The authors' full names, academic degrees, and affiliations are listed in the Appendix. Prof. Orkin can be contacted at c . m .

To extend the understanding of host genetic determinants of HIV-1 control, we performed a genome-wide association study in a cohort of 2,554 infected Caucasian subjects. The study was powered to detect common genetic variants explaining down to 1.3% of the variability in viral load at set point. We provide overwhelming confirmation of three associations previously reported in a genome-wide study and show further independent effects of both common and rare variants in the Major Histocompatibility Complex region (MHC). We also examined the polymorphisms reported in previous candidate gene studies and fail to support a role for any variant outside of the MHC or the chemokine receptor cluster on chromosome 3. In addition, we evaluated functional variants, copy-number polymorphisms, epistatic interactions, and biological pathways. This study thus represents a comprehensive assessment of common human genetic variation in HIV-1 control in Caucasians.

We have deeply investigated T cell compartment, plasma cytokines and cells producing cytokines in patients affected by Covid-19. At admission, patients were lymphopenic; in all of them SARS-CoV-2 was detected in a nasopharyngeal swab specimen by real-time RT-PCR, and pneumonia was subsequently confirmed by X-rays.Detailed 18-parameter flow cytometry was performed in 21 patients and 13 controls. Coupling polychromatic cytometry with unsupervised data analysis, we found that patients show an increased amount of CD4+ T lymphocytes that were activated, exhausted, stem memory or Treg. Similar results concerning activation and exhaustion were found in the CD8+ T cell compartment, within which the differences were even greater.Measuring plasma level of 31 cytokines linked to inflammation revealed that Covid-19 showed a dramatic increase of several molecules, such as TH1 and TH2 cytokines, chemokines, galectins, pro- and anti-inflammatory mediators, confirming the importance of a massive immune activation causing the cytokine storm. Then, intracellular staining detecting the simultaneous production of different cytokines after a para-physiologic stimulus given by anti-CD3/CD28 mAbs revealed not only a high capacity to produce a variety of molecules, including TNF-a, IFN-g and IL-2, but also a significant skewing of CD4+ T cells towards the TH17 phenotype.A therapeutic approach now exists based on the administration of drugs that block IL-6 pathway, and is now consistently improving the course of the disease. IL-17 is crucial in recruiting and activating neutrophils, cells that can migrate to the lung and are heavily involved in the pathogenesis of Covid-19. We show here that a significant skewing of activated T cells towards TH17 functional phenotype exists in Covid-19 patients. Thus, we suggest that blocking IL-17 pathway by already available biological drugs that are used to treat different pathologies could be a novel, additional strategy to improve the health of patients infected by SARS-CoV-2.

No abstract