Granulysin-Bearing Cells in the Skin Lesions of Acute Graft-versus-Host Disease: Possible Mechanisms for Hypohidrosis in Graft-versus-Host Disease

Unusual presentations of chronic graft versus host disease

Skin is commonly affected by graft versus host disease (GVHD), a complication of bone marrow transplantation (BMT). One-third of hematopoietic cell transplantation recipients develop acute eruption classically described as folliculocentric, maculopapular, or morbilliform, in contrast to the more common chronic presentations of sclerotic, poikilodermic, or lichenoid dermatitides. With the wider use of non-myeloablative (reduced-intensity) transplant therapy, various atypical presentations can occur, representing a diagnostic challenge. Herein, we report an unusual case of chronic GVHD manifested by two distinct clinical and histopathological features lacking the classical presentation. Five months after her BMT, the patient presented with a papulosquamous eruption on her neck, trunk, and arms showing a psoriasiform histopathological pattern of chronic GVHD. She also demonstrated multiple small flesh-colored papules on her distal extremities showing a solitary syringotropic pattern of GVHD, demonstrated by interface dermatitis involving the superficial eccrine duct, as the only diagnostic histopathological feature of GVHD. This report, with review of literature, highlights the uncommon psoriasiform GVHD and the novel description of isolated syringotropic chronic GVHD.

Cutaneous eccrine inflammation and necrosis: review of inflammatory disorders affecting the eccrine apparatus including new associations

Despite being frequently overlooked during the examination of histopathological sections, eccrine sweat glands can offer clues for diagnosing various skin conditions. They provide important functions and can lead to several diseases when inflamed or injured. This review article provides information regarding eccrine physiology as well as well-established and novel entities that occur in association with eccrine gland pathology.

Granulysin: killer lymphocyte safeguard against microbes

Primary T cell immunodeficiency and HIV-infected patients are plagued by non-viral infections caused by bacteria, fungi, and parasites, suggesting an important and underappreciated role for T lymphocytes in controlling microbes. Here, we review recent studies showing that killer lymphocytes use the antimicrobial cytotoxic granule pore-forming peptide granulysin, induced by microbial exposure, to permeabilize cholesterol-poor microbial membranes and deliver death-inducing granzymes into these pathogens. Granulysin and granzymes cause microptosis, programmed cell death in microbes, by inducing reactive oxygen species and destroying microbial antioxidant defenses and disrupting biosynthetic and central metabolism pathways required for their survival, including protein synthesis, glycolysis, and the Krebs cycle.

Clinical perspectives and murine models of lichenoid tissue reaction/interface dermatitis

A set of histopathological elements, that is death of epidermal basal cell layer keratinocytes and inflammatory cell infiltration, distinguishes lichenoid tissue reaction (LTR)/interface dermatitis (IFD) from other inflammatory mucocutaneous diseases with histological findings of superficial perivascular dermatitis. The LTR/IFD is observed in inflammatory mucocutaneous diseases such as lichen planus, Stevens-Johnson syndrome/toxic epidermal necrolysis, acute graft-versus-host disease, lupus erythematosus and dermatomyositis. Clinical and basic researches have suggested that keratinocytes are antigen-presenting cells and mediate LTR/IFD reaction via production of cytokines/chemokines and inhibitory molecules such as programmed cell death (PD)-L1, and that cytotoxic CD8(+) T cells producing cytotoxic granules, perforin, granzyme B and granulysin are final effector cells to cause keratinocyte death. Because interferon-γ and FasL, which are produced by not only CD8(+) but also CD4(+) T cells, are candidates of the pathogenic molecules in LTR/IFD, CD4(+) T cells may also play a role to develop LTR/IFD. On the other hand, CD4(+) Treg cells accelerate the remission of LTR/IFD. Some murine models of LTR/IFD have been established. For example, LTR/IFD reactions were induced in keratinocyte-specific membrane-binding ovalbumin-transgenic (mOVA Tg) mice by adoptive transfer of CD8(+) T cells with OVA-specific T-cell-receptor. It has also been shown that human CD8(+) T cells are pathogenic immune cells in human skin-xenografted mice. Various immunosuppressants are used to treat patients with mucocutaneous diseases with LTR/IFD. By analysis of the mOVA Tg mice, a JAK inhibitor was suggested to be a new candidate drug to inhibit not only pathogenic T cells but also keratinocyte death in LTR/IFD. More specific treatments for patients with LTR/IFD will be developed in future.

Serum granulysin as a possible key marker of the activity of alopecia areata

BACKGROUND

Alopecia areata (AA) is an organ-restricted autoimmune condition of the hair follicles (HFs) that presents as nonscarring hair loss. A collapse of immunoprivilege for cell-mediated cytotoxicity and following attacks by cytotoxic T cells to anagen HFs are considered to play a major role in the pathogenesis of AA. However, there has been no useful marker for the activity of AA to date.

OBJECTIVE

The aim of this study is to examine whether granulysin, which is known to reflect the activity of cytotoxic immune responses, is related to the disease activity of AA.

METHODS

We evaluated serum granulysin levels in acute and chronic AA patients compared to healthy controls in the perspective of bald skin areas, prognosis, and co-existence of other allergic diseases. In addition, immunohistochemical analysis for granulysin-, CD4-, CD8-, and CD56-positive cells in the lesional skin of acute and chronic AA patients was performed.

RESULTS

Serum granulysin levels were significantly elevated in both acute and chronic AA patients (p=0.00081 and p=0.0012, respectively). Intriguingly, serum granulysin levels were significantly associated with the broader bald skin areas (Spearman's r=0.59, p=0.017), and poorer prognosis in acute AA patients (p=0.0080). They were also associated with co-existence of allergic disorders in AA patients (p=0.026). Immunohistochemical staining demonstrated that perifollicular granulysin-bearing cells were mainly detected in acute AA lesions with dense lymphocytic infiltration, and that these granulysin-bearing cells were consistent with CD8(+) T cells.

CONCLUSION

The serum granulysin level may be a useful and novel marker for the disease activity in the acute phase of AA.