M. Conti

Exploring the Role of Killer Cell Immunoglobulin-Like Receptors and Their HLA Class I Ligands in Autoimmune Hepatitis

Background Natural killer cells are involved in the complex mechanisms underlying autoimmune diseases but few studies have investigated their role in autoimmune hepatitis. Killer immunoglobulin-like receptors are key regulators of natural killer cell-mediated immune responses. Methods and Findings KIR gene frequencies, KIR haplotypes, KIR ligands and combinations of KIRs and their HLA Class I ligands were investigated in 114 patients diagnosed with type 1 autoimmune hepatitis and compared with a group of 221 healthy controls. HLA Class I and Class II antigen frequencies were compared to those of 551 healthy unrelated families representative of the Sardinian population. In our cohort, type 1 autoimmune hepatitis was strongly associated with the HLA-B18, Cw5, DR3 haplotype. The KIR2DS1 activating KIR gene and the high affinity HLA-C2 ligands were significantly higher in patients compared to controls. Patients also had a reduced frequency of HLA-Bw4 ligands for KIR3DL1 and HLA-C1 ligands for KIR2DL3. Age at onset was significantly associated with the KIR2DS1 activating gene but not with HLA-C1 or HLA-C2 ligand groups. Conclusions The activating KIR gene KIR2DS1 resulted to have an important predictive potential for early onset of type 1 autoimmune hepatitis. Additionally, the low frequency of the KIR-ligand combinations KIR3DL1/HLA-Bw4 and KIR2DL3/HLA-C1 coupled to the high frequency of the HLA-C2 high affinity ligands for KIR2DS1 could contribute to unwanted NK cell autoreactivity in AIH-1.

Can antiretroviral therapy modify the clinical course of HDV infection in HIV-positive patients?

BACKGROUND Infection with hepatitis delta virus (HDV) affects approximately 6-14.5% of patients coinfected with HIV-1 and HBV, showing a more aggressive clinical course compared with an HIV-negative population. There is no universally approved treatment for chronic hepatitis D (CHD) in HIV-infected patients. Antiretroviral therapy (ART) containing tenofovir has been recently associated with HDV suppression. Our aim was to evaluate whether the outcome of CHD in HIV-infected patients can be favourably influenced by ART including reverse transcriptase inhibitors. METHODS The clinical course of four HBV/HDV/HIV-coinfected patients receiving ART were retrospectively examined. RESULTS HDV RNA became undetectable in all patients after a variable period of ART along with the disappearance of hepatitis B surface antigen in two of them, and an increase in CD4(+) T-cell count. In all patients, virological changes were associated with improved liver function tests and clinical features. CONCLUSIONS We suggest that ART regimens including drugs active against HBV could have beneficial effects on the clinical course of CHD in patients with HIV-1 by favouring immunological reconstitution.