Frank elevation of bronchoalveolar lavage fluid IgE level in hyperimmunoglobulin E syndrome

Hyperimmunoglobulin E syndrome (HIES) is a rare hereditary immunodeficiency disorder characterized mainly by an elevated serum immunoglobulin E (IgE) level. However, the IgE level in bronchoalveolar lavage fluid (BALF) of HIES patients has not been addressed before. The case of a 24-year-old non-smoking Caucasian male HIES patient with classical skin infections in childhood and recurrent staphylococcal pneumonias is reported. Out of an infectious episode, the total IgE level was measured in BALF by chemiluminescence method, along with appropriate analysis of immunoglobulins A (IgA), G (IgG) and M (IgM), albumin and cellular components. In parallel, the respective markers were measured in serum. An elevated level of BALF IgE of 15.10 ng/mL (6.24 IU/mL) along with the marked heightening of IgE in serum at 130,583 ng/mL (53,960 IU/mL) was observed. The relative coefficients of excretion (RCE), based on BALF and serum albumin concentrations (100.6 mg/L and 39 g/L, respectively), were 0.0448, 1.49, 1.94 and <3.40 for IgE, IgA, IgG and IgM, respectively. The results show a frank increase in BALF IgE level in HIES compared to that reported for healthy individuals and the low RCE value for IgE suggest a diffusion of IgE across the respiratory membrane. This case study demonstrates a markedly elevated BALF IgE level in HIES that could be used to support the diagnosis, but also raises important BALFrelated aspects in HIES that provoke further studies on BALF from HIES patients.