In situ lymphocyte subsets in alopecia areata before and during treatment with a contact allergen

Changes in distribution pattern of CD8 lymphocytes in the scalp in alopecia areata during treatment with diphencyprone

For many years, the role of T lymphocytes was hypothesized as being a major factor responsible for hair loss in alopecia areata (a.a.). While numerous lymphocytic populations were found around hair bulbs, changes in their distribution patterns in the skin during the course and recovery of the disease remain unknown. In the present study, distribution of CD8 lymphocytes in biopsies obtained from a.a. patients was measured before and during treatment using diphencyprone (DCP). Results show about a 600% increase in the number of CD8 lymphocytes under the epithelium and about a 250% increase around hair bulbs and other epidermal appendages during the study. These results were more significant in a group, which had good clinical response to the treatment. No change in the quantity of CD8 lymphocytes was observed around the blood vessels. Since CD8 lymphocytes are considered to be directly involved in the hair destruction process in a.a., their increased number around hair bulbs followed by hair regrowth may suggest that during DCP treatment they regain normal reactivity to hair antigens.

Phenotypic analysis of T-cells in extensive alopecia areata scalp suggests partial tolerance

This study demonstrates the feasibility and efficacy of using flow cytometric analysis with intracellular cytokine staining for characterization of T-cell phenotype and functional status in extensive alopecia areata (EAA) scalp skin. Cell suspensions were made from scalp punch biopsies taken from 12 patients with long-standing EAA (average disease duration 14 years, 95% hair loss) and six control subjects. EAA samples had a lower percentage of CD-3-expressing cells, but CD-4/CD-8 ratios remained similar to controls. Expression of CD-69 was found only in EAA scalp biopsies, suggesting that T-cells from EAA scalp have undergone activation. No difference was found in tumor necrosis factor alpha expression. Surprisingly, EAA scalp T-cells produced less IL-2 and CD-8 T-cells produced less IFN-gamma. Immunohistochemical staining of formalin-fixed paraffin-embedded specimens demonstrated that IFN-gamma-producing cells in EAA scalp were not greater in number than in normal specimens. The few identified IFN-gamma-producing cells demonstrated no tendency to localize to the perifollicular region, and were similarly distributed as in control specimens. The abnormalities in cytokine production may explain the relative paucity of inflammatory change observed in the clinical setting and suggest that T-cell responses in EAA scalp are tightly, albeit aberrantly, regulated via mechanisms of peripheral T-cell tolerance.

The therapeutic use of topical contact sensitizers in benign dermatoses

Topical therapy using contact sensitizers has been practised since the 1960s to treat conditions associated with an altered immunological state. Dinitrochlorobenzene, squaric acid dibutyl ester and diphencyprone are most commonly employed in the therapy of alopecia areata and viral warts. Few dermatology departments in the U.K. provide such treatment. This systematic review discusses the various contact sensitizers used for topical immunotherapy, the methodology of treatment, factors influencing efficacy and likely adverse effects.

Alopecia areata but not androgenetic alopecia is characterized by a restricted and oligoclonal T-cell receptor-repertoire among infiltrating lymphocytes

Although the etiology of alopecia areata is still unknown, evidence has accumulated to support an autoimmune pathogenesis for this disease. To evaluate the role of T cells in alopecia areata the T-cell receptor VB-repertoire was investigated in lesional skin and blood of 5 patients by means of a semiquantitative technique based on the reverse transcriptase polymerase chain reaction. Three patients with androgenetic alopecia served as controls. Amplification products were screened for clonality by temperature gradient gel electrophoresis. Four of 5 patients with alopecia areata exhibited a lesional T-cell receptor-repertoire characterized by an almost exclusive utilization of variable regions beta 2, 4, and 13. Temperature gradient gel electrophoresis revealed the oligoclonal constitution of the infiltrate. The restricted nature of the lesional T-lymphocytic infiltrate in alopecia areata strongly suggests that an antigen-specific T-cell response plays an important role in the pathogenesis of this disease.

Topical immunotherapy in alopecia areata. What, how, and why?

At present the induction and elicitation of an ACD with potent contact allergens such as DCP appear to be the most effective, but still not definitively curative, approach in treating extensive forms of AA. Experimental data suggest that cytokines and growth factors such as IL 1 beta are involved in the pathogenesis of AA as well as the therapeutic effect mediated by contact sensitizers. It seems reasonable to assume that factors inherent in the late phase of ACD modulate a T-cell mediated mechanism responsible for AA, thus inducing hair regrowth. Such counteracting activities are most likely mediated by proinflammatory cytokines such as TNF-alpha, IL-10, or TGF-beta 1. This hypothesis may oversimplify the underlying immunologic mechanisms, but the effectiveness of topical immunotherapy in AA would be compatible with this concept. This mode of treatment is, however, a rather rough approach and recurrences are possible. It is hoped that advances in basic science will eventually allow us to find a more specific mode of treatment.

Cytokine mRNA levels in Alopecia areata before and after treatment with the contact allergen diphenylcyclopropenone

Although the nature of the noxious signal and the anatomical target in alopecia areata (AA) are still unknown, it has been assumed that CD4+ T lymphocytes surrounding and infiltrating the hair bulb might trigger the hair loss. As these T lymphocytes do not promote cytotoxic activity we hypothesize that AA is triggered by cytokines. Topical immunotherapy with diphenylcyclopropenone (DCP) is at present the most effective approach. If it is true that AA results from a distinct cytokine pattern, we can hypothesize that the beneficial effect of DCP should be mediated by locally secreted cytokines during the contact allergy. Using semiquantitative reverse transcription-polymerase chain reaction with RNA extracted from scalp biopsies from patients with AA before and after successful treatment with DCP, and from healthy controls we detected a T-cell response with increased steady state mRNA levels for interferon (IFN)-gamma, interleukin (IL)-1 beta, and IL-2 in untreated AA of the totalis type. After DCP treatment, the IFN-gamma expression was reduced but still above the constitutive level found in controls, whereas mRNA expression of IL-2, IL-8, IL-10, and tumor necrosis factor-alpha was increased. Our results point towards cytokines involved in the pathogenesis in AA. A TH1 type cytokine pattern is present in untreated AA, and this is modified by cytokines secreted during DCP treatment. IL-10 has recently been described as an immunomodulator of the TH1 response and, therefore, we hypothesize that basal keratinocytes or lesional T cells secrete bioactive IL-10 after DCP application, resulting in an inhibitory effect on lesional T lymphocytes. This hypothesis would explain the effectiveness of DCP and implies the theoretical possibility of a response to topical or intralesional application of recombinant IL-10.

Immunohistological study of the development of the cellular infiltrate in the pelage follicles of the DEBR model for alopecia areata

The Dundee experimental bald rat (DEBR) undergoes hair loss associated with perifollicular infiltrates of mononuclear cells (MNC), a pathological characteristic of human alopecia areata (AA). To investigate further the pathogenesis of the disease in this animal model, we have studied the development, composition and extent of the perifollicular MNC infiltration in young (6-week-old), prelesional (3-month-old), active lesional, and established lesional DEBR rats, using 6-week- and 6-month-old Wistar rats as normal controls. The proportions of hair follicles showing infiltration by MNC and their main subsets were determined using immunohistochemical staining of serial cryostat sections of flank skin biopsies. There was a good correlation between the degree of leucocyte (OX-1+) infiltration of anagen hair follicles and the development of hair loss. In 6-week-old DEBR skin, there were few perifollicular cells expressing MHC class II, with positively stained dendritic cells in the dermis above the sebaceous gland. There was a sparse perifollicular distribution of CD4+ cells (W3/25) and macrophages (ED-1+). No CD8+ cells (OX-8+) were seen associated with DEBR hair follicles, and only small numbers were present in Wistar rats. In prelesional DEBR rats there was an increased perifollicular presence of MHC class II+ cells, macrophages, and particularly of CD8+ cells, with little change in CD4+ cells. Active and established lesional rats, i.e. animals with overt loss of hair, showed a significant increase in the degree of MNC infiltration and the proportion of infiltrated follicles, the majority of which were in dystrophic anagen. In the perifollicular infiltrate the CD4+:CD8+ ratio was approximately 2:1. An intrafollicular infiltrate was prominent, and was composed of CD8+ cells and macrophages, with bulbar and suprabulbar keratinocytes expressing MHC class II antigens. CD4+ cells were not detected in follicular epithelium. ICAM-1 expression correlated with MNC infiltration. These results show marked similarities to lesional human AA. They also focus on a possible active role for CD8+ cells in the pathogenesis of hair loss in the DEBR rat.

Alopecia universalis treated with oral cyclosporine A and prednisolone: immunologic studies

Alopecia universalis is a refractory condition. Although the cause of this disease is unknown, immunologic abnormalities have recently been suspected. Thus, we treated six cases of refractory alopecia universalis with immunotherapy. Oral administration of cyclosporine A (2.5 mg/kg) and prednisolone (5 mg/day) resulted in marked symptomatic improvement. Cyclosporine A did not produce any side effects because the administered dosage was relatively low. At present, more than 6 months after the cessation of treatment, recurrence of alopecia has not been seen. Oral administration of low-dose cyclosporine A and prednisolone is considered to be an effective treatment for this disease. Immunologic examination of peripheral blood demonstrated improvement of immunologic function. In particular, CD8-positive T cells, NK cells, and C3, which had been reduced, were increased. A reduction in active CD4 cells, eosinophils, and circulating immune complexes was observed. Histology with fluorescent antibodies showed T-cell infiltration around the hair matrixes. This phenomenon was no longer observed after treatment. These improvements in immunologic function were seen in parallel with the resolution of the clinical symptoms, indicating that immunologic abnormalities are related to this disease.

Topical minoxidil in alopecia areata: no effect on the perifollicular lymphoid infiltration

The therapeutic value of topical minoxidil in alopecia areata (AA) has been investigated in recent years, with variable results. Although the mechanism whereby minoxidil may stimulate hair regrowth in some cases of AA has not yet been elucidated, there have been reports of a decrease in the perifollicular infiltrates of mononuclear leukocytes (MNC)--particularly T lymphocytes--that characterize this condition, in patients "responding" to topical minoxidil. In a randomized and double-blind study, we have investigated the effect of 5% topical minoxidil versus placebo (vehicle alone) on the extent and composition of the perifollicular MNC infiltration in 20 patients having extensive AA (26-99% scalp hair loss). The proportions of hair follicles showing perifollicular infiltration by MNC and their main subsets were determined with histologic and immunohistochemical stainings of scalp biopsies obtained before treatment, after 12 weeks of randomized double-blind minoxidil versus placebo treatment, and after 12 additional weeks during which all patients received minoxidil. Six of the patients showed cosmetically acceptable hair regrowth (CAHR) at the end of the 24 weeks and this was associated with a significant decrease in the proportions of follicles infiltrated by total T and B lymphocytes, macrophages, and Langerhans cells at week 12, and by total T lymphocytes at week 24. However, no significant differences in the extent or composition of the perifollicular infiltrates were detected at week 12 between patients receiving minoxidil and placebo, or between the week-12 and week-24 biopsies of those patients who first received placebo and then minoxidil. These findings indicate that in AA the reduction in perifollicular T-cell infiltration associated with CAHR is not attributable to an effect of topical minoxidil.

Induction of hair growth in alopecia totalis with diphencyprone sensitization

The therapeutic use of the induction of an allergic contact sensitivity to diphencyprone in alopecia areata has been studied. Fourteen subjects had alopecia totalis and four had extensive and long-standing alopecia areata. Topical diphencyprone was capable of inducing an allergic contact sensitivity in 16 subjects (89%), and 13 of these agreed to proceed to repeated intermittent applications to the left side of the scalp, the right side acting as an untreated control; six subjects achieved cosmetically useful regrowth of normally pigmented terminal hair. No clinical features seemed to distinguish those who showed a favourable response from those who did not.