Granuloma

Don't be mistaken. I have no prejudice against B cells.

Although cellular immunity (administration) is important, the most common form of overactivity is a whole mass of T cells call a meeting and sit together - usually because of something not digestible. The result is, alas, granuloma - not an effective way of self defence (or administration).

For those with some knowledge on histology would know: granuloma do not only have T cells, and meetings do not only involve administrators. Lymphocytes invite (force) a collection of macrophage to sit around - which are working hands and not meant for the talking. No wonder when we sit there, our faces transform and change in colour - we become histiocytes !