RESUMEN
Two patients, a 34-year old man-to-woman transsexual and a 32-year-old man, with aids presented with pulmonary symptoms, fever, serious weight loss and an oral ulcer. A third patient, a 16-year-old boy, had signs of transverse myelitis and meningitis without immunodeficiency. All were South American citizens and had disseminated histoplasmosis. After antifungal treatment they recovered, although the third patient remained a wheelchair user. If pulmonary or miliary tuberculosis is suspected in a patient originating from South America, histoplasmosis should be considered. Oral ulcers and skin lesions can be diagnostic clues. Specific stainings of direct preparations and longer-lasting cultures of various materials, especially of biopsy samples, then provide the diagnosis.
Asunto(s)
Histoplasmosis/complicaciones , Histoplasmosis/diagnóstico , Infecciones Oportunistas Relacionadas con el SIDA/microbiología , Adolescente , Adulto , Antifúngicos/uso terapéutico , Diagnóstico Diferencial , Femenino , Histoplasmosis/tratamiento farmacológico , Histoplasmosis/etnología , Humanos , Masculino , Meningitis/microbiología , Mielitis Transversa/microbiología , Neumonía/microbiología , América del Sur/etnología , Estomatitis Aftosa/microbiología , Resultado del Tratamiento , Tuberculosis/diagnósticoRESUMEN
The ROP2 protein of Toxoplasma gondii possesses immunological and biological properties which have led to its proposal as a vaccine candidate. To identify epitopes recognized by human T cells in the ROP2 antigen, we submitted the sequence of this protein to three reported T-cell epitope prediction algorithms. Three sequences that were predicted by all three methods were selected (sequences 197 to 216, 393 to 410, and 501 to 524), and the corresponding peptides were synthesized. The peptides were first tested in a proliferation assay with a DPw4-restricted, ROP2-specific human T-cell clone, and the peptide corresponding to residues 197 to 216 was shown to stimulate the T-cell clone. The three peptides were further tested in proliferation assays with peripheral blood mononuclear cells from a panel of T. gondii-seropositive and -seronegative individuals. We found that cells from a high proportion of the seropositive donors (64%) recognized at least one of the three peptides. The most frequently recognized ones were peptides 197 to 216 (45%) and 501 to 524 (36%). None of the seronegative donors responded to any peptide. These results show that the ROP2 antigen of T. gondii contains T-cell epitopes recognized by a high percentage of the immune population and further strengthen its potential as a vaccine candidate.