Persistence of macroprolactinemia due to antiprolactin autoantibody before, during, and after pregnancy in a woman with systemic lupus erythematosus.

A woman with systemic lupus erythematosus (SLE) with marked increases in circulating 150-kDa PRL was studied from before conception, throughout pregnancy, and after pregnancy. The clinical features of the patient included idiopathic hyperprolactinemia without clinical symptoms such as amenorrhea and galactorrhea before pregnancy. No clinical lupus activity was present during follow-up. Serum PRL increase during pregnancy in this patient was considerably higher at weeks 27 and 33 than in normal pregnant women. In contrast, serum-free PRL levels were considerably lower at weeks 20, 27, and 33 than in normal pregnant women. A 150-kDa PRL (big big PRL) species persisted as the predominant circulating form of PRL throughout each measurement in this woman with SLE. In contrast, the predominant form of PRL in serum from healthy pregnant women was little PRL (or monomeric PRL). The nature of big big PRL was due to the presence of anti-PRL autoantibodies forming an IgG-23 kDa PRL complex, in accordance with the st...