TAP1, TAP2, and HLA-DR2 alleles are predictors of cervical cancer risk

OBJECTIVE

The likelihood of developing cervical cancer has been shown to be increased in persons with certain HLA alleles. We evaluated immune response genes in the HLA region of chromosome 6 to see if individual or interactive associations with cervical cancer risk could be identified.

METHODS

Tissue was obtained from 127 women undergoing surgical treatment for cervical cancer. Blood samples were obtained from 175 control subjects. A combination of polymerase chain reaction (PCR), sequence-specific PCR, and DNA sequencing was used to evaluate polymorphic alleles, including HLA class I B7, TNF alpha, HLA class II DR2, TAP1, and TAP2 genes. Fisher's exact test and logistic regression modeling were used for statistical analysis.

RESULTS

A significantly greater proportion of the patients with cervical cancer were found to have the HLA class II DR2 1501 allele (P = 0.023) and the TAP2 A/B heterozygous pattern of alleles (P = 0.0006) than were women without cervical cancer. A proportion of patients with cervical cancer significantly smaller than that of the control women had a polymorphism at the -238 position of the TNF promoter and the TAP1 C/C homozygous pattern of alleles. With logistic modeling, the markers that showed consistent association with the occurrence of cervical cancer were TAP2 A/B, HLA-DR2 1501, and TAP1 C/C.

CONCLUSIONS

We demonstrated a significant association between immune response genes and the risk of cervical cancer. Our data create a compelling argument for a gene or a cluster of genes in the HLA region of chromosome 6 that regulates host immune responses to human papillomavirus infection in a manner that results in inherited susceptibility or resistance to the transforming properties of oncogenic papillomaviruses.

HLA typing does not predict REM sleep behaviour disorder and hallucinations in Parkinson's disease

HLA-DR2 haplotype and DQ1 DNA alleles, characterizing 90 to 100% of all narcoleptic patients, were found to be equally distributed in 20 Parkinson's disease (PD) patients with early hallucinations, rapid eye movement (REM) sleep-related behaviour disturbances (RBD), and sleep onset in REM (SOREM), and in 20 PD patients without hallucinations, despite 10 to 15 years of treatment, and no RBD or SOREM.

HLA-related subpopulations of MS in Japanese with and without oligoclonal IgG bands. Human leukocyte antigen

BACKGROUND

Oligoclonal IgG bands (OCB) are present in most patients with MS in Western countries; however, in Japanese MS patients, the OCB-positive rate is not as high. A relationship between immunogenetic backgrounds, namely, human leukocyte antigen (HLA) DR2 and DR4 positivity, and OCB production in MS patients from Hokkaido, the northernmost island of Japan, has been previously suggested by the authors.

OBJECTIVES

To investigate the role of OCB in Japanese MS and to verify the interaction between immunogenetic backgrounds and OCB positivity.

METHODS

OCB, DR2(15), and DR4 positivity were studied in 45 patients with newly diagnosed MS. In addition to confirming the authors' previous findings, the clinical and demographic features, MRI findings, OCB positivity, and DRB1*15 and DRB1*04 polymorphisms of an expanded data set of 99 MS patients were investigated by using multivariate analysis. Patients with opticospinal MS (OS-MS) were excluded from this study.

RESULTS

A relatively low OCB-positive rate (53.3%), HLA-DR15 association with OCB-positive MS (p = 0.0044), and DR4 association with OCB-negative MS (p = 0.0410) were confirmed. DR15 was not associated with OCB-negative MS. Demographic features, disease course, and disability were similar in the OCB-negative and OCB-positive group, whereas there was a preponderance of women in the OCB-positive group. An independent negative association of DRB1*0405 (p = 0.0021, adjusted odds ratio = 0.21) with OCB positivity was found.

CONCLUSIONS

MS is heterogeneous in its association with HLA alleles, and based on the immunogenetic differences, the MS patients in this population include at least two HLA-related subpopulations with and without OCB.

The narcoleptic borderland: a multimodal diagnostic approach including cerebrospinal fluid levels of hypocretin-1 (orexin A)

OBJECTIVES

Biological markers of narcolepsy with cataplexy (classical narcolepsy) include sleep-onset REM periods (SOREM) on multiple sleep latency tests (MSLT), HLA-DQB1*0602 positivity, low levels of cerebrospinal fluid (CSF) hypocretin-1 (orexin A), increased body mass index (BMI), and high levels of CSF leptin. The clinical borderland of narcolepsy and the diagnostic value of different markers of narcolepsy remain controversial and were assessed in a consecutive series of 27 patients with hypersomnia of (mainly) neurological origin.

METHODS

Diagnoses included classical narcolepsy (n=3), symptomatic narcolepsy (n=1), narcolepsy without cataplexy (n=4), idiopathic hypersomnia (n=5), hypersomnia associated with psychiatric disorders (n=5), and hypersomnia secondary to neurological disorders or of undetermined origin (n=9). Clinical assessment included BMI, Epworth Sleepiness Scale (ESS), Ullanlinna Narcolepsy Scale (UNS), and history of REM-symptoms (sleep paralysis, hallucinations). HLA-typing, electrophysiological studies (conventional polysomnography, MSLT, 1-week actigraphy), and measurements of CSF levels of hypocretin and leptin were also performed.

RESULTS

Hypocretin-1 was undetectable in three patients with classic narcolepsy and detectable in the remaining 24 patients. Other narcoleptic markers also frequently found in patients without narcolepsy included ESS>14 (78% of 27 patients), UNS>14 (75%), REM symptoms (30%), sleep latencies on MSLT<5 min (41%), >/=2 SOREM (30%), DQB1*0602 positivity (52%), BMI>25 (52%), and increased CSF leptin (48%). Hypersomnia was documented by an increased time 'asleep' in 41% of patients. Overlapping clinical and electrophysiological findings were seen mostly in patients with narcolepsy without cataplexy, idiopathic hypersomnia, and psychiatric hypersomnia.

CONCLUSIONS

(1) Hypocretin dysfunction is not the 'final common pathway' in the pathophysiology of most hypersomnolent syndromes that fall on the borderline for a diagnosis of narcolepsy. (2) The observed overlap among these hypersomnolent syndromes implies that current diagnostic categories are not entirely unambiguous. (3) A common hypothalamic, hypocretin-independent dysfunction may be present in some of these syndromes.

Human Genetics of Common Mycobacterial Infections

There is increasing interest in and understanding of the role of human genetic factors controlling susceptibility/resistance to infectious diseases. This is of particular importance for the two most common mycobacterial infections, tuberculosis and leprosy, because this will allow a genetic dissection of antimycobacterial immunity and should open new fields of preventive and therapeutic measures. In this review we will initially discuss various methods of genetic epidemiology that have been and are being developed to identify human genes controlling infectious diseases, and then illustrate the findings obtained in the numerous studies performed in tuberculosis and leprosy. Although the most convincing results were observed for HLA-DR2 and NRAMP1 (or a closely linked gene) in pulmonary tuberculosis and leprosy subtypes and for a 10p13 locus in paucibacillary leprosy, the molecular basis of their effects remains to be established.

Risk factors of gingival overgrowth in kidney transplant recipients treated with cyclosporine A

OBJECTIVES

Gingival overgrowth is a common side effect of cyclosporine A (CsA) therapy. The pathogenesis of CsA-induced gingival overgrowth is still debated. The influence of CsA dosage and its trough level, HLA phenotype, gender and the administered calcium channel blocker on incidence and severity of overgrowth were studied. Moreover, relationship of overgrowth with plasma level of TGF-beta I was assessed.

METHODS

Degree and extent of gingival overgrowth were tested in 124 kidney transplant recipients treated with CsA, in 9 patients treated with azathioprine and in 21 patients treated with tacrolimus, and various calcium channel blockers.

RESULTS

Gingival overgrowth was found in 46% of patients treated with CsA. Total yearly CsA dosage was significantly higher in patients with overgrowth. Gingival overgrowth was observed in: 86% of patients treated with nifedipin, 47% with amlodipine, 35% with verapamil. HLA-DR antigens analysis showed that half of the patients with DR-2 allele suffered from overgrowth. Gingival overgrowth was found twice as often in males than in females. Plasma level of TGF-beta I was similar in patients with or without overgrowth. Gingival overgrowth was not found in patients treated with azathioprine or tacrolimus despite that half of the patients received nifedipine or amlodipine.

CONCLUSIONS

The study revealed high frequency of overgrowth in renal graft recipients treated with CsA. Overgrowth severity was larger in patients treated simultaneously with nifedipine or amlodipine. CsA dosage, male sex and HLA-DR2 phenotype were risk factors of gingival overgrowth. None of the patients treated with tacrolimus suffered from gingival overgrowth.

Familial Kleine-Levin syndrome: two siblings with unusually long hypersomnic spells

Kleine-Levin syndrome is a rare, sporadic disorder, with discrete spells of hypersomnolence occurring during adolescence, variously accompanied by megaphagia, behavioral changes, psychosis, and mild autonomic symptoms. Familial cases have not previously been reported. We describe 2 siblings who shared uncharacteristically prolonged episodes of hypersomnolence, and the HLA-DR2 haplotype. In one patient, levels of cerebrospinal fluid orexin (hypocretin) during an attack were normal. The presence of an increased sleep drive, despite the occurrence of large amounts of ostensibly restorative sleep, suggests the possible existence of a disorder of sleep satiety.

Analysis of human leukocyte antigens class II-DR in Brazilian children and adolescents with systemic lupus erythematosus

OBJECTIVE

To analyze the frequency of human leukocyte antigens class II-DR in children and adolescents with systemic lupus erythematosus.

PATIENTS AND METHODS

Fifty-fiveBrazilian systemic lupus erythematosus children and adolescents and 308 healthy individuals were studied. Gender, race, and age of onset of systemic lupus erythematosus were recorded. The human leukocyte antigens typing of class II-DR was carried out by polymerase chain reaction amplification with sequence-specific primers (PCR-SSP). Data were analyzed statistically using the chi square test with Yates' correction, Fisher's exact test, and Bonferroni's correction.

RESULTS

Human leukocyte antigen-DR 15 was the most frequently detected antigen in this group of children and adolescents, and it also occurred more frequently in the female group, in children with onset of systemic lupus erythematosus between 0 and 9 years and between 10 to 14 years, and in the Black race group, but these associations were not statistically significants.

CONCLUSION

In this group of children and adolescents with a high degree of racial admixture, we could not verify a significant association between human leukocyte antigens class II-DR and systemic lupus erythematosus.

Multiple susceptibility loci for multiple sclerosis

Multiple sclerosis (MS) is a common and frequently disabling autoimmune disorder mediated by autoaggressive T cells and autoantibodies that target central nervous system myelin. While numerous studies have demonstrated a strong genetic component to MS, it has been difficult to identify the specific genes involved. Several genomic screens have been undertaken to locate such genes, but have not provided consistent gene localization, except for the MHC on chromosome 6p21 and a locus on chromosome 19q13. To determine which of the original genomic locations presented in the US genome screen could be replicated, a more detailed analysis of additional families was performed. The results, derived from a population of 266 affected individuals belonging to 98 multiplex families, continue to support linkage to chromosomes 6p21, 6q27, and 19q13 with LOD scores>3.0, and suggest that regions on chromosomes 12q23-24 and 16p13 may also harbor susceptibility loci for MS. Analysis taking into account the known HLA-DR2 association identified two additional potential linkage regions on chromosomes 7q21-22 and 13q33-34. These regions can now be targeted for detailed study to identify the underlying MS susceptibility genes.

Insights into the immunopathogenesis of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Significant progress has been made in our understanding of the etiology of MS. MS is widely believed to be an autoimmune disease that results from aberrant immune responses to CNS antigens. T cells are considered to be crucial in orchestrating an immunopathological cascade that results in damage to the myelin sheath. This review summarizes the currently available data supporting the idea that myelin reactive T cells are actively involved in the immunopathogenesis of MS. Some of the therapeutic strategies for MS are discussed with a focus on immunotherapies that aim to specifically target the myelin reactive T cells.

The HLA locus and multiple sclerosis in Spain. Role in disease susceptibility, clinical course and response to interferon-beta

The HLA-DR2 haplotype (DRB1*1501, DQB1*0602) on chromosome 6p21 has consistently demonstrated both association and linkage with multiple sclerosis (MS) in case-control and family studies, particularly in Caucasians of Northern European descent. However, the role of a gene within this region in determining clinical features or response to immunotherapy remains largely unknown. A new familial MS data set from the Mediterranean Spanish Basin was collected according to rigorous ascertainment criteria. We confirm, primarily in the cohort originating from Continental Spain, that similar to other high-risk groups, there was a significant association with HLA-DR2. No other DR or DQ alleles were found to be associated with disease susceptibility nor were alleles at the class I A and B loci. Overall, the effect of HLA appears to be less substantial than that observed in a reference US population with a higher disease incidence. No effect of the HLA-DR2 haplotype on age of onset, initial clinical symptoms and disease course was observed. Similarly, no difference in the distribution of responders and nonresponders to interferon-beta (IFNB) therapy, as defined by primary and secondary end points, was observed when individuals were stratified according to HLA-DR2 status.

Evidence for additional genetic risk indicators of relapse-onset MS within the HLA region

BACKGROUND

Human leukocyte antigen (HLA)-DR2 carriership is associated with an increased risk for MS. Genome searches using microsatellite markers have consistently shown that additional genetic factors contribute to susceptibility for MS.

OBJECTIVE

To identify loci within the HLA region that predispose to relapse-onset MS independently of HLA-DR2.

METHOD

A case-control study involving 159 patients with definite relapse-onset MS and 273 control subjects was conducted. Six highly polymorphic microsatellite markers encoded within the HLA-C to DR region, that is, D6S1014, D6S273, TNFa, MIB, C1_2_5, and C1_3_2, three single-nucleotide tumor necrosis factor (TNF) promoter gene polymorphisms at positions -238, -308, and -376, and HLA-DR2 carriership were typed.

RESULTS

These data confirmed the well-known association between the HLA-DR2 haplotype and relapse-onset MS, yielding an odds ratio (OR) of 3.6 (95% CI: 2.4 to 5.4; p < 0.0001). Multivariate analyses revealed that C1_3_2*354 was also associated with an increased risk for developing relapse-onset MS independently of HLA-DR2 (OR: 2.0; 95% CI: 1.2 to 3.1; p = 0.004). This allele is encoded within an ancestral haplotype that is highly linked to HLA-DR3. The joint effect of this ancestral haplotype and HLA-DR2 resulted in an OR of 8.7 (95% CI: 2.7 to 29; p < 0.0001) to develop relapse-onset MS. In addition, a protective risk factor was found: carriers of TNFa*107 had a 0.5-fold lower risk to develop relapse-onset MS (95% CI: 0.3 to 0.9; p = 0.026).

CONCLUSION

Within the HLA region, other loci besides HLA-DR2 haplotype modulate susceptibility for relapse-onset MS.

Amino acid residue 67 (isoleucine) of HLA-DRB is associated with POHS

PURPOSE

To investigate whether presumed ocular histoplasmosis syndrome (POHS) in The Netherlands is associated with HLA-DR2 and HLA-B7, as previously shown in the United States.

METHODS

Twenty-four Dutch patients with POHS were included in this study. DNA isolated from peripheral blood leukocytes was typed for HLA by a sequence-based method. Associations were statistically determined. The frequencies of HLA alleles in bone marrow of donors listed on the European donor registry was used to represent the distribution in the normal population. Patients were included in the study only when no cells were present in the vitreous at any time and when fundus photographs fit the diagnosis made according to the following criteria: presence of peripapillary atrophy, presence of punched out chorioretinal lesions (histospots), and presence of a submacular scar. After the fundus photographs were judged, the patients were divided into two groups. Group1 contained patients who met all three diagnostic criteria (complete POHS), and group 2 contained patients who met one or two of the criteria (incomplete POHS).

RESULTS

Group 1 consisted of 14 patients and group 2 of 10 patients. An association between POHS and HLA-DR2 and -B7 was present, compared with the normal Dutch control subjects. Although significant, the association between the frequency of HLA-DR2 and -B7 of all patients with POHS was less striking than the findings in patients with POHS in the United States. The association with DR2 in patients with incomplete POHS (group 2) was significantly different from that in the group with complete POHS (group 1). According to the defined criteria the association of POHS with HLA-B7 and -DR2 was confined to the incomplete POHS group and was not found in the complete POHS group. Furthermore, analysis of DR at the amino acid level, rather than at the allele level (DR2) showed that amino acid 67 of the DRB1 alleles had the most significant HLA association with POHS, independent of the two groups.

CONCLUSIONS

POHS in Dutch patients was associated with HLA-B7 and -DR2, but more striking was the presence of isoleucine at position 67 of the HLA-DR molecule.

Antibody-mediated suppression of Vbeta5.2/5.3(+) T cells in multiple sclerosis: results from an MRI-monitored phase II clinical trial

The objective of this study was to evaluate the safety and efficacy of the humanized antibody ATM-027 in a baseline versus treatment magnetic resonance imaging-monitored study. Expansion of Vbeta5.2/5.3(+) T cells has been demonstrated in the peripheral blood, cerebrospinal fluid, and brain lesions of MS patients. In a phase I study, ATM-027 depleted these cells in peripheral blood and, in parallel, T-cell MBP reactivity and IFN-gamma expression were reduced. We studied 59 patients with relapsing-remitting MS (47 on ATM-027 and 12 on placebo) stratified for HLA-DR2 status. Monthly intravenous injections were given for 6 months. Individual dose titration was employed to obtain depletion of the target T-cell level and downregulation of antigen receptor density as monitored by flow cytometry. Five monthly magnetic resonance imaging scans were performed before treatment to establish baseline activity, six during treatment, and three during follow-up. Additional immunological assessments were performed to elucidate the mechanism of action of ATM-027. The treatment was safe and well tolerated, inducing consistent suppression of the target cell population. During run-in, active lesions were found in 78.7% (37/47) of patients treated with ATM-027. During treatment, the median number of lesions was reduced by 33% (p = 0.13) independent of DR2 status. The corresponding volume of enhancement was 221 mm(3) at baseline, with a reduction of 10% during treatment. Decreased numbers of cells expressing interferon-gamma messenger RNA, and decreased T-cell reactivity to several myelin antigens were found in ATM-027 treated patients. In conclusion, consistent suppression of Vbeta 5.2/5.3(+) T cells was achieved. However, the effect size on magnetic resonance imaging was considerably less than the targeted 60%.

Association and linkage of juvenile MS with HLA-DR2(15) in Russians

The aim of this study was to determine the role of the HLA-DRB1 gene [6p21] in susceptibility to juvenile MS (JMS) (age at onset < or =15 years) of children of Russian descent. Association of DR2(15) with JMS has been found by the comparison of patients with JMS with both unrelated and affected family-based healthy controls. The linkage of DR2(15) with JMS was shown by transmission disequilibrium test. There were no significant differences in the frequencies of DRB1 alleles and genotypes between 56 patients with JMS and 234 patients with MS with age at onset > or =16 years.

Increased frequency of HLA-DR2 in patients with paroxysmal nocturnal hemoglobinuria and the PNH/aplastic anemia syndrome

Many autoimmune diseases are associated with HLA alleles, and such a relationship also has been reported for aplastic anemia (AA). AA and paroxysmal nocturnal hemoglobinuria (PNH) are related clinically, and glycophosphoinositol (GPI)-anchored protein (AP)-deficient cells can be found in many patients with AA. The hypothesis was considered that expansion of a PNH clone may be a marker of immune-mediated disease and its association with HLA alleles was examined. The study involved patients with a primary diagnosis of AA, patients with myelodysplastic syndrome (MDS), and patients with primary PNH. Tests of proportions were used to compare allelic frequencies. For patients with a PNH clone (defined by the presence of GPI-AP-deficient granulocytes), regardless of clinical manifestations, there was a higher than normal incidence of HLA-DR2 (58% versus 28%; z = 4.05). The increased presence of HLA-DR2 was found in all frankly hemolytic PNH and in PNH associated with bone marrow failure (AA/PNH and MDS/PNH). HLA-DR2 was more frequent in AA/PNH (56%) than in AA without a PNH clone (37%; z = 3.36). Analysis of a second cohort of patients with bone marrow failure treated with immunosuppression showed that HLA-DR2 was associated with a hematologic response (50% of responders versus 34% of nonresponders; z = 2.69). Both the presence of HLA-DR2 and the PNH clone were independent predictors of response but the size of PNH clone did not correlate with improvement in blood count. The results suggest that clonal expansion of GPI-AP-deficient cells is linked to HLA and likely related to an immune mechanism.

Rudimentary TCR signaling triggers default IL-10 secretion by human Th1 cells

Understanding the process of inducing T cell activation has been hampered by the complex interactions between APC and inflammatory Th1 cells. To dissociate Ag-specific signaling through the TCR from costimulatory signaling, rTCR ligands (RTL) containing the alpha1 and beta1 domains of HLA-DR2b (DRA*0101:DRB1*1501) covalently linked with either the myelin basic protein peptide 85-99 (RTL303) or CABL-b3a2 (RTL311) peptides were constructed to provide a minimal ligand for peptide-specific TCRs. When incubated with peptide-specific Th1 cell clones in the absence of APC or costimulatory molecules, only the cognate RTL induced partial activation through the TCR. This partial activation included rapid TCR zeta-chain phosphorylation, calcium mobilization, and reduced extracellular signal-related kinase activity, as well as IL-10 production, but not proliferation or other obvious phenotypic changes. On restimulation with APC/peptide, the RTL-pretreated Th1 clones had reduced proliferation and secreted less IFN-gamma; IL-10 production persisted. These findings reveal for the first time the rudimentary signaling pattern delivered by initial engagement of the external TCR interface, which is further supplemented by coactivation molecules. Activation with RTLs provides a novel strategy for generating autoantigen-specific bystander suppression useful for treatment of complex autoimmune diseases.

HLA class II DR-DQ and increased risk of cervical cancer among Senegalese women

To examine Senegalese women to confirm and extend associations between HLA class II types and cervical cancer previously observed among African-American, Caucasian, Hispanic, and Japanese ethnic populations, 55 Senegalese women with invasive cervical carcinoma were compared with age-matched (human papillomavirus) HPV-positive (n = 83) and HPV-negative (n = 107) control women. PCR-based HPV and HLA typing methods were used. Data were analyzed using a global randomization test and conditional logistic regression. Although this study failed to confirm a previously reported association between cervical cancer and DQB1*03 alleles, the DRB1*1101-DQB1*0301 haplotype was detected more frequently among cervical carcinoma cases than among controls (adjusted odds ratio, 2.6; 95% confidence interval, 1.0-7.1). Furthermore, as reported by others, we observed a negative association of borderline statistical significance between DRB1*13 and cervical carcinoma (adjusted odds ratio, 0.5; 95% confidence interval, 0.2-1.1). Observations from this study confirm earlier findings of a negative association between DRB1*13 and cervical cancer and suggest that specific DRB1-DQB1 haplotype combinations, rather than individual DQB1*03 alleles, increase the risk for cervical cancer.

HLA-DR modulates autoantibody repertoire, but not mortality, in a humanized mouse model of systemic lupus erythematosus

To evaluate the disease-modulating role of HLA-DR2 and DR3 molecules, which have been associated with systemic lupus erythematosus, a humanized mouse model was examined. HLA-DR2 (DRB1*1502)- and DR3 (DRB1*0301)-transgenic mice were backcrossed to the New Zealand Mixed 2410 (NZM 2410, H2(z)) strain. Seventh generation DR2 and DR3 transgene-positive animals along with their transgene-negative littermates and the parental strain NZM2410 were monitored for proteinuria, azotemia, autoantibody production, development of nephritis, and mortality. The results showed no significant differences in proteinuria, azotemia, or mortality between the backcrosses with and without HLA-DR2 or HLA-DR3. However, the genetic analysis of different backcrosses showed that heterozygosity at the endogenous H2-E locus (E(z)/E(b)) was strongly linked with acceleration of lupus nephritis in both HLA-DR2 and HLA-DR3 transgenics. More importantly, the presence of the HLA-DR2, but not the HLA-DR3, transgene significantly enhanced the production of anti-dsDNA, but not anti-ssDNA, anti-histone-dsDNA complex, or anti-histone, Abs. In contrast, neither HLA-DR2 nor HLA-DR3 influenced the development of glomerulonephritis or the degree of immune complex deposition. Moreover, nephritic kidneys from mice with and without HLA-DR2 or HLA-DR3 transgenes showed similar patterns of cytokine expression. Collectively, these findings provide molecular evidence that the association of HLA-DR2 or HLA-DR3 with lupus susceptibility is related to the type of autoantibody rather than to disease mortality. The use of a humanized mouse model provides a way of dissecting the roles of human MHC genes in systemic lupus erythematosus pathogenesis.

In vivo staphylococcal superantigen-driven polyclonal Ig responses in mice: dependence upon CD4(+) cells and human MHC class II

Staphylococcal enterotoxin (SE) B and seven other staphylococcal superantigens (SAg), despite promoting vigorous Ig production in human peripheral blood mononuclear cell cultures, are exceedingly poor at eliciting Ig responses in cultures of spleen cells from C57BL/10J (B10) or C3H/HeJ mice. In contrast, SEB elicits Ig responses in cultures of spleen cells from human MHC class II-transgenic mice. Whereas i.p. administration of SEB (0.2-20 microg) to non-transgenic B10 mice elicits very weak in vivo Ig responses, identical treatment of CD4(+) cell-intact (but not CD4(+) cell-depleted) human MHC class II-transgenic mice elicits dramatic increases in both splenic Ig-secreting cells and serum Ig levels. Over a 2-week period, the SEB-induced in vivo Ig responses peak and then plateau or fall in association with a preferential increase in splenic CD8(+) cells. Nevertheless, in vivo depletion of CD8(+) cells has no sustained effect on SEB-driven Ig responses. Taken together, these observations demonstrate that the effects of SAg on in vivo humoral immune responses are highly CD4(+) cell dependent, are substantially CD8(+) cell independent and can be successfully investigated using human MHC class II-transgenic mice. This model system may be useful in investigating the polyclonally activating effects of microbial products (prototypic environmental insults) on the development of systemic autoimmunity.

HLA class II polymorphism influences onset and severity of pathology in Schistosoma mansoni-infected transgenic mice

Genetic factors that might influence susceptibility or resistance in naive individuals and early-stage pathology in schistosomiasis are difficult to study in clinical trials, since in areas where the disease is endemic the first contact with the parasite occurs most often at very early ages. Therefore, four strains (DR1.Abeta degrees, DR2.Abeta degrees, DQ8.Abeta degrees, and DQ6.Abeta degrees ) of major histocompatibility complex class II-deficient mice (Abeta degrees ), transgenic for different HLA alleles, have been used to evaluate the potential role of HLA class II polymorphism in the onset of the infection by Schistosoma mansoni. The survival rates and parasitological and immunological parameters after infection were evaluated and compared against the control values obtained with Abeta degrees mice. All four mouse strains used in this study were able to generate a specific immune response against S. mansoni antigens (cytokine production and antibody production). However, only mice expressing DR alleles survived until the chronic stage of the infection and were able to mount protective granulomatous response avoiding hepatic damage, presenting predominant gamma interferon production. In contrast, strains expressing DQ alleles revealed an impairment in generating effective granulomas, resulting in earlier death, which was associated with an impaired hepatic granulomatous response and liquefactic necrosis, reflecting the influence of HLA polymorphism in the establishment of protective response in the early stage of infection.

Stratification analysis of MICA triplet repeat polymorphisms and HLA antigens associated with ulcerative colitis in Japanese

We previously reported a conserved haplotype of HLA B52-DR2 and a significantly high frequency of the major histocompatibility complex (MHC) class I chain-related gene A (MICA) transmembrane-short tandem repeat (TM-STR) 6 allele in Japanese patients with ulcerative colitis (UC). To examine the predominance of the MICA TM-STR 6 allele as a marker of the susceptibility to UC within the susceptible haplotype, the association of each allele with UC was estimated following stratification of the patients to control for any possible confounding effects of other alleles positively associated with UC. Sixty-four patients with UC and 236 unrelated healthy controls were included in this study. All subjects were Japanese. HLA-A, -B, -C, and -DR antigens were determined serologically. A triplet repeat polymorphism of the MICA was determined by direct sequencing. To control for the effect of linkage disequilibrium, Mantel-Haenszel weighed odds ratios were calculated. Significantly higher phenotype frequencies of B52, MICA TM-STR 6, and DR2 were observed in patients with UC. Linkage disequilibria among alleles associated with UC revealed that a B52 - MICA TM-STR 6 - DR2 haplotype was conserved in patients with UC, as in controls. When the association of HLA-B52 was estimated after patient stratification for the possible confounding effect of MICA TM-STR 6 or DR2, a strong significant association of B52 with UC was still observed. In contrast, no association with UC was observed for MICA TM-STR 6 or DR2, after stratification of the possible confounding effect of HLA-B52. These results imply that the significant increase in MICA TM-STR 6 in Japanese patients with UC is attributable to linkage disequilibrium with HLA-B52.

Narcolepsy and the HLA region

Narcolepsy was first shown to be tightly associated with HLA-DR2 and DQ1 in 1983, suggesting a possible autoimmune mechanism. Early investigations failed to demonstrate this hypothesis, postulating that HLA-DR2 was only a linkage marker for another, unknown narcolepsy-causing gene. The autoimmune hypothesis is now being re-evaluated under the light of recent results. Like many other autoimmune disorders, narcolepsy usually starts during adolescence, is human leukocyte antigen (HLA)-associated, multigenic and environmentally influenced. Furthermore, HLA-association studies indicated a primary HLA-DQ effect with complex HLA class II allele interactions and a partial contribution of HLA to overall genetic susceptibility. Finally, recent result suggests that human narcolepsy is associated with the destruction of a small number of hypothalamic neurons containing the peptide hypocretins (orexins). This data is consistent with an immune destruction of hypocretin-containing cells as the most common etiology for human narcolepsy.