title: Long-term persistence of cellular hyporesponsiveness to filarial antigens after clearance of microfilaremia.
abstract: The persistence of parasite-specific cellular hyporesponsiveness after clearance of blood microfilariae (mf) was studied in 18 individuals who had been treated with a single dose of ivermectin, diethylcarbamazine, or a combination 2-3 years previously and who had initially cleared their parasitemia. At recruitment into the present study, 50% were again mf+ and 50% remained mf-. There were no significant differences between the mf+ and mf- groups in the amount of interferon-gamma (IFN-gamma) produced by peripheral blood mononuclear cells in response to adult or microfilarial antigens, although IFN-gamma production in response to purified protein derivative was greater in the mf+ group (geometric mean [gm] = 3,791 pg/ml; P = 0.02) than in the mf- group (gm = 600 pg/ml). These data suggest that although microfilaremic individuals may temporarily regain the ability to produce IFN-gamma to parasite antigens post-treatment, they subsequently revert to a state of hyporesponsiveness to mf-containing antigens that appears to be independent of the recurrence of microfilaremia and the response to nonparasite antigens.
authors.affiliation: Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: R
authors.initials: R
authors.lastname: Gopinath
authors.forename: L E
authors.initials: LE
authors.lastname: Hanna
authors.forename: V
authors.initials: V
authors.lastname: Kumaraswami
authors.forename: S V
authors.initials: SV
authors.lastname: Pillai
authors.forename: V
authors.initials: V
authors.lastname: Kavitha
authors.forename: V
authors.initials: V
authors.lastname: Vijayasekaran
authors.forename: A
authors.initials: A
authors.lastname: Rajasekharan
authors.forename: T B
authors.initials: TB
authors.lastname: Nutman
mesh_terms: D000328:Adult; D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D004049:Diethylcarbamazine / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D005368:Filariasis / Q000188:drug therapy / Q000276:immunology* / Q000469:parasitology; D005369:Filaricides / Q000627:therapeutic use; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D015848:Interleukin-5 / Q000096:biosynthesis*; D007559:Ivermectin / Q000627:therapeutic use; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008842:Microfilariae / Q000276:immunology; D018512:Parasitemia / Q000469:parasitology; D014373:Tuberculin / Q000276:immunology; D014958:Wuchereria bancrofti / Q000276:immunology*
chemical_list: D000947:Antigens, Helminth; D005369:Filaricides; D015848:Interleukin-5; D014373:Tuberculin; D007559:Ivermectin; D007371:Interferon-gamma; D004049:Diethylcarbamazine