Cryoglobulins: Putative effectors of adaptive immune response

Cryoglobulinaemia consists of circulating monoclonal and/or polyclonal immunoglobulins with rheumatoid factor (RF) activity that precipitate at temperatures <37°C. Cryoglobulinaemic syndrome, characterised by clinical signs of systemic vasculitis, is associated with chronic infection of hepatitis C virus (HCV) and might evolve in B-cell malignancies. In about one third of all HCV infection cases, serum autoantibodies are commonly found. This is probably due directly to the transformation of infected B cells but, also, indirectly, to the viral chronic stimulation of a pool of autoreactive B cells. The pattern of IgG subclasses seems to contribute to the worsening progression of HCV infection into lymphoproliferative and/or autoimmune diseases. Many evidences showed that B cells circulating in patients with HCV-associated mixed cryoglobulinaemia (MC) are profoundly abnormal;moreover, in most of cases, normal B cells are replaced by expanded clonal B cells characterised by the low expression of CD21. After viral eradication, these cells persist in circulation and their occurrence does not correlate with serum cryoglobulins nor with vasculitis response or relapse. It is probably due to the persistence of monoclonal B cells producing RF, that in course of MC can be reactivated by circulating immune complexes, highly produced during infections or tumours. Here, we aimed to review current literature focusing the pathogenesis of MC referring to specificity and immunochemical characteristics of the immunoglobulins involved in cryoprecipitation.

Gastrointestinal symptoms and digestive comorbidities in an Italian cohort of patients with COVID-19.

OBJECTIVE: The Coronavirus Disease 2019 (COVID-19) pandemic mainly involves respiratory symptoms, though gastrointestinal (GI) symptoms are increasingly being recognized. In this context, the presence of comorbidities appears to be associated with adverse outcomes. However, the role of digestive manifestations is not yet well defined. The primary aim of this study was to assess the prevalence of GI symptoms and digestive comorbidities in a cohort of patients with COVID-19 compared to controls. The secondary aim was to determine the association of GI-symptoms and digestive comorbidities with clinical outcomes. PATIENTS AND METHODS: Inpatients with COVID-19 and controls with similar symptoms and/or radiological findings were enrolled. Symptoms at admission and throughout hospitalization were collected as they were comorbidities. The measured clinical outcomes were mortality, intensive care unit admission and cumulative endpoint. RESULTS: A total of 105 patients were included: 34 with COVID-19 and 71 controls. At admission, the prevalence of GI symptoms among COVID-19 patients was 8.8%. During hospitalization, the frequency of GI symptoms was higher in patients with COVID-19 than in controls (p=0.004). Among patients with COVID-19, the mortality and a cumulative endpoint rates of those with GI symptoms were both lower than for those without GI symptoms (p=0.016 and p=0.000, respectively). Finally, we found digestive comorbidities to be associated with a milder course of COVID-19 (p=0.039 for cumulative endpoint). CONCLUSIONS: Our results highlighted the non-negligible frequency of GI symptoms in patients with COVID-19, partly attributable to the therapies implemented. In addition, the presence of GI symptoms and digestive comorbidities is associated with better outcomes. Most likely, digestive comorbidities do not hinder the host's immune response against SARS-COV-2, and the occurrence of GI symptoms might be linked to a faster reduction of the viral load via the faecal route.

SARS-CoV2 RNA detection in a pancreatic pseudocyst sample.

The involvement of gastrointestinal system in SARS-CoV2 related disease, COVID-19, is increasingly recognized. COVID-19 associated pancreatic injury has been suggested, but its correlation with pancreatic disease is still unclear. In this case report, we describe the detection of SARS-CoV2 RNA in a pancreatic pseudocyst fluid sample collected from a patient with SARS-CoV2 associated pneumonia and a pancreatic pseudocyst developed as a complication of an acute edematous pancreatitis. The detection of SARS-CoV2 within the pancreatic collection arise the question of whether this virus has a tropism for pancreatic tissue and whether it plays a role in pancreatic diseases occurrence.