Evolução e perfil dos anticorpos antiespermatozóides nos primeiros 180 dias em indivíduos vasectomizados

Abstract

The contraceptive method of vasectomy can be reversed, in certain circumstances, through surgical procedures; but the incidence of autoimmune antisperm humoral responses in some vasectomized individuals may impede attempts to restore fertility. In this context, investigations on the incidence and evolution of autoimmune responses in vasectomized individuals may contribute for the understanding of autoimmune infertility associated with vasectomy, as also for the assessment of viability of restorative surgeries for fertility. Twenty individuals who have requested voluntary vasectomy for contraception, most referred by the Assis Chateaubriand School of Maternity of the Federal University of Ceará, were selected for the study. Surgical vasectomy was performed by the author, in the Ambulatory ward of the Faculty of Medicine. Blood and semen samples were collected from the individuals prior to, and 30, 90 and 180 days after vasectomy. Antisperm IgG and IgA were evaluated in the Center for Assisted Reproduction of Ceará (CONCEPTUS), by “Immunobead” technique (IBT), using the direct method for the detection of antibodies in pre-vasectomy seminal samples, and the indirect IBT for evaluation of antibodies in semen samples after vasectomy, and for sera. Antibody presence was measured as >0% (all positive results) and ≥ 20% of spermatozoa bound to antibodies. The parameters studied were: i) comparative evaluations of the incidences of IgG and/or IgA in serum and/or semen; ii) evolution of the titers of these antibodies with time; and iii) the sites of binding of the antibodies in the spermatozoa of volunteers. All the pre-vasectomy serum and semen samples were devoid of antisperm antibodies; however, IgG and/or IgA were present in post-vasectomy serum and semen samples in a majority of individuals, in increasing numbers from 30 to 180 days. The simultaneous presence of IgG and IgA was always predominant. At >0% positivity, 25% of the individuals were positive in 30 days, with IgG or IgA individually present in very few. In 90 days, 60% of the vasectomized were positive, rising to 85% in 180 days. No positive reactivity was detected for ≥ 20%. Evaluation of antibodies in serum individually showed that positive results at ≥ 20% increased from one (30 days) to three in 90days, and to four in 180 days. In semen, this positivity was not detected. The evaluation of antibody titers (% of spermatozoa bound to antibodies) revealed increase of IgG and IgA with time both in serum and semen, with the former always ahead of IgA, and reaching mean values at 180 days of 7,9% (median – 5%) and 6,35% (4,5%); respectively for IgG and IgA. The midpiece and the tail of spermatozoa were the principal binding sites, in that order, for both IgG and IgA. These results show that up to 85% of individuals develop antisperm antibodies in 180 days after vasectomy, with a steadily increasing level of positivity reaching ≥ 20% in some; which may potentially compromise efforts to restore fertility in them.