The HLA system and schizophrenia. A study in a German population

Various diseases with a noticeable autoimmune component and frequent occurrence within one family show a statistically significant correlation with specific human leukocyte antigens (HLA). This correlation was also shown in studies of HLA in psychiatric disorders. However, results have been contradictory. The phenotype frequencies of HLA specificities were investigated in 100 schizophrenic patients and 472 controls from the same geographic area in Germany. The frequency of HLA B27 was significantly increased in the patient group as a whole (P=0.017) and in the subgroups of paranoid patients (P=0.005), chronic schizophrenics (P less than 0.001), patients with poor prognosis (P less than 0.001), and in patients with onset of the disease before the age of 20 years (P=0.004). In the latter three groups an elevated incidence of HLA A9 was also found. The combination A9-B27 was detected in 0.63% of our control group and in 7% of the patients (P less than 0.001). Of these patients 85.7% were chronic paranoid patients with poor prognostic features. This study gives support to the possibility of using HLA typing in genetic studies of schizophrenia, as well as in the differential diagnosis and prognosis.