Immunopathological studies on alopecia areata

A "hair-raising" history of alopecia areata

A 3500-year-old papyrus from ancient Egypt provides a list of treatments for many diseases including "bite hair loss," most likely alopecia areata (AA). The treatment of AA remained largely unchanged for over 1500 years. In 30 CE, Celsus described AA presenting as scalp alopecia in spots or the "windings of a snake" and suggested treatment with caustic compounds and scarification. The first "modern" description of AA came in 1813, though treatment still largely employed caustic agents. From the mid-19th century onwards, various hypotheses of AA development were put forward including infectious microbes (1843), nerve defects (1858), physical trauma and psychological stress (1881), focal inflammation (1891), diseased teeth (1902), toxins (1912) and endocrine disorders (1913). The 1950s brought new treatment developments with the first use of corticosteroid compounds (1952), and the first suggestion that AA was an autoimmune disease (1958). Research progressively shifted towards identifying hair follicle-specific autoantibodies (1995). The potential role of lymphocytes in AA was made implicit with immunohistological studies (1980s). However, studies confirming their functional role were not published until the development of rodent models (1990s). Genetic studies, particularly genome-wide association studies, have now come to the forefront and open up a new era of AA investigation (2000s). Today, AA research is actively focused on genetics, the microbiome, dietary modulators, the role of atopy, immune cell types in AA pathogenesis, primary antigenic targets, mechanisms by which immune cells influence hair growth, and of course the development of new treatments based on these discoveries.

Does Complement Have a Role in the Pathogenesis of Alopecia Areata?

Alopecia areata (AA) is an autoimmune disorder in which immune attack of the anagen follicle causes hair loss in approximately 2% of the population. Although the pathogenesis of AA has not been fully determined, most likely it is mediated by a variety of factors including cellular/humoral immunity and genetic predisposition. Researchers have been interested in the possible role of the complement pathway in AA since the 1970s. Given recent evidence suggesting that complement plays a role in many immunologic and inflammatory dermatologic diseases including systemic lupus erythematosus, bullous diseases, angioedema, lipodystrophy, and skin infections, it is likely that complement also contributes to AA pathogenesis. Although early serum studies and immunohistochemical staining have been unimpressive, recent genetics studies may provide evidence that complement does indeed contribute to AA. By determining if complement plays a role in AA, options for novel targeted treatments will become available for those patients with refractory disease.

Alopecia areata and multifocal bone involvement in a young adult with Hodgkin's disease

A 17-year-old girl presented with a 3 month history of alopecia areata, a generalized scaling skin, enlargement of the inguinal lymph nodes and severe back pain. Staging procedures revealed multifocal bone disease and generalized lymphadenopathy. The diagnosis of nodular sclerosing Hodgkin's disease was established by biopsies of the os ileum and a left inguinal lymph node. Complete clinical remission was achieved after 2 OPPA (vincristine, prednisone, procarbazine, and doxorubicin) and 4 COPP (cyclophosphamide, vincristine, prednisone, and procarbazine) cycles and treatment completed with involved-field irradiation. After the completion of therapy, skeletal lesions had mostly resolved or become sclerotic and the patient had normal hair regrowth and skin appearance. Conclusively, this case illustrates that alopecia areata may occur as a paraneoplastic phenomenon or an autoimmune process related to the deranged cellular immune system in children and adolescents with Hodgkin's disease.

Cutaneous manifestations in celiac disease

Celiac disease (CD) is an autoimmune gluten-dependent enteropathy characterized by atrophy of intestinal villi that improves after gluten-free diet (GFD). CD is often associated with extra-intestinal manifestations; among them, several skin diseases are described in CD patients. The present review reports all CD-associated skin manifestations described in the literature and tries to analyze the possible mechanisms involved in this association. The opportunity to evaluate the possible presence of CD in patients affected by skin disorders is discussed.

Characterization of hair follicle antigens targeted by the anti-hair follicle immune response

Alopecia areata is a common disfiguring hair loss disorder that primarily affects the hair follicle as it enters the prolonged growth phase called anagen. The last few years have yielded an explosion of more rigorously obtained data on the etiology and pathogenesis of this disorder. While a consensus is rapidly building in support of an autoimmune pathogenesis, there are still several enigmatic issues to be resolved. These include the possibility that alopecia areata is really a multientity disorder with causes that are multifactorial. This will have important implications for the research scientist's search for the jigsaw puzzle's largest missing piece--the identification of the target autoantigen(s). There is now much evidence that autoimmune diseases with both T and B cell components have shared target autoantigens/epitopes. It is likely that alopecia areata is similar, as there is now very strong evidence for the generation of autoantibodies as well as autoreactive T cells to hair follicles in the pathogenesis of this disease. The following brief review outlines the progress we have made over the last five to ten years in the characterization of hair follicle antigens targeted by antibodies in alopecia areata. Results of these studies now show that the elicitation of antibodies to hair follicle-specific proteins is a highly conserved phenomenon in all affected species studied to date. Candidate autoantigens that have been identified include the 44/46 kDa hair-specific keratin (expressed in the precortical zone of anagen hair follicles) and trichohyalin (an important intermediate filament-associated protein) expressed in the inner root sheath of the growing hair follicle. Moreover, there is evidence that anti-hair follicle antibodies are modulated during the disease process, can occur before clinically detectable hair loss, and may be reduced in titer during successful treatment. Preliminary data from passive transfer experiments suggest that in some species these antibodies may disrupt hair cycling. We are currently applying a more molecular approach (e.g., cDNA library screening) to identify hair follicle antigens truly associated with the onset of the disorder.

Alopecia universalis in a patient with common variable immunodeficiency

A 12-year-old boy with common variable immunodeficiency (CVI) who developed severe alopecia is presented. His sister also had alopecia and recurrent infections and died of lung infection at the age of 7 years. The loss of hair in both children was total; the pathology of a scalp skin biopsy specimen was typical for alopecia areata. The boy was subjected to clinical and immunologic evaluation and the results were compatible with common variable immunodeficiency.

Simultaneous onset of alopecia areata and idiopathic thrombocytopenic purpura: A potential association?

Alopecia areata (AA) has been associated with a variety of autoimmune diseases. Immune thrombocytopenic purpura (ITP) is an autoimmune disease marked by isolated thrombocytopenia. We present a young girl with the simultaneous onset of AA and ITP. To the best of our knowledge, this association has not previously been reported. We hypothesize that ITP may be one of many autoimmune diseases associated with AA via antibodies that cross-react between platelet membrane glycoproteins and follicular glycoproteins.

Severe alopecia areata treated with systemic corticosteroids

BACKGROUND

Treatment of severe alopecia areata is difficult, and most efforts to successfully treat this condition have been disappointing. Systemic corticosteroids have been demonstrated as an effective treatment of severe alopecia areata.

METHODS

Eighteen patients with alopecia areata (extensive patchy and totalis universalis types) were treated with systemic corticosteroids.

RESULTS

Satisfactory hair regrowth was achieved in seven patients (38.9%). Hair fall subsequently occurred in all of these patients on discontinuation or tapering of corticosteroid therapy.

CONCLUSIONS

Systemic corticosteroid therapy does not prevent the spread or relapse of severe alopecia areata and, when complete regrowth is obtained, it is rarely maintained off therapy.

The pathogenesis of alopecia areata

Knowledge of the disease mechanisms in alopecia areata is discussed in the light of progress in hair biology, immunology, and genetics. A disease model is presented incorporating polygenic determination of disease severity and susceptibility with largely unknown trigger factors responsible for initiating clinical disease expression. Experimental systems including animal models for alopecia areata offer new opportunities for investigation of alopecia areata and developing novel therapies.

Celiac disease and alopecia areata: report of a new association

Celiac disease is frequently associated with other autoimmune disorders but has never been reported in association with alopecia areata. In a routine clinical practice, 3 patients with such an association were observed. In one of the patients, celiac disease was diagnosed after the occurrence of malabsorption symptoms. In the youngest patient, a 14-year-old boy, gluten-free diet resulted in complete regrowth of scalp and body hair. A prospective screening program for celiac disease using antigliadin and antiendomysial antibodies was therefore set up in 256 consecutive outpatients with alopecia areata. Three patients, all completely asymptomatic for intestinal diseases, were found to be positive and underwent biopsy. Histological analysis showed a flat intestinal mucosa consistent with the diagnosis of celiac disease. The results show that alopecia areata may constitute the only clinical manifestation of celiac disease and that the association between these two conditions is a real one because the observed frequency of association is much greater than can be expected by chance. It is suggested that antigliadin and antiendomysial antibodies should be included in the work-up of patients with alopecia areata.

Antismooth muscle and antiparietal cell antibodies in Indians with alopecia areata

BACKGROUND

Alopecia areata is suspected to be an autoimmune disease. We studied 104 consecutive patients with alopecia areata for the presence of autoantibodies and associated autoimmune diseases.

METHODS

A detailed history and examination was carried out in all patients to look for associated atopy, diabetes mellitus, hypertension, rheumatoid arthritis, vitiligo, lupus erythematosus, and thyroid disorders, etc. in the patients or their family members. Venous blood for estimation of fasting and postprandial blood glucose was collected in 30 patients, especially in those with family history of diabetes mellitus. Antimitochondrial (AMA), antismooth muscle (SMA), antinuclear antibodies (ANA), antiparietal cell antibody (PCA), and antibody against thyroid microsome (TMA) were detected employing indirect immunofluorescence on a composite section of rat liver, stomach, kidney, and human thyroid. Skin biopsy was processed for direct immunofluorescence by a conventional technique.

RESULTS

Disseminated discoid lupus erythematosus, lichen planus, urticaria, psoriasis, and seronegative spondylarthritis were associated with alopecia areata in one case each. Antismooth-muscle-antibodies and PCA were found in 36 (34.6%) and 44 (42.3%) patients respectively, followed by TMA in 8 (7.7%), AMA in 6 (5.7%), antithyroglobulin antibodies in 3 (2.8%), and ANA in 2 (1.9%) patients. The incidence of SMA was higher in men with alopecia areata (P < 0.001). Direct immunofluorescence carried out in 24 patients did not reveal significant findings, except for occasional immunoglobulin deposits around hair follicles and blood vessels.

CONCLUSION

Alopecia areata in India is associated more often with antismooth muscle and antiparietal cell antibodies.

Increased risk for type I (insulin-dependent) diabetes in relatives of patients with alopecia areata (AA)

The prevalence of various chronic diseases was compared in 517 individuals with alopecia areata, and 2,969 of their first degree relatives. As previous reports have suggested an increased incidence of diabetes in relatives of patients with alopecia areata, special attention was given to the prevalence of Type 1 and Type 2 diabetes in the patients and in their relatives. Several immunologic diseases were increased in alopecia probands and relatives. Thyroid disease, vitiligo, Addison disease, and pernicious anemia were more prevalent in probands and in their relatives than in the general population. Specifically, a high rate of thyroid disease was found in probands (14.7%) and in their first degree relatives (4.2%). Only one proband had Type 1 diabetes, yet there were 14 sibs with Type 1 diabetes. Thus, Type 1 diabetes was significantly more prevalent in the sibs (1.2%) than in either the probands with alopecia (0.2%), or the general population (0.12-0.25%) (P < 0.05)). In contrast, Type 2 diabetes was not more common in probands or in sibs than in the general population. These data suggest that alopecia areata protects against Type 1 diabetes in predisposed individuals. The high rate of thyroid disease suggests that screening probands and first degree relatives for thyroid disease should be considered.

The aetiology and pathogenesis of alopecia areata

In common with a number of inflammatory autoimmune diseases, genetic factors including HLA class II associations have been identified in alopecia areata. No consensus has been reached on the identity of a specific disease target within the hair follicle in alopecia areata. Suggested candidate cell types include the dermal papilla cells, the keratinocytes of the matrix and presumptive cortex and the hair bulb melanocytes, but these need not be mutually exclusive. The pathogenesis is known to involve disturbance of immune function but there is no proof that an autoimmune mechanism is fundamental. We propose a pathogenetic model incorporating polygenic determination of disease susceptibility and severity with additional, possibly environmental, factors as triggers for disease expression.

Antibodies to hair follicles in alopecia areata

Although alopecia areata is suspected to be an autoimmune disease, no direct evidence of an altered immune response to components of the hair follicle has been reported. We studied whether antibodies to normal human anagen scalp hair follicles are present in individuals with alopecia areata. Thirty-nine alopecia areata sera and 27 control sera were tested by Western immunoblotting for antibodies to 6 M urea-extractable proteins of normal anagen scalp hair follicles. At serum diluted 1:80, all alopecia areata subjects (100%), but only 44% of control individuals, had antibodies directed to one or more antigens of approximately 57, 52, 50, 47, or 44 kD. The incidence of antibodies to individual hair follicle antigens in alopecia areata was up to seven times more frequent than in control sera and their level up to 13 times greater and was statistically significant for all five antigens. Tissue specificity analysis indicated that these antigens were selectively expressed in hair follicles. These findings indicate that individuals with alopecia areata have abnormal antibodies directed to hair follicle antigens, and support the hypothesis that alopecia areata is an autoimmune disease.

Ulcerative colitis and total alopecia in a mother and her son

Extraintestinal autoimmune disorders are associated with ulcerative colitis in selected patients and lend support to the theory of immune-mediated injury in inflammatory bowel disease. Rarely, alopecia areata has been associated with ulcerative colitis, and familial aggregation and an HLA association have been reported for both disorders. The occurrence of both alopecia and ulcerative colitis in a mother and son are reported with a detailed investigation of antineutrophil cytoplasmic antibodies and HLA alleles in this family. Treatment with the immunosuppressive agent cyclosporine proved beneficial in the child leading to remission of the ulcerative colitis and nascent growth of scalp and body hair.

Simultaneously occurring alopecia areata and Hodgkin's lymphoma: complete remission of both diseases with MOPP/ABV chemotherapy

A 43-year-old man presented with simultaneously occurring alopecia areata and stage IIIB nodular sclerosing Hodgkin's disease. Systemic symptoms of Hodgkin's disease were present for 6 months, and rapidly developing patchy hair loss of the scalp was present for 2 weeks prior to presentation. The patient was treated with eight cycles of MOPP-ABV chemotherapy that resulted in complete remission of Hodgkin's-disease. Four months after the completion of chemotherapy, the patient had normal hair regrowth with no evidence of alopecia areata. Alopecia areata may be an autoimmune disease and may respond to chemotherapy.

Alopecia totalis and vitiligo in common variable immunodeficiency

Three cases of severe and irreversible alopecia occurring in patients with common variable immunodeficiency are described. In all three cases, hair loss developed after the diagnosis of immune deficiency; one of the patients also had extensive vitiligo. A fourth patient had vitiligo in the absence of alopecia. No change in the alopecia or vitiligo was noted in any patient as a result of immunoglobulin replacement therapy.

Angiogenic activity is defective in monocytes from patients with alopecia universalis

Monocyte/macrophages are important components of cell-mediated immune responses in presentation of antigen, as regulators of lymphocyte function, and as sources of cytokines that modulate functions of cells other than those of the immune system. Their role in the pathogenesis of alopecia areata (AA) and universalis (AU) has not been explored. This study is an investigation of the function of peripheral blood monocytes from normal subjects and patients with AA, AU, and alopecia totalis (AT), with respect to the principal macrophage-derived angiogenic factor, tumor necrosis factor alpha (TNF alpha). Because neovascularization is a necessary component in the anagen phase of hair growth and may play a role in the pathology of these disorders, we asked whether monocyte/macrophage angiogenic activity was compromised in these alopecias. Purified preparations of monocytes were activated in culture. Conditioned media were assessed for angiogenic activity on the chick chorioallantoic membrane and for concentration of TNF alpha by enzyme-linked immunosorbent assay (ELISA). Both angiogenic and the TNF concentration were significantly diminished in conditioned media from AU monocytes when compared to those from normal subjects and patients with AA. These results show that the function of AU monocytes may be abnormal and that the abnormality may distinguish AU from AA. Defective monocyte/macrophage function could also play a pathogenic role via effects on neovascularization and/or modulation of the immune response.

Abnormal expression of class I and class II major histocompatibility antigens in alopecia areata: modulation by topical immunotherapy

Fifty-eight scalp biopsies were immunohistologically investigated with monoclonal antibodies against HLA-ABC, HLA-DR, and T6 antigens. The following 3 groups were compared: control biopsies obtained from healthy volunteers (n = 5) or patients with unrelated scalp diseases (n = 6); biopsies from untreated alopecia areata (AA), obtained either from untreated patients (n = 19) or from the untreated side in patients receiving unilateral treatment with the contact allergen diphencyprone (DCP) (n = 13); biopsies obtained from the treated side in patients receiving unilateral treatment with DCP (n = 13). While HLA-ABC antigens were strongly expressed by epidermal keratinocytes and the infundibular epithelium of hair follicles in all biopsies, these antigens were either not detectable or only faintly expressed on the subinfundibular epithelium and the hair matrix in the control series. By contrast, 30 out of 32 biopsies from untreated AA showed expression of HLA-ABC antigens on hair matrix epithelium, and the subinfundibular epithelium was HLA-ABC-positive in 15 out of 32 cases. In the biopsies from treated AA, HLA-ABC antigens were expressed on hair matrix epithelium in 9 out of 13 cases, and on the subinfundibular epithelium in 1 case. In the controls and untreated AA, HLA-DR expression was confined to dendritic cells in the epidermis and the follicular infundibulum. Its expression on hair matrix epithelium was found in 15 out of 32 biopsies from untreated AA and in 4 out of 13 biopsies from treated AA. In the control series, intrabulbar T6+ dendritic cells were either absent or present in low numbers. High numbers of intrabulbar T6+ cells were present in 7 out of 32 biopsies from untreated AA and in 0 out of 13 biopsies from treated AA. The data show that abnormal expression of class I major histocompatibility (MHC) antigens on hair matrix epithelium is a constant feature in AA, whereas class II MHC antigens are less frequently expressed. Topical immunotherapy with DCP, which induced expression of HLA-DR in epidermal keratinocytes in 6 out of 13 cases, reduced the abnormal expression of both HLA-ABC and -DR antigens in the epithelium of lower hair follicles in AA.

Hair loss. Common congenital and acquired causes

Hair loss is a common problem likely to be encountered by a clinical practitioner. The most frequent causes of hair loss in pediatric patients include tinea capitis, alopecia areata, traction alopecia, and trichotillomania. In the adult population, causes to be considered are alopecia areata and hair loss associated with systemic disease and hormonal influence. The clinician must be able to separate the types and causes of hair loss into those that reflect primary dermatologic conditions and those that represent reaction to systemic disease.

Expression of HLA-DR by anagen hair follicles in alopecia areata

The expression of HLA-DR within hair follicles in alopecia areata was studied using an immunoperoxidase method. Scalp biopsies were taken from 12 patients with alopecia areata and from 6 normal control subjects. Frozen sections were stained with a panel of 4 anti-HLA-DR monoclonal antibodies, Leu 2, Leu 3, Leu 4, and T6 antibodies. The expression of DR in normal hair follicles and in most anagen follicles from nonlesional alopecia skin was confined to dendritic cells which were sparse below the level of the arrector pilorum insertion. Of the 37 anagen follicles examined in lesional skin, 25 displayed staining for DR on epithelial cells in the precortical matrix and presumptive cortex. Six follicles showed DR staining in other epithelial compartments, the lower bulb matrix, inner root sheath, and outer root sheath. Infiltration of the hair bulb matrix by T cells was seen in the majority of follicles where epithelial cells were DR+. The aberrant expression of DR antigens by hair follicle epithelium provides direct evidence that immune mechanisms are operating in the pathogenesis of alopecia areata. In a previous study of alopecia areata we found evidence of cell injury confined to the precortical matrix and presumptive cortex in lesional anagen follicles. The relative restriction of epithelial DR expression to the same site suggests that this region of the follicle is of fundamental importance in the disease process.

Alopecia areata: pathogenesis and treatment

Although its etiology remains unknown, evidence has accumulated to support an autoimmune pathogenesis for alopecia areata. Our review summarizes the immunologic data and also examines the role of genetics, atopy, and psychologic stress in this disorder. Until etiology is better understood, treatments for alopecia areata are likely to remain palliative. Nevertheless, newer therapies such as photochemotherapy, topical immunotherapy, and perhaps systemic immunotherapy (e.g., inosiplex) offer new hope for patients with extensive disease.

T cell subpopulations in alopecia areata

Alopecia areata remains a disease of unknown cause and unsatisfactory treatment. Histologically it is characterized by a lymphocytic infiltrate that surrounds the lower half of the hair follicle. Our findings show that 64% to 92% of this infiltrate is composed of T lymphocytes bearing the Leu 3a (helper-inducer) phenotype. The remaining lymphocytes demonstrate the Leu 2a (cytotoxic-suppressor) phenotype. This helper T cell predominance is present in all patients, irrespective of clinical activity or duration of disease. The Leu 3a/Leu 2a ratio ranged from 2.6 to 19.8, the higher ratios being seen in patients with clinically active disease. The cutaneous infiltrate also is Ia-positive, indicating the activated nature of these lymphocytes.

Increased ratio of helper to suppressor T cells in alopecia areata

We studied lymphocyte subsets in the blood of twenty-four patients with alopecia areata of various degrees of severity. There was an increase in the ratio of helper to suppressor cells that correlated with the extent of the disease, providing further evidence that the immune system may be involved in its pathogenesis.

Immunological profiles in alopecia areata

Cell-mediated immunity and auto-immune phenomena were investigated in sixty patients with active alopecia areata of various degrees of severity. Serum auto-antibodies to thyroid antigens were detected in twenty-three patients. Examination of T-lymphocyte populations, lymphocyte DNA synthesis, and lymphokine production in response to mitogen stimulation revealed no differences between the sixty patients and matched healthy control subjects. However, patients with thyroid auto-immunity and/or the presence of alopecia totalis or universalis showed significant reductions in interactive T lymphocytes (recognized by rosette formation with human B lymphoblastoid cells) and diminished production of leukocyte migration inhibition factor in response to stimulation with phytohaemagglutinin. This suggests that immune mechanisms may be involved in the pathogenesis of alopecia areata which is associated with thyroid auto-immunity or which progresses to total hair loss.

Studies on the immunologic aspects of keloids and hypertrophic scars

A significant difference between keloids and hypertrophic scars could be demonstrated by means of acid elution of lymphoid blood cells and immunofluorescence studies. A total of 20 patients (13 patients with keloids and seven with hypertrophic scars) were investigated. All the 13 patients with keloids revealed in the eluates antinuclear antibodies belonging to one or more of the five main classes and directed mainly against fibroblasts. On the other hand, there were no antinuclear antibodies detectable in the eluates of the seven patients with hypertrophic scars and in over 40 healthy controls.

Keloids and hypertrophic scars--immunological aspects

A significant difference between keloids and hypertrophic scars could be demonstrated by means of acid elution technique of lymphoid blood cells and immunofluorescence studies. Tests on 20 patients with keloids revealed in the eluates antinuclear antibodies belonging to one or more of the 5 main classes and directed mainly against fibroblasts. On the other hand, there were no antinuclear antibodies detectable in the eluates of the 7 patients with hypertrophic scars and in 40 healthy controls.

Suppressor cell decrease in alopecia areata

There is considerable evidence to suggest that autoimmunity plays a role in the pathogenesis of alopecia areata. Since it is known that T cells regulate the immune system, a study was undertaken to measure T helper (OKT-4) and T suppressor (OKT-8) cells in the peripheral blood of patients with alopecia areata (both active and stable) and in controls. Total T cells, B cells, immunoglobulins, and autoantibodies were also measured. There was a highly significant decrease in the T-suppressor cell population of patients with alopecia areata (P less than 0.001). Two of ten patients had microsomal antibodies and three of ten had elevated IgE levels. Other parameters were not significantly different. The decrease in suppressor cells suggest an impairment of the prime negative regulator of the immune system, with loss of tolerance and resultant autoimmunity.

Cell-mediated immunity in alopecia areata

A study of cell-mediated immunity was carried out in total of 69 subjects with alopecia areata (AA) of the scalp in various phases of its evolution. The blastic responses to mitogens PHA, Con A, and PWM proved significantly reduced, quite independently of the phase of the disease. The total E-rosettes test demonstrated a significant reduction in T-lymphocytes in patients with active AA. On the other hand, no significant differences could be demonstrated between the patients and the controls by means of active E rosette test. The mean values for Tgamma and for theophylline-sensitive T-lymphocytes were reduced in patients with active AA. The significance of the results is discussed.