HLA-DR3 antigens in erosive oral lichen planus, cutaneous lichen planus, and lichenoid reactions

Crossroads between Skin and Endocrine Glands: The Interplay of Lichen Planus with Thyroid Anomalies

In this narrative review, we aimed to overview the interplay between lichen planus (LP) and thyroid conditions (TCs) from a dual perspective (dermatologic and endocrine), since a current gap in understanding LP-TC connections is found so far and the topic is still a matter of debate. We searched PubMed from Inception to October 2023 by using the key terms "lichen planus" and "thyroid", (alternatively, "endocrine" or "hormone"). We included original clinical studies in humans according to three sections: LP and TC in terms of dysfunction, autoimmunity, and neoplasia. Six studies confirmed an association between the thyroid dysfunction (exclusively hypothyroidism) and LP/OL (oral LP); of note, only one study addressed cutaneous LP. The sample size of LP/OLP groups varied from 12-14 to 1500 individuals. Hypothyroidism prevalence in OLP was of 30-50%. A higher rate of levothyroxine replacement was identified among OLP patients, at 10% versus 2.5% in controls. The highest OR (odd ratio) of treated hypothyroidism amid OLP was of 2.99 (p < 0.005). Hypothyroidism was confirmed to be associated with a milder OLP phenotype in two studies. A single cohort revealed a similar prevalence of hypothyroidism in LP versus non-LP. Non-confirmatory studies (only on OLP, not cutaneous LP) included five cohorts: a similar prevalence of hypothyroidism among OLP versus controls, and a single cohort showed that the subjects with OLP actually had a lower prevalence of hypothyroidism versus controls (1% versus 4%). Positive autoimmunity in LP/OLP was confirmed in eight studies; the size of the cohorts varied, for instance, with 619 persons with LP and with 76, 92, 105, 108, 192, 247, and 585 patients (a total of 1405) with OLP, respectively; notably, the largest control group was of 10,441 individuals. Four clusters of approaches with respect to the autoimmunity in LP/OLP were found: an analysis of HT/ATD (Hashimoto's thyroiditis/autoimmune thyroid diseases) prevalence; considerations over the specific antibody levels; sex-related features since females are more prone to autoimmunity; and associations (if any) with the clinical aspects of LP/OLP. HT prevalence in OLP versus controls was statistically significantly higher, as follows: 19% versus 5%; 12% versus 6%; and 20% versus 9.8%. A single study addressing LP found a 12% rate of ATDs. One study did not confirm a correlation between OLP-associated clinical elements (and OLP severity) and antibody values against the thyroid, and another showed that positive TPOAb (anti-thyroperoxidase antibodies) was more often found in erosive than non-erosive OLP (68% versus 33%). Just the reverse, one cohort found that OLP subjects had a statistically significantly lower rate of positive TPOAb versus controls (9% versus 15%). Five case-control studies addressed the issue of levothyroxine replacement for prior hypothyroidism in patients that were diagnosed with OLP (no study on LP was identified); three of them confirmed a higher rate of this treatment in OLP (at 8.9%, 9.7%, and 10.6%) versus controls. In conclusion, with regard to LP/OLP-TC, we note several main aspects as practical points for multidisciplinary practitioners: OLP rather than LP requires thyroid awareness; when it comes to the type of thyroid dysfunction, mostly, hypothyroidism should be expected; female patients are more prone to be associated with ATDs; a potential higher ratio of OLP subjects taking levothyroxine was found, thus a good collaboration with an endocrinology team is mandatory; and so far, OLP individuals have not been confirmed to be associated with a higher risk of thyroid nodules/cancer.

Gastric parietal cell and thyroid autoantibodies in patients with burning mouth syndrome

BACKGROUND/PURPOSE

Gastric parietal cell antibody (GPCA), thyroglobulin antibody (TGA), and thyroid microsomal antibody (TMA) are organ-specific autoantibodies. This study mainly assessed the frequencies of serum GPCA, TGA, and TMA positivities in burning mouth syndrome (BMS) patients.

METHODS

Serum GPCA, TGA, and TMA levels were measured in 884 BMS patients and in 442 age- and sex-matched healthy control subjects.

RESULTS

We found that 12.3%, 21.6%, and 22.7% of 884 BMS patients and 1.8%, 2.3%, and 2.9% of 442 healthy control subjects had the serum GPCA, TGA, and TMA positivities, respectively. BMS patients had significantly higher frequencies of GPCA, TGA, and TMA positivities than healthy control subjects (all P-values < 0.001). We also found that 20 (2.3%), 130 (14.7%), and 181 (20.5%) BMS patients and 3 (0.7%), 8 (1.8%), and 6 (1.4%) healthy control subjects had the presence of three (GPCA + TGA + TMA), two (GPCA + TGA, GPCA + TMA, or TGA + TMA), or one (GPCA only, TGA only, or TMA only) organ-specific autoantibody in their sera, respectively. Of 255 TGA/TMA-positive BMS patients whose serum thyroid-stimulating hormone (TSH) levels were measured, 87.8%, 5.1%, and 7.1% of these TGA/TMA-positive BMS patients had normal, lower, and higher serum TSH levels, respectively.

CONCLUSION

Approximately 37.5% of 884 BMS patients have serum GPCA/TGA/TMA positivity. Moreover, 12.3%, 21.6%, and 22.7% of 884 BMS patients have the serum GPCA, TGA, and TMA positivities, respectively. Only 5.1% and 7.1% of TGA/TMA-positive BMS patients have hyperthyroidism and hypothyroidism, respectively. It needs further studies to know whether GPCA-positive BMS patients may finally become as having autoimmune atrophic gastritis.

Possible Mechanisms Involved in the Cooccurrence of Oral Lichen Planus and Hashimoto's Thyroiditis

Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disorder mediated by T cells, with a multifactorial etiology. Hashimoto's thyroiditis (HT) is a common autoimmune disease characterized by hypothyroidism. Although many clinical studies conducted over the past several decades have reported the cooccurrence of OLP and HT, the underlying mechanism remains unclear. This review summarizes potential mechanisms that might be involved in the cooccurrence of OLP and HT. We find that OLP and HT share a common or overlapping pathogenesis in terms of immune, heredity, environmental, and hormonal factors, which might cause cooccurrence. Furthermore, considering the latency of HT, a routine screen for thyroid diseases, particularly HT, is suggested for confirmed OLP patients.

Gastric parietal cell and thyroid autoantibodies in recurrent aphthous stomatitis patients with concomitant oral lichen planus

BACKGROUND/PURPOSE

Gastric parietal cell antibody (GPCA), thyroglobulin antibody (TGA), and thyroid microsomal antibody (TMA) have not yet been reported in recurrent aphthous stomatitis (RAS) patients with concomitant oral lichen planus (OLP/RAS patients). This study mainly assessed the frequencies of serum GPCA, TGA, and TMA (GPCA/TGA/TMA) positivities in 44 OLP/RAS patients.

METHODS

The frequencies of serum GPCA/TGA/TMA positivities in 44 OLP/RAS patients, OLP/RAS patients of four different subgroups, 520 RAS patients, and 352 healthy control subjects were calculated and compared.

RESULTS

We found that 20.5%, 27.3%, and 31.8% of 44 OLP/RAS patients, 75.0%, 100.0%, and 100.0% of 4 OLP/major-typed RAS (OLP/major RAS) patients, 15.0%, 20.0%, and 25.0% of 40 OLP/minor-typed RAS (OLP/minor RAS) patients, 45.5%, 72.7%, and 54.5% of 11 atrophic glossitis-positive OLP/RAS (AG⁺OLP/RAS) patients, and 12.1%, 12.1%, and 24.2% of 33 AG-negative OLP/RAS (AG־OLP/RAS) patients had the presence of GPCA, TGA, and TMA in their sera, respectively. OLP/RAS patients and OLP/RAS patients of four different subgroups all had significantly higher frequencies of GPCA/TGA/TMA positivities than healthy control subjects. Moreover, OLP/RAS patients had a significantly higher frequency of TMA positivity than RAS patients, and OLP/major RAS and AG⁺OLP/RAS patients had significantly higher frequencies of GPCA/TGA/TMA positivities than RAS patients. Furthermore, OLP/major RAS patients had significantly higher frequencies of GPCA/TGA/TMA positivities than OLP/minor RAS patients.

CONCLUSION

For OLP/RAS patients, the concomitant OLP may play a role in causing an increased frequency of TMA positivity, and major RAS and the concomitant AG are contributory factors causing the elevated frequencies of GPCA/TGA/TMA positivities.

Urban legends series: lichen planus

Oral Diseases (2012) Lichen planus (LP) is a common disorder affecting the oral cavity (OLP) and skin. Despite intensive research, LP/OLP etiology and treatment remain controversial. We investigated four controversial topics: (i) Is hepatitis C virus (HCV) infection associated with LP and involved in its pathogenesis? (ii) Should all patients with LP be screened for HCV? (iii) Should patients with OLP have all their amalgam restorations removed? (iv) Are there any new treatments for OLP? Results from extensive literature searches suggested that: (i) Robust evidence from three meta-analyses indicate that HCV is associated with LP and might be involved in OLP pathogenesis (ii) It would be prudent to screen patients with LP/OLP at significant risk with an ELISA for HCV antibodies using country-specific screening strategies (iii) There is no evidence that either OLP or oral lichenoid lesions patients would routinely benefit from having all their amalgam restorations replaced. Weak evidence from potentially very biased, small, non-randomized, unblinded studies suggests that a small fraction of patients may benefit from targeted amalgam replacement. (iv) There is weak evidence that, among new OLP treatments, topical pimecrolimus, aloe vera, and oral curcuminoids may be useful. The development of specific formulations for oral delivery of topical medications is a promising field.

Local adverse effects of amalgam restorations

Amalgam has been used for the restoration of teeth for well over 100 years, and is the most successful of the direct restorative materials with respect to longevity. Despite the increasing use of tooth-coloured materials, with advantages of aesthetics and adhesion, amalgam is one of the most widely used dental restorative materials. One of the principal disadvantages of amalgam, apart from aesthetics, is that it may have adverse biological effects, both locally and systemically. Locally, it can cause an erythematous lesion on the adjacent oral soft tissues (tongue and buccal mucosa), and systemically free mercury in the amalgam may give rise to a hypersensitivity reaction. The purpose of this paper is to review the literature concerning the local adverse reactions to dental amalgam. The focus will be on the reactions of the oral mucosa, and brief consideration will be given to laboratory cytotoxicity of dental amalgam and its components, and to the 'amalgam tattoo'.

HLA-DRB1*0101 is associated with the genetic susceptibility to develop lichen planus in the Mexican Mestizo population

The etiology of lichen planus (LP) is still unknown and previous studies have found an association between LP and HLA-DR1, DR2, DR3, DR9 and DR10 in different populations. The aim of this study was to analyze the distribution of the HLA-DRB1 alleles in Mexican Mestizo patients with LP. The aim of this study was to determine the gene frequency of HLA-DR locus in Mexican Mestizo patients with LP. We studied 20 patients with LP and 99 healthy Mexican Mestizo controls. HLA-DRB1 was performed by PCR-SSO reverse dot blot hybridization. High resolution HLA typing was performed by PCR-SSP. The HLA-DRB1*0101 allele was associated significantly in LP patients compared with healthy controls (pC = 0.0007, OR = 5.46, 95% CI = 1.86-16.06). HLA-DRB1*0101 is a marker for the development of LP in Mexican Mestizo population, yet another gene or HLA marker within MHC region may be the causatively associated gene.

Tumor necrosis factor-alpha and interferon-gamma polymorphisms contribute to susceptibility to oral lichen planus

Most lymphocytes in the lamina propria of oral lichen planus (OLP) lesions express and secrete interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), whereas they do not secret interleukin-4 and -10 or transforming growth factor-beta. We analyzed whether the polymorphisms of several cytokines may influence the susceptibility to OLP. Cytokine typing was performed by a sequence-specific PCR assay. Thirteen cytokine genes with 22 single-nucleotide polymorphisms were studied. IFN-gamma UTR 5644 genotype frequencies showed a significant increase in number of T/T homozygotes in OLP patients compared with controls (40.9 vs. 22.9%; p=0.0022). Moreover, in OLP patients, the frequency of the -308A TNF-alpha allele was higher than in the controls (21.6 vs. 9.3%; p < 0.05) causing a significantly increased frequency of the genotype G/A in OLP (43.2 vs. 14.3%; p=0.0002). Because in patients with mucocutaneous lichen planus (LP), the frequency of the -308A TNF-alpha allele was more than double the values in the pure OLP patients (40.9 vs. 15.1%; p=0.003), the -308G/A TNF-alpha genotype showed a significantly higher frequency in patients with mucocutaneous LP than in patients with pure OLP (81.8 vs. 30.3%, p=0.003). In conclusion, we suggest that genetic polymorphism of the first intron of the promoter gene of IFN-gamma may be an important risk factor to develop oral lesions of LP, whereas an increase in the frequency of -308A TNF-alpha allele may best contribute to the development of additional skin involvement.

Oral lichen planus part I: epidemiology, clinics, etiology, immunopathogeny, and diagnosis

This article presents a review of the literature on oral lichen planus, focusing on important aspects of its epidemiology, etiopathogeny, and clinical manifestations. The oral form is an important clinical presentation of lichen planus. It may precede or accompany the skin lesions, or it may be the only manifestation of the disease. Dermatologists, dentists, otorhinolaryngologists, and other specialists who deal with the oral cavity must be aware of this disease so they can diagnose, treat, and keep these patients under observation.

Immunopathogenesis of oral lichen planus and recurrent aphthous stomatitis

Oral mucosal bullous/desquamative/ulcerative diseases involve immunopathological mechanisms that account for loss of adhesion between contiguous keratinocytes or to structures within the basal lamina. Some are antibody mediated, in which specific adhesion molecules of the desmosome, hemidesmosome, and basement membrane become antigenic targets. Oral lichen planus and recurrent apthous ulcers, although manifesting disparate clinical appearances and natural history, share immunopathological features that involve T cell-mediated immunity. Although the antigens, haptens, or autoantigens are not usually apparent, current research poses the hypothesis that both of these common oral mucosal diseases are a delayed-type hypersensitivity or cell-mediated response to an antigenic stimulus residing within the epithelium. This article reviews the research evidence for this hypothesis.

Immunologic aspects of dermal and oral lichen planus: a review

There have been many investigations, both experimental and epidemiologic, of the forms of LP affecting the skin and oral mucosae. These studies have provided a varied range of hypotheses to explain not only the factors determining susceptibility to and onset of this disease, but also the immunologic mechanisms leading to the pathosis with which LP is associated. Much progress has been made, especially through in vitro studies, regarding detailed aspects of the immunology of LP. However, data is often conflicting or incomplete. In this review we attempt to bring together the currently available data regarding the immunologic basis of LP.

Mercury-specific lymphocytes: an indication of mercury allergy in man

In this study, 18 patients with oral lichen planus (OLP), adjacent to amalgam fillings, were tested in vitro with an optimized lymphocyte proliferation test, MELISA (memory lymphocyte immunostimulation assay) and with a patch test. Twenty subjects with amalgam fillings but without oral discomfort and 12 amalgam-free subjects served as controls. The results show that patients with OLP have significantly higher lymphocyte reactivity to inorganic mercury, a corrosion product of amalgam, compared to control groups. Removal of amalgam fillings resulted in the disappearance of oral mucosal changes, thus indicating a causal relationship. Positive responses to phenylmercury (phenyl-Hg), a bactericidal agent in root fillings and in pharmaceutical preparations, were also noted in the oral lichen group but not in the control groups. Thus, low-grade chronic exposure to mercury may induce a state of systemic sensitization as verified by Hg-specific lymphocyte reactivity in vitro.

Heat shock protein expression in oral lichen planus

To assess the potential role of heat shock protein (HSP) in the pathogenesis of oral lichen planus (OLP), sections of OLP, normal oral mucosa, non-specific oral ulceration (NSOU) and dysplastic OLP were assessed for HSP expression using avidin-biotin complex immunohistochemistry with an anti-HSP 70 polyclonal antibody. There were statistically significant differences in both the vertical and horizontal staining distribution when other groups were compared with the OLP group (p < 0.01). Using microdensitometry, the mean staining intensity in OLP, dysplastic OLP and NSOU was elevated in comparison with normal oral mucosa (p < 0.001). In a standard tritiated thymidine uptake assay, lymphocytes extracted from nine OLP lesions demonstrated significant proliferation when stimulated with purified protein derivative (PPD), of which HSP is a major constituent, with stimulation indices ranging from 2 to 132. These results are consistent with the hypothesis that, in OLP patients, diverse exogenous agents may cause upregulated expression of HSP by oral mucosal keratinocytes. A reaction of cytotoxic T lymphocytes to these activated keratinocytes may then result in the tissue destruction which is characteristic of OLP lesions.

Serologic and molecular analysis of the HLA system in Israeli Jewish patients with oral erosive lichen planus

Oral erosive lichen planus is a distinct subtype of the common dermatosis lichen planus. Although the etiology of lichen planus is still obscure, it is known that cell-mediated immune mechanisms and genetic factors underlie its pathogenesis. Previous studies have found an association between lichen planus and HLA-DR3 or DR9 in different population groups. The present work was designed to elucidate, at the serologic and molecular levels, whether and which HLA genes are associated with oral erosive lichen planus in Israeli Jewish patients. A significant association with HLA-DR2 (RR = 4.7; pc < 0.0013) and a decrease in DR4 (RR = 0.3; p < 0.03) among the patients were noted. Oligotyping of DR2 alleles showed the presence of all three common variants (DRB1*1501, DRB1*1502 and DRB1*1601) in the patients, although none of the variants was overrepresented significantly. Three possible explanations for the role of HLA genes in the predisposition to oral erosive lichen planus are discussed. The most attractive theory for the pathogenesis of the disease seems to include the involvement of non-classical HLA genes.

Alteration in peripheral blood mononuclear cell function and serum cytokines in oral lichen planus

Different activation parameters of peripheral blood mononuclear cells (PBMC) from 31 patients with oral lichen planus (OLP) were examined and compared with 23 healthy donors. Impaired spontaneous (450 +/- 241 vs 1290 +/- 480 cpm) and mitogen-induced (39580 +/- 14470 vs 67000 +/- 11810 cpm) lymphocyte blastogenesis was observed in OLP patients. Furthermore, reduced cytokine production was found after phytohemagglutinin A (PHA) stimulation for all cytokines studied-tumour necrosis factor alpha (TNF alpha, 432.2 +/- 73.4 vs 979.8 +/- 46.3 units/ml), interleukin 2 (IL-2, 156.2 +/- 14.9 vs 572.6 +/- 12.9 pg/ml), interferon gamma (IFN gamma, 48.5 +/- 11.9 vs 82.6 +/- 12.4 pg/ml) and interleukin 6 (IL-6, 253.6 +/- 57.7 vs 1,419.0 +/- 279.6 units/ml)-except for interleukin 1 beta (IL-1 beta) and lymphotoxin (LT). In contrast, unstimulated culture supernatants showed increased TNF alpha (38.2 +/- 13.1 vs 8.0 +/- 0.2 units/ml), LT (10.2 +/- 2.2 units/ml vs < 0.4) and IL-6 (18.5 +/- 5.6 units/ml vs < 0.5) activity. Similarly, elevated concentrations of TNF alpha (19.6 +/- 6.3 units/ml) and IL-6 (22.9 +/- 4.7 units/ml) were detected in the sera of OLP patients. Combination of PHA and phorbol myristate acetate (PMA) could restore OLP proliferative T cell response and cytokine production to the level of healthy donors, whereas exogenous recombinant human IL-2 (rhuIL-2) plus PMA did not seem to be an effective stimulant for OLP T cells. These results indicate an alteration in the immune condition of OLP patients and an impairment in T lymphocyte function.

Disease mechanisms in oral lichen planus. A possible role for autoimmunity

Current evidence for the involvement of cell-mediated immunological mechanisms in the pathogenesis of oral lichen planus is reviewed. Both a spatial and temporal relationship between cytotoxic T Lymphocytes and epithelial damage have been reported. Although keratinocytes appear to be the target for destruction in oral lichen planus, their role in antigen presentation is unclear. We propose that in oral lichen planus patients, diverse exogenous agents such as drugs, trauma and infection, stimulate the expression of a common self molecule by oral mucosal keratinocytes. An autoimmune reaction by cytotoxic T lymphocytes to these activated keratinocytes may result in the tissue destruction which is characteristic of oral lichen planus.

Class I and II HLA antigens in British patients with oral lichen planus

The frequencies of human leukocyte antigens--HLA-A, HLA-B, HLA-C, HLA-DR, and HLA-DQ1--were determined in a group of 40 white British patients with oral lichen planus and compared with those of healthy controls. Alterations in the frequencies of several HLA antigens were noted. In particular, an increase in HLA-Bw57 and a decrease in the frequency of HLA-DQ1 were seen in the group with lichen planus. When different clinical subgroups of lichen planus were compared with the control group, significant changes were also noted in the frequencies of HLA antigens. This suggests that lichen planus may represent a heterogeneity of diseases and that HLA-Bw57 may predispose a person to lichen planus whereas HLA-DQ1 may be associated with resistance to it.

Suppressor cell function in oral lichen planus

Oral lichen planus (OLP) is a common inflammatory condition of the oral mucous membranes which affects between one and two percent of the general population. In accordance with the protracted clinical course of OLP and its association with known auto-immune diseases, the level of self-tolerance is questionable and possibly diminished in patients with this disorder. Normal suppressor T lymphocyte function is reputedly an essential element in the maintenance of self-tolerance, and deficient cell-mediated suppressor activity is implicated in the pathogenesis of auto-immune diseases. For assessment of in vitro cell-mediated suppressor activity in OLP, peripheral blood mononuclear cells (PBMC) from ten patients with OLP and from 11 control subjects were activated with the plant mitogen concanavalin A (Con A), followed by co-culture with autologous responder cells. The ability of irradiated Con A-activated cells to suppress the proliferation of Con A-stimulated responder cells was determined. Con A-induced suppressor activity of PBMC in the OLP patients was significantly less than that in control subjects (p = 0.001). Results of the present investigation complement previous in vitro findings which provided indirect evidence of deficient cell-mediated suppressor activity in OLP, particularly a decreased proportion of circulating CD4+CD45RA+ lymphocytes and reduced Con A-stimulated PBMC proliferation. The depressed Con A-induced suppressor activity of PBMC in the OLP patients provides direct evidence of deficient in vitro cell-mediated suppressor function in OLP, and suggests that defective cell-mediated suppressor circuits and reduced self-tolerance may be involved in the pathogenesis of this disorder.

Phenotypic and functional analysis of peripheral blood lymphocytes in oral lichen planus

To assess cellular immunity in oral lichen planus (OLP), peripheral blood mononuclear cells (PBMC) were obtained from 19 OLP patients and 30 control subjects. The proportions of circulating CD45RA+ and CD29+ lymphocyte subsets were determined. The proliferative activity of PBMC to the non-specific plant mitogens phytohemagglutinin (PHA) and concanavalin A (Con A) was examined together with the spontaneous proliferative response and the response in the autologous mixed lymphocyte reaction (AMLR). In the OLP group, the proportion of CD4+ CD45RA+ T lymphocytes was significantly less than control subjects and the proportion of CD4+ CD29+ T lymphocytes was increased significantly. The proliferative response to PHA was similar in OLP and controls subjects. Con A-stimulated PBMC proliferation was decreased significantly in the OLP group. Spontaneous PBMC proliferation in patients with non-reticular lesions was significantly less than control subjects. Despite a mildly depressed response in the AMLR in OLP patients, this result was not statistically significant. Results of the phenotypic analysis of peripheral blood lymphocytes indicate a decreased proportion of naive T cells and an increased proportion of primed memory T cells, although the antigen specificity of these memory cells remains to be determined. Results of the functional assays would seem to reflect this phenotypic shift, and as T cells responding to Con A stimulation and in the AMLR possess suppressor-inducer activity, these results may also suggest an association between OLP and defective innate T cell-mediated suppressor circuits.

Pancreatic ductal morphology and function in primary Sjögren's syndrome

In six patients with primary Sjögren's syndrome defined with HLA-antigens and no clinical signs of pancreatitis, the pancreatic ductal morphology (as described by endoscopic retrograde pancreatography), serum pancreatic enzymes, and fecal fat excretion were examined and secretin test was carried out. Further, oral glucose tolerance test with concomitant determination of serum insulin and C-peptide were done. All patients had at least two pathological signs of exocrine function and/or ductal morphology. There was no evidence of endocrine malfunction. The findings are suggestive of the existence of a clinically silent pancreatitis, perhaps of autoimmune etiology.

HLA-DR and DQ antigens in Chinese patients with oral lichen planus

A study of HLA-DR and DQ typing in 44 patients with oral lichen planus (OLP) (28 women and 16 men) and in 107 normal controls of both sexes was performed by using Terasaki's oriental tray. Twenty-eight patients had erosive forms of lichen planus (OLPe). Serologic typing revealed a highly significant increase of HLA-DR 9 and Te 22 antigens in the patient group. Considering our findings and those in other autoimmune diseases, it is hypothesized that OLP is a localized autoimmune disease and the HLA-DR9 in Chinese takes the place of HLA-DR3 in Caucasians in carrying the genes which predispose to the development of autoimmune disease.

Transient liver hypoxia after liver hilus dearterialization

Lichen planus (LP) is a chronic inflammatory disorder that most often affects middle-aged adults. LP can involve the skin or mucous membranes including the oral, vulvovaginal, esophageal, laryngeal, and conjunctival mucosa. It has different variants based on the morphology of the lesions and the site of involvement. The literature suggests that certain presentations of the disease such as esophageal or ophthalmological involvement are underdiagnosed. The burden of the disease is higher in some variants including hypertrophic LP and erosive oral LP, which may have a more chronic pattern. LP can significantly affect the quality of life of patients as well. Drugs or contact allergens can cause lichenoid reactions as the main differential diagnosis of LP. LP is a T-cell mediated immunologic disease but the responsible antigen remains unidentified. In this paper, we review the history, epidemiology, and clinical subtypes of LP. We also review the histopathologic aspects of the disease, differential diagnoses, immunopathogenesis, and the clinical and genetic correlations.