Low Lymphocytes? What does this mean? is it bad?

My husband was recently told his blood work came back with Low Lymphocytes?  Can someone please explain what that could mean?  Is this really bad?  He has been sick for 3 years with a variety of things from tonsils to gallbladder but this is the latests.  He says he is tired ALL the time, and when he wakes up he feels like he has been beaten....very sore and stiff and exhausted.  Everything else comes back "normal" except for this low lymphocystes and a low IGg3 (I think that is the one) but that has gone up from 13 to 15 from the last blood work.  Any ideas?  Is this something we should be really, really worried about?  Is it treatable?

[karajo]

Low lymphocytes: rule out corticosteroids, stress, pain, acute systemic infections, immunosuppressive drugs, irradation, loss of lymph, chylous thoratic effusion, lymphosarcoma, enteric neosplasms, granulomatous enteritis, Johne's disease, protein losing enteropathies, ulcerative enteritis, lymphatic cancer and hereditary T-cell deficiency.

I don't know what low IGg3 would indicate.  

Worry won't change anything.  And I don't recommend anyone worry about anything.  Arm youself with the facts.  This will certainly help you and your husband to ask the right questions, thus expiditing the dx process.