The antiviral action of natural killer (NK) cells is regulated by a wide repertoire of germ-line encoded membrane receptorswhich recognize the expression of certain self-molecules on target cells. Among the receptors, killer cell immunoglobulinlikereceptor (KIR) which recognizes the expression of human leukocyte antigen (HLA) class I has a predominant role inregulating the effector functions of NK cells, particularly in viral infections.We studied a total of 128 hepatitis B virus (HBV)patients (15 acute, 43 asymptomatic, 27 chronic and 43 with other liver diseases) while attending the Department of MedicalGastroenterology, Government Rajaji Hospital, Madurai, India, and 128 ethnic matched control to find the association betweenthe KIR : HLA genes and differential manifestations of HBV. KIR and its ligand HLA polymorphism were identified by DNAPCRmethods. The activatory receptor KIR-2DS1 was significantly elevated in various disease categories, namely asymptomatic,chronic and other HBV, except acute HBV infection. Whereas, KIR 2DS3 in acute and chronic patients and KIR2DS5 and 3DS1 in asymptomatic individuals. Among various KIR–HLA combinations, homozygous 2DS2:C1 and individualswith 3DSI:BW4 (OR = 3.23, CI = 1.55–6.7, Pc = 0.02) are associated with HBV asymptomatism, while most of thetwo domain inhibitory receptors with their ligands showed significant risk in other liver diseases. Further, KIR3DL1 : HLABw4Iso80 (OR = 3.89, 95% CI = 1.58–9.55, Pc = 0.004) is related with higher risk for asymptomatic infection when comparedwith chronic HBV. Thus, the select KIR : HLA alleles and combinations seem to direct the NK cell activities and immuneresponse in different directions resulting in varied symptoms and manifestations in the subgroups of HBV-infected patientsstudied.
Volume 100, 2021
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