Abstract: The present invention identifies autoantibodies to folate receptors. Methods to identify these autoantibodies to the human folate receptors are also provided. The present invention also contemplates diagnostic methods and test kits to be used in a clinical setting for identifying a subject at risk of folate-sensitive abnormalities or disorders as observed in neural tube defect complicated pregnancies. In addition, infertility, spontaneous abortion, male sterility, unsuccessful in vitro fertilization, neurologic disorders and impaired folate absorption may also be associated with these autoantibodiesto folate receptors.

Abstract: There is disclosed anti-receptor and growth blocking agents to the vitamin B12/transcobalamin II receptor and binding sites. The anti-receptor and growth blocking agents antagonize or modulate the vitamin B12/transcobalamin II receptor or binding sites, causing cellular depletion of vitamin B12, thus inhibiting cell division or causing apoptosis. Anti-receptor and growth blocking agents of the present invention include proteins (such as antibodies and antibody derivatives), peptides and small organic molecules. In a preferred embodiment, the anti-receptor agent is an antibody to the vitamin B12/transcobalamin II receptor.