RESUMO
Resistance to intracellular pathogens such as Mycobacterium leprae is dependent upon an effective T helper type 1 (Th1)-type immune response. On the other hand, intestinal helminths are known to subvert the host's immune response towards to either a Th2-type immune response or a regulatory T cell up-regulation, which may affect the host's ability to mount an effective response to mycobacteria. Here, we report a significant association between intestinal helminth infections and lepromatous leprosy [odds ratio (OR), 10.88; confidence interval (CI) 95%: 4.02-29.4; P<0.001]. We also observed that the frequency of intestinal helminths correlated strongly with the mycobacterial index (r=0.982, P<0.01). Corroborating with our hypothesis, intracellular levels of interferon-gamma were decreased significantly in leprosy patients co-infected with intestinal helminths when compared to leprosy patients without worms. Conversely, lepromatous leprosy patients with intestinal worms produced higher levels of both interleukin (IL)-4 and IL-10. Our results suggest that a pre-existing infection by intestinal helminths may facilitate the establishment of M. leprae infection or its progression to more severe forms of leprosy.
Assuntos
Enteropatias Parasitárias/imunologia , Hanseníase Virchowiana/imunologia , Hanseníase Tuberculoide/imunologia , Células Th1/imunologia , Adolescente , Adulto , Idoso , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/farmacologia , Antígenos de Helmintos/imunologia , Antígenos de Helmintos/farmacologia , Brasil/epidemiologia , Estudos de Casos e Controles , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/imunologia , Comorbidade , Progressão da Doença , Feminino , Humanos , Interferon gama/sangue , Interleucina-10/sangue , Interleucina-4/sangue , Enteropatias Parasitárias/sangue , Enteropatias Parasitárias/complicações , Enteropatias Parasitárias/epidemiologia , Hanseníase Virchowiana/sangue , Hanseníase Virchowiana/complicações , Hanseníase Virchowiana/epidemiologia , Hanseníase Tuberculoide/sangue , Hanseníase Tuberculoide/complicações , Hanseníase Tuberculoide/epidemiologia , Leucócitos Mononucleares/química , Ativação Linfocitária/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Mycobacterium leprae/imunologia , Prevalência , Estudos Prospectivos , Fatores de Risco , Adulto JovemRESUMO
Intestinal helminths are known to subvert the host's immune response towards a Th2 response, which in turn may lead to both eosinophilia and high immunoglobulin E titers often associated with these parasites. Mycobacterium leprae infection may lead to different clinical and pathological forms. Multibacillary forms are associated with Th2 cytokines, whereas paucibacillary forms are associated with Th1 cytokines. We report a significantly higher frequency of intestinal helminthic infections in patients with the lepromatous form, a multibacillary form of leprosy (odds ratio, 2.99; 95% confidence interval, 1.82-4.95; P = 0.006) when compared with patients with paucibacillary leprosy or to a control group without leprosy. A direct correlation was also found between mycobacterial index and the frequency of intestinal helminths. Our results suggest that the presence of intestinal helminths may facilitate the establishment of M. leprae infection or the progression to more severe forms of leprosy.