Polyclonal B-cell activation and increased lymphocyte helper-suppressor ratios in discoid lupus erythematosus.

We studied polyclonal B-cell activation in twenty-six patients with discoid lupus erythematosus (DLE). Spontaneous plaque-forming cells of the IgA class (IgA-SPFC) as determined by a reverse haemolytic plaque assay were significantly more common in patients with DLE than in fifty control subjects. The patients showed a positive correlation between IgA-SPFC and OKT4/8 ratios and also had a significantly higher mean OKT4/8 ratio. The two groups did not differ with regard to cells producing IgG or IgM or cells with OKT3, OKT4, OKT8 or OKMI markers. None of the three patients with DLE who had IgA-SPFC values which were above the mean (+2 s.d.) for the control subjects had positive tests for ANA or low serum C3 or C4, but two of the three also had increased IgG-SPFC values. The results indicate that polyclonal B-cell activation occurs in a small proportion of patients with DLE.