Abnormalities of delayed hypersensitivity in systemic lupus erythematosus

Abnormalities of delayed hypersensitivity were found in patients with active systemic lupus erythematosus (SLE). The following immune responses were noted in 39 patients with SLE compared to 30 normal controls: (1) delayed hypersensitivity skin test responses to purified protein derivative (PPD) and trichophyton were significantly reduced in the patients with SLE, (2) in vitro lymphocyte transformation to PPD was normal, (3) the majority of patients with SLE had circulating antibodies to native deoxyribonucleic acid (nDNA), (4) these patients did not exhibit increased skin test responses or lymphocyte transformation to nDNA. The impairment in delayed hypersensitivity to PPD and trichophyton suggests that skin testing with PPD is inadequate to screen patients with SLE for tuberculosis. Furthermore, frequent infections which occur in some patients with SLE may result in part from their impaired cellular immune responses. The dissociation between skin response and lymphocyte transformation to PPD suggests that defects in cellular immunity may be selective. The dissociation between humoral and cellular immunity to nDNA suggests that control mechanisms exerted on one or both of these responses may be defective in SLE.