Plasmodium falciparum and Helminth Coinfections Increase IgE and Parasite-Specific IgG Responses

Coinfection with Plasmodium falciparum and helminths may impact the immune response to these parasites because they induce different immune profiles. We compared the antibody profile between groups of Mozambican individuals defined by P. falciparum and helminth previous exposure and/or current infection.

Plasmodium falciparum and helminth coinfections increase IgE and parasite-specific IgG responses

Coinfection with Plasmodium falciparum and helminths may impact the immune response to these parasites since they induce different immune profiles. We studied the effects of coinfections on the antibody profile in a cohort of 715 Mozambican children and adults using the Luminex technology with a panel of 16 antigens from P. falciparum and 11 antigens from helminths (Ascaris lumbricoides, hookworm, Trichuris trichiura, Strongyloides stercoralis and Schistosoma spp.) and measured antigen-specific IgG and total IgE responses. We compared the antibody profile between groups defined by P. falciparum and helminth previous exposure (based on serology) and/or current infection (determined by microscopy and/or qPCR). In multivariable regression models adjusted by demographic, socioeconomic, water and sanitation variables, individuals exposed/infected with P. falciparum and helminths had significantly higher total IgE and antigen-specific IgG levels, magnitude (sum of all levels) and breadth of response to both types of parasites compared to individuals exposed/infected with only one type of parasite (p≤ 0.05). There was a positive association between exposure/infection to P. falciparum and exposure/infection to helminths or the number of helminth species, and vice versa (p≤ 0.001). In addition, children coexposed/coinfected tended (p= 0.062) to have higher P. falciparum parasitemia than those single exposed/infected. Our results suggest that an increase in the antibody responses in coexposed/coinfected individuals may reflect higher exposure and be due to a more permissive immune environment to infection in the host.

Impact of convalescent plasma therapy on SARS CoV-2 antibody profile in COVID-19 patients

Convalescent plasma (CP) have been used for treatment of COVID-19, but their effectiveness varies significantly. Moreover, the impact of CP treatment on the composition of SARS-CoV-2 antibodies in COVID-19 patients and antibody markers that differentiate between those who survive and those who succumb to the COVID-19 disease are not well understood. Herein, we performed longitudinal analysis of antibody profile on 115 sequential plasma samples from 16 hospitalized COVID-19 patients treated with either CP or standard of care, only half of them survived. Differential antibody kinetics was observed for antibody binding, IgM/IgG/IgA distribution, and affinity maturation in ‘survived’ vs. ‘fatal’ COVID-19 patients. Surprisingly, CP treatment did not predict survival. Strikingly, marked decline in neutralization titers was observed in the fatal patients prior to death, and convalescent plasma treatment did not reverse this trend. Furthermore, irrespective of CP treatment, higher antibody affinity to the SARS-CoV-2 prefusion spike was associated with survival outcome, while sustained elevated IgA response was associated with fatal outcome in these COVID-19 patients. These findings propose that treatment of COVID-19 patients with convalescent plasma should be carefully targeted, and effectiveness of treatment may depend on the clinical and immunological status of COVID-19 patients as well as the quality of the antibodies in the convalescent plasma.