Cellular immune alterations associated with human insulin therapy

Area of Science:

• Immunology
• Endocrinology
• Diabetology

Background:

• Human insulin preparations are widely used for diabetes management.
• Assessing the immunogenicity of different insulin types is crucial for patient outcomes.
• Previous studies focused on antibody responses, potentially overlooking cellular immune alterations.

Purpose of the Study:

• To evaluate the immunogenicity of human insulin preparations by comparing cellular immune responses.
• To investigate changes in T lymphocyte subsets and mononuclear cell responses.
• To determine if cellular immune alterations correlate with antibody levels.

Main Methods:

• Prospective study involving 10 insulin-dependent diabetic patients.
• Patients switched from porcine insulin to either biosynthetic human insulin (BHI) or semisynthetic human insulin (SSHI).
• Monitored T lymphocyte subsets (Leu 1, Leu 3, Leu 7), T cell ratios (Leu 3:Leu 2), in vitro mononuclear cell proliferation (mitogens), and insulin antibody levels over 24 weeks.

Main Results:

• No significant changes in insulin antibody levels were observed in either human insulin group.
• Biosynthetic human insulin (BHI) treatment led to a reduction in total T lymphocytes, helper/inducer T cells, and the helper/inducer to suppressor/cytotoxic T cell ratio at 8 weeks.
• Semisynthetic human insulin (SSHI) treatment showed an increase in natural killer cells (Leu 7) at 4 weeks and decreased mononuclear cell proliferation at 12 weeks.
• Both groups exhibited increased responses to phytohemagglutinin at 24 weeks.

Conclusions:

• Switching to human insulin preparations can induce changes in cellular immune parameters.
• Cellular immune responses appear more sensitive than humoral (antibody) responses to alterations from insulin preparations.
• These findings highlight the importance of monitoring cellular immunity in patients receiving human insulin.