Quantification of local Ig isotype production in the bronchoalveolar lavage fluid (BALF) samples from patients with or without BOS who had undergone LTx (Table 1) showed that the titers of all 4 IgG subclasses (IgG1, IgG2, IgG3, IgG4) were significantly increased in BOS, whereas no differences were detected for IgE, IgM, IgA, or IgD isotypes comparing patients with and without BOS who had undergone LTx (Figure 4B). This evidence concerns the gene IGHE and Buschke-Ollendorff syndrome.