Increased HIV Incidence in Wuchereria bancrofti Microfilaria Positive Individuals in Tanzania

Background: Infections with Wuchereria bancrofti are associated with reduced immunity against concomitant infections. Indeed, our previous study described a 2.3-fold increased HIV incidence among individuals with W. bancrofti infection, as measured by the circulating filarial antigen of the adult worm. This new study aimed to retrospectively determine microfilariae status of the participants to assess if the previously described increased HIV susceptibility was associated with the presence of MF in the same cohort. Methods: CFA positive but HIV negative biobanked human blood samples (n = 350) were analyzed for W. bancrofti MF chitinase using real time PCR. Results: The PCR provided a positive signal in 12/350 (3.4%) samples. During four years of follow-up (1109 person years (PY)), 22 study participants acquired an HIV infection. In 39 PY of W. bancrofti MF chitinase positive individuals, three new HIV infections occurred (7.8 cases per 100 PY), in contrast to 19 seroconversions in 1070 PY of W. bancrofti MF chitinase negative individuals (1.8 cases per 100 PY, p = 0.014). Conclusions: In the subgroup of MF-producing Wb-infected individuals, the HIV incidence exceeded the previously described moderate increased risk for HIV seen in all Wb-infected individuals (regardless of MF status) compared with uninfected persons from the same area.

The effect of age on the magnitude and longevity of Th1-directed CD4 T cell responses to SARS-CoV-2

Age is associated with changes in the immune system which increase the risk for severe COVID‐19. Here, we investigate SARS‐CoV‐2‐reactive CD4 T cells from individuals recovered from SARS‐CoV‐2 infection with mild COVID‐19 symptoms after 3, 6 and 9 months using incubation with SARS‐CoV‐2 S1, S2 and N‐peptide pools, followed by flow cytometry for a Th1‐activation profile or proliferation analyses. We found that SARS‐CoV‐2‐reactive CD4 T cells are decreasing on average after 9 months but highly polyfunctional CD4 T cells can peak after 6‐month recovery. We show that individuals older than 60 years of age have significantly more SARS‐CoV‐2‐reactive T cells in their blood after 3 months of recovery compared to younger individuals and that the percentage of SARS‐CoV‐2‐reactive Th1‐directed CD4 T cells in the blood of mild‐COVID‐19‐recovered individuals correlates with age. Finally, we show that individuals over the age of 40 have significantly increased the amounts of highly polyfunctional SARS‐CoV‐2‐S‐peptide‐reactive CD4 T cells, compared to SARS‐CoV‐2 naïve individuals, than those under the age of 40. These findings suggest that in individuals recovered from mild COVID‐19, increased age is associated with significantly more highly polyfunctional SARS‐CoV‐2‐reactive CD4 T cells with a Th1‐profile and that these responses persist over time.

Podoconiosis - From known to unknown: Obstacles to tackle

Podoconiosis is a non-filarial and non-communicable disease leading to lymphedema of the lower limbs. Worldwide, 4 million individuals live with podoconiosis, which is accompanied by disability and painful intermittent acute inflammatory episodes that attribute to significant disability adjusted life years (DALYs). Different risk factors like contact with volcanic red clay soil, high altitude (above 1000 m), high seasonal rainfall (above 1000 mm/year) and occupation (e.g., subsistence farmer) are associated with the risk of podoconiosis. Although podoconiosis was described to be endemic in 32 countries in Africa, parts of Latin America and South East Asia, knowledge about related genetics, pathophysiology, immunology and especially the causing molecule(s) in the soil remain uncertain. Thus, podoconiosis can be considered as one of the most neglected diseases. This review provides an overview about this non-filarial related geochemical disease and aim to present perspectives and future directions that might be important for better understanding of the disease, prospect for point-of-care diagnosis, achieving protection and developing novel treatment strategies.