Lihui Luo

Activating killer cell immunoglobulin-like receptors 3DS1 and 2DS1 protect against developing the severe form of recurrent respiratory papillomatosis

The polymorphic killer cell immunoglobulin-like receptors (KIR) control natural killer (NK) cell response against viral infection and tumor transformation. Here we investigated if select KIR genes are associated with recurrent respiratory papillomatosis (RRP), a rare disease of the larynx and upper airway caused by human papillomaviruses (HPV)-6/11. DNA from 66 RRP patients and 195 healthy controls were characterized for KIR and HLA gene polymorphism. Patients lacking activating KIR genes 3DS1 and 2DS1 were more common in severe RRP compared with mild-moderate RRP (78.8% vs 48.5%, p = 0.019). Further, patients carrying any of the known susceptible HLA-DRB1/DQB1 alleles were more frequently negative for KIR3DS1 (p = 0.006), KIR2DS1 (p = 0.003) or KIR2DS5 (p = 0.004) compared with controls carrying any of these HLA allotypes. Nearly 80% of the patients with severe disease were missing the protective HLA-DQB1*0602 allele as well as both KIR3DS1 and KIR2DS1 genes. Phenotyping of papilloma-infiltrating mononuclear-cells revealed an elevated numbers of NK cells and CD57(+)CD4(+) T cells in KIR3DS1(-)KIR2DS1(-) patients compared with patients carrying either one or both of these KIRs. Our data suggest that NK cells expressing activating receptors KIR3DS1 and KIR2DS1 may be necessary to trigger an effective early immune response against HPV-infected targets to establish resistance to RRP development.

Combination of KIR and HLA gene variants augments the risk of developing birdshot chorioretinopathy in HLA-A*29-positive individuals.

Birdshot chorioretinopathy (BCR), a chronic ocular inflammatory disease with characteristic choroidal lymphocytic infiltrates, has been strongly associated with human leukocyte antigen (HLA)-A29. Although HLA-A29 occurs frequently in all populations, BCR affects only a small percentage of HLA-A29-positive Caucasians, indicating additional susceptibility factors for BCR. Discovery of HLA class I-specific killer cell immunoglobulin-like receptors (KIR) led to a series of epidemiological studies implicating KIR–HLA gene combinations in disease. Here, we characterized KIR–HLA pairs in BCR patients and controls carrying HLA-A*29 as well as controls lacking HLA-A*29. KIR–HLA pairs implicated for weak inhibition (KIR2DL2/3+HLA-C1 and KIR3DL1+HLA-Bw4T80) in combination with activating KIR genes associated with autoimmunity (KIR2DS2, 2DS3 and 2DS4) augment the risk of developing BCR in HLA-A*29-positive individuals. The reciprocal association of strong inhibitory pairs (KIR3DL1+HLA-Bw4I80 and KIR2DL1+HLA-C2) in combination with those implicated in protection from infection (KIR3DS1+HLA-Bw4I80 and KIR2DS1+HLA-C2) was observed in HLA-A*29-negative controls. These results suggest that a profound effect of KIR2DS2/S3/S4 in the absence of strong inhibition may enhance the activation of natural killer cells and T-cell subsets against intraocular self-antigens, thereby contributing to pathogenesis of BCR.

KIR and HLA gene combinations in Vogt-Koyanagi-Harada disease

Vogt-Koyanagi-Harada (VKH) disease is a putative autoimmune ocular inflammatory disease and is known to be associated with HLA-DR4 and -DR1 in Mestizos. We examined the genes encoding KIR receptors and human leukocyte antigen (HLA) class I ligands in patients with VKH disease and compared to published controls. We found trends toward more group B KIR haplogroups (p=0.059), with more activating KIR genes, in patients compared to controls. All putative activating KIR-HLA combinations were more common in patients, and some inhibitory KIR-HLA combinations were more common in controls, although the differences were not statistically significant. The trends observed in this study are consistent with those reported for other autoimmune diseases.

Killer Cell Immunoglobulin-like Receptors in HLA-B27–Associated Acute Anterior Uveitis, with and without Axial Spondyloarthropathy

PURPOSE To determine associations between polymorphic genes that encode KIRs and their HLA class I ligands in patients with HLA-B27-associated acute anterior uveitis (AAU), with and without axial spondyloarthropathy (axial SpA). METHODS Molecular DNA typing methods were used to define the frequencies of variable KIR genes and their relevant HLA class I ligands in HLA-B27(+) (B27(+)) Caucasian subjects with AAU and 429 healthy Caucasian control subjects. The patients were evaluated for axial SpA based on their histories using published criteria. RESULTS Of 143 Caucasian subjects with AAU, 71 (49.6%) had features of axial SpA. The only difference between cases and controls in KIR gene frequencies was a trend toward fewer activating KIRs in subjects with AAU with axial SpA, which reached statistical significance for 2DS5 (P = 0.025, corrected P [P(c)] = 0.05; odds ratio [OR], 0.48; 95% CI, 0.25-0.90). The 3DL1+Bw4(T80) combination implicated in weak inhibition was more frequent in subjects with AAU than in control subjects (P = 2.73 x 10(-28), P(c) = 8.2 x 10(-27); OR, 13.5; 95% CI, 7.73-23.68). The 2DL1+HLA-C2 combination was decreased in subjects with axial SpA compared with subjects with AAU without axial SpA (P = 0.022; P(c) = NS; OR, 0.43; 95% CI, 0.21-0.88). CONCLUSIONS Evidence was found of a role for KIR-HLA combinations that trigger weaker inhibition in subjects with AAU. Furthermore, there was a trend toward fewer KIR3DS1, -2DS1, and -2DS5 in AAU patients with axial SpA, which have been implicated in NK cell activation. HLA-B27(+) without KIR2DS3 (and -2DS1 and -3DS1) may fail to trigger an early NK cell response to clear antigenic stimuli, which may in part contribute to disease pathogenesis.

Chain-terminating natural mutations affect the function of activating KIR receptors 3DS1 and 2DS3

To determine the nucleotide polymorphism of activating killer-cell immunoglobulin-like receptors (aKIR) 3DS1 and 2DS3, we developed a novel direct-sequencing method and analyzed DNA samples of 175 KIR3DS1+ individuals and 72 KIR2DS3+ individuals from the white population. The putative ligand-binding extracellular immunoglobulin (Ig)-like domains of these aKIR receptors are highly conserved, a scenario contrary to inhibitory KIRs that recognize polymorphic human leukocyte antigen (HLA) class I molecules. Null alleles 3DS1*049N and 2DS3*003N that do not express cell-surface receptors were discovered, and they occur commonly in whites (3DS1*049N = 2%; 2DS3*003N = 0.8%). Sequence-specific polymerase chain reaction (PCR) detecting these null alleles is negative with DNA from nonwhite subjects, suggesting that these null alleles are specific to whites and probably originated after the colonization of modern humans in Europe.