Photosensitivity and antinuclear antibodies in black patients with systemic lupus erythematosus

Black patients with systemic lupus erythematosus (SLE) have a lower prevalence of photosensitivity rashes than white patients. The reasons for this are unknown, but some studies suggest a correlation between the presence of antinuclear antibodies and protection from photosensitivity. In our study, we determined serum antinuclear-antibody profiles, including anti-dsDNA, anti-Sm, anti-RNP, anti-Ro/SS-A, and anti-La/SS-B antibodies, in 91 black Jamaican patients with SLE. All 91 serum samples from SLE patients (100%) were positive in the fluorescent antinuclear-antibody test. Using the crithidia luciliae immunofluorescence test, anti-dsDNA was found in 27.5% of the samples. By a double immunodiffusion method, anti-Sm antibodies were found in 15.4%, anti-RNP in 18.7%, anti-Ro/SS-A in 9.9%, and anti-La/SS-B in 11.0%. However, no statistically significant differences were observed in the seroprevalence of these antinuclear antibodies when sera from patients of the following groups were compared: only photosensitivity rashes (n = 17), photosensitivity and other rashes (n = 23), other rashes without photosensitivity (n = 27), and patients with no skin rash of any type (n = 24). These results suggest that photosensitivity in black Jamaican patients with SLE is not associated with antinuclear-antibody specificity.