You mention food intolerance, have you been formally tested for Celiac Disease? Celiac blood tests (called a Celiac Panel) measure your immune system’s response to gluten in the food you eat.
tTG-IgA or tissue transglutaminase-IgA
AGA-IgG or Antigliadin IgG
AGA-IgA or Antigliadin IGA
Total IGA
The first one tTG-IgA, if positive, is highly suggestive of Celiac. The AGAs can be elevated in wheat allergy as well.
Total IGA can rule out the possibility of a primary immune problem, like Selective IGA deficiency. People with this disorder may have no symptoms, or may have recurrent problems with infections of the sinus, lung, stomach, or urinary tract.
Mesenteric adenitis usually goes away on it's own - both Celiac and/or Selective IGA Def can cause these glands to remain inflamed, even after the viral illness is gone.