Anticardiolipin antibodies are elevated in drug-free, multiply affected families with schizophrenia.

The objective of this study was to measure anticardiolipin antibodies in patients and healthy relatives in multicase families with schizophrenia. Twenty-eight (28) multicase families with schizophrenia were examined. One hundred three drug-free patients and 66 first-degree relatives consented to evaluation by DSM-III-R criteria. Criteria for patient definition included the following: age > or = 16, a confirmed hospital diagnosis of schizophrenia, knowledge of biological parents, and consent to participate. Additional data were drawn from family history and medical records. Serum samples were tested separately for IgG and IgM anticardiolipin by enzyme-linked immunosorbent assay (ELISA) and designated positive/negative by comparison to the reactivity of an age-matched control group. IgG anticardiolipin antibodies were significantly more common in both patients and relatives compared to controls. IgM anticardiolipin antibodies were significantly more common in patients. In 75% of families at least one member was anticardiolipin positive and this positivity correlated with patient positivity. The relevance of anticardiolipin antibodies in both patients and healthy relatives of some multicase families to the pathogenesis of schizophrenia is discussed.