Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA–viral peptide interaction as the major factor modulating durable control of HIV infection.

Tuberculosis-immune reconstitution inflammatory syndrome is an excessive immune response against Mycobacterium tuberculosis that may occur in either HIV-infected or uninfected patients, during or after completion of anti-TB therapy. In HIV-infected patients it occurs after initiation of antiretroviral therapy independently from an effective suppression of HIV viremia. There are two forms of IRIS: paradoxical or unmasking. Paradoxical IRIS is characterized by recurrent, new, or worsening symptoms of a treated case. Unmasking IRIS is an antiretroviral-associated inflammatory manifestation of a subclinical infection with a hastened presentation. The pathogenesis is incompletely understood and the epidemiology partially described. No specific tests can establish or rule out the diagnosis. Treatment is based on the use of anti-tuberculosis drugs sometime with adjunctive corticosteroids. Mortality is generally low.

Risk assessment of central nervous system (CNS) infection patients is of key importance in predicting likely pathogens. However, data are lacking on the epidemiology globally. We performed a multicenter study to understand the burden of community-acquired CNS (CA-CNS) infections between 2012 and 2014. A total of 2583 patients with CA-CNS infections were included from 37 referral centers in 20 countries. Of these, 477 (18.5%) patients survived with sequelae and 227 (8.8%) died, and 1879 (72.7%) patients were discharged with complete cure. The most frequent infecting pathogens in this study were Streptococcus pneumoniae (n = 206, 8%) and Mycobacterium tuberculosis (n = 152, 5.9%). Varicella zoster virus and Listeria were other common pathogens in the elderly. Although staphylococci and Listeria resulted in frequent infections in immunocompromised patients, cryptococci were leading pathogens in human immunodeficiency virus (HIV)-positive individuals. Among the patients with any proven etiology, 96 (8.9%) patients presented with clinical features of a chronic CNS disease. Neurosyphilis, neurobrucellosis, neuroborreliosis, and CNS tuberculosis had a predilection to present chronic courses. Listeria monocytogenes, Staphylococcus aureus, M. tuberculosis, and S. pneumoniae were the most fatal forms, while sequelae were significantly higher for herpes simplex virus type 1 (p < 0.05 for all). Tackling the high burden of CNS infections globally can only be achieved with effective pneumococcal immunization and strategies to eliminate tuberculosis, and more must be done to improve diagnostic capacity.

The introduction of highly active anti-retroviral therapy (HAART) led to a radical change in the natural history of HIV infection and of the associated neurological opportunistic infections. However, the mortality of central nervous system (CNS) complications and opportunistic infections is still high in untreated HIV-infected individuals or in patients unaware of their HIV infection. We describe the outcome of HIV-infected patients followed at a single center for AIDS-related neurological syndromes in the 16 years following the introduction of HAART, and compare the findings with those in patients admitted up to 1996. We have conducted a retrospective study of patients with HIV infection or AIDS (based on WHO criteria and classified according to the 1993 CDC criteria) admitted during 20 years (January 1992 to March 2012) to the Infectious Diseases Unit of the University of Verona for the presence of focal or widespread CNS lesion on neuroimaging. Clinical history, CD4 cell count, HIV-RNA level, neurological examination, imaging, cerebrospinal fluid examination and eventual cerebral biopsy results were reviewed as well as the final neurological diagnosis and the treatment. The survival time from the clinical onset of the neurologic syndrome to death was calculated for each patient who died. A statistical analysis was performed comparing data collected up to and after 1996, i.e., before and after HAART introduction. Among 1043 patients with HIV infection or AIDS admitted to the Infectious Diseases Unit of the University of Verona between January 1992 and March 2012, 114 had a CNS lesion. The following diseases were observed: neurotoxoplasmosis (NT), progressive multifocal leukoencephalopathy), primary central nervous system lymphoma (PCNSL), the severe form of HIV-associated neurocognitive disorder, cryptococcal encephalitis (CE) and lesions of undetermined origin. The follow-up period was 4 weeks to 72 months both in the pre-HAART and HAART era. Cerebral lesions were detected in 53/243 patients (21.8%) in the pre-HAART era and in 61/801 patients (7.6%) in the HAART era (p < 0.001). Most patients who developed a neurological complication in the HAART period (40/59, 67.8%) were untreated or did not know to be HIV-infected; in particular, 27.9% of patients with a CNS lesion in the HAART era were unaware of their HIV infection vs 13.2% in the pre-HAART era (p < 0.05). Some patients were not virologically suppressed (14/59, 23.7%) or were immunological non-responders (undetectable viral load, with CD4 count <200 cells/μL; 4/59, 6.8%). Other statistically significant data were the mean age at the onset of neurological complications (32.6 ± 5.4 years in the pre-HAART, 40.3 ± 9.5 in the HAART group, p < 0.001) and the mean CD4 cell count at the onset of illness (median of 38 cells/µL (2-215) in the pre-HAART, 77 cells/µL (2-752) in the HAART group; p < 0.001). In the HAART era a reduction of PCNSL and NT was observed. Our results, while confirming a decrease in the incidence of opportunistic infections of the CNS in the ...

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