KIR2DL2 enhances protective and detrimental HLA class I-mediated immunity in chronic viral infection.

Killer cell immunoglobulin-like receptors (KIRs) influence both innate and adaptive immunity. But while the role of KIRs in NK-mediated innate immunity is well-documented, the impact of KIRs on the T cell response in human disease is not known. Here we test the hypothesis that an individual's KIR genotype affects the efficiency of their HLA class I-mediated antiviral immune response and the outcome of viral infection. We show that, in two unrelated viral infections, hepatitis C virus and human T lymphotropic virus type 1, possession of the KIR2DL2 gene enhanced both protective and detrimental HLA class I-restricted anti-viral immunity. These results reveal a novel role for inhibitory KIRs. We conclude that inhibitory KIRs, in synergy with T cells, are a major determinant of the outcome of persistent viral infection.

Role of Kenae/CCDC125 in cell motility through the deregulation of RhoGTPase.

Isaac's syndrome is a movement disorder characterized by hyperexcitability of peripheral motor nerves. Patients with Isaac's syndrome often develop auto-antibodies to voltage-gated potassium channels (VGKCs) which block their function. However, anti-VGKC antibodies are not detected in all patients with Isaac's syndrome, suggesting the existence of another etiology. In this study, we performed immunoscreening using the serum from a patient with Isaac's syndrome and identified the novel gene named Kenae/CCDC125. Expression analysis of Kenae/CCDC125 revealed that its transcript was highly expressed in tissues associated with the immune system, such as the thymus, spleen and bone marrow. In cells stably expressing Kenae/CCDC125, delay in cell motility and deregulation of RhoGTPase (RhoA, Rac1 and cdc42) activity to extracellular stimuli were demonstrated. These results suggest that the novel gene, Kenae/CCDC125, acts as a regulator of cell motility through RhoA, Rac1 and cdc42.

CD8 positive T-cell infiltration in the dentate nucleus of paraneoplastic cerebellar degeneration.

Recent reports have discussed the presence of cytotoxic T cells in paraneoplastic cerebellar degeneration (PCD). We report an autopsy case of PCD associated with anti-Hu antibody, in which we revealed infiltration of CD8+ T cells in and around the dentate nucleus but not in the cerebellar cortex, in addition to severe Purkinje cell loss. Some infiltrated mononuclear cells expressed cytotoxic cell marker, Granzyme B. Decrease of neurons and reduced presynapses were demonstrated in the dentate nucleus. This is the first report that suggests the possibility of the dentate nucleus being primarily attacked followed by Purkinje cell loss in PCD.

Accumulation of human T-lymphotropic virus type I (HTLV-I)-infected cells in the cerebrospinal fluid during the exacerbation of HTLV-I-associated myelopathy.

Human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a slowly progressive, inflammatory disease of the central nervous system (CNS). We report a patient with transverse myelitis, who exhibited acute onset and rapid progression of the disease and whose symptoms resembled those observed in multiple sclerosis with spinal cord presentation. During neurological exacerbation of the condition, the HTLV-I proviral load in the cerebrospinal fluid (CSF) increased to 10 times that in the peripheral blood. This suggests that the accumulation of HTLV-I-infected cells in the CNS contributes to neurological exacerbation. Based on the increased proviral load in the CSF, we diagnosed the disease as acute progressive HAM/TSP. The measurement of the HTLV-I proviral load in the CSF is useful for the diagnosis of HAM/TSP and for monitoring its progression.

Reduced Foxp3 expression with increased cytomegalovirus-specific CTL in HTLV-I-associated myelopathy.

Human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients show high immune responses to HTLV-I. However, it is unclear whether the cytotoxic T lymphocyte (CTL) responses to other chronic viruses also increase. We investigated the responses in the peripheral blood by using HLA-A*0201/peptide pentamers. The frequency of cytomegalovirus (CMV)-specific CTL tended to be higher in HAM/TSP patients than in healthy controls (HCs). The frequency of CMV-specific CTL positively correlated with that of HTLV-I Tax-specific CTL. The frequency of Foxp3+ cells in CD4+ lymphocytes tended to be higher in HAM/TSP patients than in ACs and HCs. The expression level of Foxp3 was lower in HAM/TSP patients than in HCs and was inversely correlated with the CMV-specific CTL frequency. A percentage of Foxp3+ cells showed a positive correlation with the HTLV-I proviral load. These results suggest that a decrease in the Foxp3 expression may contribute to the high immune response to CMV and that the Foxp3+ regulatory T cells may play a role in the immune surveillance of HTLV-I.

Impaired function of human T-lymphotropic virus type 1 (HTLV-1)-specific CD8+ T cells in HTLV-1-associated neurologic disease.

Despite abundant activated virus-specific cytotoxic T lymphocytes (CTLs), patients with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) showed a significantly higher frequency of infected T cells than did healthy virus carriers (HVCs). Here, we demonstrate that at a given proviral load, the frequency of CD8(+) T cells that are negative for specific costimulatory molecules was significantly higher in HAM/TSP than in age-matched HVCs and uninfected healthy controls (HCs), whereas the frequency of intracellular perforin-positive CD8(+) T cells was significantly lower in both HAM/TSP and HVCs than in HCs. An inverse correlation between HTLV-1 proviral load (PVL) and percent perforin-positive CD8(+) T cells were observed only in disease-protective allele HLA-A*02-positive HVCs, but not in HAM/TSP patients, whether HLA-A*02 positive or negative, nor in HLA-A*02-negative HVCs. Significantly lower perforin expression was observed in HTLV-1-specific than in cytomegalovirus-specific CD8(+) T cells. Majority of HTLV-1-specific CD8(+) T cells in HVCs showed a CD28(-)CD27(+) phenotype, whereas HAM/TSP showed a CD28(-)CD27(-) phenotype. HTLV-1-specific CD8(+) T cells from HAM/TSP patients showed significantly lower degranulation than HVCs by CD107a mobilization assay. These findings suggest that an impaired function of HTLV-1-specific CTLs is associated with failing antiviral control and disease HAM/TSP.

Significantly increased antibody response to heterogeneous nuclear ribonucleoproteins in cerebrospinal fluid of multiple sclerosis patients but not in patients with human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis.

It has been reported that antibodies (Abs) against heterogeneous nuclear ribonucleoproteins (hnRNPs) are associated with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and multiple sclerosis (MS). However, these studies were done under nonmasked conditions. In order to determine whether Abs against hnRNPs associate with HAM/TSP and MS, the authors assayed Abs against two major hnRNPs, hnRNP A1 and A2/B1, in 105 cerebrospinal fluid (CSF) samples under fully masked conditions. Samples included 40 cases of HAM/TSP, 28 of MS, and 37 of other neurological diseases. Anti-hnRNP A1 Abs, and especially anti-hnRNP A2/B1 Abs, were found significantly more often in the CSF of MS patients than in other groups. However, there was no difference in the incidence of anti-hnRNP A1 Abs between HAM/TSP and other disease groups.

Expression of the heparin-binding growth factor midkine in the cerebrospinal fluid of patients with neurological disorders.

OBJECTIVE: This study was to clarify the roles of midkine (MK) in the brain. METHODS: We determined cerebrospinal fluid MK levels in patients with neurological disorders by enzyme-linked immunoassay and immunostained autopsied brain samples in patients with meningitis. RESULTS: MK levels were 0.37+/-0.21 ng/ml in controls (n=46, mean +/- S.D.), 0.67+/-0.19 ng/ml in patients with cerebral infarction (n=8), 1.78+/-1.32 ng/ml in patients with meningitis (n=25; ANOVA and post-hoc Fisher's PLSD test, p<0.0001), 0.31+/-0.25 ng/ml in patients with human T-lymphotrophic virus type I-associated myelopathy/tropical spastic paraparesis (n=29), and 0.42+/-0.17 ng/ml in patients with amyotrophic lateral sclerosis (n=8). The regression equations were Y=0.005X+0.498 (Y, CSF MK level; X, cell number) and Y=0.007X+0.326 (Y, MK level; X, protein level) for all CSF samples. Autopsy brain samples from patients with meningitis expressed MK weakly in mononuclear cells on immunohistochemical examination. Western blot and polymerase chain reaction analyses showed that leukocytes were MK positive. CSF MK levels were not high in patients with cerebral infarction but were increased in patients with meningitis. CSF MK levels were high in normal controls, compared to those of other cytokines. MK was expressed in choroid plexus of normal brain and released there. CONCLUSION: Our findings suggested that MK may maintain normal adult brain as a neurotrophic factor, and that MK may be released from leucocytes in brain of patients with meningitis as an immunological mediator.

Increased frequency of CD4+T cells expressing fractalkine receptor CX3CR1 in patients with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), but its AIDS susceptible polymorphisms are not associated with the disease.

To investigate whether fractalkine receptor CX3CR1 polymorphisms that have been associated with rapid progression to AIDS among HIV-1 positive individuals also affects the risk of human T cell lymphotropic virus type 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP), we compared the allele frequencies of V249I and T280M between 233 HAM/TSP patients and 213 HTLV-1 seropositive asymptomatic carriers (HCs). Although the frequency and absolute number of peripheral blood CX3CR1+CD4+T cells were significantly increased in HAM/TSP patients compared to HCs and uninfected controls independent of HTLV-1 trans-activator protein Tax, we could not observe any association between the two polymorphisms and the risk of HAM/TSP in our cohort.

Inclusion body myositis associated with human T-lymphotropic virus-type I infection: eleven patients from an endemic area in Japan.

The objective of this study was to investigate the association of human T-lymphotropic virus-type I (HTLV-I) infection with sporadic inclusion body myositis in 11 patients from an endemic area in Japan. The clinical features were consistent with sporadic inclusion body myositis, and anti-HTLV-I antibodies were present in the sera of all patients. Their muscle biopsies showed the diagnostic features of inclusion body myositis, including endomysial T-cell infiltration, rimmed vacuoles, deposits of phosphorylated tau, and abnormal filaments in the nuclei and cytoplasm of the myofibers. The fibers expressed major histocompatibility complex class I antigens and were invaded by CD8 and CD4 cells. In a single human leukocyte antigen-A2-positive patient, in situ human leukocyte antigen-A*0201 / Tax11-19-pentamer staining showed pentamer-positive cells surrounding the muscle fibers. Double-immunogold silver staining and polymerase chain reaction in situ hybridization revealed that HTLV-I proviral DNA was localized on helper-inducer T cells, but not on muscle fibers. Human T-lymphotropic virus-type I proviral loads in peripheral blood mononuclear cells from each patient were similar to those in HTLV-I-associated myelopathy/tropical spastic paraparesis. This study suggests that HTLV-I infection may be one of the causes of sporadic inclusion body myositis, as has been reported in human immunodeficiency virus type-1 infection.

Analysis of CCG repeats in Huntingtin gene among HD patients and normal populations in Japan.

BACKGROUND: Huntington's disease (HD) is a hereditary autosomal dominant neurodegenerative disease characterized by motor, cognitive, and psychiatric symptoms. The molecular basis of the disease is the expansion of the trinucleotide CAG in the first exon of a gene on chromosome four (4p 16.3). There is another triplet sequence, a CCG repeat, immediately 3' adjacent to the CAG repeat in Huntingtin. This triplet sequence is also polymorphic, alleles of 7 or 10 repeats are predominant in populations, and strong linkage disequilibrium between the CCG (7) allele and HD has been shown in western HD chromosomes, whereas Japanese HD chromosomes strongly associate with an allele of (CCG)10. METHODS: Distribution of CAG and the CCG repeats in Huntingtin in 15 patients with HD living in southern Japan were selected to evaluate the regional difference in the CCG repeat number in Japan. RESULTS: Among our 15 HD patients, only 4 patients had the (CCG)7 allele, and the (CCG)10 alleles were found in the remaining 11 patients. CONCLUSIONS: In this study, a linkage disequilibrium was found between Japanese HD chromosomes and (CCG)10, whereas western HD chromosomes are strongly associated with (CCG)7. These data suggest that (CCG)10 allele is dominant in southern Japan.

Increased prevalence of group A ß-hemolytic streptococcus among an ethnic population in Kyrgyzstan detected by the rapid antigen detection test.

The incidence of rheumatic fever (RF) has markedly increased in the last 10 years in Kyrgyzstan. Therefore, investigating the prevalence of group A ß-hemolytic streptococcus (GABHS), which is the cause of RF, in the Kyrgyzstan population is crucial. We studied 189 subjects: 59 children [29 with RF and/or rheumatic heart disease (RHD)] and 130 adults (15 with RHD). The average age of the subjects was 41.0±10.0 years (range 8 months to 72 years). A general clinical examination and medical history including eating habits was carried out. The prevalence of GABHS was tested using the highly sensitive rapid antigen detection test (RADT) to detect the outcrop of streptococcus antigen in smears taken from the mucosal surface of the tonsils or the back of the throat. GABHS antigen was positive in 70 of a total 189 subjects [37.0%; 22/59 children (37.2%), 48/130 adults (36.9%)]. In patients with RF/RHD (n=44), GABHS was positive in 14 subjects [31.8%; 8/29 children (27.6%), 6/15 adults (40.0%)]. Thirty-two subjects with RF/RHD had frequent episodes of tonsillopharyngitis. In subjects without RF/RHD (n=145), GABHS was positive in 56 subjects [38.6%; 14/30 children (46.6%), 42/115 adults (36.5%)]. Thirty of these subjects had frequent episodes of tonsillopharyngitis. Of the 130 adults, the most-consumed dairy products included yoghurt (n=115; 88.4%), milk kasha (n=75; 57.7%) and milk (n=40; 30.7%). Of the 115 subjects in the yoghurt-consuming group, 44 (38.2%) had positive results for GABHS. In the non-yoghurt-consuming group, 4/15 subjects (26.6%) had positive results for GABHS. Using RADT for GABHS, a high prevalence of GABHS antigen was detected not only in patients with RF/RHD, but also in the healthy population (without RF/RHD). The low GABHS prevalence in children with RF/RHD (27.6%) was probably due to corresponding antibiotic therapy. In conclusion, the high prevalence of GABHS is one of the main reasons for the rapid increase in RF/RHD in Kyrgyzstan, and RADT would be an effective tool for its detection.