Effects of IgG and IgM autoantibodies on non-infected erythrocytes is related to ABO blood group in Plasmodium vivax malaria and is associated with anemia

Sterile protection against P. vivax malaria by repeated blood stage infection in the Aotus monkey model

The malaria parasite Plasmodium vivax remains a major global public health challenge, and no vaccine is approved for use in humans. Here, we assessed whether P. vivax strain-transcendent immunity can be achieved by repeated infection in Aotus monkeys. Sterile immunity was achieved after two homologous infections, whereas subsequent heterologous challenge provided only partial protection. IgG levels based on P. vivax lysate ELISA and protein microarray increased with repeated infections and correlated with the level of homologous protection. Parasite transcriptional profiles provided no evidence of major antigenic switching upon homologous or heterologous challenge. However, we observed significant sequence diversity and transcriptional differences in the P. vivax core gene repertoire between the two strains used in the study, suggesting that partial protection upon heterologous challenge is due to molecular differences between strains rather than immune evasion by antigenic switching. Our study demonstrates that sterile immunity against P. vivax can be achieved by repeated homologous blood stage infection in Aotus monkeys, thus providing a benchmark to test the efficacy of candidate blood stage P. vivax malaria vaccines.

Autoantibodies during infectious diseases: Lessons from malaria applied to COVID-19 and other infections

Autoimmunity is a common phenomenon reported in many globally relevant infections, including malaria and COVID-19. These and other highly inflammatory diseases have been associated with the presence of autoantibodies. The role that these autoantibodies play during infection has been an emerging topic of interest. The vast numbers of studies reporting a range of autoantibodies targeting cellular antigens, such as dsDNA and lipids, but also immune molecules, such as cytokines, during malaria, COVID-19 and other infections, underscore the importance that autoimmunity can play during infection. During both malaria and COVID-19, the presence of autoantibodies has been correlated with associated pathologies such as malarial anemia and severe COVID-19. Additionally, high levels of Atypical/Autoimmune B cells (ABCs and atypical B cells) have been observed in both diseases. The growing literature of autoimmune B cells, age-associated B cells and atypical B cells in Systemic Lupus erythematosus (SLE) and other autoimmune disorders has identified recent mechanistic and cellular targets that could explain the development of autoantibodies during infection. These new findings establish a link between immune responses during infection and autoimmune disorders, highlighting shared mechanistic insights. In this review, we focus on the recent evidence of autoantibody generation during malaria and other infectious diseases and their potential pathological role, exploring possible mechanisms that may explain the development of autoimmunity during infections.

Systems biology of malaria explored with nonhuman primates

"The Primate Malarias" book has been a uniquely important resource for multiple generations of scientists, since its debut in 1971, and remains pertinent to the present day. Indeed, nonhuman primates (NHPs) have been instrumental for major breakthroughs in basic and pre-clinical research on malaria for over 50 years. Research involving NHPs have provided critical insights and data that have been essential for malaria research on many parasite species, drugs, vaccines, pathogenesis, and transmission, leading to improved clinical care and advancing research goals for malaria control, elimination, and eradication. Whilst most malaria scientists over the decades have been studying Plasmodium falciparum, with NHP infections, in clinical studies with humans, or using in vitro culture or rodent model systems, others have been dedicated to advancing research on Plasmodium vivax, as well as on phylogenetically related simian species, including Plasmodium cynomolgi, Plasmodium coatneyi, and Plasmodium knowlesi. In-depth study of these four phylogenetically related species over the years has spawned the design of NHP longitudinal infection strategies for gathering information about ongoing infections, which can be related to human infections. These Plasmodium-NHP infection model systems are reviewed here, with emphasis on modern systems biological approaches to studying longitudinal infections, pathogenesis, immunity, and vaccines. Recent discoveries capitalizing on NHP longitudinal infections include an advanced understanding of chronic infections, relapses, anaemia, and immune memory. With quickly emerging new technological advances, more in-depth research and mechanistic discoveries can be anticipated on these and additional critical topics, including hypnozoite biology, antigenic variation, gametocyte transmission, bone marrow dysfunction, and loss of uninfected RBCs. New strategies and insights published by the Malaria Host-Pathogen Interaction Center (MaHPIC) are recapped here along with a vision that stresses the importance of educating future experts well trained in utilizing NHP infection model systems for the pursuit of innovative, effective interventions against malaria.

The clinical characteristic of eight patients of COVID-19 with positive RT-PCR test after discharge

Corona virus disease 2019 (COVID‐19) was caused by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2). The phenomenon of positive real time reverse transcription polymerase chain reaction (RT‐PCR) result of SARS‐CoV‐2 in recovered patients had occurred and the research about these patients was rare. In our study, we did a retrospective review of medical records from COVID‐19 patients admitted to one ward of Tongji Hospital of Hua Zhong University of Science and Technology from 10 February to 13 April 2020. From 10 February to 13 April 2020, there were 108 patients of COVID‐19 admitted in the one ward of Tongji Hospital. Among them, eight cases were readmission patients because the RT‐PCR result of SARS‐CoV‐2 was positive again after discharge. On the second admission, they had no symptoms and their chest computed tomography was almost normal. Data from laboratory tests of the readmission patients showed that all eight patients had normal white blood cell count, lymphocyte count. The inflammatory factors like procalcitonin and interleukin 6 were normal. After treatment, two patients met the standard and were discharged. The other six patients were still in the hospital because their RT‐PCR of SARS‐CoV‐2 did not get three consecutive negative results and the course of two patients had persisted more than 90 days. We still needed to be alert that these patients could infect other people as a source of infection, and we also needed to be alert that these patients become chronic virus carriers. It also aroused our concern about the discharge standard of COVID‐19.

From 10 February to 13 April 2020, there were 108 patients of COVID‐19 admitted in the one ward of Tongji Hospital.

Among them, eight cases were readmission patients because the RT‐PCR result of Severe Acute Respiratory Syndrome Coronavirus‐2 (SARS‐COV‐2) was positive again after discharge.

The course of two patients had persisted more than 90 days.

We still needed to be alert that these patients become chronic virus carriers.

It also aroused our concern about the discharge standard of COVID‐19.