Their cases showed, in addition to recurrent chest and sinus bacterial infections, also Pneumocystis pneumonia, frequent CMV visceral infection, both infectious (C. jejunii, E. coli) and non-infectious colitis with diarrhea and, among the immunologic findings, the absence or low numbers of B cells, CD4 lymphopenia with inverted CD4/CD8 ratios and in one case reduced NK cells [52]. The gene discussed is CD4; the disease is lymphopenia.