Fecal Immunoglobulin A Against a Sporozoite Antigen at 12 Months Is Associated With Delayed Time to Subsequent Cryptosporidiosis in Urban Bangladesh: A Prospective Cohort Study

Abstract

In this prospective cohort study of Bangladeshi children, greater fecal immunoglobulin A, but not plasma immunoglobulin G, directed against the Cryptosporidium sporozoite-expressed antigen Cp23 at 12 months of age was associated with delayed time to subsequent cryptosporidiosis. This finding suggests a protective role for mucosal antibody-mediated immunity in naturally exposed children.

Protection From Natural Immunity Against Enteric Infections and Etiology-Specific Diarrhea in a Longitudinal Birth Cohort

“…Protection for Cryptosporidium was larger against diarrhea (70% vs 25%) and smaller against subclinical infection (20% vs 50+%) compared with a study in India [ 32 ]. The evidence for natural immunity to Cryptosporidium is supported by protection observed among adults with pre-existing serum antibodies [ 33 ] and delayed cryptosporidiosis among children with higher levels of anti- Cryptosporidium fecal immunoglobulin A (IgA) [ 34 ].…”

Nonsterile immunity to cryptosporidiosis in infants is associated with mucosal IgA against the sporozoite and protection from malnutrition

“…(Slope: -0.294 ± 0.05; R squared value: 0.08; Significance p < 0.0001). C) Relationship of all-cause diarrhea with HAZ at 3 years of age (p = NS).Mucosal IgA against the sporozoite Cp23 protein was associated with protection from growth falteringIn previous work it was shown in this cohort that a high level (> mean value) of fecal anti-Cp23IgA at one year of age was associated with an increased resistance to cryptosporidiosis through age three[14,20]. Here we additionally discovered that children with high levels (upper 50 th percentile) of fecal anti-Cp23 IgA at one year of age were protected from growth faltering through year 3(Fig 6).…”

“…infections [0 -3 years] (both diarrhea and sub-clinical) ( Table 2, Fig S5 & 6). The association between cryptosporidiosis and HAZ score at three years was examined by multiple regression in order to account for the effect of the confounding variables previously identified (Table 3) [13,21]. infections was unaffected by whether the event was a sub-clinical infection or diarrheal disease ( Fig S7).…”

“…For example we observed that high fecal IgA against the sporozoite protein Cp23 delayed but did not prevent a repeat infection with Cryptosporidium spp. [20,21]. Ajjampur et al observed a decrease in the incidence of diarrhea in reinfected children [22].…”

Nonsterile immunity to cryptosporidiosis in infants is associated with mucosal IgA against the sporozoite and protection from malnutrition

“…Children with high levels of fecal anti-Cp23 IgA were regarded as being previously exposed to the Cryptosporidium parasite even if the parasite had been missed during surveillance for subclinical infections. In previous work it was shown that even if Cryptosporidium DNA had not been identified high levels (> mean value) of fecal anti-Cp23 IgA at one year of age was associated with an increased resistance to cryptosporidiosis through age three [14,20]. In children with high fecal anti-Cp23 IgA there was an increase in the number of days until a child was reinfected and a subsequent decrease in the proportion of children in this group reinfected during years 2-3 (in children with high fecal anti-Cp23 IgA 77.8% were reinfected versus 92.2%) Here we additionally discovered that children with high levels (upper 50 th percentile) of fecal anti-Cp23 IgA at one year of age were protected from growth faltering through year 3…”