Complex sentence: It is not known if XLA patients are able to generate an allergic reaction, as they lack IgE antibodies, and there is no special hazard for XLA patients in dealing with pets or outdoor activities.
Split into simpler sentences: It is not known if XLA patients are able to generate an allergic reaction, as they lack IgE antibodies. There is no special hazard for XLA patients in dealing with pets or outdoor activities.