For the patient who has the highest Ig A within the normal range, what is his or her diagnosis?
highest Ig A within the normal range refers to MAX(IGA BETWEEN 80 AND 500);
SELECT patientData.Diagnosis FROM Patient AS patientData INNER JOIN Laboratory AS labData ON patientData.ID = labData.ID WHERE labData.IGA BETWEEN 80 AND 500 ORDER BY labData.IGA DESC LIMIT 1