Serological investigations on penicillin-induced antibodies in the Thai population

The study aimed to assess the conditions for coating RBCs with penicillin and examine the anti-penicillin reactions of random Thai patients' sera against penicillin-coated RBCs and normal sera from Thai donors testing in the presence of the drug.

Penicillin-induced immunologic haemolytic anaemia (IHA) is reportedly related to possessing antipenicillin antibodies, immunoglobulin G (IgG), which has been identified in testing penicillin-coated red blood cells (RBCs). In addition, low titre penicillin antibodies, often IgM, are detected in donors by testing in the presence of a solution of the penicillin.

Penicillin-coated RBCs were produced, and antipenicillin was tested against those penicillin-coated RBCs amongst random Thai patients who had strongly positive direct antiglobulin (≥3+). Additionally, sera from Thai blood donors were tested in the presence of the penicillin. These relationships were determined by comparing the numbers of penicillin-antibody positive patients with their diagnosis, sex, age and blood type.

Penicillin requires a high pH to optimally adhere to RBCs that showed validated reactions with controls. Enrolment of 304 random patients, of whom 17 (5.59%) had positive antipenicillin tests using penicillin-coated RBCs. Of the 246 donor samples, 3 (1.22%) displayed positive reactivities in the presence of soluble penicillin. Furthermore, no association was discovered between the patient's characteristics and antipenicillin positivity.

This is the first study to develop and report on the low percentage of patients' and donors' sera without IHA. Investigating suspected cases of penicillin-induced IHA requires following our suggested method to identify clinically significant antipenicillin.