Occurrence of deficient monocyte yeast cell phagocytosis in presence of rheumatic sera.

Monocyte yeast cell phagocytosis was studied in 164 rheumatic sera. The results showed that the phagocytic activity (PA) was low in 51 per cent of SLE-sera, in 12 per cent of other connective tissue disease (CTD)-sera, in 16 percent of RA-sera but in none of 30 sera from patients with other chronic arthritides. Low PA was associated with cryoglobulinaemia and subnormal C1q, C4 and C3 in the SLE-group and with subnormal C4 and signs of extra-articular disease in the RA-group. In the CTD-group, low PA was only found in 4 cases of SLE-like syndromes, all having evidence of vasculitis. The findings suggest that low phagocytic activity in presence of rheumatic sera may be related to clinical syndromes with circulating immune complexes and/or hypocomplementaemia, most often SLE.