo espectro de subtipos que abrange, concluiu-se que a técnica de identificação de PCR-SSP para o HLA-B*27 pode ser utilizada como auxílio diagnóstico de rotina para espondiloartropatias.
ABSTRACT
Dengue is an infectious disease of viral etiology transmitted by the mosquitoes Aedes aegypti, A. albopictus, and A. scutellaris. It can develop either as a benign form or as a severe hemorrhagic form. Previous work showed an association of the hemorrhagic form with human leukocyte antigens (HLA), suggesting a role of genetic factors in disease susceptibility. Nevertheless, data on HLA association with the classical form of the disease is scarce in literature. Sixty-four patients and 667 normal individuals, living in the state of Paraná, Southern Brazil, were used as test and control group, respectively. The patients developed the disease during a virus 1 dengue outbreak either in Maringá city in 1995 (47) or in Paranavaí city in 1999 (17). The diagnostic was confirmed through serology and/or viral culture. HLA class I and II typing was performed by the classical microlynfocitotoxicity test using monoclonal antisera and fluorobeads. Qui-square statistical analysis confirmed a positive association with HLA-DQ1 (76.6 percent vs 57.7 percent; p = 0.005243; pc = 0.026215). HLA-DR1 also presented an increased frequency in the test group, not statistically significant after p correction though (32.8 percent vs 15.9 percent; p = 0.005729; pc = 0.080206). In conclusion, genetic factors may play a role on the susceptibility to the classical dengue, virus 1, in the Brazilian population. Further independent studies should be performed in the Brazilian population to confirm these preliminary data.