Chronic Immune Activation Associated with Chronic Helminthic and Human Immunodeficiency Virus Infections: Role of Hyporesponsiveness and Anergy

Abstract

Chronic immune activation is one of the hallmarks of human immunodeficiency virus (HIV) infection. It is present also, with very similar characteristics, in very large human populations infested with helminthic infections. We have tried to review the studies addressing the changes in the immune profiles and responses of hosts infected with either one of these two chronic infections. Not surprisingly, several of the immune derangements and impairments seen in HIV infection, and considered by many to be the “specific” effects of HIV, can be found in helminth-infected but HIV-noninfected individuals and can thus be accounted for by the chronic immune activation itself. A less appreciated element in chronic immune activation is the immune suppression and anergy which it may generate. Both HIV and helminth infections represent this aspect in a very wide and illustrative way. Different degrees of anergy and immune hyporesponsiveness are present in these infections and probably have far-reaching effects on the ability of the host to cope with these and other infections. Furthermore, they may have important practical implications, especially with regard to protective vaccinations against AIDS, for populations chronically infected with helminths and therefore widely anergic. The current knowledge of the mechanisms responsible for the generation of anergy by chronic immune activation is thoroughly reviewed

Tuberculin Skin-Test Reactions Are Unaffected by the Severity of Hyperendemic Intestinal Helminth Infections and Co-Infections

“…The present research extended this knowledge by showing that there was no association between TST results and low versus high helminth egg burden or co-infections with multiple helminth species. Also, in contrast with other studies in communities with a high prevalence of intestinal helminths, we found no participants with completely unreactive TST, 21,22 despite almost universal intestinal helminth infections and frequent co-infections with multiple intestinal helminths. Potential explanations for this include the likely lifelong helminth infections in the indigenous community in the present research.…”

Intestinal parasitic infections in HIV/AIDS patients: epidemiological, nutritional and immunological aspects

“…Few studies have reported the relationship between cytokines in individuals with HIV and parasitic intestinal infections. Some authors evaluated cytokines and their relationship with parasites such as Schistosoma mansoni, Wuchereria bancrofti, and Trichinella spiralis (71)(72)(73)(74)(75)(76)(77)(78)(79). No correlation between serum INF-γ, IL-2, and IL-10 levels and intestinal parasitic infections was seen.…”

Effect of Helminth Infestationin Children Infected with Human Immunodeficiency Virus (HIV)

“…Chronic infl ammation from helminth infection results in immune dysregulation and reduction in CD4 T-cell count 10,11,12 . This was corroborated in index study where prevalence rates of helminth infection were highest in subjects with advanced and severe immunodefi ciency stages of the disease.…”

“…Many helminth parasites are long-lived and cause chronic infections 8,9 . Chronic helminth infestation was reported to cause immune dysregulations, characterized by a dominant Th2 type of cytokine immune response (predominantly IL-4 and IL-5, IL-10), a high IgE levels, eosinophilia, low CD4+ and a high CD8+ cells count 10,11,12 .…”