Sjögren's syndrome: a systemic autoimmune disease

Sjögren's syndrome is a chronic autoimmune disease characterized by ocular and oral dryness resulting from lacrimal and salivary gland dysfunction. Besides, a variety of systemic manifestations may occur, involving virtually any organ system. As a result, the disease is characterized by pleomorphic clinical manifestations whose characteristics and severity may vary greatly from one patient to another. Sjögren's syndrome can be defined as primary or secondary, depending on whether it occurs alone or in association with other systemic autoimmune diseases, respectively. The pathogenesis of Sjögren's syndrome is still elusive, nevertheless, different, not mutually exclusive, models involving genetic and environmental factors have been proposed to explain its development. Anyhow, the emergence of aberrant autoreactive B-lymphocytes, conducting to autoantibody production and immune complex formation, seems to be crucial in the development of the disease. The diagnosis of Sjögren's syndrome is based on characteristic clinical signs and symptoms, as well as on specific tests including salivary gland histopathology and autoantibodies. Recently, new classification criteria and disease activity scores have been developed primarily for research purposes and they can also be useful tools in everyday clinical practice. Treatment of Sjögren's syndrome ranges from local and symptomatic therapies aimed to control dryness to systemic medications, including disease-modifying agents and biological drugs. The objective of this review paper is to summarize the recent literature on Sjögren's syndrome, starting from its pathogenesis to current therapeutic options.

Single-nucleotide polymorphisms in 3'-untranslated region inducible costimulator gene and the important roles of miRNA in alopecia areata

Background

Alopecia areata (AA) spares the stem cell compartment and attacks only the base of the hair follicle, which is surrounded by infiltrating lymphocytes. AA is associated with polymorphisms in immune-related genes and with decreased function of CD4+CD25+ T regulatory (Treg) cells. Treg function is modulated by the costimulatory molecules, like inducible costimulator (ICOS) that are crucial in orienting T cell differentiation and function so that they strongly impact on the immunologic decision between tolerance or autoimmunity development.

Objective

The aim of our study was to investigate the possible association of AA with single-nucleotide polymorphisms (SNP) present in the ICOS 3'-untranslated region (3'UTR) region and to elucidate how SNPs modulate ICOS gene expression by affecting miRNA binding sites.

Methods

This is a case-control study performed in 184 patients with AA and 200 controls. ICOS gene and miRNA expression were analyzed by real-time polymerase chain reaction.

Results

The genotype carrying the rs4404254(C) [p = 0.012, OR (95% CI): 0.5 (0.3-0.8)] and rs4675379(C) [p = 0.015, OR (95% CI): 0.3 (0.1-0.8)] 3' UTR alleles was more frequently observed in AA patients than in controls and correlated with a reduced ICOS expression. miR-1276 significantly suppressed ICOS expression by binding to the 3'UTR of ICOS mRNA. Also, we observed that, miR-101 and miR-27b are upregulated, while miR-103 and miR-2355-3p are downregulated in peripheral blood mononuclear cells of AA patients compared to controls.

Conclusion

Our data show that rs4404254 and rs4675379 SNPs of ICOS gene are associated with AA and also reveal that the presence of rs4404254 polymorphism correlates with ICOS post-transcriptional repression by microRNA binding.

Rationale for an Association Between PD1 Checkpoint Inhibition and Therapeutic Vaccination Against HIV

The pathogenesis of HIV immunodeficiency is mainly dependent on the cytopatic effects exerted by the virus against infected CD4+ T cells. However, CD4+ T cell loss cannot be the only pathogenic factor since severe opportunistic infections may develop in HIV infected patients with normal CD4+ T cell counts and since the recent START study indicated that absolute CD4+ T cell counts are not predictive for AIDS and non-AIDS events. Recently our group demonstrated that CD8+CD28-CD127lowCD39+ regulatory T lymphocytes, previously found highly concentrated within tumor microenvironment, circulate with elevated frequency in the peripheral blood of HIV infected patients. Here, we show that these cells, that at least in part are HIV specific, express the PD1 immune checkpoint. Based on these evidences and considerations, in this Perspective article we speculate on the opportunity to treat HIV infected patients with anti-PD1 immune checkpoint inhibitors as a way to counteract the T regulatory cell compartment and to unleash virus-specific immune responses. In order to potentiate the immune responses against HIV we also propose the potential utility to associate immune checkpoint inhibition with HIV-specific therapeutic vaccination, reminiscent of what currently applied in oncologic protocols. We suggest that such an innovative strategy could permit drug-sparing regimens and, perhaps, lead to eradication of the infection in some patients.

Beyond APECED: An update on the role of the autoimmune regulator gene (AIRE) in physiology and disease

The autoimmune regulator gene (AIRE) is a transcription factor expressed both in the thymus, by medullary thymic epithelial cells, and in secondary lymphoid organs. AIRE controls the local transcription of organ- specific proteins typically expressed in peripheral tissues, thus allowing the negative selection of self- reactive T cells. The crucial role played by AIRE in central immune tolerance emerged in the studies on the pathogenesis of Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy, a rare inherited polyendocrine/autoimmune disease. Thereafter, several studies found evidences indicating that AIRE impairment might be pathogenically involved in several autoimmune diseases and in tumorigenesis. In this review, we focus on recent advances relative to AIRE's effect on T cell development in physiology and disease. In particular, we address the following issues: 1) AIRE function and mTECs biology, 2) the impact of AIRE gene mutations in autoimmune diseases, and 3) the role of AIRE gene in anti-tumor immune response.

Effect of clotting factors concentrates on lymphocyte and neutrophil function in vitro

Immunological abnormalities have been reported in haemophiliacs. Although infections with HIV, hepatitis and other viruses may contribute to these abnormalities, immune defects are detectable also in HIV seronegative haemophiliacs. It is likely that chronic exposure to extraneous proteins in clotting factor concentrates (CFCs) may play a role in immunomodulation, but the underlying mechanisms remain unclear. The results of the present paper show that: a) soluble HLA class I (sHLA-I), soluble Fas-ligand (sFas-L) and transforming growth factor beta 1 (TGF-β1) are detectable in plasma derived but not in recombinant CFCs; b) the level of sHLA-I and sFas-L is proportional to the grade of CFCs purity whereas TGF-β1 showed very variable levels; c) soluble molecules detected in CFCs exert immunomodulatory effects in vitro like apoptosis induction in Jurkat cells and inhibition of mixed lymphocyte reaction response, antigen-specific lymphocyte cytotoxic activity and neutrophil chemotaxis.

AIRE polymorphism, melanoma antigen-specific T cell immunity, and susceptibility to melanoma

AIRE is involved in susceptibility to melanoma perhaps regulating T cell immunity against melanoma antigens (MA). To address this issue, AIRE and MAGEB2 expressions were measured by real time PCR in medullary thymic epithelial cells (mTECs) from two strains of C57BL/6 mice bearing either T or C allelic variant of the rs1800522 AIRE SNP. Moreover, the extent of apoptosis induced by mTECs in MAGEB2-specific T cells and the susceptibility to in vivo melanoma B16F10 cell challenge were compared in the two mouse strains.The C allelic variant, protective in humans against melanoma, induced lower AIRE and MAGEB2 expression in C57BL/6 mouse mTECs than the T allele. Moreover, mTECs expressing the C allelic variant induced lower extent of apoptosis in MAGEB2-specific syngeneic T cells than mTECs bearing the T allelic variant (p < 0.05). Vaccination against MAGEB2 induced higher frequency of MAGEB2-specific CTL and exerted higher protective effect against melanoma development in mice bearing the CC AIRE genotype than in those bearing the TT one (p < 0.05). These findings show that allelic variants of one AIRE SNP may differentially shape the MA-specific T cell repertoire potentially influencing susceptibility to melanoma.

The antiphospholipid syndrome: from pathophysiology to treatment

Antiphospholipid antibody syndrome (APS) is an autoimmune acquired thrombophilia characterized by recurrent thrombosis and pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). APS can be primary, if it occurs in the absence of any underlying disease, or secondary, if it is associated with another autoimmune disorder, most commonly systemic lupus erythematosus. The exact pathogenetic mechanism of APS is unknown, but different, not mutually exclusive, models have been proposed to explain how anti-PL autoantibodies might lead to thrombosis and pregnancy morbidity. Diagnosis of APS requires that a patient has both a clinical manifestation (arterial or venous thrombosis and/or pregnancy morbidity) and persistently positive aPL, but the clinical spectrum of the disease encompasses additional manifestations which may affect every organ and cannot be explained exclusively by a prothrombotic state. Treatment for aPL-positive patients is based on the patient's clinical status, presence of an underlying autoimmune disease, and history of thrombotic events. In case of aPL positivity without previous thrombotic events, the treatment is mainly focused on reduction of additional vascular risk factors, while treatment of patients with definite APS is based on long-term anticoagulation. Pregnancy complications are usually managed with low-dose aspirin in association with low molecular weight heparin. Refractory forms of APS could benefit from adding hydroxychloroquine and/or intravenous immunoglobulin to anticoagulation therapy. Promising novel treatments include anti-B cell monoclonal antibodies, new-generation anticoagulants, and complement cascade inhibitors. The objective of this review paper is to summarize the recent literature on APS from pathogenesis to current therapeutic options.

A multi-peptide, dual-adjuvant telomerase vaccine (GX301) is highly immunogenic in patients with prostate and renal cancer

BACKGROUND

Anti-tumor vaccination is a new frontier in cancer treatment applicable to immunogenic neoplasms such as prostate and renal cancers. GX301 is a vaccine constituted by four telomerase peptides and two adjuvants, Montanide ISA-51 and Imiquimod.

OBJECTIVE

The aim of this study was to analyze safety and tolerability of GX301 in an open-label, phase I/II trial. Immunological and clinical responses were also evaluated as secondary endpoints.

EXPERIMENTAL DESIGN

GX301 was administered by intradermally injecting 500 μg of each peptide (dissolved in Montanide ISA-51) in the skin of the abdomen. Imiquimod was applied as a cream at the injection sites. The protocol included 8 administrations at days 1, 3, 5, 7, 14, 21, 35, 63. Eligible patients were affected with stage IV prostate or renal cancer resistant to conventional treatments. Patients were clinically and immunologically monitored up to 6 months from the first immunization.

RESULTS

No grade 3-4 adverse events were observed. Evidence of vaccine-specific immunological responses was detected in 100 % of patients. Disease stabilization occurred in 4 patients. Prolonged progression-free survival and overall survival were observed in patients showing a full pattern of vaccine-specific immunological responses.

CONCLUSION

GX301 demonstrated to be safe and highly immunogenic. Further studies are needed to determine its clinical efficacy.

Cyclophosphamide inhibits the generation and function of CD8(+) regulatory T cells

CD8(+) regulatory T cells (Treg) and CD4(+)CD25(+) Treg infiltrate human cancers, thus favoring tumor immune escape. Therefore, in the setting of antitumor therapeutic protocols, it is important to associate antitumor treatment with agents that are able to inhibit Treg function. Cyclophosphamide (CY) has been demonstrated to be effective in counteracting CD4(+)CD25(+) Treg activity. Hence, we tested its inhibitory efficacy on human CD8(+) Treg. Because CY is a prodrug, 4-hydroperoxycyclophosphamide (4-HC), a derivative of CY that in aqueous solution is converted to 4-hydroxycyclophosphamide, an active metabolite of CY, was used. 4-HC significantly inhibited CD8(+) Treg generation and function but only at the higher tested concentration (0.5 μg/mL), that is, in the therapeutic range of the drug. The lower 4-HC concentration tested (0.1 μg/mL) was almost ineffective. 4-HC inhibitory effects were related to apoptosis/necrosis induction. When CD8(+)CD28(+) non-Treg were analyzed for comparative purposes, significantly lower cytotoxic rates among these cells were observed than among CD8(+) Treg, which were differentiated because they did not express the CD28 molecule. These data demonstrate that CD8(+) Treg are inhibited through cytotoxic phenomena by CY, thus supporting the use of this drug at adequate concentrations and schedules of administration as a Treg inhibitor in combinatorial chemo- or immunotherapeutic anticancer protocols.

Role of advanced oxidation protein products and Thiol ratio in patients with acute coronary syndromes

OBJECTIVES

To identify systemically detectable vascular inflammation associated to redox system unbalance, advanced oxidation protein products (AOPP), formed by HClO reaction with proteins, Thiol levels, and their ratio (AOPP/Thiol ratio) were measured in patients with acute coronary syndromes (ACS).

DESIGN AND METHODS

We evaluated AOPP/Thiol ratio together with CRP and IL-1β in 18 acute myocardial infarction (AMI) and in 16 unstable angina (UA) patients at admission, and in 16 control subjects (CTR); the measurements were repeated at 1 and at 6 months.

RESULTS

At admission, AMI and UA patients displayed higher AOPP/Thiol ratio and CRP and IL-1β compared to CTR subjects. A correlation between AOPP/Thiols and IL-1β in AMI was found. At follow-up, in UA only, AOPP/Thiol ratio and IL-1β levels still remained high.

CONCLUSIONS

The AOPP/Thiol ratio seems to affect the inflammatory process in ACS, and may represent a reliable marker of oxidative unbalance in this setting of patients.

Iodized oil pleural effusion in a patient previously treated with transarterial chemoembolization for hepatocellular carcinoma

Transarterial chemoembolization (TACE) is a nonsurgical therapeutic option for the control of hepatocellular carcinoma (HCC) in patients with cirrhosis. Although less invasive than surgical approaches, this procedure can have severe side effects, with both local and extrahepatic complications, mostly related to treatment-induced ischemic damage. Here, we describe the case of a cirrhotic female patient affected by multinodular HCC, who presented with sudden onset dyspnea and chest pain. After a thorough follow-up, her condition was found to be due to iodinized oil pleural effusion following diaphragm rupture by a fistula. This had developed from a sterile abscess formed on the site of a previously performed TACE. We discuss the differential diagnosis and the management of this case, which, to our knowledge, has never been described as a late side effect of TACE.

CD8(+) T regulatory/suppressor cells and their relationships with autoreactivity and autoimmunity

Regulatory T lymphocytes (Treg) are fundamental for immune homeostasis since they contribute to the induction of peripheral tolerance to autologous antigens and regulate effector immune responses. Treg subsets are present within both the CD4+and the CD8(+) T cell compartments. Considering the CD8(+) Treg, in the last decades several subpopulations, provided with different phenotypes and mechanisms of action, have been characterized. This review is an attempt of integrating in an organic scenario the different CD8(+) Treg subpopulations. Moreover, it summarizes the findings so far achieved on the existence of CD8(+) Treg alterations in autoimmune diseases.

Phenotypical and functional alterations of CD8 regulatory T cells in primary biliary cirrhosis

The mechanisms that lead to loss of tolerance in autoimmune disease have remained both elusive and diverse, including both genetic predisposition and generic dysregulation of critical mononuclear cell subsets. In primary biliary cirrhosis (PBC), patients exhibit a multilineage response to the E2 component of pyruvate dehydrogenase involving antibody as well as autoreactive CD4 and CD8 responses. Recent data from murine models of PBC have suggested that a critical mechanism of biliary destruction is mediated by liver-infiltrating CD8 cells. Further, the number of autoreactive liver-infiltrating CD4 and CD8 cells is significantly higher in liver than blood in patients with PBC. Based on this data, we have studied the frequencies and phenotypic characterization of both CD4 and CD8 regulatory T cell components in both patients with PBC and age-sex matched controls. Our data is striking and indicate that CD8 Treg populations from PBC patients, but not controls, have significant phenotypic alterations, including increased expression of CD127 and reduced CD39. Furthermore, in vitro induction of CD8 Tregs by incubation with IL10 is significantly reduced in PBC patients. Importantly, the frequencies of circulating CD4+CD25+ and CD8+ and CD28- T cell subpopulations are not significantly different between patients and controls. In conclusion, these data identify the CD8 Treg subset as a regulatory T cell subpopulation altered in patients with PBC.

The role of AIRE polymorphisms in melanoma

Polymorphisms of AIRE, a transcription factor that up-regulates intrathymic expression of tissue-specific antigens including melanoma-associated antigens (MAAs), may variably affect the selection of MAAs-specific thymocytes, generating T-cell repertoires protecting or predisposing individuals to melanoma. We found that AIRE single nucleotide polymorphisms (SNPs) rs1055311, rs1800520 and rs1800522 were significantly more frequent in healthy subjects than in melanoma patients, independently from sex, age and stages of melanoma. The presence of these SNPs was associated with increased frequency of two T-cell clonotypes specific for MAGE-1 linking their protective effect to selection/expansion of MAA-specific T cells. Interestingly, mRNA transcribed on the rs1800520 SNP showed increased free energy than the wild type suggesting that its reduced stability may be responsible for the different activity of the polymorphic AIRE molecule. This finding may contribute at identifying subjects with increased risk of developing melanoma or patients with melanoma that may take benefit from immunotherapy.

Characteristics of joint involvement and relationships with systemic inflammation in systemic sclerosis: results from the EULAR Scleroderma Trial and Research Group (EUSTAR) database

OBJECTIVE

To determine the prevalence of and independent factors associated with joint involvement in a large population of patients with systemic sclerosis (SSc).

METHODS

This study was cross-sectional, based on data collected on patients included in the European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) registry. We queried this database to extract data regarding global evaluation of patients with SSc and the presence of any clinical articular involvement: synovitis (tender and swollen joints), tendon friction rubs (rubbing sensation detected as the tendon was moved), and joint contracture (stiffness of the joints that decreased their range of motion). Overall joint involvement was defined by the occurrence of synovitis and/or joint contracture and/or tendon friction rubs.

RESULTS

We recruited 7286 patients with SSc; their mean age was 56 +/- 14 years, disease duration 10 +/- 9 years, and 4210 (58%) had a limited cutaneous disease subset. Frequencies of synovitis, tendon friction rubs, and joint contractures were 16%, 11%, and 31%, respectively. Synovitis, tendon friction rubs, and joint contracture were more prevalent in patients with the diffuse cutaneous subset and were associated together and with severe vascular, muscular, renal, and interstitial lung involvement. Moreover, synovitis had the highest strength of association with elevated acute-phase reactants taken as the dependent variable.

CONCLUSION

Our results highlight the striking level of articular involvement in SSc, as evaluated by systematic examination in a large cohort of patients with SSc. Our data also show that synovitis, joint contracture, and tendon friction rubs are associated with a more severe disease and with systemic inflammation.

Brachial artery endothelial-dependent flow-mediated dilation identifies early-stage endothelial dysfunction in systemic sclerosis and correlates with nailfold microvascular impairment

OBJECTIVE

To assess possible correlations between endothelial-dependent flow-mediated dilation (FMD) of the brachial artery and nailfold videocapillaroscopy (NVC) in patients with systemic sclerosis (SSc). Evidence has shown that vascular impairment in SSc may be a sign of endothelial dysfunction involving both microvascular and macrovascular systems, although the pathological mechanisms of the dysfunction are poorly understood.

METHODS

Forty-three consecutive patients (mean age 51 +/- 11 yrs) with SSc were studied. Thirty patients had limited cutaneous SSc, 13 had diffuse cutaneous SSc. Twenty-seven healthy subjects (mean age 48 +/- 8 yrs) were recruited as controls. Ultrasound assessment of FMD was performed on all subjects in order to evaluate macrovascular function. Patients were divided into 3 patterns of microvascular damage on the basis of NVC (early, active, and late), and the microangiopathy evolution score was calculated, as reported elsewhere.

RESULTS

FMD was significantly reduced in patients with SSc compared to healthy subjects [median 8.0% (3.0%-9.0%) vs 15.0% (12.0%-16.0%), respectively; p < 0.0001]. Patients with an early pattern of microangiopathy showed reduced FMD values compared to controls (p = 0.0001). FMD was significantly reduced in patients with SSc who had the late NVC pattern of microangiopathy compared to active and early patterns (p = 0.003 and p = 0.001, respectively). FMD was inversely correlated with the microvascular damage rate in patients with SSc (p < 0.0001).

CONCLUSION

We demonstrated the simultaneous presence of macrovascular and microvascular impairment in patients with SSc, which was already present in the early phase of the vascular disease.

[Possible connection between gastroesophageal reflux and interstitial pulmonary fibrosis in patients with systemic sclerosis]

Interstitial lung disease represents the main cause of morbidity and mortality in patients with systemic sclerosis. The mechanisms leading to interstitial lung disease are poorly understood and thus current strategies have little effect on this progressive and fatal disease. Therefore, it appears relevant the importance to assess the possible risk factors involved in its pathogenesis. Previous studies in vivo and in vitro suggested that pulmonary fibrosis can occur after repeated aspiration of small amounts of gastric contents over long periods of time. Recently, our group observed that patients with systemic sclerosis and pulmonary fibrosis have a more severe degree of gastroesophageal reflux with a greater number of reflux events and a higher percentage of reflux episodes reaching the proximal esophagus, causing an increasing risk of microaspiration, compared to patients with systemic sclerosis without lung involvement. Further larger controlled studies are necessary to evaluate whether or not the development of interstitial lung disease in systemic sclerosis patients can be prevented by treating gastroesophageal reflux.

Behavior of non-classical soluble HLA class G antigens in human immunodeficiency virus 1-infected patients before and after HAART: comparison with classical soluble HLA-A, -B, -C antigens and potential role in immune-reconstitution

We have reported that serum level of soluble HLA-A, -B, -C (sHLA-A,-B,-C) antigens is elevated in HIV-infected subjects and decreases after antiretroviral therapy (HAART). In this study, we measured the levels of soluble HLA-G (sHLA-G) antigens in a cohort of HIV-infected patients before and during HAART. sHLA-G and sHLA-A, -B, -C levels were significantly elevated in HIV-infected subjects as compared with controls before antiretroviral treatment and significantly decreased after 36 months of HAART. sHLA-G levels were correlated with sHLA-A, -B, -C levels, the decrease of plasma HIV-RNA level, the increase of CD4+ T-lymphocyte number and the decrease of CD8+ T-lymphocyte number. These results suggest that the measurement of sHLA-G and sHLA-A, -B, -C antigen serum levels might represent a useful surrogate marker to monitor virological response and immune reconstitution in HIV-positive subjects undergoing HAART treatment.

Flu vaccination with a virosomal vaccine does not affect clinical course and immunological parameters in scleroderma patients

Safety and efficacy of adjuvanted vaccines in autoimmune individuals raises growing clinical and scientific interest. Protection from influenza would bring particular benefits in these patients with common cardiac and respiratory impairment. This study evaluates efficacy, clinical safety and immune effects of the administration of a single dose of a virosomal flu vaccine in 46 scleroderma patients. The following parameters were evaluated before and after administration of Inflexal: clinical conditions, inflammation and autoimmunity parameters, humoral response, lymphocyte proliferation and cytokine production upon flu antigen stimulation by specific and non-specific cells. Inflexal was found effective in scleroderma patients. In no subject was worsening of clinical conditions, inflammation and immunological parameters observed.

Gastroesophageal reflux and pulmonary fibrosis in scleroderma: a study using pH-impedance monitoring

RATIONALE

Interstitial lung disease (ILD) in patients with systemic sclerosis (SSc) is associated with increased morbidity and mortality. Gastroesophageal reflux (GER) is considered a contributing factor in the pathogenesis of ILD.

OBJECTIVES

To characterize GER (acid and nonacid) in patients with SSc with and without ILD.

METHODS

Patients with SSc underwent pulmonary high-resolution computer tomography (HRCT) scan and 24-hour impedance-pH monitoring off-proton pump inhibitor therapy. The presence of pulmonary fibrosis was assessed using validated HRCT-scores. Reflux monitoring parameters included number of acid and nonacid reflux episodes, proximal migration of the refluxate, and distal esophageal acid exposure. Unless otherwise specified, data are presented as median (25th-75th percentile).

MEASUREMENTS AND MAIN RESULTS

Forty consecutive patients with SSc (35 female; mean age, 53 yr; range, 24-71; 15 patients with diffuse and 25 with limited SSc) were investigated; 18 (45%) patients with SSc had pulmonary fibrosis (HRCT score >or= 7). Patients with SSc with ILD had higher (P < 0.01) esophageal acid exposure (10.3 [7.5-15] vs. 5.2 [1.5-11]), higher (P < 0.01) number of acid (41 [31-58] vs. 19 [10-23]) and nonacid (25 [20-35] vs. 17 [11-19]) reflux episodes, and higher (P < 0.01) number of reflux episodes reaching the proximal esophagus (42.5 [31-54] vs. 15 [8-22]) compared with patients with SSc with normal HRCT scores. Pulmonary fibrosis scores (HRCT score) correlated well with the number of reflux episodes in the distal (r(2) = 0.637) and proximal (r(2) = 0.644) esophagus.

CONCLUSIONS

Patients with SSc with ILD have more severe reflux (i.e., more reflux episodes and more reflux reaching the proximal esophagus). Whether or not the development of ILD in patients with SSc can be prevented by reflux-reducing treatments needs to be investigated.

Advancements on phenotypic and functional characterization of non-antigen-specific CD8+CD28- regulatory T cells

Among the different regulatory T lymphocyte (Treg) subpopulations, non-antigen-specific CD8+CD28- Treg (CD8+CD28- Treg) have been characterized for being involved in the pathogenesis of autoimmune diseases and cancer. A better phenotypic and functional characterization of this regulatory T-cell subset could help in identifying modulators of their activity with therapeutic finalities. The results of the present work show that Foxp3, a transcriptional marker of natural CD4+CD25+ Treg, is not expressed by CD8+CD28- Treg, thus indicating different origin and pathways of function for the latter with respect to the former regulatory cell type. Moreover, the results underline that the glucocorticoid induced TNF receptor is involved in generation processes but not in suppressor function of CD8+CD28- Treg. Phenotypic analyses demonstrate that, during their commitment from circulating nonregulatory CD8+CD28- T lymphocytes to Treg (an interleukin-10-dependent process), these cells downmodulate the IL7-receptor, thus differentiating them from long-lived, memory CD8+ T lymphocytes. Interestingly, CD8+CD28- Treg have been found to be resistant to the inhibitory effects of methylprednisolone, one of the most frequently administered corticosteroid drug used in therapy for immunosuppressive purposes.

Relationship between soluble HLA-G and HLA-A,-B,-C serum levels, and interferon-gamma production after sublingual immunotherapy in patients with allergic rhinitis

Allergic rhinitis (AR) is characterized by a T-helper (Th)-2 (Th2) polarized immune response. Soluble human leukocyte antigen (sHLA) molecules play an immunomodulatory role. Specific immunotherapy is the only causal treatment for AR and is able to shift the immune response to Th1 polarization. The aim of this study was to evaluate the relationship between sHLA-G and sHLA-A,-B,-C serum levels and interferon-gamma (IFN-gamma) production in AR patients with pollen allergy before and after a preseasonal course of sublingual immunotherapy (SLIT). A total of 40 AR patients with pollen allergy were enrolled and given a course of preseasonal SLIT for 3 months. Serum sHLA-G and sHLA-A,-B,-C levels were determined by enzyme-linked immunoabsorbent assay, and cell production of IFN-gamma was evaluated by enzyme-linked immunoabsorbent spot assay at baseline and 3 months after the end of the SLIT course. There was a significant relationship between sHLA-G serum level change and IFN-gamma increase as well as between sHLA-A,-B,-C level change and IFN-gamma increase after SLIT. The present study provides the first published evidence that the reduction of sHLA molecules serum levels and the increased IFN-gamma production after SLIT in AR patients with pollen allergy are significantly related phenomena.

Small intestinal bacterial overgrowth in patients suffering from scleroderma: clinical effectiveness of its eradication

OBJECTIVES

After the skin, the gastrointestinal tract is the second most common target of systemic sclerosis (SSc).

AIM

Our aims were to investigate orocecal transit time (OCTT) and the presence of small intestinal bacterial overgrowth (SIBO) in SSc as a cause of intestinal symptoms.

METHODS

Fifty-five SSc patients and 60 healthy controls, sex and age matched, entered the study. Enrolled subjects completed a questionnaire for intestinal symptoms and a global symptomatic score (GSS) was calculated. OCTT and the presence of SIBO were assessed by a lactulose breath test (LBT). Patients with SIBO were treated with rifaximin 1,200 mg/day for 10 days. Finally, a second questionnaire and LBT were performed 1 month after the end of therapy.

RESULTS

The prevalence of SIBO was higher in SSc patients compared with controls (30/54 vs 4/60, respectively, P < 0.001). OCTT was significantly slower in SSc patients compared with controls (150 min, 25-75th percentile 142.5-165 vs 105 min, 25-75th percentile 90-135, respectively, P < 0.001). In patients with SIBO, the median GSS score was 8 (25-75th percentile 3.25-10.75). Eradication of SIBO was achieved in 73.3% of patients, with a significant reduction of symptoms in 72.7% of them (GSS score 2, 25-75th percentile 1-3, P < 0.05).

CONCLUSIONS

These data suggest that SIBO occurs more frequently in SSc patients than in controls. Intestinal symptoms in these patients may be related to this syndrome and its eradication seems useful to improve clinical features. OCTT is significantly delayed in SSc patients, suggesting an impairment of intestinal motility, a further risk factor for the development of SIBO.

Safety and immunogenicity of two influenza virus subunit vaccines, with or without MF59 adjuvant, administered to human immunodeficiency virus type 1-seropositive and -seronegative adults

The objective of this study was to evaluate and compare both the safety and tolerability and the humoral and cell-mediated immune responses for two influenza virus subunit vaccines, one with MF59 adjuvant (Fluad) and one without an adjuvant (Agrippal), in healthy and in human immunodeficiency virus type 1 (HIV-1)-infected adult individuals. To achieve this aim, an open, randomized, comparative clinical trial was performed during the 2005-2006 season. A total of 256 subjects were enrolled to receive one dose of vaccine intramuscularly. Blood samples were taken at the time of vaccination and at 1 and 3 months postvaccination. A good humoral antibody response was detected for both vaccines, meeting all the criteria of the Committee for Medical Products for Human Use. After Beyer's correction for prevaccination status, Fluad exhibited better immunogenicity than Agrippal, as shown from the analysis of the geometric mean titers, with significant differences for some virus strains; however, no definitive conclusions on the clinical significance of such results can be drawn, because the method used to estimate antibody response is currently nonstandard for influenza virus vaccines. Significant induction of an antigen-specific CD4+ T-lymphocyte proliferative response was detected at all time points after immunization, for both the vaccines, among HIV-1-seronegative subjects. This was different from what was observed for HIV-1-infected individuals. In this group, significance was not reached at 30 days postvaccination (T30) for those immunized with Agrippal. Also when data were compared between treatment groups, a clear difference in the response at T30 was observed in favor of Fluad (P = 0.0002). The safety profiles of both vaccines were excellent. For HIV-1-infected individuals, no significant changes either in viremia or in the CD4+ cell count were observed at any time point. The results showed good safety and immunogenicity for both vaccines under study for both uninfected and HIV-1-infected adults, confirming current recommendations for immunization of this high-risk category.

Gene vaccination for the induction of immune tolerance

DNA vaccination is a strategy of immunization based on the injection of a gene encoding for a target protein with the goal of eliciting a potentially protective immune response in the host. Compared to traditional immunization procedures, DNA vaccination offers several advantages: increased availability of antigenic peptides because of the endogenous and long-term synthesis of the gene product, improved antigen processing and presentation, possibility of antigen structure modeling through molecular engineering, coexpression of immunologically relevant agents, and low cost of vaccine production. Although the choice of the most appropriate vector for gene transfer may still be controversial, the application of DNA vaccination to the treatment of autoimmune diseases in different experimental animal models has demonstrated the great potential of this procedure for therapeutic purposes. DNA vaccination has been successful in protecting mice from the development of organ-specific autoimmunity (experimental allergic encephalomyelitis (EAE), autoimmune diabetes, experimental arthritis, experimental uveitis) as well as systemic autoimmune disease (systemic lupus erythematosus (SLE), antiphospholipid syndrome). The protection appears to be highly influenced by the capacity of DNA vaccination to modulate immune responses affecting the Th1, Th2 and, importantly, the T cell immunoregulatory arms. We review here the experimental evidence and most recent data supporting the use of DNA vaccination in the induction of immune tolerance.

Cardiac magnetic resonance imaging detects subclinical right ventricular impairment in systemic sclerosis

OBJECTIVE

To assess myocardial involvement in patients with systemic sclerosis (SSc) with no signs or symptoms of cardiac impairment (New York Heart Association functional class I).

METHODS

Fifty patients (45 women, 5 men, age 53.3 +/- 12.9 yrs) who did not complain of serious diseases other than SSc were recruited out of 119 consecutive patients with SSc. Thirty-three were found to have limited cutaneous SSc (lSSc) and 17 diffuse SSc (dSSc). All underwent cardiovascular magnetic resonance imaging (MRI) to determine right and left systolic and diastolic volumes and ventricular ejection fractions (RVEF and LVEF). Thirty-one healthy subjects matched for sex, age, and body surface area (BSA) were studied as controls. Diffusion lung capacity test (DLCO) and high resolution computed tomography were performed to evaluate lung involvement.

RESULTS

Disease duration between patients with lSSc (14.1 +/- 11.4 yrs) and those with dSSc (6.9 +/-4.4yrs) was found to be significantly different (p < 0.003). lSSc patients were older than those with dSSc (54.8 +/- 13.7 yrs vs 50.4 +/- 9.9 yrs, respectively; p < 0.04). Anticentromere antibodies and Scl-70 were positive in 23 (46%) and 17 patients (34%). Except for the left and right systolic volumes, all unadjusted cardiac MRI measures were significantly reduced in SSc compared to the controls (p < 0.001 and p < 0.009). These differences persisted after adjustment for subjects' height and BSA. Raw RVEF data and RVEF data matched for height and BSA were significantly reduced in dSSc patients in comparison to lSSc (p < 0.03).

CONCLUSION

Compromised RVF was found in patients with asymptomatic SSc. Unlike standard diagnostic techniques, cardiac MRI appears to be a rapid and noninvasive means of determining subclinical right myocardial involvement that is otherwise undetected in patients with SSc.

Behavior of serum human major histocompatibility complex class I antigen levels in human immunodeficiency virus-infected patients during antiretroviral therapy: correlation with clinical outcome

Human major histocompatibility complex class I antigens (HLA-A, -B, and -C) are heterodimeric molecules composed of a alpha heavy chain noncovalently associated with an invariant protein known as beta(2)-microglobulin. Beside being expressed on the membrane of the large majority of nucleated cells, HLA class I antigens are evident in serum (sHLA-I). We have previously detected a significant increase in the serum level of beta(2)-microglobulin-associated HLA-I antigens in human immunodeficiency virus (HIV)-infected patients compared with HIV-negative controls. The introduction of highly active antiretroviral therapy (HAART) modified the clinical course of the disease and decreased the acquired immunodeficiency syndrome-related morbidity and mortality. Therefore, we measured the levels of sHLA-I antigens in 64 HIV-infected patients before and during HAART treatment and correlated them with the immunological and virological response to antiretroviral treatment. Serum sHLA-I antigen level was elevated in all HIV-infected patients before and significantly decreased after 36 months of HAART treatment, correlating with the decrease of plasma HIV-RNA level and with the increase of CD4+ T-lymphocyte number. These results suggest that the measurement of sHLA-I antigens serum level might represent a useful surrogate marker to monitor HIV-positive patients undergoing HAART treatment.

CD8+CD28− T Regulatory Lymphocytes Inhibiting T Cell Proliferative and Cytotoxic Functions Infiltrate Human Cancers

Tumor growth is allowed by its ability to escape immune system surveillance. An important role in determining tumor evasion from immune control might be played by tumor-infiltrating regulatory lymphocytes. This study was aimed at characterizing phenotype and function of CD8+ CD28- T regulatory cells infiltrating human cancer. Lymphocytes infiltrating primitive tumor lesion and/or satellite lymph node from a series of 42 human cancers were phenotypically studied and functionally analyzed by suppressor assays. The unprecedented observation was made that CD8+ CD28- T regulatory lymphocytes are almost constantly present and functional in human tumors, being able to inhibit both T cell proliferation and cytotoxicity. CD4+ CD25+ T regulatory lymphocytes associate with CD8+ CD28- T regulatory cells so that the immunosuppressive activity of tumor-infiltrating regulatory T cell subsets, altogether considered, may become predominant. The infiltration of regulatory T cells seems tumor related, being present in metastatic but not in metastasis-free satellite lymph nodes; it likely depends on both in situ generation (via cytokine production) and recruitment from the periphery (via chemokine secretion). Collectively, these results have pathogenic relevance and implication for immunotherapy of cancer.

Protection against renal disease in (NZB x NZW)F(1) lupus-prone mice after somatic B cell gene vaccination with anti-DNA immunoglobulin consensus peptide

OBJECTIVE

Ig molecules contain epitopes that can induce T cell-mediated immune responses. B cells can process and present such epitopes and activate T cells. The purpose of the present study was to test our hypothesis that T cells that recognize an Ig consensus sequence presented by B cells will modulate lupus-like disease in mice.

METHODS

(NZB x NZW)F(1) (NZB/NZW) lupus mice received somatic B cell gene transfer of a DNA plasmid encoding a consensus sequence of T cell determinants of murine anti-DNA IgG or control plasmids. Treated animals were monitored for the production of antibody, the development of renal disease, and the phenotype, number, and function of T cells.

RESULTS

Treatment of mice with Ig consensus plasmid induced transforming growth factor beta-producing CD8+,CD28- T cells that suppressed the antigen-specific stimulation of CD4+ T cells in a cell-contact-independent manner, reduced antibody production, retarded the development of nephritis, and improved survival. Significantly, adoptive transfer of CD8+,CD28- T cells from protected mice into hypergammaglobulinemic NZB/NZW mice effectively protected the transferred mice from the development of renal disease.

CONCLUSION

Gene expression of anti-DNA Ig consensus sequence induces immunoregulatory T cells that delay the development of lupus nephritis by suppressing hypergammaglobulinemia and renal disease.

Intima-Media Thickness: A Marker of Accelerated Atherosclerosis in Women with Systemic Lupus Erythematosus

Accelerated atherosclerosis is an emerging problem in patients with systemic lupus erythematosus (SLE). We planned an observational study to determine whether in patients with SLE carotid intima-media thickness (IMT) represents an early sign of accelerated atherosclerosis and to confirm that SLE adds to the traditional cardiovascular Framingham risk factors. Thirty females with SLE (age 18-65 years) underwent anamnestic, clinical, and laboratory evaluation and B-mode ultrasonography of carotid arteries, which provides a direct and noninvasive assessment of subclinical atherosclerosis. IMT measurements were performed on the right and left common carotid arteries 1.0 cm proximal to the carotid bulb and the mean IMT value was calculated with a dedicated software. The Framingham Point Score was also calculated for each subject. SLE patients showed a mean IMT value of 0.73 +/- 0.12 (SD) mm. This value is significantly (P < 0.05) higher than that reported for an age-matched healthy female control population (0.66 +/- 0.11 SD mm). A preliminary evaluation of the Framingham Point Score, estimating the 10-year risk for women to develop cardiovascular events, indicated an increased risk of early cardiovascular events in SLE patients. In our study we have shown that patients with SLE have an increased mean IMT value compared with a healthy females control. Moreover, the evaluation of the Framingham Point Score suggests that SLE is an additional risk factor for cardiovascular disease.

Association of -318 C/T and +49 A/G cytotoxic T lymphocyte antigen-4 (CTLA-4) gene polymorphisms with a clinical subset of Italian patients with systemic sclerosis

Systemic sclerosis (SSc) is a complex and heterogeneous autoimmune disorder with a multi-factorial pathogenesis. Like other autoimmune disorders, the possible role of specific cytotoxic T lymphocyte antigen-4 (CTLA-4) gene polymorphisms in predisposing to SSc has been hypothesized, but it remains controversial. CTLA-4 promoter (-318C/T) and exon 1 (+49 A/G) polymorphisms have been analysed in 43 Italian females with SSc and in 93 unrelated matched healthy controls by a newly designed tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) method. No significant association has been found with either polymorphisms.Nevertheless, SSc patients without concomitant Hashimoto's thyroiditis (HT) were carrying both the -318T allele (P = 0.031) and the +49 G allele (P = 0.076) more frequently than SSc patients with HT [defined by positivity for anti-thyroperoxidase (TPO) and anti-thyroglobulin (TGA) autoantibodies] than controls. Haplotype analysis confirms this association (P = 0.028), and suggests the predominant role of the -318T, whereas that of the +49 G, if any, seems weak. Thus, in Italian SSc patients the CTLA-4 -318C/T promoter polymorphism appears to be associated with the susceptibility to develop SSc without thyroid involvement. Larger studies are needed to confirm these findings and to clarify whether the -318C/T polymorphism is the functional responsible or whether it reflects the presence of another linked genetic element in the same chromosomal region.

AIRE gene polymorphisms in systemic sclerosis associated with autoimmune thyroiditis

Mutations in the autoimmune regulator (AIRE) gene are responsible for autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). Systemic sclerosis (SSc) is a non-organ-specific autoimmune disease mainly characterized by cutaneous involvement, that is frequently associated with other autoimmune manifestations common to APECED. Nineteen SSc patients, 22 patients affected by SSc associated with autoimmune thyroiditis, and 100 healthy controls were analyzed. We identified 11 AIRE gene variants, one of which has never previously been described. Intronic polymorphism G11107A was significantly correlated to SSc/thyroiditis. Data show that variants of the AIRE gene might be correlated to different clinical manifestations in SSc patients.

Migraine during systemic lupus erythematosus: findings from brain single photon emission computed tomography

OBJECTIVE

Headache in systemic lupus erythematosus (SLE) is controversial, as is evidence of brain impairment in patients with SLE and headache. Perfusion single photon emission computed tomography (SPECT) was performed to investigate brain impairment in SLE patients with migraine-like headache either from the period of diagnosis or later in the course of disease.

METHODS

Eighteen patients with SLE (mean age 40.8 +/- 13.6 yrs) matching these characteristics underwent brain SPECT with 99mTc-HMPAO in the interictal period. Electroencephalography (EEG) and magnetic resonance imaging (MRI) were performed in 12 and 10 patients, respectively. SPECT was analyzed through visual and asymmetry combined analysis as well as by voxel-based statistical analysis compared to a control group of matched healthy subjects (statistical threshold: p = 0.01).

RESULTS

Focal hypoperfusion was evidenced in 15 (83%) patients, often matching the main side of pain location, whereas EEG and MRI each gave a positive result in 50% of cases. Using voxel-based analysis, significant hypoperfusion was found in 8 (44%) patients, either lateralized to one side or localized to the anterior cingulate cortex, independent of pain location.

CONCLUSION

Brain perfusion SPECT is a sensitive tool for identifying brain impairment in SLE-related migraine, although the mechanisms of brain damage remain to be elucidated. Besides confirming focal hypoperfusion in some patients, in 4 patients statistical analysis revealed interictal hypofunction of the anterior cingulate cortex, a key structure for cortical elaboration of pain in the midline network.

Endocrine Regulation of Suppressor Lymphocytes: Role of the Glucocorticoid-Induced TNF-Like Receptor

Mechanisms responsible for peripheral immune tolerance are currently under investigation in several laboratories, in order to define the role of immune homeostasis in physiological processes and pathologic conditions, such as autoimmunity and cancer. In this context, recent studies attributed a relevant role to the glucocorticoid-induced TNFR-related gene (GITR). GITR is expressed at high levels on CD4(+)CD25(+). T regulatory (Treg) cells, but only at low levels on resting responder T lymphocytes, and is upregulated after activation. GITR triggering induces both pro- and anti-apoptotic effects through different intracellular pathways, abrogates the suppressive activity of Treg cells, and co-stimulates responder T cells. These data hint that GITR triggering overstimulates the immune system. Indeed, in vivo studies demonstrated that GITR stimulation may both induce autoimmune diseases and strengthen anti-virus and anti-tumor immune responses. Therefore, the GITR-GITRL system appears crucial in regulating immunity. Currently, the majority of studies about GITR's role on regulatory cells are focused on CD4(+)CD25(+) Treg cells, while very little is known about the importance of this molecule in other Treg subtypes. We have recently characterized a subpopulation of CD8+ T suppressor lymphocytes able to inhibit both T cell proliferation and cytotoxicity. Preliminary data show that GITR is expressed on such CD8+ T suppressor cells and that its activation by a specific antibody inhibits generation, but not function, of these cells. These early results suggest the importance of GITR in human T suppressor lymphocytes other than CD4(+)CD25(+) Treg cells.

Frequency of telomerase-specific CD8+ T lymphocytes in patients with cancer

Telomerase is considered a universal tumor-associated antigen (TAA) due to its high rate of expression by cancers (≈90%), and clinical trials are in progress to test the immunotherapeutical efficacy of antitelomerase immunization in patients with cancer. However, the data concerning frequency and functional activity of telomerase-specific cytotoxic T lymphocytes (CTLs) in patients with cancer are few and conflicting, although their knowledge would be mandatory to predict the efficacy of telomerase-specific immunotherapy in selected patients. We performed this study to analyze frequency and cytolytic function of circulating CD8+ T lymphocytes specific for the p540 telomerase peptide in a series of human leukocyte antigen (HLA)–A2+ cancer patients. The results show that most patients with cancer have circulating telomerase-specific CD8+ T lymphocytes, but a high frequency of telomerase-specific CTLs are present only in a fraction of them. Furthermore, CTL lines able to kill telomerase-positive tumor cells, including autologous cancer cells, can be expanded ex vivo from some, but not all, patients with cancer. In conclusion, the results of the study support the development of clinical protocols using telomerase peptides as an immunizing agent. However, they underline the necessity to study single patients immunologically before undergoing vaccination, to select the patients adequately, and to eventually adapt the immunization schedule to the patient's immunologic status.

Disruption of immunological tolerance: role of AIRE gene in autoimmunity

The mechanism underlying the generation of T and B autoreactive clones in autoimmune diseases is still unknown. Among genetic factors implicated in autoimmunity, Autoimmune Regulator gene (AIRE) is one of the candidates to better understand the complex scenario of autoimmune manifestations. AIRE mutations are responsible for the development of autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) with monogenic autosomal recessive inheritance; it has been shown that AIRE regulates the negative selection of autoreactive T cells clones, driving the transcription of tissue-specific antigens in thymic epithelial cells. In various autoimmune manifestations correlated or not to APECED, AIRE variants act in a semidominant manner, leading to a reduction in AIRE protein amount per cell, and consequently to a marked decrease in ectopic proteins expression in the thymus. The co-occurrence of autoimmune diseases in the same individual has prompted several studies aimed to recognize shared patho-physiological mechanisms; in this scenario small reductions in function could explain the predisposition to autoimmunity in AIRE-heterozygous carriers of missense mutations; further studies to investigate whether the AIRE gene is involved in determining these autoimmune manifestations should be carried out.

Apoptosis of antigen-specific T lymphocytes upon the engagement of CD8 by soluble HLA class I molecules is Fas ligand/Fas mediated: evidence for the involvement of p56lck, calcium calmodulin kinase II, and Calcium-independent protein kinase C signaling pathways and for NF-kappaB and NF-AT nuclear translocation

The binding of soluble HLA class I (sHLA-I) molecules to CD8 on EBV-specific CTL induced up-regulation of Fas ligand (FasL) mRNA and consequent sFasL protein secretion. This, in turn, triggered CTL apoptosis by FasL/Fas interaction. Molecular analysis of the biochemical pathways responsible for FasL up-regulation showed that sHLA-I/CD8 interaction firstly induced the recruitment of src-like p56(lck) and syk-like Zap-70 protein tyrosine kinases (PTK). Interestingly, p59(fyn) was activated upon the engagement of CD3/TCR complex but not upon the interaction of sHLA-I with CD8. In addition, sHLA-I/CD8 interaction, which is different from signaling through the CD3/TCR complex, did not induce nuclear translocation of AP-1 protein complex. These findings suggest that CD8- and CD3/TCR-mediated activating stimuli can recruit different PTK and transcription factors. Indeed, the engagement of CD8 by sHLA-I led to the activation of Ca2+ calmodulin kinase II pathway, which eventually was responsible for the NF-AT nuclear translocation. In addition, we found that the ligation of sHLA-I to CD8 recruited protein kinase C, leading to NF-kappaB activation. Both NF-AT and NF-kappaB were responsible for the induction of FasL mRNA and consequent CTL apoptosis. Moreover, FasL up-regulation and CTL apoptotic death were down-regulated by pharmacological specific inhibitors of Ca2+/calmodulin/calcineurin and Ca2+-independent protein kinase C signaling pathways. These findings clarify the intracellular signaling pathways triggering FasL up-regulation and apoptosis in CTL upon sHLA-I/CD8 ligation and suggest that sHLA-I molecules can be proposed as therapeutic tools to modulate immune responses.

Decay of human immunodeficiency virus type 1 unintegrated DNA containing two long terminal repeats in infected individuals after 3 to 8 years of sustained control of viremia

Covert human immunodeficiency virus (HIV) replication was ongoing during the first 3 years of aviremia in 22 patients, as determined by detection of DNA containing two long terminal repeats (2 LTR DNA). Although total HIV DNA was detected in 60 2 LTR DNA-negative samples, the absence of 2 LTR DNA in 90% of patients following 7 to 8 years of highly active antiretroviral therapy suggests suppression of cryptic viral replication.