A patient who has developed immunity to a viral infection would be expected to have which of the following serology results?

A patient who has developed immunity to a viral infection would be expected to have which of the following serology results?

• A. IgM+, IgG-
• B. IgM-, IgG+
• C. IgM+, IgG+
• D. IgM-, IgG-

Answer: (B)

Immunity to a virus is indicated by antibodies that signal long-term protection rather than an ongoing infection. After a primary infection, the immune system first makes IgM, which then wanes, while IgG is produced later and persists, providing lasting immunity. So, a serology pattern showing IgG present and IgM absent fits someone who has developed protective immunity from a prior exposure or vaccination, rather than someone currently infected. If the person were being re-exposed, IgG would generally rise quickly due to memory B cells, often with little or no IgM involved.

Immunity to a virus is indicated by antibodies that signal long-term protection rather than an ongoing infection. After a primary infection, the immune system first makes IgM, which then wanes, while IgG is produced later and persists, providing lasting immunity. So, a serology pattern showing IgG present and IgM absent fits someone who has developed protective immunity from a prior exposure or vaccination, rather than someone currently infected. If the person were being re-exposed, IgG would generally rise quickly due to memory B cells, often with little or no IgM involved.