Aggregability of red blood cells of schizophrenia patients with negative syndrome is selectively enhanced

Schizophrenia patients can be categorized into positive and negative syndromes (PS and NS) by the behavioral criteria of the Positive and Negative Syndrome Scale (PANSS), but these symptoms can also be evaluated as a continuous trait. Both types exhibit cerebral microcirculatory disorders, which are ameliorated by drug treatment in PS but not in NS patients. Red blood cell (RBC) aggregability plays a major role in the microcirculation. Previously reported changes in RBC membrane phospholipid composition indicate a difference in aggregability between RBCs of NS and PS patients. In this study the aggregability of PS RBCs and NS RBCs was analyzed using a computerized cell flow-properties analyzer, as a physiological marker of NS and PS. Results showed that while the aggregability of PS RBCs was normal, that of NS RBCs was markedly enhanced and strongly correlated with the NS score. The results exhibited stability and reproducibility over 1 to 8 weeks test-retest and were independent of gender, age at testing and onset of illness, fibrinogen levels, smoking, and current medication. NS RBCs have constitutively elevated aggregability, which can contribute to cerebral microcirculatory disorders and may be a biological marker for distinguishing between PS and NS in genetic studies of schizophrenia.