High prevalence of long-term olfactory, gustatory, and chemesthesis dysfunction in post-COVID-19 patients: a matched case-control study with one-year follow-up using a comprehensive psychophysical evaluation

BACKGROUND

Using an age and gender matched-pair case-control study, we aimed to estimate the long-term prevalence of psychophysical olfactory, gustatory , and chemesthesis impairment at least one year after SARS-CoV-2 infection considering the background of chemosensory dysfunction in non-COVID-19 population.

METHODOLOGY

This case-controlled study included 100 patients who were home-isolated for mildly symptomatic COVID-19 between March and April 2020. One control regularly tested for SARS-CoV-2 infection and always tested negative was matched to each case according to gender and age. Chemosensory function was investigated by a comprehensive psychophysical evaluation including ortho- and retronasal olfaction and an extensive assessment of gustatory function. Differences in chemosensory parameters were evaluated through either Fisher's exact test or Kruskal-Wallis test.

RESULTS

The psychophysical assessment of chemosensory function took place after a median of 401 days from the first SARS-CoV-2 positive swab. The evaluation of orthonasal smell identified 46% and 10% of cases and controls, respectively, having olfactory dysfunction, with 7% of COVID-19 cases being functionally anosmic. Testing of gustatory function revealed a 27% of cases versus 10% of controls showing a gustatory impairment. Nasal trigeminal sensitivity was significantly lower in cases compared to controls. Persistent chemosensory impairment was associated with emotional distress and depression.

CONCLUSION

More than one year after the onset of COVID-19, cases exhibited an excess of olfactory, gustatory , and chemesthesis disturbances compared to matched-pair controls with these symptoms being associated to emotional distress and depression.

Telecardiology: One-lead electrocardiogram monitoring and nurse triage in chronic heart failure

We investigated a home-based intervention based on telecardiology in patients with chronic heart failure (CHF). Two hundred and thirty CHF patients, aged 59 years (SD 9), in stable condition and with optimized therapy were enrolled. The programme consisted of trans-telephonic follow-up and electrocardiogram (ECG) monitoring followed by visits from a paramedical and medical team. The patient could call the centre when required (tele-assistance), while the team could call the patient at pre-scheduled times (telemonitoring). During the first 12 months, there were 3767 calls (873 ad hoc and 2894 scheduled calls). There were 648 events, including 126 episodes of asymptomatic hypotension and 168 episodes which were not due to cardiological symptoms. No actions were taken by the nurse after 2417 calls (64%). A change in therapy was suggested after 418 calls, hospital admission in 62 patients, further investigations for 243 patients and a consultation with the general practitioner in 41 patients. A total of 2303 one-lead ECG recordings were received (10 per patient); 126 recordings (6%) were diagnosed as pathological in comparison with the baseline one. The one-lead ECG recording was used for titration of beta-blockers in 79 patients (mean dosage 38 mg vs 42 mg, P<0.01). Home telenursing could be an important application of telemedicine and single-lead ECG recording seems to offer additional benefit in comparison with telephone follow-up alone.

Effect of home-based telecardiology on chronic heart failure: Costs and outcomes

Chronic heart failure (CHF) remains a common cause of disability. We have investigated the use of home-based telecardiology (HBT) in CHF patients. Four hundred and twenty-six patients were enrolled in the study: 230 in the HBT group and 196 in the usual-care group. HBT consisted of trans-telephonic follow-up and electrocardiogram (ECG) monitoring, followed by visits from the paramedical and medical team. A one-lead ECG recording was transmitted to a receiving station, where a nurse was available for reporting and interactive teleconsultation. The patient could call the centre when assistance was required (tele-assistance), while the team could call the patient for scheduled appointments (telemonitoring). The one-year clinical outcomes showed that there was a significant reduction in rehospitalizations in the HBT group compared with the usual-care group (24% versus 34%, respectively). There was an increase in quality of life in the HBT group (mean Minnesota Living Questionnaire scores 29 and 23.5, respectively). The total costs were lower in the HBT group (107,494 and 140,874, respectively). The results suggest that a telecardiology service can detect and prevent clinical instability, reduce rehospitalization and lower the cost of managing CHF patients.

Cardiac event recording yields more diagnoses than 24–hour Holter monitoring in patients with palpitations

Palpitation is a common symptom that sometimes results from a substantial cardiac arrhythmia. We compared the diagnostic yield of trans-telephonic event monitors with those of Holter monitoring in patients with intermittent palpitations. In all, 310 patients were randomly assigned to receive an event recorder or 24–hour Holter monitoring. Event recorders were used for seven days or until two recordings were obtained while symptoms occurred. The main end-point was an electrocardiogram (ECG) recorded during symptoms. The patients with palpitation recorded the one-lead ECG trace and sent it to a telemedicine call centre, where a nurse responded. There were 119 symptomatic patients in the event recorder group and 74 in the Holter group. The total costs were €6019 for event recording and €9605 for Holter monitoring. The average costs were €51 per symptomatic patient detected by event recorder monitoring and €1 30 per symptomatic patient detected by Holter monitoring. More patients therefore received a clear diagnosis, and more quickly, when using event recording than with Holter monitoring. For this reason, event recorders are preferable to Holter monitors for patients with palpitations.

Involving patients who attempt suicide in suicide prevention: a focus groups study

The aim of this study is to gain insight into the individual experiences of patients who attempt suicide in order to better understand the reasons for and emotions behind a suicide attempt, thus also gaining insight, through the patients' own input, into the risk and protective factors which might influence possible repeat attempts and the attitude towards the assistance they receive. Two focus groups were conducted involving 17 participants, all hospitalized at the time of research for attempting suicide. The patients proved themselves competent, even expert in indicating reasons for, risk factors of and prevention strategies for suicide. The main findings suggest that the relational factor represents a key point both as a trigger for the suicide attempt and for promoting the communication of the intent or for preventing a repeat suicide attempt, as interpersonal relationships and an empathic environment were, in essence, what was perceived as therapeutic and protective and enabled the expression of thoughts and self-understanding. Accordingly psychotherapy, non-specific relationship 'monitoring' after discharge and tutored self-help groups have been suggested. Feasibility and implementing methods as well as the role of the nurse for such interventions were discussed.

Multicenter randomised trial on home-based telemanagement to prevent hospital readmission of patients with chronic heart failure

BACKGROUND

Chronic heart failure (CHF) remains a common cause of disability, death and hospital admission. Several investigations support the usefulness of programs of disease management for improving clinical outcomes. However, the effect of home-based telemanagement programs on the rate of hospital readmission is still unclear and the cost-effectiveness ratio of such programs is unknown. The aim of the study was to determine whether a home-based telemanagement (HBT) programme in CHF patients decreased hospital readmissions and hospital costs in comparison with the usual care (UC) follow-up programme over a one-year period.

METHODS AND RESULTS

Four hundred-sixty CHF patients (pts), aged 57+/-10 years were randomised to two management strategies: 230 pts to HBT programme and 230 pts to UC programme. The HBT pts received a portable device, transferring, by telephone, a one-lead trace to a receiving station where a nurse was available for interactive teleconsultation. The UC pts were referred to their primary care physicians and cardiologists. The primary objective of the study was one-year hospital readmission for cardiovascular reasons. During one-year follow-up 55 pts (24%) in HBT group and 83 pts (36%) in UC group had at least one readmission (RR=0.56; 95% CI: 0.38-0.82; p=0.01). After adjusting for clinical and demographic characteristics, the HBT group had a significantly lower risk of readmission compared with the UC group (HR=0.50, 95% CI: 0.34-0.73; p=0.01). The intervention was associated with a 36% decrease in the total number of hospital readmissions (HBT group: 91 readmissions; UC group: 142 readmissions) and a 31% decrease in the total number of episodes of hemodynamic instability (101 in HBT group vs 147 in UC group). The rate of hearth failure-related readmission was 19% (43 pts) in HBT group and 32% (73 pts) in UC group (RR=0.49, 95% [CI]: 0.31-0.76; p=0.0001). No significant difference was found on cardiovascular mortality between groups. Mean cost for hospital readmission was significantly lower in HBT group (euro 843+/-1733) than in UC group (euro 1298+/-2322), (-35%, p<0.01).

CONCLUSIONS

This study suggests that one-year HBT programme reduce hospital readmissions and costs in CHF patients.

HLA haplotypes and susceptibility to rheumatoid arthritis. More than class II genes

Our aim was to examine, using microsatellite (ms) markers, the contribution of the telomeric part of the HLA region to rheumatoid arthritis (RA) predisposition in the Spanish population. We have looked at the distribution of DQB1, DRBI and five ms loci (D6S1014, D6S273, D6STNFa, MIB and C1-2-5) within the HLA region in 147 Spanish RA patients and 202 control subjects. A total of 19 conserved ms configurations were observed, twelve of them in linkage disequilibrium with particular DQB1-DRB1 haplotypes. Interestingly, haplotype c1 (DQB1*0201-DRB1*0301-D6S1014*143-D6S273*139-D6STNFa*99-MIB*350-C1-2-5*196) was significantly associated with RA predisposition. As part of this haplotype, the MIB*350 allele was found to be a risk factor independently of the RA-predisposing haplotypes. The present results along with data from others prove the existence of a second predisposing locus located inside the MHC region, and suggest that might be located within the TNFa-HLA-B region.

Complete characterization of the DQB1 first exon polymorphism

Here we report an additional source of variation resulting from genetic polymorphism in HLA-DQbeta1 genes, namely, allelic diversity in the first exon of the HLA-DQB1 locus, which encodes the leader peptide sequence. Six different variants, including a novel polymorphic site, were detected among the DBQ1 haplotypes.

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.

Sarcoid arthritis: clinical characteristics, diagnostic aspects, and risk factors

OBJECTIVES

(a) To describe the clinical characteristics of acute sarcoid arthritis and the diagnostic value of its presenting clinical features; (b) to evaluate whether disease onset is seasonal; and (c) to evaluate whether smoking behaviour or the presence of HLA class II alleles is a risk factor for the disease.

METHODS

579 consecutive patients with recent onset arthritis who had been newly referred to a rheumatology outpatient clinic were included in a prospective cohort study. The presenting clinical features, the smoking behaviour, and the results of HLA-DQ and HLA-DR DNA typing of 55 patients with sarcoid arthritis, 524 patients with other arthritides of recent onset, and samples of the normal population were compared.

RESULTS

In all cases the disease showed a self limiting arthritis and overall good prognosis. The diagnostic ability of a combination of four clinical features--symmetrical ankle arthritis, symptoms of less than two months, age below 40 years, and erythema nodosum--was exceptionally high. When test positivity is defined as the presence of at least three of four criteria the set rendered a sensitivity of 93%, a specificity of 99%, a positive predictive value of 75%, and a negative predictive value of 99.7%. The disease clustered in the months March-July. The disease was negatively associated with smoking (odds ratio (OR) 0.09; 95% confidence interval (95% CI) 0.02 to 0.37) and positively associated with the presence of the DQ2 (DQB1*0201)-DR3 (DRB1*0301) haplotype (OR 12.33; 95% CI 5.97 to 25.48).

CONCLUSION

The disease entity acute sarcoid arthritis has highly diagnostic clinical features. The seasonal clustering, the protective effect of smoking, and the association with specific HLA class II antigens support the hypothesis that it results from exposure of susceptible hosts to environmental agents through the lungs.

Early and aggressive treatment of rheumatoid arthritis patients affects the association of HLA class II antigens with progression of joint damage

OBJECTIVE

The presence of certain HLA class II antigens is strongly associated with the progression of joint destruction in rheumatoid arthritis (RA). Such antigens may be more effective than other class II antigens in inducing the formation of autoreactive T cells after presentation of (auto)antigens. We investigated whether early and aggressive treatment with disease-modifying antirheumatic drugs could modify this relationship.

METHODS

We analyzed data from 2 studies of patients with early RA treated according to different strategies. The first study consisted of 2 cohorts, one (n = 109; median disease duration before treatment 4 months) was treated according to the pyramid strategy (initial nonsteroidal antiinflammatory drugs, followed by chloroquine [CQ] or sulfasalazine [SSZ] when necessary), and the other (n = 97; median disease duration before treatment 2 weeks) was immediately treated with CQ or SSZ. The second study comprised 155 patients (median disease duration 4 months) from the Combinatietherapie Bij Reumatoide Artritis (COBRA) trial, in which patients were randomly assigned to combination treatment with step-down prednisolone, methotrexate (MTX), and SSZ (n = 76) or with SSZ alone (n = 79). Prednisolone and MTX dosages were tapered and stopped after 28 and 40 weeks, respectively. The extent of joint damage was measured by the modified Sharp method.

RESULTS

In the pyramid treatment cohort, the median increase in Sharp score after 2 years was 12 in patients positive for the shared epitope (SE) and 1 in SE- patients. In the immediate treatment cohort, the median increase was 3 in SE+ patients and 2 in SE- patients. In the SSZ group of the COBRA study, the median increase in Sharp score after 1 year was 11 in DR4+ patients and 3 in DR4- patients. In the combination treatment group, the median increase was 4 in DR4+ patients and 2 in DR4- patients. Significance was confirmed by multiple regression using log-transformed scores.

CONCLUSION

Early and aggressive antirheumatic drug treatment affects the association of HLA class II alleles with progression of joint damage in RA.

Influence of HLA polymorphism on persistent remission in rheumatoid arthritis

BACKGROUND

Several studies have reported an association between the presence of the shared epitope (SE) and susceptibility to rheumatoid arthritis (RA). Recent studies have shown that certain HLA-DRB1 alleles in combination with predisposing DQB1 and DQA1 alleles may protect against the development of RA. This model is known as the rheumatoid arthritis protection (RAP) hypothesis.

OBJECTIVE

To determine the distribution of HLA-DRB1 and DQB1/DQA1 alleles in a cohort of patients with RA in remission and to determine the association between these HLA alleles and the persistence of remission.

PATIENTS AND METHODS

HLA-DRB1 and DQB1 typings were performed in 167 patients with RA in remission, defined according to the American College of Rheumatology criteria. The disease course, as defined by the persistence of remission during a follow up of two years, was compared between subgroups. According to the RAP hypothesis patients were divided into three subgroups: patients carrying predisposing DQ alleles, patients carrying predisposing alleles in combination with protective alleles (DQ(RA+)/DERAA phenotype), and patients lacking the predisposing alleles. According to the SE hypothesis, patients were divided into three subgroups based on whether they were carrying two, one, or no predisposing alleles (SE alleles).

RESULTS

Predisposing DQ alleles along with a DERAA-bearing allele were present in 14 (8%) of the 167 patients. At least one SE allele was present in 116 (69%) patients; 34 of them (20%) were carrying two copies. The disease course was not significantly different between the subgroups according to the SE and RAP hypothesis, respectively.

CONCLUSION

The frequency of DQ(RA+)/DERAA combinations and of SE alleles in patients with RA clinically in remission was similar to that found in other RA populations. Persistent remission of RA was not associated with any particular HLA subtypes, indicating that HLA typing is not useful for predicting persistent clinical remission.

Six microsatellite markers on the short arm of chromosome 6 in relation to HLA-DR3 and TNF-308A in systemic lupus erythematosus

Differences in allelic distribution at loci surrounding the human HLA-DRB1 and tumor necrosis factor (TNF) genes have been observed in association with systemic lupus erythematosus (SLE). We investigated whether the association of HLA-DRB1*0301 (HLA-DR3) and TNF-308A with SLE could be attributed to polymorphic markers in the chromosomal region encompassed by HLA-DRB1 and HLA-C. Ninety-one consecutive Caucasian patients with SLE and 253 controls (organ donors) were typed for HLA-DRB1, microsatellites D6S1014, D6S273, TNFa, MIB, C1_2_5, and C1_3_2 and the single nucleotide polymorphism at position -308 in the promoter of TNF. The independent contribution of alleles to disease susceptibility was estimated by cross-tabulation and multivariate logistic regression. Possession of TNF-308A was associated with susceptibility to SLE (odds ratio [95% confidence interval], 3.70 [2.24-6.11]). This remained present after stratification on possession of HLA-DR3 (pooled odds ratio, 2.53 [1.37-4.70]). Stratification revealed a possible association of possession of C1_2_5*192 with protection from SLE beyond the effects of HLA-DR3 and TNF-308A. A gene dosage effect was observed for -308A only (homozygotes, 7.75 [3.01-20.0], heterozygotes, 3.15 [1.85-5.37]). In multivariate analysis, possession of HLA-DR3, TNF-308A, and C1_2_5*192 remained independently associated with susceptibility to SLE (2.58 [1.29-5.18], 2.76 [1.43-5.31], and 0.26 [0.10-0.66], respectively). The association of possession of TNF-308A with susceptibility to SLE cannot be attributed to linkage to HLA-DR3 alone, nor to other polymorphic markers in the vicinity of the TNF gene. Further loci that are independently associated with SLE might be in the vicinity of marker C1_2_5.

[Potential cost reductions for the National Health Service through a telecardiology service dedicated to general practice physicians]

BACKGROUND

Rising health care costs resulted in increasing pressure on the health care system and stimulated new strategies for improving the efficiency of care. A telecardiology service provides a useful support to general practitioners in the management of cardiac patients and contributes to the optimization of health care costs in terms of appropriateness of hospital admission and diagnostic testing. The aim of our study was to evaluate the reduction in the number of referrals to the Emergency Department and to cardiological evaluation resulting from the employment of a telecardiology service by general practitioners.

METHODS

Eight hundred and ninety-one consecutive calls arrived to the receiving station of the telecardiology service were analyzed. One hundred and fifty general practitioners received a portable electrocardiographer (Card-Guard 7100, Rehovot, Israel) transferring, by a mobile or fixed telephone, a 12-lead ECG to a receiving station, where a cardiologist was available for reporting and for interactive teleconsultation. At the onset of the phone call, a question was asked to the general practitioner: "What would you have done without the telecardiology service?". The possible answers were: "No actions"; "Referral to the Emergency Department"; "Cardiological consultancy"; "Further investigations". Then we collected the history, risk factors, symptoms and therapy of the patients; the general practitioner sent the ECG tracing by phone.

RESULTS

Eight hundred and ninety-one patients were enrolled (402 males, 489 females, mean age 59 +/- 19 years); 465 (52%) patients were symptomatic; 36.4% had no evidence of previous cardiac disease, 35.1% had systemic hypertension, 10.6% had ischemic cardiac disease, 3.7% had atrial fibrillation, and 11.9% other diseases. ECG was normal in 55%. The general practitioners would have sent to the Emergency Department 106 patients (11.9%), and requested further investigations in 717 patients (80.5%). The cardiologist of the telecardiology service solved the problems of the general practitioners in 657 cases (73.7%), sent 56 patients (6.3%) to the Emergency Department, and asked for further investigations in 178 patients (20%), with a reduction of 47% of Emergency Department admission (p < 0.001) and of 95% of further investigations (p < 0.0001) respectively. The cost analysis showed a reduction, between the two modalities, varying from Itl 22,760,000 and Itl 140,060,000 for 891 calls.

CONCLUSIONS

Telemedicine is a useful tool for the support of general practitioners' daily activity, with a possible cost reduction due to increased appropriateness of hospital admission and of diagnostic testing.

Precipitating factors and decision-making processes of short-term worsening heart failure despite "optimal" treatment (from the IN-CHF Registry)

This study sought to prospectively assess which factors were related to short-term worsening heart failure (HF) leading to or not to hospital admission, in long-term outpatients followed by cardiologists. The subsequent decision-making process was also analyzed. The study population consisted of 2,701 outpatients enrolled in the registry of the Italian Network on Congestive Heart Failure (IN-CHF) and followed by 133 cardiology centers (19% of all existing Italian cardiology centers). Clinical and follow-up data were collected by local trained clinicians; 215 patients (8%) had short-term decompensation (on average 2 months after the index outpatient visit). Multivariate analysis showed that previous hospitalization, long duration of symptoms, ischemic etiology, atrial fibrillation, higher functional class (New York Heart Association classification III to IV), higher heart rate, and low systolic blood pressure were independently associated with HF destabilization. Poor compliance (21%) and infection (12%) were the most frequent precipitating factors, but a precipitating factor was not identified in 40% of the patients. Poor compliance was more common in women, but no other clinical characteristics emerged as being related with a specific precipitating factor. Fifty-seven percent of the patients with a short-term recurrence of worsening HF required hospital admission; infusion treatment with inotropes and/or vasodilators was necessary in 19% of them. Long-term therapy was changed in 48% of the patients. Thus, in ambulatory HF patients, short-term worsening HF can be predicted according to the clinical characteristics on an outpatient basis. Nearly 1/3 of precipitating factors can be prevented. Patient education and avoidance of inappropriate treatment may reduce the number of relapses.

Protection against severe disease is conferred by DERAA-bearing HLA-DRB1 alleles among HLA-DQ3 and HLA-DQ5 positive rheumatoid arthritis patients

Experimental studies in transgenic mice have suggested that HLA-DQ predisposes to rheumatoid arthritis (RA), but could also modulate disease severity by presenting peptides derived from self-DR molecules. In particular, a short amino acid sequence, (70)DERAA(74), in the third hypervariable region of HLA-DRB1 confers protection for the disease, while particular HLA-DQ [DQB1*0501/DQA1*01 (DQ5) and DQB1*03/DQA1*03 (DQ3)] molecules predispose to the disease. We have therefore analyzed the allelic distribution of HLA-DRB1, DQA1, and DQB1 and the presence of rheumatoid factor and nodules among 199 German RA patients and 196 healthy controls. Our results show that HLA-DQB1*03/DQA1*03 (or DRB1*04) predisposes to RA more than HLA-DQB1*0501/DQA1*01 (i.e., DRB1*01 and DRB1*10). Homozygosity for DQ3 confers the strongest genetic risk for RA (OR = 19.79 compared to OR = 10.05 for two doses of shared epitope (SE) positive HLA-DRB1 alleles). Furthermore, patients carrying both predisposing DQ and (70)DERAA(74)-positive HLA-DRB1 alleles are more often rheumatoid factor (RF) negative than patients carrying predisposing DQ alleles alone. Only one out of 14 patients (7%) with a protective combination (DQ3/(70)DERAA(74) and DQ5/(70)DERAA(74)) had rheumatoid nodules compared to 67 out of 144 patients (46.5%) with predisposing DQ alleles alone (OR = 0.12, 95% CI: 0.02-0.72, p = 0.004). These results demonstrate a protective role of (70)DERAA(74)-positive DRB1 alleles against disease severity among RA patients.

Distribution of HERV-LTR elements in the 5'-flanking region of HLA-DQB1 and association with autoimmunity

We established the detailed polymorphism of the 5'-flanking region and the first exon of the human leukocyte antigen (HLA)-DQB1 alleles. One hundred and forty-five Spanish rheumatoid arthritis (RA) patients and 200 healthy voluntary blood donors from southern Spain along with 42 B-cell lines were analyzed for the presence of the retrovirus-derived long terminal repeats (LTRs) LTR3, LTR5, and LTR13. LTR3 positivity was always associated with certain DQB1 alleles, i.e., *0302, *0402, *0601, *0202, and *0305. Sequencing analysis of the 5'-flanking region of DQB1*0301, *0303 and *0502 alleles in homozygous B-cell lines showed the absence of LTR3 and a massive deletion of 5635 base pairs. The undetected deletion in the flanking region of some DQB1 alleles and a lack of stratification for HLA typing explain previously reported associations of the LTR3 element with RA and type I diabetes (IDDM). LTR5 showed identical distribution to LTR3, consistent with a previously suggested LTR3-LTR5 tandem arrangement. LTR13 positivity was associated with DQB1*0302, *0303, and *0402 alleles. Distributions of the LTR elements in all B-cell lines, RA patients, and controls could be explained entirely by linkage disequilibrium with DQB1 alleles, independently of the haplotypes carrying them. LTR elements are known to regulate gene expression. Therefore, a possible involvement of LTR13 in the association of DQB1*0302, *0303, and *0402 with IDDM requires further investigation. The sequencing results of the DQB1 first exon demonstrated that DQB1*0601 was generated by a recombination event between a DR53 and a non-DR53 haplotype. Our results shed new light on the phylogeny of the HLA region and the possible contribution of DQB1 to susceptibility to autoimmunity.

Evidence for a protective role of the human leukocyte antigen class II region in early rheumatoid arthritis

OBJECTIVE

To analyse the distribution of predisposing DQ3 (DQB1*03(*04)/DQA1*03) and DQ5 (DQB1*0501/DQA1*01), shared epitope encoding and protective DRB1 alleles in patients with early rheumatoid arthritis (RA) and undifferentiated arthritis (UA).

METHODS

Consecutive patients enrolled in an early arthritis clinic were DNA-typed for HLA-DQ and DR. RA patients (n=195), UA patients (n=160) and controls from the same region (n=306) were sorted according to their DQ-DR phenotypes: DQ3 vs DQ5 and the presence or absence of a protective DERAA-positive DRB1 molecule. The three groups were also sorted according to the shared epitope (SE) hypothesis.

RESULTS

We observed the association of both DQ3 and DQ5 with RA. DQ3/3 homozygous individuals had the highest risk of developing disease [odds ratio (OR)=20.00]. Conversely DQ5, but not DQ3, was associated with undifferentiated arthritis (OR=2.15 vs 1.25). Consistent with these differences, DQ3-positive individuals had significantly more active disease at the first visit at the outpatient clinic than DQ5-positive patients. DRB1 alleles encoding a DERAA motif in their third hypervariable region provided a strong dominant protection against RA among DQ5-positive individuals and decreased arthritis activity among DQ3-positive patients. Individuals with SE-positive DR1, DR4 and DR10 alleles were also predisposed to RA, DR4/4 homozygous individuals having the highest risk of developing RA (OR=11.00).

CONCLUSION

The DQ3-DR4/9 haplotypes are associated with RA. The DQ5-DR1/10 haplotypes are associated with less active disease, i.e. UA, and DERAA encoding DRB1 alleles modulate either predisposition to or the severity of RA. We propose that HLA polymorphism influences not only the initiation or perpetuation of RA but also protection against the disease.

Rheumatoid arthritis in southern Spain: toward elucidation of a unifying role of the HLA class II region in disease predisposition

OBJECTIVE

To evaluate the contributions of HLA-DQ and -DR polymorphisms to susceptibility to rheumatoid arthritis (RA) in a population in southern Spain, and to compare the value of the shared epitope (SE) and RA protection (RAP) models in accounting for the HLA class II region's contribution to RA predisposition.

METHODS

One hundred sixty RA patients and 153 healthy controls were typed for HLA-DRB1 and -DQB1 using high-resolution DNA techniques. Distributions of predisposing DRB1 alleles in patients and control subjects according to the SE model were compared with distributions of predisposing DQ and protective DERAA-positive DRBI alleles according to the RAP model.

RESULTS

DQ3 (DQBI*03 and *04 combined with DQA1*03) and DQ5 (DQB1*0501/DQA1*0101) alleles predisposed individuals to RA independently of SE-positive DRB1 alleles. DQ3/3-homozygous individuals had the strongest risk of developing RA. DQ3 molecules predisposed to RA more than did DQ5 molecules. The weaker predisposition mediated by DQ5 included the DRB1*1001-carrying haplotype; no DRB1*1001-homozygous patients were observed. DRBI*0401 played a unique role in the contribution of DQ3-DR4 haplotypes to RA, in spite of its low frequency in southern Spain.

CONCLUSION

The low prevalences of RA and of mild disease observed in Spain, and in southern Europe in general, can be explained in great part by the low frequency of DQ3-DR4 haplotypes, especially those carrying DRB1*0401. However, the overall distribution of HLA-DQ and -DR alleles in RA patients compared with control subjects is similar to that in other European and North American populations. A model involving both DQ and DR can best account for the contribution of HLA to RA.

The telomeric part of the HLA region predisposes to rheumatoid arthritis independently of the class II loci

We have evaluated the possible contribution of genes besides DQ and DR to the association of HLA with rheumatoid arthritis (RA). To this end, we have looked at the allele distributions of six microsatellites, D6S1014, D6S2673, TNFalpha, MIB, C1-2-5, and C1-3-2 among 132 RA patients and 254 controls. We have defined 19 microsatellite clusters corresponding to previously described ancestral haplotypes. One of them was D6S1014*143-D6S273*139-TNFalpha*99-MIB*350-C1-2-5*196-C1-3-2*354, often found associated with DQB1*0201-DRB1*0301. As part of this microsatellite cluster, the allele MIB*350 was found to be a RA-predisposing factor, independent of DRB1*0301 and RA-predisposing haplotypes DQB1*03-DRB1*04 and DQB1*0501-DRB1*01. We conclude that the telomeric part of the HLA region contains a locus conferring predisposition to RA independently of HLA class II.

HLA class II association with rheumatoid arthritis: facts and interpretations

We have reviewed the literature on the association of HLA class II with rheumatoid arthritis (RA). Strong linkage disequilibrium among DQB1, DQA1 and DRB1 alleles makes it difficult to evaluate the individual contribution of each locus. Nonetheless, there is a strong case for the role of DQB1*03 and *04 combined with DQA1*03 in susceptibility to severe RA while DQB1*0501 combined with DQA1*0101 and *0104 weakly predisposes to a mild form of RA. However, it is also clear that DRB1*0401 has a particular role in predisposition to the most severe form of the disease while other DRB1 alleles might provide protection. We would like to propose that in RA, as in type I diabetes, both DQ and DR loci contribute to predisposition to the disease.

HLA association with autoimmune disease: a failure to protect?

That certain HLA specificities are associated with predisposition to autoimmune disease does not necessarily imply that self-reactive T cells restricted to particular HLA alleles are eliciting the disease. In the present essay, we argue that HLA can be a major genetic factor in the development of autoimmune diseases without T cells being primarily involved in its initiation or perpetuation. There is now ample evidence that self-reactive, regulatory T cells can protect against pernicious autoimmunity. Hereafter, we propose that extended HLA haplotypes, such as DQ3-DR4, DQ3-DR9, DQ5-DR1 and DQ5-DR10 in the case of rheumatoid arthritis, predispose to impaired T-cell-mediated immune regulation. The haplotypes associated with impaired regulation are the combination of certain class II alleles and a yet unknown 'amplifier'. In this model, products of the HLA class II region are not involved in the presentation of particular organ-specific autoantigens. Therefore, HLA does not predispose to autoimmune disease per se, but rather fails to provide efficient protection.

[Appropriateness of referral to the emergency department through a telecardiology service. "Boario Home-Care" researchers]

BACKGROUND

The use of telemedicine appears particularly promising in cardiovascular diseases; it may reduce the decisional time during an acute myocardial infarction, which is the greater part of the so-called "avoidable delay" and the inappropriate admission to the Emergency Department with the possibility of ruling out an acute pathology. The aim of our study was to show the diagnostic accuracy of a telecardiology service in the daily activity of general practitioners.

METHODS

From February 1998 to February 1999, 150 general practitioners received a portable electrocardiographer (Card-Guard 7100) transferring, by a mobile or fixed telephone, a 12-lead ECG to a receiving station, where a cardiologist was available for the reporting and interactive teleconsultation.

RESULTS

During 1 year 3456 calls took place. At the time of the ECG recording 44% of patients were symptomatic. Chest pain was present in 669 patients (44%), dyspnea in 21%, palpitation in 18%, dizziness in 7%, and asthenia in 13%. ECG and teleconsultation solved all the problems for 2452 patients (71%) and further diagnostic tests were requested in 862 patients (25%); 142 patients (4%) were sent to the Emergency Department. Cardiological diagnosis was confirmed in 95 patients (73%), while anxiety or gastritis were presumed in 35 patients (27%). In the group of patients (n = 3314) for whom the cardiologist solved the problem without admission to the Emergency Department, there were 5 patients who were admitted to the Emergency Department for myocardial ischemia in the following 48 hours after the teleconsultation. Telecardiology service showed versus Emergency Department admission a sensitivity of 95%, a specificity of 97.5%, and a diagnostic accuracy of 92.5%.

CONCLUSIONS

These data confirm a good diagnostic value to the service and a useful support to the general practitioners' activity.

TNF-308A and HLA-DR3 alleles contribute independently to susceptibility to systemic lupus erythematosus

OBJECTIVE

To evaluate the respective contributions of tumor necrosis factor (TNF) promoter polymorphisms and HLA-DR alleles to susceptibility to systemic lupus erythematosus (SLE).

METHODS

TNF-238G/A and 308G/A promoter polymorphisms and HLA-DRB1 alleles were determined in 99 consecutive Caucasian SLE patients and 177 Caucasian controls. Standard and Mantel-Haenszel odds ratios were calculated to assess the magnitude of the susceptibility factors. The presence or absence of the SLE classification criteria was determined and correlated with the TNF promoter and HLA-DRB1 genotypes.

RESULTS

The frequency of the TNF-308A/A and 308G/A genotypes was significantly higher in SLE patients (odds ratio 5.0). Conversely, TNF-238G/A and 238A/A genotypes were equally prevalent in SLE patients and controls. The HLA-DR3 specificity (DRBI*0301 allele) was significantly more prevalent in the SLE population (odds ratio 4.4). Stratification to correct for interdependence of the 2 loci confirmed the association of both TNF-308A and HLA-DR3 with SLE (Mantel-Haenszel odds ratio 3.2 and 2.4, respectively). No correlation was found between TNF promoter and HLA-DRB1 genotypes and any SLE classification criterion or disease manifestation.

CONCLUSION

TNF-308A and HLA-DR3 alleles are independent susceptibility factors for SLE.

Association of the TNF +489 polymorphism with susceptibility and radiographic damage in rheumatoid arthritis

Multiple genetic factors contribute to susceptibility to rheumatoid arthritis (RA). The extent of variability in disease presentation in RA may be related to genetic heterogeneity. In this study we investigated the association of the TNF gene polymorphism at position +489 with susceptibility to and severity of RA. Analysis of the frequency of the +489 A and G alleles in a group of 293 consecutive RA patients and 138 healthy controls revealed a significant decrease of the A allele. The +489 GA patients had a 3.9 times decreased chance of having erosive disease than +489 GG patients. These results were confirmed in a prospective study using a cohort of 112 patients who were followed for 12 years. The progression rate of the erosion score over 12 years expressed as Sharp score for X-rays of hands and feet was 3.4 per year for the GA-genotyped patients and 12.1 for the GG-genotyped patients. These associations were independent of rheumatoid factor and HLA-shared epitope positivity. In conclusion, these data suggest that the intron TNF +489 polymorphism is associated with susceptibility to and disease severity of RA independently of HLA-shared epitope-positive alleles.

Telecardiology community: a new approach to take care of cardiac patients. "Boario Home-Care" Investigators

BACKGROUND

Cardiovascular diseases are the leading cause of morbidity and mortality in Western countries and represent, in terms of diagnostic and treatment measures, a large amount of health care expenses. A telecardiology service may offer to general practitioners, in real time, a useful diagnostic tool and the possibility of an accurate screening of patients with suspected ischemic heart disease.

METHODS

From February to July 1998, in the provinces of Bergamo and Brescia (Italy), 178 general practitioners received a portable Card Guard 7100 electrocardiographer transferring, by a mobile or fixed telephone, a 12 lead ECG to a receiving station, where a cardiologist was available for the reporting and interactive teleconsultation.

RESULTS

During the first 6 months a total 2800 calls took place. Due to incompleteness of requested data only 2254 traces, corresponding to 2254 subjects (mean age 63 +/- 18 years) were entered in the study. In 27% of patients (n = 609) there was a history of systemic hypertension, in 12.5% (n = 283) there was a history of coronary artery disease, and in 38% (n = 834) there was no history of cardiovascular diseases. At the time of ECG recording, 42% of patients (n = 949) were symptomatic: more common symptoms were chest pain (39%), dyspnea (23%), palpitation (19%), dizziness or faint (10%), and asthenia (9%). No action was suggested by cardiologists in 74% of cases. Of the remaining patients, 16% (n = 92) were referred to the Emergency Department, 27% (n = 158) were offered further diagnostic tests as an out patient, and 56% (n = 328) were started on medication or had their treatment changed.

CONCLUSIONS

A telecardiology system provides a useful support to general practitioners in the management, in real time, of patients with cardiovascular conditions, and possibly contributes to optimization of health care costs in terms of appropriateness of hospital admissions and diagnostic tests.

HLA-DQ-associated predisposition to and dominant HLA-DR-associated protection against rheumatoid arthritis

We have recently proposed a new hypothesis to explain the association of Human Leukocyte Antigen (HLA) with rheumatoid arthritis (RA) predisposition. In this model, which challenges the Shared Epitope (SE) hypothesis, HLA-DQ predisposes while HLA-DR protects. In the present study, we have compared these two models in an Early Arthritis Clinic started in 1993 in the Department of Rheumatology at the Leiden University Medical Centre. Out of 524 patients who enrolled this programme in the period 1993-1998 and completed the one year follow-up, 155 have been classified as RA. These patients along with 306 consecutive cadaveric renal organ donors have been typed for HLA-DR and -DQ. The distributions of predisposing DR alleles according to SE, and predisposing DQ and protective DR according to our model were analysed. We found that two doses of predisposing DQ alleles strongly predisposed to RA, even in individuals with a single dose of SE while DRB1 alleles carrying the motif DERAA confered a dominant protection in DQ5-positive individuals. We conclude that the present findings are consistent with our previously described model of HLA and RA association. Using this new model, we have been able to characterise two novel groups of individuals on the basis of their HLA typing: one strongly predisposed to RA and one protected. Knowing the mechanism of HLA-related dominant natural protection may help in designing novel treatment modalities for RA.

Effects of oxygen on autonomic nervous system dysfunction in patients with chronic obstructive pulmonary disease

Chronic hypoxaemia can play a pathological role in abnormalities of the autonomic nervous system (ANS). In patients with chronic obstructive pulmonary disease (COPD), chronic hypoxaemia is associated with increased mortality and only long-term oxygen therapy is able to improve their survival. Normoxaemic COPD patients have been shown to suffer from abnormalities in ANS function. The aims of this study were to evaluate ANS function in COPD patients with chronic hypercapnic respiratory insufficiency and to test whether oxygen supplementation could reverse any ANS dysfunction. Eleven stable COPD patients with chronic hypercapnic respiratory insufficiency underwent evaluation of ANS by analysis of variability in cardiac frequency at rest and during both vagal (controlled breathing) and sympathetic (tilting) stimuli breathing with and without oxygen supplementation. Thirteen male, healthy, nonsmoking volunteers served as controls. Evaluation of ANS in COPD patients during hypoxic conditions showed alterations both at rest and in response to vagal and sympathetic stimuli. Oxygen supply reversed hypoxaemia without significant changes in arterial carbon dioxide tension and, therefore, ANS alterations were corrected during sympathetic stimulus only. Breathing room air and oxygen, the resting low-frequency (LF) powers were 45+/-15 and 148+/-55 ms2 x Hz(-1), respectively, and controlled breathing LF were 107+/-41 and 141+/-113 ms2 x Hz(-1), respectively. In stable patients with chronic obstructive pulmonary disease with chronic respiratory insufficiency, hypoxaemia is associated with derangements in the autonomic nervous system which may be partially reversed by oxygen administration.

Is heart rate variability a reliable method to assess autonomic modulation in left ventricular dysfunction and heart failure? Assessment of autonomic modulation with heart rate variability

Autonomic dysfunction seems to be involved in the progression and prognosis of congestive heart failure. Measurement of heart rate variability (HRV) provides a noninvasive method to obtain reliable and reproducible information on autonomic modulation of heart rate, but there is a difficulty in using HRV as a quantitative estimate of autonomic dysfunction in heart failure. This study was aimed at testing the hypothesis that abnormal modulation of heart rate assessed by power spectrum analysis may be present also in asymptomatic patients with left ventricular dysfunction and progress in patients with overt symptoms of congestive heart failure. HRV was measured in three groups of subjects: Group 1: 30 patients with chronic heart failure; Group 2: 21 patients with asymptomatic left ventricular dysfunction; and Group 3: 25 healthy volunteers as control group. HRV was evaluated by autoregressive spectral analysis with 600-beat ECG samples, while subjects were quietly recumbent (BSI), in conditions of controlled breathing (15 acts/min) (RSC) and passive orthostatism after tilting (80 degrees) (TLT). Patients in group 1 showed a reduction in the standard deviation of the R-R intervals (SDRR) (p<0.0003) and in the low frequency component (LF) (p<0.0001) compared to normal subjects. Low frequency component was not detectable in 11 patients of group I (p<0.0008). On RSC and TLT, group 1 failed to show any modification in the low frequency and high frequency components (HF) under any stimulation. Group 2 showed no modification at baseline evaluation, no increase in the high frequency component on RSC and in LF during TLT compared to controls (p<0.01 and p<0.0001 respectively). At baseline, group 1 had a lower SDRR (p<0.03) and LF (p<0.0001) vs. group 2, whereas during stimulation the two groups exhibited the same behaviour. In conclusion, reduced heart rate variability is specific for both asymptomatic and symptomatic post-ischemic left ventricular dysfunction. Our results suggest that frequency domain analysis of heart rate variability during a stimulation test allows a more accurate definition of the degree of autonomic control of heart rate.

An extended HLA-DQ-DR haplotype rather than DRB1 alone contributes to RA predisposition

In the present study, we tested our hypothesis on the role of a DQ-DR haplotype in rheumatoid arthritis (RA) predisposition. Using two groups of patients and controls, one from The Netherlands and one from Switzerland, we found that DQA1*0301-homozygous and DQA1*0301//DQA1*0101/04-heterozygous individuals are highly predisposed to RA in both populations, while DQA1*0101/04-homozygous are not. The DQA1*0301-DRB1*0403/06/07 and DQA1*0301-DRB1*0901 haplotypes are not associated with RA by themselves but strongly increase the risk of developing disease in DQA1*0301- and DQA1*0101/04-heterozygous. DRB1 alleles carrying the motif DERAA in their third hypervariable region, i.e., *0103, *0402, *1102, *1103, *1301, and *1302, provide a long-lasting protection against RA in DQA1*0101/04- but not in DQA1*0301-positive individuals. These data show that considering both DQ and DR gives a better distinction between patients and controls than the shared epitope hypothesis.

Identification of HLA class II-restricted determinants of Mycobacterium tuberculosis-derived proteins by using HLA-transgenic, class II-deficient mice

T helper 1 cells play a major role in protective immunity against mycobacterial pathogens. Since the antigen (Ag) specificity of CD4(+) human T cells is strongly controlled by HLA class II polymorphism, the immunogenic potential of candidate Ags needs to be defined in the context of HLA polymorphism. We have taken advantage of class II-deficient (Ab0) mice, transgenic for either HLA-DRA/B1*0301 (DR3) or HLA-DQB1*0302/DQA*0301 (DQ8) alleles. In these animals, all CD4(+) T cells are restricted by the HLA molecule. We reported previously that human DR3-restricted T cells frequently recognize heat shock protein (hsp)65 of Mycobacterium tuberculosis, and only a single hsp65 epitope, p1-20. DR3.Ab0 mice, immunized with bacillus Calmette-Guérin or hsp65, developed T cell responses to M. tuberculosis, and recognized the same hsp65 epitope, p1-20. Hsp65-immunized DQ8.Ab0 mice mounted a strong response to bacillus Calmette-Guérin but not to p1-20. Instead, we identified three new DQ8-restricted T cell epitopes in the regions 171-200, 311-340, and 411-440. DR3.Ab0 mice immunized with a second major M. tuberculosis protein, Ag85 (composed of 85A, 85B, and 85C), also developed T cell responses against only one determinant, 85B p51-70, that was identified in this study. Importantly, subsequent analysis of human T cell responses revealed that HLA-DR3+, Ag85-reactive individuals recognize exactly the same peptide epitope as DR3.Ab0 mice. Strikingly, both DR3-restricted T cell epitopes represent the best DR3-binding sequences in hsp65 and 85B, revealing a strong association between peptide-immunodominance and HLA binding affinity. Immunization of DR3.Ab0 with the immunodominant peptides p1-20 and p51-70 induced T cell reactivity to M. tuberculosis. Thus, for two different Ags, T cells from DR3.Ab0 mice and HLA-DR3+ humans recognize the same immunodominant determinants. Our data support the use of HLA-transgenic mice in identifying human T cell determinants for the design of new vaccines.

Critical residues on HLA-DRB1*0402 HV3 peptide for HLA-DQ8-restricted immunogenicity: implications for rheumatoid arthritis predisposition

Recently, we have proposed that the combination of HLA-DQ and -DR alleles is responsible for the association of the HLA class II region with rheumatoid arthritis (RA). According to this model, some HLA-DQ alleles, namely DQ4, DQ7, DQ8, and DQ9, predispose carriers to severe RA, but a self peptide of sequence KDILEDERAAVDTYC from the third hypervariable (HV3) region of some DRB1 alleles, including DRB1*0402, can protect from the disease if presented by DQ molecules. This model implies that DQ4, DQ7, DQ8, and DQ9 should be able to present a set of common peptides, despite polymorphisms in their Ag binding groove. In the present study, we have further analyzed the immunogenicity of the DRB1*0402 HV3 peptide in DQ8-transgenic mice. We found that the motif DERAA guarantees DQ8-restricted immunogenicity, and that R is the main anchor residue for binding of the DRB1*0402 peptide to DQ. Interestingly, the p1 pocket that probably controls binding of the R residue is identical in all four RA-associated DQ molecules. Our results imply that the association of RA with some DR subtypes can be explained by their linkage with DQ alleles displaying a binding site for similar "arthritogenic" peptides.

Critical residues on HLA-DRB1*0402 HV3 peptide for HLA-DQ8-restricted immunogenicity: implications for rheumatoid arthritis predisposition

Recently, we have proposed that the combination of HLA-DQ and -DR alleles is responsible for the association of the HLA class II region with rheumatoid arthritis (RA). According to this model, some HLA-DQ alleles, namely DQ4, DQ7, DQ8, and DQ9, predispose carriers to severe RA, but a self peptide of sequence KDILEDERAAVDTYC from the third hypervariable (HV3) region of some DRB1 alleles, including DRB1*0402, can protect from the disease if presented by DQ molecules. This model implies that DQ4, DQ7, DQ8, and DQ9 should be able to present a set of common peptides, despite polymorphisms in their Ag binding groove. In the present study, we have further analyzed the immunogenicity of the DRB1*0402 HV3 peptide in DQ8-transgenic mice. We found that the motif DERAA guarantees DQ8-restricted immunogenicity, and that R is the main anchor residue for binding of the DRB1*0402 peptide to DQ. Interestingly, the p1 pocket that probably controls binding of the R residue is identical in all four RA-associated DQ molecules. Our results imply that the association of RA with some DR subtypes can be explained by their linkage with DQ alleles displaying a binding site for similar "arthritogenic" peptides.

Contribution of left atrial pressure and dimension to signal-averaged P-wave duration in patients with chronic congestive heart failure

In a group of patients with chronic heart failure, a longer P-wave duration on signal-averaged electrocardiogram was found in those patients with higher pulmonary capillary wedge pressure, whereas the left atrium end-systolic diameter was not significantly different. Furthermore, an acute reduction in pulmonary capillary wedge pressure induced by sodium nitroprusside infusion was associated with a reduction in P-wave duration.

Human leukocyte antigen-DRB1*1502 (DR2Dw12) transgene reduces incidence and severity of arthritis in mice

A strong correlation exists between susceptibility to RA in humans and some DRB1 alleles of the MHC region, such as DRB1*0401 and DRB1*0101. Meanwhile, incidences of other DR specificities, such as DR2, DR5, or DR7 have often been found reduced among RA patients. Like RA, susceptibility to mouse CIA is influenced by the MHC class II loci. To analyze the effect of a DRB1 molecule associated with low incidence of RA on mouse CIA, a human DRB1*1502 (DR2Dw12) transgene was introduced into CIA-susceptible B10.RQB3 (H2Aq) mice. Transgene-positive DRB1*1502 mice showed a significant reduction in the incidence and severity of arthritis. Moreover, the clinical reduction of arthritis correlated with the T-cell proliferative response of B10.RQB3-DRB1*1502 mice against a self-derived DRB1 peptide from the third hypervariable region. Our results suggest that the DRB1*1502-mediated protection against CIA can be explained by the DRB1 molecule acting as a source of self-antigenic peptide which interferes with the T-cell response against immunodominant regions(s) of the arthritogenic type II collagen molecule. By analogy, a similar mechanism might play a critical role in influencing the class II-associated predisposition to RA.

Immune response of HLA-DQ8 transgenic mice to peptides from the third hypervariable region of HLA-DRB1 correlates with predisposition to rheumatoid arthritis

The major histocompatibility complex class II genes play an important role in the genetic predisposition to many autoimmune diseases. In the case of rheumatoid arthritis (RA), the human leukocyte antigen (HLA)-DRB1 locus has been implicated in the disease predisposition. The "shared epitope" hypothesis predicts that similar motifs within the third hypervariable (HV3) regions of some HLA-DRB1 alleles are responsible for the class II-associated predisposition to RA. Using a line of transgenic mice expressing the DQB1*0302/DQA1*0301 (DQ8) genes in the absence of endogenous mouse class II molecules, we have analyzed the antigenicity of peptides covering the HV3 regions of RA-associated and nonassociated DRB1 molecules. Our results show that a correlation exists between proliferative response to peptides derived from the HV3 regions of DRB1 chains and nonassociation of the corresponding alleles with RA predisposition. While HV3 peptides derived from nonassociated DRB1 molecules are highly immunogenic in DQ8 transgenic mice, all the HV3 peptides derived from RA-associated DRB1 alleles fail to induce a DQ8-restricted T-cell response. These data suggest that the role of the "shared epitope" in RA predisposition may be through the shaping of the T-cell repertoire.

Could HLA-DRB1 be the protective locus in rheumatoid arthritis?

Extensive studies in different ethnic groups have associated the susceptibility to development of rheumatoid arthritis (RA) with the third hypervariable region of the major histocompatibility complex (MHC) HLA-DR beta 1 molecule. On the basis of recent findings in the experimental mouse model of collagen-induced arthritis, Eric Zanelli, Miguel Gonzalez-Gay and Chella David propose that the HLA-DRB1 locus is associated with protection to RA and that the actual arthritogenic peptide-presenting molecule is HLA-DQ. Thus, the development of RA would depend upon the expression of the susceptible DQ allele and the nonprotective DRB1 alleles, along with environmental factors that trigger the autoimmune process.

Polymorphism of the MHC class II Eb gene determines the protection against collagen-induced arthritis

Collagen-induced arthritis (CIA) is an animal model of auto immune polyarthritis, sharing similarities with rheumatoid arthritis (RA). Paradoxally, susceptibility to mouse CIA is controlled by the H2A loci (DQ homologous) while RA is linked to HLA.DR genes (H2E homologous). We recently showed that the E beta d molecule prevents CIA development in susceptible H2q mice. We addressed the question of whether H2Eb polymorphism will influence CIA incidence as HLA.DRB1 polymorphism does in RA. In F1 mice, only H2Ebd and H2Ebs molecules showed protection. Using recombinant B10.RDD (Ebd/b) mice, we found that CIA protection was mediated by the first domain of the E beta d molecule. Using peptides covering the third hypervariable region of the E beta chain, we found a perfect correlation between presentation of E beta peptides by the H2Aq molecule and protection on CIA. Therefore, the mechanism by which H2Eb protects against CIA seems to rely on the affinity of E beta peptides for the H2Aq molecule.