RELATIONSHIP OF INTERLEUKIN-4 TO ISOTYPIC DISTRIBUTION OF ANTI-DOUBLE-STRANDED DNA ANTIBODIES IN SYSTEMIC LUPUS-ERYTHEMATOSUS

IgG subclasses of anti-double-stranded DNA antibodies were determined in 182 patients with systemic lupus erythematosus. All isotypes were d etected, but IgG1 and IgG3 were predominant (62 and 51% of the cases, respectively). An average of 64 +/- 27% was IgG1, 16 +/- 22% IgG2, 16 +/- 19% IgG3 and 4 +/- 10% IgG4. The rank order or frequency was IgG1, IgG3, IgG2 and IgG4 in patients with musculoskeletal involvement; IgG 1, IgG2, IgG3 and IgG4 in those with renal complications; IgG3, IgG1, IgG2 and IgG4 in those with cutaneous involvement; and IgG1, IgG3, IgG 2 and IgG4 in those with hematological manifestations. Interleukin-4 ( IL-4) was dectectable in 17 of 36 selected patients, as opposed to 1 o f 40 normal controls. The percentage of the total autoantibody contrib uted by IgG1 was significantly higher (p < 0.03) in these patients tha n in the remainder with undetectable levels of IL-4.