Autoantibodies to Interferons in Infectious Diseases.

Anti-cytokine autoantibodies and, in particular, anti-type I interferons are increasingly described in association with immunodeficient, autoimmune, and immune-dysregulated conditions. Their presence in otherwise healthy individuals may result in a phenotype characterized by a predisposition to infections with several agents. For instance, anti-type I interferon autoantibodies are implicated in Coronavirus Disease 19 (COVID-19) pathogenesis and found preferentially in patients with critical disease. However, autoantibodies were also described in the serum of patients with viral, bacterial, and fungal infections not associated with COVID-19. In this review, we provide an overview of anti-cytokine autoantibodies identified to date and their clinical associations; we also discuss whether they can act as enemies or friends, i.e., are capable of acting in a beneficial or harmful way, and if they may be linked to gender or immunosenescence. Understanding the mechanisms underlying the production of autoantibodies could improve the approach to treating some infections, focusing not only on pathogens, but also on the possibility of a low degree of autoimmunity in patients.

Sex differences in a cohort of COVID-19 Italian patients hospitalized during the first and second pandemic waves.

BACKGROUND: Coronavirus disease 2019 (COVID-19) severity seems to be influenced by genetic background, sex, age, and presence of specific comorbidities. So far, little attention has been paid to sex-specific variations of demographic, clinical, and laboratory features of COVID-19 patients referred to the same hospital in the two consecutive pandemic waves. METHODS: Demographic, clinical, and laboratory data were collected in 1000 COVID-19 patients (367 females and 633 males), 500 hospitalized in the first wave and 500 in the second one, at the ASST Spedali Civili of Brescia from March to December 2020. Statistical analyses have been employed to compare data obtained in females and males, taking into account their age, and during the first and second COVID-19 waves. RESULTS: The mean age at the time of hospitalization was similar in females and males but was significantly higher for both in the second wave; the time elapsed from symptom onset to hospital admission did not differ between sexes in the two waves, and no correlation was observed between delayed hospital admission and length of hospitalization. The number of multi-symptomatic males was higher than that of females, and patients with a higher number of comorbidities were more frequently admitted to intensive care unit (ICU) and more frequently died. Older males remained in the ICU longer than females and showed a longer disease duration, mainly the first wave. The highest levels of white blood cells, neutrophils, C-reactive protein, and fibrinogen were significantly higher in males and in the first, and along with higher levels of D-dimer, ferritin, lactate dehydrogenase, and procalcitonin which were preferentially documented in patients requiring ICU or died. While the rate of death in ICU was higher in males, the overall death rate did not differ between the sexes; however, the deceased women were older. CONCLUSIONS: These data indicate that once patients were hospitalized, the risk of dying was similar between females and males. Therefore, future studies should aim at understanding the reasons why, for a given number of SARS-CoV-2 infections, fewer females develop the disease requiring hospitalization. HIGHLIGHTS: Although the hospitalized males were significantly more, the similar number of hospitalizations of the > 75-year-old females and males could be due to the fact that in Brescia province, elderly women are about twice as many as men. Although males spent more days in the hospital, had a longer disease duration, developed a critical illness more frequently, and were admitted and died in the ICU more than females, the total rate of deaths among patients was not significantly different between sexes. Overall, the most frequent comorbidities were cardiovascular diseases, which were preferentially seen among patients hospitalized in the second wave; it is possible that the knowledge gained in the first wave concerning the association between certain comorbidities and worse disease evolution has guided the preferential hospitalization of patients with these predominant comorbidities.

Prevalence of TAU mutations in an Italian clinical series of familial frontotemporal patients.

Frontotemporal dementia (FTD) is a clinical entity grouping different diagnostic conditions. FTD can occur in a sporadic form; however in 30-50% of cases a familial form of FTD has been observed. Mutations in the TAU gene were associated to familial FTD linked to chromosome 17. Our aim was to investigated the proportion of FTD cases attributable to TAU gene mutations in an Italian clinical series. We analyzed 38 patients with FTD; of these, 13 had a positive family history of FTD. All TAU gene exons and flanking intronic regions were sequenced. In our familial FTD sample the estimation of TAU gene mutations accounted for a relative low prevalence (7.6%); based on our results we could argue the existence of other mutations in regulatory regions in the TAU gene or, on the other hand, other genes might be responsible for the most cases of familial FTD.

The H2 MAPT haplotype is associated with familial frontotemporal dementia.

There is now considerable evidence that the gene encoding for tau protein (MAPT) is implicated in frontotemporal dementia (FTD). The role of MAPT haplotypes in neurodegenerative diseases has been suggested, but their contribution in familial dementia has not been extensively investigated. Here, we investigated (1) the association between the MAPT haplotypes and sporadic (sFTD) or familial FTD (FFTD) (controls n = 99, sFTD n = 53, FFTD n = 50), (2) the interactive effect between MAPT haplotypes and APOE gene. We found an overrepresentation of H2 haplotype (OR = 1.83, P = 0.029) and of H2H2 genotype in FFTD patients (OR = 6.09, P = 0.007). This association was even stronger in APOE e4 negatives FFTD (H2: OR = 2.9, P = 0.001; H2H2: OR = 12.67, P = 0.001). Our results support idea that the MAPT H2 haplotype is a risk factor for FFTD. This locus could contain this or other inheritable genetic determinants contributing to increase risk of developing dementia.

Interaction between tau and alpha-synuclein proteins is impaired in the presence of P301L tau mutation.

Deposits of tau and alpha-synuclein are hallmarks of distinct neurodegenerative diseases: tauopathies and alpha-synucleinopathies. Affinity chromatography experiments demonstrated a direct binding of the two proteins, and alpha-synuclein was shown to induce fibrillization of tau. Here, we verify the presence of this physical interaction by using different cellular systems. This binding was abolished by the most common tau mutation (P301L) associated with frontotemporal dementia. We restored the impaired interaction by inducing heat shock proteins 70 and 90. In addition, we show that P301L tau mutation strongly affects tau and alpha-synuclein neuronal distribution.

Alzheimer disease-associated cystatin C variant undergoes impaired secretion.

CST3 is the coding gene for cystatin C (CysC). CST3 B/B homozygosity is associated with an increased risk of developing Alzheimer disease. We performed CysC analysis on human primary skin fibroblasts obtained from donors carrying A/A, A/B, and B/B CST3. Pulse-chase experiments demonstrated that the release of the B variant of CysC has a different temporal pattern compared to that of the A one. Fibroblasts B/B homozygous displayed a reduced secretion of CysC due to a less efficient cleavage of the signal peptide, as suggested by high-resolution Western blot analysis and by in vitro assay. In the brain, the reduced level of CysC may represent the molecular factor responsible for the increased risk of Alzheimer disease.

Atypical dementia associated with a novel presenilin-2 mutation.

We describe an Italian pedigree with hereditary dementia associated with a novel T122R mutation in the presenilin-2 gene (PSEN2). The clinical history, symptom presentation, and structural neuroimaging were consistent with an atypical form of dementia. Disease expression varied within family members. One in a pair of mutated monozygotic twins had evident signs of disease, whereas the other did not, even if her functional neuroimaging investigations, cerebrospinal fluid levels of Abeta1-42, and Tau protein were able to provide markers for future disease development. These observations suggest the importance of still unknown biological and perhaps environmental factors in the disease determination.