Unusual course of a Chlamydia pneumonia in an infant with IgG2/IgG4-deficiency.

An unusual case of Chlamydia trachomatis (C. trachomatis) pneumonia, complicated by the development of a pneumothorax, is reported in an IgG2/IgG4 deficient infant delivered by caesarean section. C. trachomatis was isolated initially from a throat smear and subsequently from pleural effusions. Serological examinations using the complement fixation test were negative in sera of both mother and child. However, using immunofluorescence the presence of an acute or recent infection was confirmed by IgM-antibodies in the serum of the infant and IgA-antibodies in the serum of the mother. At the age of 7 months the girl suffered from impetigo contagiosa which was partially resistant to antibiotic treatment. IgG-subclass deficiency was diagnosed after the onset of this disease and the girl was then treated by immunoglobulin transfusion.