Increased frequency and specific reactivity of serum antinuclear antibodies in patients with nonimmune chronic idiopathic neutropenia of adults.

This study describes the frequency of serum organ-specific and organ-nonspecific autoantibodies in 157 patients with nonimmune chronic idiopathic neutropenia of adults (NI-CINA). Forty-two age- and gender-matched volunteers were used as controls. We found that patients with NI-CINA had increased frequency of antinuclear antibodies (ANA) compared to controls (33.1 vs. 9.5%, p = 0.0025), and that ANA positivity inversely correlated with the number of circulating neutrophils (r = -0.2765, p < 0.0001). Speckled pattern of reactivity was seen in 84.6% of ANA-positive patients, and diffuse pattern in the remaining 15.4%. Patients had also increased levels of circulating immune complexes compared to controls (3.30 +/- 2.41 vs. 1.70 +/- 1.19 microg/ml, p = 0.0042), which inversely correlated with the number of circulating neutrophils (r = -0.2405, p = 0.0154) but not with the titer of ANA positivity. No significant differences were found between the patients and the normal controls in the frequency of positive tests for antibodies to dsDNA, Sm, nRNP, SSA, SSB and Scl-70 antigens, or for parietal cell antibodies, anti-neutrophil cytoplasmic antibodies (ANCA), anti-cardiolipin and anti-thyroid antibodies. Serum levels of rheumatoid factor, C-reactive protein (CRP) and complement factors C3 and C4 ranged within normal limits in the patients studied, but a highly significant correlation was noted between the levels of CRP and ANA positivity (r = 0.3936, p < 0.0001). These findings are suggestive of a chronic inflammation in NI-CINA patients which provides the antigenic stimulus for ANA production, and they further support our previously reported suggestion for the possible involvement of such a low-grade chronic inflammatory process in the pathogenesis of neutropenia in the affected subjects.