Seasonal and daytime variation in multiple immune parameters in humans: Evidence from 329,261 participants of the UK Biobank cohort.

Seasonal disease outbreaks are perennial features of human infectious disease but the factors generating these patterns are unclear. Here we investigate seasonal and daytime variability in multiple immune parameters in 329,261 participants in UK Biobank and test for associations with a wide range of environmental and lifestyle factors, including changes in day length, outdoor temperature and vitamin D at the time the blood sample was collected. Seasonal patterns were evident in lymphocyte and neutrophil counts, and C-reactive protein CRP, but not monocytes, and these were independent of lifestyle, demographic, and environmental factors. All the immune parameters assessed demonstrated significant daytime variation that was independent of confounding factors. At a population level, human immune parameters vary across season and across time of day, independent of multiple confounding factors. Both season and time of day are fundamental dimensions of immune function that should be considered in all studies of immuno-prophylaxis and disease transmission.

HIV and systemic lupus erythematosus: where immunodeficiency meets autoimmunity.

We report a case of a new diagnosis of systemic lupus erythematosus (SLE) in a patient with HIV who presented to the outpatient department with a fever, headache and lymphadenopathy. Cerebrospinal fluid analysis showed lymphocytic pleocytosis. Initial concerns were for an infectious process, and investigations for systemic and central nervous system infection were negative. Serum testing for ANA, dsDNA, nucleosome, anti-histone and ribosomal-P antibodies was positive. A magnetic brain imaging scan of the brain showed a well-circumscribed lesion in the right cerebellar peduncle on T2/FLAIR. The patient was commenced on prednisolone and rituximab, and had a good clinical response. The cerebellar lesion resolved and has not recurred with sequential imaging. SLE and HIV are both multi-systemic diseases which rarely co-occur. Autoimmune processes should be considered in HIV patients with multi-systemic symptoms and signs.

Patterns of presentation for attempted suicide: analysis of a cohort of individuals who subsequently died by suicide.

All suicides and related prior attempts occurring in Northern Ireland over two years were analyzed, focusing on number and timing of attempts, method, and mental health diagnoses. Cases were derived from coroner's records, with 90% subsequently linked to associated general practice records. Of those included, 45% recorded at least one prior attempt (with 59% switching from less to more lethal methods between attempt and suicide). Compared with those recording one attempt, those with 2+ attempts were more likely to have used less lethal methods at the suicide (OR = 2.77: 95% CI = 1.06, 7.23); and those using less lethal methods at the attempts were more likely to persist with these into the suicide (OR = 3.21: 0.79, 13.07). Finally, those with preexisting mental problems were more likely to use less lethal methods in the suicide: severe mental illness (OR = 7.88: 1.58, 39.43); common mental problems (OR = 3.68: 0.83, 16.30); and alcohol/drugs related (OR = 2.02: 0.41, 9.95). This analysis uses readily available data to highlight the persisting use of less lethal methods by visible and vulnerable attempters who eventually complete their suicide. Further analysis of such conditions could allow more effective prevention strategies to be developed.

The role of platelets in the pathogenesis of cerebral malaria.

Malaria is a major cause of morbidity and mortality in the developing world and cerebral malaria is responsible for the majority of malaria-associated deaths. There is a strong association between thrombocytopenia and outcome in malaria, suggesting a role for platelets in the pathogenesis of malaria. This thrombocytopenia is likely due to platelet activation possibly through an interaction between PfEMP1 on plasmodium and CD36 on platelets. Platelet activation by plasmodium has two potential consequences. It can lead to the formation of micro-aggregates of infected red blood cells and platelets which can occlude blood vessels and it also leads to binding to and activation of the endothelium.