Baughman and Hurtubise found a correlation between low PB CD4+ T-lymphocytes and high BALF CD4+ T-lymphocytes and Sweiss et al. found an association between severe organ involvement and PB lymphopenia, speaking for a migration of these cells and subsequent sequestration in the lung and/ or extra pulmonary organs [11, 12]. The gene discussed is CD4; the disease is lymphopenia.