CD4 and respiratory system disorder: BALF samples from camels with clinical respiratory disease contained higher percentages of CD4+ T helper cells (25.2 ± 3.4% of total lymphocytes versus 16.7 ± 2.3% in healthy animals; p = 0.02) and B cells (22.6 ± 3.8% of total lymphocytes versus 10.7 ± 2.1% in healthy animals; p = 0.006) when compared to lymphocyte composition in healthy animals (Fig. 3B).