CD79A and infection: Besides a careful history for infections (particularly gastro-intestinal, dental, ENT) our reliable routine diagnostic work-includes i) differential blood count and C-reactive protein, ii) Helicobacter pylori monoclonal stool antigen test, and iii) serology for streptococci (antistreptolysin, antiDNase B), staphylococci (antistaphylolysin), yersinia (IgA, IgG, immunoblot).