Immunohistochemical analysis of dermal mononuclear cell infiltrates in cutaneous lupus erythematosus, polymorphous light eruption, lymphocytic infiltration of Jessner, and cutaneous lymphoid hyperplasia: a comparative differential study

Lichenoid and interface dermatoses

The terms 'lichenoid' and 'interface' dermatitis are often used interchangeably to describe an inflammatory pattern characterized histologically by damage to the basal keratinocytes in the epidermis. The mechanism of cell damage of such cells is now best understood as apoptosis, or programmed cell death. This inflammatory pattern of dermatoses, is also accompanied frequently by a band of lymphocytes and histiocytes in the superficial dermis, that often obscures the dermal-epidermal junction, hence the term 'lichenoid'. A discussion of the more common lichenoid/interface dermatitides encountered in the routine clinical practice encompasses the following entities: lichen planus, lupus erythematosus, dermatomyositis, erythema multiforme, graft versus host disease, fixed drug reactions, and multiple others.

Clinicopathologic Study of Cutaneous Pseudolymphomas

A study was conducted to determine the clinical and histopathologic findings of cutaneous pseudolymphomas. In the period between July of 1989 and December of 2002, 42 cases were collected. Clinical records and pathology slides of the patients were reviewed retrospectively. A striking common clinical feature was a pruritic papule, nodule, or plaque with a smooth surface on the head and neck. The histologic patterns were diverse, MF-like, perivascular/periadnexal, nodular, diffuse, pseudolymphomatous folliculitis, and acral pseudolymphomatous angiokeratoma of children (APACHE) patterns. The most common pattern was a multinodular pattern with an extension into the deep dermis and subcutaneous adipose tissue. The differentiation between cutaneous lymphomas and pseudolymphomas must depend on a constellation of criteria, never on a single criterion.

Could Jessner’s Lymphocytic Infiltrate of the Skin Be a Dermal Variant of Lupus Erythematosus? An Analysis of 210 Cases

BACKGROUND AND OBJECTIVE

The objective of this study was to evaluate the relationship between Jessner's lymphocytic infiltration of the skin (JLI) and lupus erythematosus (LE), which has been the subject of debate since its initial description in 1953.

MATERIAL AND METHODS

This is a retrospective study including all patients with a histopathologically ascertained diagnosis of JLI performed at the Laboratoire d'Histopathologie Cutanée of the Strasbourg University Hospital between 1993 and 2003. Information about patient characteristics and follow-up data were retrieved between 2004 and 2005. Special attention was paid to features indicative of LE.

RESULTS

210 consecutive patients (102 women and 108 men) with a mean age 42 years were diagnosed with JLI in the reference period. 175 patients (83%) had multiple lesions and 32 patients (15%) had only a single lesion at the time of diagnosis (data not available in 3 patients). The head, neck and upper part of the thorax were involved in 171 patients (81%). An annular or arciform configuration and/or arrangement were present in 111 patients (53%). Lesions consisted of red (100%) papules or plaques (98%). Mean follow-up was 4 years. Sixteen patients (7.6%) had proven LE. Only 2 patients (1%) developed >4 ACR criteria of systemic LE. Furthermore, 1 patient had antiphospholipid antibody syndrome and 2 patients had rheumatoid arthritis.

CONCLUSIONS

This high frequency of patients with typical features of LE strongly argues that JLI could be a dermal variant of LE and not an autonomous entity. It might be the cutaneous marker of a subset of LE patients with excellent prognosis.

Immunopathology of the human hair follicle

Although patients are told that, in many instances, their hair loss is precipitated by stress, they are certainly stressed and saddened by their alopecia. They would be elated with the ability to regrow their hair. Ideally, therapy would be specific and targeted at the cascade of inflammatory, cytokine-mediated, and mesenchymal events which lead to hair loss. Such is the case with infectious folliculitides: Pityrosporum folliculitis is cleared with antifungal agents, bacterial folliculitis is cleared with antibiotics, and herpetic folliculitis is treated with antiviral agents. Future studies of the hair follicle will perhaps unlock the mechanisms that drive and maintain normal hair growth. Until that time scientists will, no doubt, continue to be fascinated by the intricate developmental and immunologic mechanisms that drive this micro-organ of the skin.

Shlomchik M. A New Role for B Cells in Systemic Autoimmunity: B Cells Promote Spontaneous T Cell Activation in MRL-lpr/lpr Mice

A conventional view of the pathogenesis of systemic lupus erythematosus has emerged. The role of B cells is to secrete pathogenic autoantibodies, while the role of T cells is to provide help for autoantibody-producing B cells. A problem with this view is that spontaneous T cell activation as well as T cell infiltration of organs such as kidney and skin are prominent features in systemic lupus erythematosus patients and murine models of lupus. The identification of T cell infiltrates, in particular, suggests that autoantibody-mediated damage may be only part of the story and that T cells could also play a primary role in immune-mediated pathology. To test the role of B cells directly, we previously generated autoimmune-prone MRL-lpr/lpr mice that lack B cells. The complete absence of T cell infiltrates in these mice was surprising, and it prompted us to examine whether a key role of B cells in disease evolution is to prime autoreactive T cells. Here we demonstrate, by comparing B cell-deficient and control mice, that the expansion of activated and memory T cells in the MRL-lpr/lpr mouse is indeed highly dependent on B cells. These results suggest a novel role for B cells in autoimmune disregulation.