Selective desensitization to seminal plasma protein fractions after immunotherapy for postcoital anaphylaxis

A 24-year-old white woman reported sexual intercourse-related pruritus, hives, wheezing, and dyspnea within 5 minutes after ejaculation. Systemic reactions (SRs) were prevented by use of condoms. Prick testing confirmed sensitization to five Sephadex G-100-separated fractions of her husband's seminal plasma. The intradermal end point threshold concentrations (ETC) were 10 −4 and 10 −1 μg of protein per milliliter to fractions 2 and 3, respectively. Leukocyte histamine release studies exhibited 100% release to fraction 2 and 37% release to fraction 3. A 2-day protocol of rapid immunotherapy (IT) was performed with subcutaneous incremental doses of human seminal plasma (HuSePl) fractions 2 and 3. The patient experienced an SR after receiving a cumulative dose of 38.55 μg of fraction 2 on day 1. On day 2, rapid IT with fraction 2 was administered until the patient experienced a mild SR after havin received a cumulative dose of 102.8 μg. There was a one-log 10 increase in the intradermal ETC to both fractions 2 and 3 at the end of day 2. It was continued three times weekly for 4 months until the patient tolerated 100 μg doses of both fractions 2 and 3. At 4 months, coitus was resumed without SRs, and HuSePl IT was stopped. The intradermal ETC to fractions 1, 3, 4, and 5 was increased 6 months after cessation of HuSePl injections, but there was a one-log decrease in the ETC to fraction 2. Our experience demonstrated that systemic tolerance can be achieved by parenteral administration of selected HuSePl fractions. Partial immunologic desensitization of patients with anaphylactic sensitivity can be achieved. This appears to be selective for most, but not all, allergenic fractions contained in HuSePl.