Combined in vivo and in vitro approach for the characterization of penicillin-specific polyclonal lymphocyte reactivity: tolerance tests with safe penicillins instead of challenge with culprit drugs.
BACKGROUND
Amino-penicillins are a major cause of delayed-type reactions to penicillins.


OBJECTIVE
The aim of this study was to establish a diagnostic approach for the characterization of the individual penicillin-specific polyclonal lymphocyte reactivity in order to detect side chain-specific sensitization to amino-penicillins. Patients can then be advised to undergo a tolerance test with safe penicillins instead of provocation with culprit penicillins for confirmation of penicillin allergy.


METHODS
We investigated penicillin-specific polyclonal lymphocyte reactivity in nine patients with delayed-type reactions to amino-penicillins by a combined in vivo (patch, prick and intracutaneous tests with delayed readings) and in vitro (lymphocyte transformation test, LTT) approach.


RESULTS
A combination of LTT and skin tests improved the sensitivity for the characterization of penicillin-specific polyclonal lymphocyte reactivity and allowed the detection of three different patterns of lymphocyte reactivity. Four patients showed a side chain-specific sensitization to amino-penicillins in vivo and in vitro and were advised to undergo tolerance tests with safe penicillins. Two patients agreed and were exposed to parenteral benzyl-penicillin and oral phenoxymethyl-penicillin which they tolerated without complications.


CONCLUSIONS
These data suggest that a combined in vivo and in vitro approach is helpful for the detection of side chain-specific sensitization to amino-penicillins. Patients with such sensitization are very likely to tolerate safe penicillins, thereby expanding their therapeutic options when antibiotic treatment is required.
Sachs
B
B
Department of Dermatology and Allergology, Rheinisch-Westfälische Technische Hochschule Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany. bcsachs@tiscalinet.de
Al Masaoudi
T
T
Merk
H F
HF
Erdmann
S
S
D000667:Ampicillin / Q000494:pharmacology; D002478:Cells, Cultured; D002511:Cephalosporins / Q000494:pharmacology; D003429:Cross Reactions; D003875:Drug Eruptions / Q000175:diagnosis* / Q000209:etiology; D004361:Drug Tolerance; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D010400:Penicillin G / Q000009:adverse effects; D010406:Penicillins / Q000009:adverse effects* / Q000494:pharmacology; D012882:Skin Tests / Q000379:methods; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000187:drug effects*
D002511:Cephalosporins; D010406:Penicillins; D000667:Ampicillin; D010400:Penicillin G