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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Soluble antigen was prepared from adult worms and microfilariae of Onchocerca volvulus. In 27 patients clinically characterized as having generalized type (17) and localized reaction type (10) onchocerciasis, the response to this antigen was assessed in vivo by skin testing and in vitro by leucocyte migration inhibition assay. Three varieties of skin hypersensitivity were observed: Immediate, Arthus-type and delayed or type IV hypersensitivity. The first 2 occurred in all patients, but type IV hypersensitivity was noted only in 10, eight of whom had localized reactive type onchocerciasis, whilst the other 2 had mild generalized lesions which had for the most part healed with treatment. The leucocyte migration inhibition assay showed a spectrum of responsiveness with significant inhibition in the presence of antigen in 8 patients with localized lesions and in 2 others with mild generalized disease which had largely healed.--The specificity of the skin reaction and leucocyte migration inhibition to the antigen used was confirmed by the results obtained when a control group of 18 subjects, with no evidence of previous filarial infection, was similarly tested. 16 of them showed no skin hypersensitivity and 2 had a doubtful immediate reaction. No significant inhibition of leucocyte migration in the presence of antigen was noted in this group.
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PMID:Immunological studies on onchocerciasis. Varying skin hypersensitivity and leucocyte migration inhibition in a clinical spectrum of the disease. 3 81

Soluble antigen preparations were made from Onchocerca volvulus adults recovered from subcutaneous nodules, and from Necator americanus third-stage larvae. Intradermal skin tests were carried out on a total of 100 individuals clinically classified as having either the generalized form of onchocerciasis (86 cases, or the localized sowda form (14 cases). 91 of the people studied produced immediate reactions to the onchocercal antigen, but only those with sowda showed delayed reactions, though one person with generalized disease showed a doubtful delayed reaction. Reactions to N. americanus antigen, both immediate and delayed, were seen in both forms of the disease. The lack of delayed skin reaction in the generalized form of onchocerciasis is discussed, and a comparison is made with other diseases. Preliminary evidence for the existence of a true spectrum of clinical and immunological forms of onchocerciasis is suggested by one case in this study.
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PMID:Variation in delayed hypersensitivity in onchocerciasis. 70 43

Leucocyte adherence to infective larvae of Onchocerca volvulus in the presence of serum was evaluated using sera from four clinically distinct groups of patients with Onchocerciasis from an area hyperendemic for the disease. Significant cellular adherence to infective larvae occurred for the most part in the presence of sera obtained from subjects with either no microfilaridemia and few or no palpable nodules. These patients had, as well, the highest serum titres of specific anti-O. volvulus IgG antibodies. In contrast, sera from subjects with many palpable nodules and heavy skin infiltration with microfilariae (generalised disease) did not mediate significant adherence of leucocytes to infective larvae targets. Further, this group had the lowest serum levels of specific anti-O. volvulus antibodies of the IgG isotype. The findings are in keeping with the hypothesis that specific protective immunity may occur in O. volvulus infections.
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PMID:Immunity to Onchocerca volvulus. Serum mediated leucocyte adherence to infective larvae in vitro. 274 Jul 26

Circulating immune complexes were detected in sera of patients with both localized and generalized onchocerciasis by a 125I-Clq binding assay but not by the IgG latex agglutination inhibition method. Gel filtration of sera demonstrated high molecular weight Clq-reactive material(greater than 2 x 10(6) Daltons) which contained IgM but no IgG. Antibody titres to Onchocerca volvulus antigen were higher in patients with generalized disease than in those with the localized form. The lack of correlation between antibody titres and levels of immune complexes suggests that these immune complexes contain antigens other than those derived exclusively from the parasite. Although few of the symptoms of this disease are likely to be due to deposition of circulating immune complexes, the depression of delayed hypersensitivity reactions to the parasite found in patients with generalized onchocerciasis may be due to IgM immune complexes exerting an immuno-regulatory role on T cell function.
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PMID:Circulating immune complexes in onchocerciasis. 737 29

Human infections with the tissue nematode Onchocerca volvulus result in a variety of clinical conditions that possibly include protective immunity. In a West African area hyperendemic for human onchocerciasis, 120 residents were classified according to clinical and laboratory findings as presenting with generalized onchocerciasis, localized onchocerciasis, or as being putatively immune. The three groups differed in the distribution of HLA-D variants as determined by DNA typing. The most pronounced differences were found among alleles of the DQ loci. The haplotype DQA1*0501-DQB1*0301 was significantly more frequent among putatively immune individuals than among patients with generalized or localized disease. Conversely, DQA1*0101-DQB1*0501 and, independently, the allele DQB1*0201 were more frequent in generalized disease than in localized disease or putative immunity. In these correlations, the frequencies of allelic variants were in localized disease intermediate to those of the two other groups. The only distinct association found with localized disease was that of the DP allele DPB1*0402. The findings indicate that HLA-D variants influence the course of O. volvulus infection and help to define a state that may reflect protective immunity.
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PMID:HLA-D alleles associated with generalized disease, localized disease, and putative immunity in Onchocerca volvulus infection. 805 11

Onchocerciasis, also known as "river blindness", presents a plenum of clinical manifestations which vary from one individual to another, and from one area to another. This large spectrum of clinical manifestations of the disease is an indication of the complexity of the pathogenesis of onchocerciasis and suggests that many interacting factors might influence the clinical features of the disease. The present study has focused on the heterogenicity of the host immune response as a plausible explanation for differences in clinical manifestations of the infection. Host genetic factors, namely HLA genes, might play an important role in determining the nature of the immune response mounted against the parasite Onchocerca volvulus, and thus the development of different manifestations of the infection. Genetic diversity of onchocerciasis was assessed in different endemic foci in Cameroon. In order to investigate the possibility that the Major Histocompatibility Complex (MHC) genes might be associated with the different clinical types of onchocerciasis, 146 subjects living in three endemic areas of Cameroon were studied. They were classified in four groups: A (asymptomatic subjects), P (putatively immune subjects) L (patients with localised disease) and G (patients with generalised disease). The four groups differed in the distribution of HLA class II alleles as determined by Direct Heteroduplex Analysis. On the one hand, allele HLA-DQA1*0501 appeared to be associated with protection against severe onchocerciasis; on the other, allele HLA-DQB1*0201 might play an important role in the severe form of the disease.
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PMID:[Variations under genetic control of onchocerca infection as a function of clinical profile in the endemic center of Cameroon]. 1039 95

In recent years, associations of particular factors of the human leukocyte antigen (HLA) system with two major infectious diseases of tropical countries have been recognized: common West African HLA antigens are associated with protection from severe Plasmodium falciparum malaria, and HLA-D alleles are associated with generalized disease, localized disease and putative immunity in Onchocerca volvulus infection. Here, Christian Meyer and Peter Kremsner summarize current information on the involvement of HLA factors in P. falciparum malaria and O. volvulus infection, and briefly report on HLA-related immunological characteristics of various conditions in these infectious diseases.
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PMID:Malaria and onchocerciasis: On HLA and related matters. 1527 11