T-cell cytokine network in cutaneous lupus erythematosus.

BACKGROUND

A variety of immunologic abnormalities have been described in systemic and experimental lupus erythematosus (LE). Several T-cell defects, especially in helper T (Th) cell cytokines, have been reported.

OBJECTIVE

Our purpose was to identify the Th cytokine profile in cutaneous LE.

METHOD

Total RNA was extracted from punch biopsy specimens from 19 patients with cutaneous LE (nine, discoid LE; two, subacute cutaneous LE; and eight, systemic LE) and from four healthy control subjects. RNA was reverse transcribed into complementary DNA and amplified with polymerase chain reaction (PCR) primers specific for interleukin-2 (IL-2), IL-4, IL-5, IL-10, interferon gamma (IFN-gamma), and beta actin. PCR products were detected by agarose gel electrophoresis and Southern blot with 32P-labeled, nested probes.

RESULTS

Sixteen of 19 cutaneous LE specimens lacked IL-2, all were negative for IL-4, and 10 of 19 had detectable IL-10, whereas IFN-gamma and IL-5 messenger RNAs were present in the majority of LE specimens. IFN-gamma and IL-10 mRNAs were found in all normal skin controls, whereas IL-2, IL-4, and IL-5 mRNAs were undetectable. Functional IFN-gamma protein was evidenced by intercellular adhesion molecule-1 and HLA-DR staining of keratinocytes in nine of nine LE specimens but not in normal skin. The pattern of cytokine mRNAs, intercellular adhesion molecule-1, and/or HLA-DR expression in cutaneous LE specimens did not vary with different subtypes of LE, antinuclear antibody titer, or the magnitude of inflammation.

CONCLUSION

The presence of IL-5 mRNA in cutaneous LE specimens suggests that Th type 2 cells combine with local IFN-gamma production to augment disease and may be related to the pathophysiology of cutaneous LE.