Precipitating antibodies to factor VII/von Willebrand factor can develop in patients with severe homozygous-like von Willebrand's disease following multiple transfusions with blood derivatives. This study of 4 patients treated with cryoprecipitate for 13 different bleeding episodes demonstrates that the occurrence of such antibodies interferes with the management of the disease. The control of mucosal bleeding was poor, whereas more favorable responses were obtained in soft-tissue hemorrhages. These findings probably relate to failure of replacement therapy to shorten the prolonged bleeding time. Immediately after treatment, measurement of plasma factor VIII/von Willebrand factor-related antigen and ristocetin cofactor showed either no increase, or very low values, depending on the pre-infusion antibody titer. Levels of the factor VIII/von Willebrand factor-related procoagulant activity in the circulation were also lower than predicted and usually there was no evidence of the delayed and sustained rise typically observed in uncomplicated von Willebrand's disease. An anamnestic rise in antibody titer appeared 6–15 days after treatment and showed no obvious relationship with the amount of cryoprecipitate infused. Replacement therapy invariably caused severe side effects during, or immediately after, concentrate infusion. The results of in vitro studies support the view that these reactions were due to the appearance of circulating immune complexes.

Ninety-seven women who had h a d t h r e e or more miscarriages had also h a d at least one pregnancy with a singleton birth t h a t h a d reached 28 weeks gestation. Information was available on these 118 babies: 30% were small-for-gestational age (birthweight d 10th centile using figures f r o m Scotland 1973-79), 28% w e r e born preterm, a n d t h e perinatal mortality r a t e (excluding babies of <28 wecks gestation) w a s 16111000 births, all of which are significantly increased a b o v e t h e prevalence f o r a n o r m a l obstetric population. These observations m a y serve to alert the clinician t o t h e increased risk of these complications when dealing with women who have a history of recurrent miscarriage.

Diagnostic methods employed in enterovirus laboratories are generally laborious, slow and expensive. This is largely because type-specific neutralization tests still play the major role in identification and diagnostic serology. In the companion paper we describe the derivation of monoclonal antibodies against epitopes of the VPI peptide which are shared by all of the enteroviruses tested to date, with the exception of hepatitis A virus. This study describes the application of one of these monoclonal antibodies in several research and diagnostic procedures, illustrating a special utility in a wide variety of assay systems. This monoclonal antibody has proved particularly useful in the detection of enterovirus antigens in circulating immune complexes, and in identifying field isolates of this group of viruses. Immunohistochemistry, previously almost impossible in enterovirus diagnosis and research due to the large number of serotypes, is now shown to be practical and informative when this monoclonal antibody is used.

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