{'fraction_non_alphanumeric': 0.024242424242424242, 'fraction_numerical': 0.012121212121212121, 'mean_word_length': 5.1234567901234565, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
IgM receptors on human lymphocytes: detection by direct binding.

Radioiodinated IgM isolated from a patient with Waldenström macroglobulinemia binds with high avidity (apparent Ka = 2.5 x 10(9) M-1) to freshly isolated human peripheral blood lymphocytes. Binding occurred through the Fc region of the molecule and involved a receptor specific for immunoglobulins of the IgM class. The avidity and specificity of this binding are consistent with a biologic role for IgM receptors on lymphocytes.