My lld told me that all blood work was normal-excpt my c3 & c4 levels were low. my online paperwork shows high ch50 too. two years ago, he said the ch50 was high too. my issue has been recurring minor sinus infections with a mold allergy...thoughts?

Autoimmune?: The low C3 and C4 levels suggest the presence of an inflammatory process which is likely of autoimmune origin. The elevated CH50 also supports the presence of inflammation such as infection. With your frequent sinus infections, an immune evaluation is indicated since immunodeficiency is often associated with autoimmune disorders Consult an allergist/immunologist .