Lack of Basophilia in Human Parasitic Infections

Abstract

While basophilia is often found in animal models of parasitic infection, it has not yet been established whether it occurs in parasite-infected humans. We investigated the relationship between basophilia and parasitic infections in humans by reviewing charts from 668 patients with confirmed parasitic infection (472 with only helminths, 146 with only protozoa, and 50 with both helminth and protozoan infections) and from 50 patients without parasitic infections. Basophilia (> 290 cells/mm3) occurred in only four of the 668 parasite-infected patients (0.6%), and there were no statistically significant differences in the percentages of patients with basophilia or in the absolute basophil counts among either the helminth-infected, protozoa-infected, or uninfected populations. Analysis with regard to relative basophil levels revealed that basophils constituted more than 3% of the peripheral white blood cell population in only four patients. Thus, basophilia occurs only rarely in human parasitic infections and is consequently not a useful clinical marker in the evaluation of suspected parasitic disease. * Statistically greater than frequency in protozoa only patients and in uninfected patients (P < 0.0001). † Statistically greater than frequency in uninfected patients (P < 0.001).

Human basophils as effectors and immunomodulators of allergic inflammation and innate immunity

“…In mice infected with N. brasiliensis basophils have been identified as the main IL-4-producing cell type [61] and similar findings were found in humans during filarial infections [62]. While systemic basophilia appears to be less prominent in humans (though it has been observed in N. americanus infections), basophils react to a wide variety of antigens in Schistosoma-, Toxocaria-, Wuchereria-, Strongyloides-, Onchocerca-and Ascaris-infected patients [63]. Of interest concerning a possible innate role for basophils here is that basophils from non-immune donors release substantial amounts of IL-4 (and other mediators) to certain parasitic products, as has been shown using Schistosoma mansoni egg antigen as well as Echinococcus multicularis metacestode extract [64][65][66].…”

Hookworm virulence factors: making the most of the host

“…This correlation exists in various diseases, including in helminth-infected individuals [73]. Although there appears to be no correlation between blood basophilia and helminth infection, basophils are involved in the initiation and execution of an effective immune response against helminths [74]. Moreover, basophils have been observed to peak during the period of N. brasiliensis expulsion, during N. americanus infection in humans and after effective chemotherapy [75].…”

Granulocytes: effector cells or immunomodulators in the immune response to helminth infection?

“…Indeed a worldwide study of basophilia in different helminth infections showed that IgE and eosinophils were raised in all 668 confirmed helminth‐infected patients even if they had concurrent protozoal infections, while people infected with protozoal infections alone or uninfected people did not have raised eosinophils or IgE. In contrast, basophils were raised in only four helminth‐infected patients (172).…”