IgA-type macroprolactin among 130 patients with macroprolactinemia

Area of Science:

• Endocrinology
• Immunology
• Clinical Chemistry

Background:

• Macroprolactin (macro-PRL) is a complex of prolactin (PRL) with immunoglobulin G (IgG).
• The existence and prevalence of IgA-type macro-PRL have not been clearly defined.

Purpose of the Study:

• To determine if IgA-type macro-PRL exists.
• To investigate the prevalence of IgA-type macro-PRL compared to IgG-type.
• To analyze differences in laboratory data between macro-PRL types.

Main Methods:

• Analyzed 130 patients diagnosed with macroprolactinemia using polyethylene glycol precipitation and gel filtration chromatography (GFC).
• Identified IgA-type and IgG-type macro-PRLs using Jacalin column/SDS-PAGE and protein G columns.
• Utilized SDS-PAGE with IgA antibody and western blotting for identification.

Main Results:

• Confirmed the existence of IgA-type macro-PRL.
• Prevalence rates: 83.8% IgG-type, 7.7% IgA-type, 5.4% non-IgA/non-IgG, and 3.1% IgA plus IgG.
• No significant differences in PRL or macro-PRL ratios between IgA- and IgG-type macro-PRLs, but lower ratios in non-IgA/non-IgG type.

Conclusions:

• IgA-type macroprolactin has been demonstrated to exist.
• IgG-type macro-PRL is the most prevalent form.
• Prevalence order: IgG-type > IgA-type > non-IgA/non-IgG > IgA plus IgG.