Failure of physiologic doses of pure UVA or UVB to induce lesions in photosensitive cutaneous lupus erythematosus: implications for phototesting

Characterization of clinical photosensitivity in cutaneous lupus erythematosus

BACKGROUND

Photosensitivity (PS) in lupus erythematosus (LE) is frequently determined by patient report.

OBJECTIVE

We sought to characterize self-reported PS in cutaneous LE (CLE).

METHODS

The PS survey was used to classify subject responses into 5 phenotypes: direct sun-induced CLE flare (directCLE); general exacerbation of CLE (genCLE); polymorphic light eruption-like reactions (genSkin); general pruritus/paresthesias (genRxn); and sun-induced systemic symptoms (genSys). In all, 91 subjects with CLE alone or with CLE and systemic LE were interviewed.

RESULTS

In all, 81% ascribed to 1 or more PS phenotypes. CLE-specific reactions (direct sun-induced CLE flare or general exacerbation of CLE) were reported by 86% of photosensitive subjects. Higher CLE disease activity (measured by CLE Disease Area and Severity Index activity scores) was suggestive of direct sun-induced CLE flare reactions (P = .09). In all, 60% of photosensitive subjects described CLE-nonspecific reactions: polymorphic light eruption-like rash and general pruritus/paresthesias. These phenotypes often co-occurred with CLE-specific reactions and were predicted by more systemic disease activity as measured by Physicians Global Assessment (PGA) scores in regression analyses (genSkin, P = .02) and (genRxn, P = .05). In all, 36% of subjects reported systemic reactions and higher PGA scores were predictive of the sun-induced systemic symptoms phenotype (P = .02); a diagnosis of systemic LE was not (P = .14).

LIMITATIONS

PS was inferred from patient report and not directly observed.

CONCLUSIONS

Characterization of self-reported PS in LE reveals that patients experience combinations of CLE-specific, CLE-nonspecific, and systemic reactions to sunlight. Sun-induced CLE flares are associated with more active CLE disease. Polymorphic light eruption-like, generalized pruritus/paresthesias, and systemic reactions are associated with more active systemic disease. Recognition of PS phenotypes will permit improved definitions of clinical PS and allow for more precise investigation into its pathophysiology.

High mobility group box1 (HMGB1) in relation to cutaneous inflammation in systemic lupus erythematosus (SLE)

Summary

Photosensitivity is characteristic of systemic lupus erythematosus (SLE). Upon ultraviolet B (UVB) exposure, patients develop inflammatory skin lesions in the vicinity of sunburn cells (SBCs). High mobility group box 1 (HMGB1) is released from apoptotic and activated cells and exerts inflammatory actions through ligation to its receptors.

Methods

Eleven SLE patients and 10 healthy controls (HCs) were exposed to UVB. Skin biopsies were taken before and at one, three and 10 days after irradiation. Sections were stained for SBC, HMGB1, CD3, CD68, interferon-induced protein MxA and cleaved caspase 3. In vitro experiments with UVB-irradiated keratinocytes were also performed. Higher numbers of cells that had released HMGB1 were seen in the skin of SLE patients compared to HCs before and after irradiation. HMGB1-negative nuclei correlated with the presence of SBCs, and with the number of cleaved caspase 3 positive cells in lupus skin.

Results

HMGB1 release is increased in the skin of SLE patients compared to HCs. Upon UVB exposure, HMGB1 release further increases in SLE patients and is related to the number of apoptotic cells. Our data suggest that HMGB1, probably released from apoptotic keratinocytes, contributes to the development of inflammatory lesions in the skin of SLE patients upon UVB exposure.

Prevalence of self-report photosensitivity in cutaneous lupus erythematosus

BACKGROUND

Little is known about the prevalence of self-reported photosensitivity (PS) and its effects on quality of life in a US cutaneous lupus population.

OBJECTIVE

We sought to determine the prevalence of self-reported PS among a cutaneous lupus population and to examine its impact on quality of life.

METHODS

A total of 169 patients with lupus were interviewed about PS symptoms and completed the modified Skindex-29+3, a quality-of-life survey. A complete skin examination was conducted and the Cutaneous Lupus Erythematosus Disease Area and Severity Index was completed.

RESULTS

In all, 68% of patients reported some symptoms of PS. The PS group (those who reported a history of and current PS) scored worse on PS-related items of the modified Skindex-29+3 and had higher cutaneous disease activity as determined by the Cutaneous Lupus Erythematosus Disease Area and Severity Index. Patients with PS had worse symptoms and emotions and experienced significant functional impairments compared with patients who had cutaneous lupus without PS.

LIMITATIONS

This study was done at a single referral center.

CONCLUSIONS

Self-reported PS is very common among patients with cutaneous lupus and is associated with significant impairments related to symptoms, emotions, and daily functioning.